Dissertations / Theses on the topic 'Plants, Useful Plants, Useful'

Dendrochronological problems in dating tropical tree species are responsible for a large gap in global dendroclimatic reconstructions. Study of Cedrela and Juglans in the low-latitude forests of northern Argentina and Bolivia has resulted in development of four chronologies. These genera have good tree-ring characteristics, and statistics indicate that they have good potential for dendroclimatology. Longer series should be obtained from older stands.

Mestrado em Arquitectura Paisagista - Instituto Superior de Agronomia
A autora promoveu uma aproximação junto da população de Penha Garcia, que visava recolher e reconhecer as plantas e suas utilizações nesta aldeia, o que fez sobressair o valor de um conhecimento adquirido ao longo da vida. Esta dissertação apresenta os resultados de um levantamento etnobotânico como meio de proteccao de um conhecimento que corre o risco de desaparecer e como valorização de um património cultural imaterial

Thesis (M.A(Folklore)) --University of Limpopo, 2009
This study contains documentation and naming of indigenous plant species of the GaMamabolo area. Knowledge about their classification and their local natural resources has been acknowledged through this study. It is not only naming and classification but extending information about interaction of useful indigenous plants with human society. This is followed by a survey of 85 plant species found in the Mamabolo area. The immense cultural significance of the traditional knowledge system is portrayed in this study. ii

Si bien en los últimos años se han realizado en Cataluña un número relevante de estudios etnobotánicos, el territorio se encuentra prospectado de forma desigual. Uno de los principales objetivos de esta tesis doctoral era llenar los vacíos existentes, especialmente las zonas áridas y semiáridas que ocupan las áreas internas del territorio catalán, para obtener una visión general sobre el estado de los conocimientos tradicionales, haciendo hincapié en las plantas y en sus usos, y su capacidad de resiliencia frente a la globalización. Otro objetivo general fue utilizar la gran cantidad de datos registrados hasta el momento para realizar análisis globales del territorio. La metodología llevada a cabo durante el trabajo de campo ha sido la recopilación de información etnobotánica mediante entrevistas semiestructuradas a informantes locales, generalmente seleccionados mediante el método bola de nieve, para el posterior análisis. Los resultados de esta tesis han sido agrupados en cuatro bloques, cada uno de les cuales incluye uno o más trabajos. El primero, Prospecciones etnoflorísticas, está compuesto por tres estudios etnobotánicos realizados en tres zonas geográficas. El segundo, Datos etnobotánicos, territorio y metanálisis, incluye varios trabajos metanalíticos con diferentes enfoques específicos. El tercer bloque, Nuevos enfoques etnobotánicos, trata aspectos poco comunes en estudios etnobotánicos, como la recopilación de datos de los herbarios históricos o los usos populares de la plantas para el tratamiento del cáncer. Finalmente, el último bloque, Temática colateral, analiza la información etnobotánica a través de la filogenia del género Artemisia, así como las concentraciones de artemisinina de diferentes especies de este género con el objetivo de detectar otras especies que posean propiedades antimaláricas. En esta tesis, también se han incluido tres catálogos, uno etnoflorístico, otro de mezclas de plantas medicinales y el último dedicado a las mezclas de plantas alimentarias, fruto de la prospección etnobotánica en una zona árida o semiárida de Catalunya. Las principales conclusiones de esta tesis son que Cataluña es un territorio bien prospectado, con un sólido conocimiento tradicional sobre las plantas, que aún está vivo, a pesar de la erosión que sufre, y que los estudios etnobotánicos pueden ser la base para futuros alimentos, drogas y otros elementos o productos que aumentan el bienestar de nuestra sociedad.
Although a relevant number of ethnobotanical studies have been carried out in Catalonia during the last years, the sampling remained unequally distributed and incomplete. Especially, research was lacking for the arid and semi-arid zones occupying the inner areas of this part of the Catalan- language territories, located in the NE of the Iberian Peninsula. In this scenario, one of the main objectives of this PhD thesis was to fill the existing gaps in the ethnobotanically-sampled territories in order to get an overview about the state of the traditional knowledge, emphasising on plants and on their uses, and its resilience to globalization. Another general objective was to use the high amount of data recorded to undertake global analyses. The methodology to reach this general objective has been to collect and to analyse the data obtained from the semi-structured interviews to local informants, usually selected by the snowball method. The results have been grouped in four major chapters, each of which including one or more studies. The first one, Ethnofloristic prospections, is composed by three ethnobotanical studies carried out in three geographic zones. The second one, Ethnobotanical data, territory and meta- analyses, includes several meta-analytic studies, each of them highlighting a specific focus. The third chapter, New ethnobotanical approaches, deals with unusual aspects of the ethnobotanical studies, such as the data collection from the historical herbaria or the plant popular uses in the cancer treatment. Finally, the last chapter, Collateral subject, is devoted to analysing artemisinin concentrations and ethnobotanical information across the phylogeny of the genus Artemisia with the aim of detecting other species possessing antimalarial properties. Three catalogues have been included in this thesis, an ethnofloristic one, another one of medicinal plant mixtures and a last one devoted to food plant mixtures. The main conclusions that come out from this thesis are that Catalonia is a well-prospected territory, with a robust traditional knowledge on plants, which is still alive, despite the erosion it is suffering, and that ethnobotanical studies can be the basis for future foods and drugs and other elements or products that increase the well-being of our society.

Thesis (PhD. (Anthropology)) --University of Limpopo, 2008
In this study, the multidisciplinary epistemology of ethnobotany is reviewed within the wider context of ethnoecology and indigenous knowledge systems. The major problems derived from this theoretical framework cover aspects of the relationship between cultural groups and their natural environment - particularly the botanical component of the latter. Problems and critical questions about this relationship were investigated in selected areas of the Bushbuckridge district, which are inhabited by a number ofTsonga-Shangana communities. Salient aspects of the natural habitat in the study area are discussed with special reference to the vegetation, climate and soil types. A proper understanding of the culturally-based exploitation of plant resources necessitates a sound knowledge of the culture concerned, including relevan t aspects of its value-system and cosmology. In this review, emphasis is placed on those aspects of culture that are directly concerned with the utilisation of plant resources. The latter include a wide range of economic, technological and medicinal uses. Specimens of 200 plants were collected and identified by the University of Limpopo Herbarium. The uses of every species are described. Systematised tables of plant uses are presented, as well as comparative lists in which selected uses are compared to those of other cultures in which the same species are used. The effects of plant utilisation, as well as indigenous forms of resource management, are also discussed. Recommendations are made on how to counter the process of environmental degradation which is caused by over-exploitation .

Le Tombac est une plante à fumer plantée au Liban, pays méditerranéen doté de conditions climatiques uniques reflétant une biodiversité particulière permettant la présence de nombreux habitats végétaux à différents niveaux de la mer. Cependant, cette variété de plante à fumer locale libanaise est principalement plantée dans la vallée d’Akkar (nord du Liban) du côté de la mer, ce qui lui confère une saveur et un arôme uniques qui la différencie du fameux tabac oriental de haute valeur aromatique qui est cultivé dans quelques-uns des très rares pays méditerranéens voisins. Étant donné que le Tombac a besoin de conditions de croissances particulières et afin de conserver son arôme et sa saveur uniques, une procédure de récolte et de séchage spéciale est supposée contribuer à la production de ses métabolites secondaires qui jouent un rôle important en tant que bio-pesticide végétal préliminaire. La production de feuilles sèches de Tombac au Liban est continue car elle est subventionnée par une entreprise gouvernementale appelée Régie Libanaise des Tabacs et Tombacs, sous la supervision du ministère des Finances, dans le but de réduire l'immigration des agriculteurs de leurs villages. Les plantes sèches de Tombac nécessitent un appareil à fumer spécial appelé pipe à eau (Shisha ou Arguilet en arabe), qui peut également être utilisé pour le tabac Mouassel (un mélange spécial contenant du saccharose et de la glycérine) après avoir changé le type de tête, où les feuilles sont séchées pour être fumées, elles sont ensuite trempées dans de l’eau et, après le rinçage, elles sont fixées sur la tête en forme de selle sur le tuyau d’eau avec des braises de charbon au-dessus. Le Tombac est considéré comme une plante cancérigène et dangereuse, non seulement pour la santé des fumeurs, mais également pour les mains et les parties du corps des agriculteurs et les travailleurs dans les champs ou dans les ateliers d’emballage qui sont en contact avec sa sève à tous les stades de la production en raison de l’effet de la maladie du tabac vert (MTV). De nos jours, les pesticides bio-essences dérivés de certains extraits de métabolites végétaux sont considérés comme l'une des solutions les plus prometteuses pour la lutte antiparasitaire respectueuse de l'environnement en agriculture. En raison de ces faits, un certain nombre d’études ont été menées sur la plante Tombac afin de la définir, de déterminer son origine, sa taxonomie, ses plantations, ses utilisations, ses effets sur la santé de l’homme, que ce soit pour les fumeurs ou les travailleurs, et en tant que source prometteuse d’utilisation écologique de Tombac comme bio-essence pour l’avenir par l’analyse chromatographique de cette huile
Tombac is a smoking plant that is planted in Lebanon a Mediterranean country that has unique climatic conditions which reflect a special biodiversity allowing the presence of many plants habitats at different sea levels. However, this Lebanese local smoking plant variety is planted mainly in Akkar valley north of Lebanon and located on the sea side (Fig.1) giving it a unique smoking flavor and aroma which makes it different from the famous valuable high aromatic oriental tobacco that is grown in some of very few nearby Mediterranean countries. Since Tombac needs a special growing conditions, and in order to keep its unique aroma and flavor, a special harvest and drying procedures are performed that is believed to contribute in the production of its secondary metabolites that play an important role as a preliminary plant biopesticides. Tombac dry leaf production in Lebanon is continuous because it is subsidized by a governmental enterprise called Régie Libanaise des Tabacs & Tombacs under the supervision of the Ministry of finance in the purpose of reducing the immigration of the farmers from their villages. Tombac dry plants needs a special smoking apparatus known as water pipe or shisha (fig.2) that can be used also for tobacco Mouassel (a special mix contains sucrose and glycerine) after changing the head type (fig.2) where the dried leaves to be smoked are soaked in water and after rinsing it is fixed on the bowel-shaped head of the water pipe with the heated charcoal on it (fig.3). Tombac is considered a carcinogenic and hazardous plant not only on the health of their smokers , but also for the hands and body parts of those farmers and labors who work in the field, packaging, and get in contact with its sap(fig.4) in all the stages of production because of the effect of Green Tobacco Sickness (GTS). Nowadays, Bio-oil pesticide derived from some plant secondary metabolite extracts is considered one of the most promising solutions for Eco-friendly pest control in agriculture. Because of these facts, a number of studies were done on Tombac plant to define it, cover its origin, taxonomy, plantation, uses, effects on human health as smokers as well as workers and the alternative eco-friendly use of Tombac as promising source bio oil pesticide for the future

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2015-08-08T00:17:42Z No. of bitstreams: 1 Disserta??oFinal.CORRIGIDA.Regina.pdf: 7075716 bytes, checksum: 23fbdf64abf1f7854256e33234630f36 (MD5)
Made available in DSpace on 2015-08-08T00:17:42Z (GMT). No. of bitstreams: 1 Disserta??oFinal.CORRIGIDA.Regina.pdf: 7075716 bytes, checksum: 23fbdf64abf1f7854256e33234630f36 (MD5) Previous issue date: 2013-07-31
Communities living around the areas of access to natural resources hold important information about the use and potential of useful plants available, as well as the skills and techniques adopted for collection. However, overpumping of plants can modify their population structure and change the dynamics of the individual in the long term. Thus, this study collected data on knowledge, use and collection techniques of candomb? (Vellozia sincorana L.B.Sm. & Ayensu), an endemic plant of the rocky fields of Chapada Diamantina, Bahia, Brazil, used by locals as fuel to start burning in wood stoves, and evaluate their population structure in collection areas suggested by local collectors, whose populations are under varying degrees of accessibility. The study was outlined to answer the following questions: a) To what purpose the residents of local communities in the Chapada Diamantina use candomb?? b) The uses listed vary by occupation and gender of the informants? c) What are the most used categories of use in communities? d) What are the main sites for the extraction of the species? e) What are the techniques used to cut and plant selection? f) There are differences in the densities, heights and diameters of the individual populations of V. sincorana two operating environments? We interviewed 37 key informants in six rural communities in the Chapada Diamantina. The usage category "Fuel" was the most reported with 55 citations, followed by trade (12) technology (10) ritual (2). Both men (G = 14.1272, p <0.01), compared to women, as the ex-miners (G = 32.643, p <0.001) compared to other occupations seem significantly better understand the utility of the species indicating that probably the difficult access to candomb?, associated with its location in the vicinity of the old mining areas benefited men to better knowledge of candomb?. We sampled 814 individuals of V. sincorana the six populations studied. Environments more distant tracks presented density (ind.m?) is significantly higher compared to the environments closest track, indicating that the environments more accessible to the resource are more disturbed, but now seem to be being replaced by more distant areas, which can be found higher plant density and individuals with characteristics preferred by collectors. It can be inferred that currently candomb? has no economic importance, but has great cultural significance for human populations in rural communities of the Chapada Diamantina, which hold techniques and skills for collecting the resource that are relevant to subsidize actions management and conservation of V. sincorana, since this species populations showed changes in structure between different access environments the species.
Comunidades que vivem nos arredores de ?reas de acesso a recursos naturais det?m informa??es importantes sobre o uso e potencial de plantas ?teis dispon?-veis, assim como as t?cnicas e habilidades adotadas para coleta. No entanto, a extra??o exagerada de plantas pode modificar a sua estrutura populacional e alte-rar a din?mica do indiv?duo em longo prazo. Desta forma, o presente estudo le-vantou informa??es sobre conhecimento, uso e t?cnicas de coleta do candomb? (Vellozia sincorana L.B.Sm. & Ayensu), planta end?mica dos campos rupestres da Chapada Diamantina, Bahia, Brasil, utilizada por moradores locais como combus-t?vel para iniciar queima em fog?es a lenha, al?m de avaliar a sua estrutura po-pulacional em ?reas de coleta sugeridas por coletores locais, cujas popula??es est?o sob diferentes graus de acessibilidade. O estudo foi esquematizado para responder as seguintes perguntas: a) Para qual finalidade os moradores de co-munidades locais da Chapada Diamantina utilizam o candomb?? b) Os usos indi-cados variam de acordo com a ocupa??o e g?nero dos informantes? c) Quais s?o as categorias de uso mais utilizadas nas comunidades? d) Quais s?o os principais locais para extra??o da esp?cie? e) Quais s?o as t?cnicas usadas para corte e sele??o da planta? f) H? diferen?as nas densidades, alturas e di?metros dos indi-v?duos de popula??es de V. sincorana em dois ambientes de explora??o? Entre-vistaram-se 37 informantes-chave em seis comunidades rurais da Chapada Dia-mantina. A categoria de uso ?combust?vel? foi a mais reportada com 55 cita??es, seguida de com?rcio (12), tecnol?gico (10) e Ritual (2). Tanto os homens (G=14,1272; p<0,01), em rela??o ?s mulheres, quanto os ex-garimpeiros (G=32,643; p<0,001), em rela??o ?s demais ocupa??es parecem significativamente conhecer melhor as utilidades da esp?cie, indicando que provavelmente o dif?cil acesso ao candomb?, associado ? sua localiza??o no entorno das antigas ?reas de minera??o beneficiou os homens para melhor conhecimento do candomb?. Foram amostrados 814 indiv?duos de V. sincorana nas seis popula??es estudadas. Os ambientes mais distantes das trilhas apresentaram densidade (ind.m?) significativamente maior em rela??o aos ambientes mais pr?ximos da trilha, indicando que os ambientes mais acess?veis ao recurso s?o mais perturbados, por?m atualmente parecem estar sendo substitu?dos por ?reas mais distantes, onde pode ser encontrada maior densidade de plantas e indiv?duos com caracter?sticas preferidas por coletores. Pode-se inferir que atualmente o candomb? n?o possui import?ncia econ?mica, mas tem grande import?ncia cultural para as popula??es humanas de comunidades rurais da Chapada Diamantina, que det?m t?cnicas e habilidades para coleta do recurso que s?o relevantes para subsidiar a??es de manejo e conserva??o de V. sincorana, uma vez que as popula??es desta esp?cie apresentaram altera??es na sua estrutura entre os diferentes ambientes de acesso a esp?cie.

Ecological research aimed at the conservation of useful plants has rarely considered the spatial distribution of resources nor the potential implications for management. In this thesis I examined the spatial patterning of a group of 23 useful plant species on the 3,500 ha territory of a Kuna community in Darien, Panama. A systematic random sampling scheme was used to survey the distribution and abundance of the species, as well as the physical environment. A series of canonical analyses was conducted to evaluate the species-environment relationships and to identify spatial structures in the species distributions left unexplained by the environmental variables. Four distinct distribution patterns were identified among the species; these were most strongly explained by land-use, the degree of canopy closure and topography. Significant spatial structures, independent of the environmental variables, were related to anthropogenic pressures and an edaphic gradient. The habitat associations of the individual species are described and data on one species, Sabal mauritiiformis , is used to illustrate the utility of these data in the management of plant resources on human landscapes.

Aquest treball estableix el catàleg etnoflorístic de Mallorca. És el primer estudi etnobotànic complet sobre l’illa i contribueix a incrementar les dades etnobotàniques disponibles dels territoris del domini lingüístic català. L’estudi es basa en 235 informants d’una mitjana d’edat de 76 anys i abraça 75 nuclis de població de tots els 53 municipis mallorquins. El 97% dels informants són autòctons de l’illa, el 89% són jubilats, i el 57% són homes. S’ha recollit majoritàriament informació de persones nascudes entre el 1931 i el 1940. La mitjana de citacions d’ús per informant és de 42,31 i el factor de consens d’informants (FIC) per a tot Mallorca és 0,94, un valor molt proper al consens total (1). La informació obtinguda de les entrevistes ha estat analitzada des del punt de vista botànic i etnogràfic, i s’ha fet servir el gestor de dades del grup EtnobotCat, ideat en el transcurs d’aquest estudi a partir de versions anteriors d’altres bases de dades etnobotàniques del nostre equip. El total de tàxons recollit de les entrevistes és de 517, i les citacions globals (amb consens u, és a dir, citades per almenys un informant) per a cada categoria d’ús són 1900 per a medicinals, 2872 per a alimentàries i 2235 per a altres usos. S’han recollit un total de 600 dades etnogràfiques no referents directament als vegetals. Dels 517 tàxons que conformen el catàleg etnoflorístic, majoritàriament fanerògames i hemicriptòfits de tipus biològic, un 52% són silvestres i la resta cultivats o obtinguts al comerç. L’índex d’etnobotanicitat és del 28%, o sigui, els informants han qualificat prop d’un terç de la flora de Mallorca com a útil. S’han recopilat 1401 noms populars, dels quals se n’identifiquen 250 de catalans no documentats en les obres incloses al projecte Recull de noms catalans de plantes. S’han recopilat 255 tàxons útils en medicina humana (137 de silvestres), amb un total de 1811 citacions d’ús amb un consens de tres informants. S’han recopilat 159 mescles de plantes (110 tàxons i 662 citacions d’ús), també amb activitat medicinal, majoritàriament anticatarral. Per a les dades referides a la medicina animal, els informants citen 92 remeis veterinaris referits a 53 tàxons. D’aquests remeis, 52 són exclusius per a animals i 40 són compartits amb la medicina humana. Del total de tàxons citats com a alimentaris en humans (199), el 67% són cultivats o comprats, i la resta, silvestres. S’han recollit 103 citacions d’ús de vegetals en alimentació animal per a 62 tàxons. Per als usos que no són ni alimentaris ni medicinals els informants han citat 351 tàxons i 1142 reports d’ús únics. El grau de novetat de l’etnomedicina mallorquina, després de fer un buidatge de més de 200 obres amb informació d’interès etnobotànic d’àmbit majoritàriament mediterrani, és força alt per a ser un estudi etnobotànic tan actual, car consisteix en 38 tàxons poc citats i 306 reports d’ús que no apareixen o són recollits en menys de tres obres de referència. Els estudis etnobotànics com aquest poden ser una eina molt útil per a les administracions en salut pública per tal de facilitar i millorar la detecció i prevenció d’interaccions i altres problemes resultants de combinar plantes medicinals i medicaments de síntesi, i també per a encoratjar la seguretat en la prescripció i el consell farmacèutic per part dels professionals de la salut. L’interès principal de portar a terme un estudi etnobotànic de Mallorca ha estat el de contribuir a conèixer l’ús tradicional que es fa de les plantes de l’illa i valorar els beneficis que es poden extraure d’aquests sabers, aplicats al present i futur de la societat estudiada.
This work is a contribution to the ethnobotany of Mallorca. This is the first approach in this field entirely based on interviews with local people. We spoke with a total of 235 informants with a mean age of 76, covering 75 villages in all the 53 municipalities of Mallorca. The data collected has been analyzed from the botanical and ethnographical point of view, and managed using an online database designed in the course of this study starting from earlier versions developed in our research group, EtnobotCat. The organisation of the data into groups of three, for example, the categories of use, the results of the discussion and consensus facilitates both the design and the systematization of data analysis. The basic unit of the analysis is the use report, and the information has been organized into two catalogues (taxa and mixtures), and additional ethnographic data referred to plants has also been considered. The total number of collected taxa from the interviews is 517, and the overall citations (with consensus of one, i.e. cited by at least one informant) for each category of use are 1900 for medicinals, 2872 for food and 2235 for other uses. Moreover, we have collected a total of 600 ethnographic data not directly related to the plants. The main interest of carrying out an ethnobotanical study of Mallorca has been to contribute to the knowledge of the traditional use of plants of the island and appreciate the benefits of this knowledge, applied to the present and future of our society.

IAS 39 and recorded structured interviews with the respondents. The accounting treatment of commodity derivatives was investigated by utilising nine transaction types which are typically found when producers sell grain to an agribusiness or a processor purchases grain from an agribusiness. The seven case studies were identified by utilising convenience sampling (unrestricted non–probability sampling). A literature review and empirical study were conducted. The findings on the accounting treatment of commodity derivatives were communicated thematically. The main findings were discussed during interviews with representatives of the technical departments of three of the Big Four audit firms in South Africa. A discussion of similar studies performed globally was performed. The recommendations following from this research study include that entities carrying “own use” inventory and applying hedge accounting can elect to apply the base adjustment consistently as part of their accounting policy on the valuation of inventory. Entities holding grain inventory for trading purposes should, based on industry practice, fair value such inventory. Various recommendations regarding the classification of a supply contract with a producer (as defined in a pre–season fixed price contract) depending on whether an entity applies hedge accounting or not, were made. Recommendations regarding the determination of fair value include that, based on industry practice and guidance by IAS 39, the SAFEX–based price should be utilised to fair value derivatives and to fair value inventory held by commodity–broker traders. The fair value movement on the option contracts taken out on behalf of the producer by an agribusiness should be transferred to the relevant producer's loan account. The recommendations concluded with a recommendation that entities should proactively consider and plan the impact of the replacement of IAS 39 on current business practices. Areas for further research could include investigating the accounting treatment of commodity derivatives of the newly issued accounting standards on financial instruments by IASB and the impact of these new standards on the business practices of entities. indices were measured, Shannon–Wiener Diversity, Pieolou’s Evenness, Margalef’s Species Richness and Simpson’s Index of diversity. In all the indices homegardens had the highest value in comparison with other land–use types followed by natural areas. Questionnaires were used to gather information regarding indigenous knowledge used by residents to manage their homegardens and to determine the different socio–economic classes in the study area. The majority of the population was still utilizing indigenous knowledge to manage their homegardens. However, there was some disparity whether or whether not indigenous knowledge has been lost. This study confirms that homegardens contribute significantly to household diet and income especially for the people living in rural areas due to the production and diversity of cultivated edible species. This is the case despite a high percentage of ornamentals being cultivated. Although the extent of household dependency on homegardens varies considerably, its contribution is quite significant towards the livelihood of the people because it requires minimal investment and is easily accessible. Homegardens also serve as sites for the conservation of rare, vulnerable, endangered and endemic species.
Thesis (M.Sc. (Botany))--North-West University, Potchefstroom Campus, 2011.

[EN] Abstract Introduction Salinity and drought are the most important environmental stress conditions reducing crop yields worldwide and limiting the distribution of wild plants in nature. Soil salinity, especially secondary salinity caused by anthropogenic practices, such as prolonged irrigation, lead to substantial agricultural yield losses, especially in arid and semiarid regions. Drought, caused by reduced water content in the soil, occurs due to disorders in nature's water cycle, chiefly when evapotranspiration exceeds precipitation in a certain area, to the point where soil water reserves can no longer support plant growth. Drought and salt stress trigger the activation of a series of basic stress mechanisms that includes among others, the control of ion transport, exclusion and compartmentalization, as well as the accumulation of compatible solutes ('osmolytes'), and the activation of antioxidant systems. These mechanisms are conserved in all plants, stress tolerant and sensitive alike, and don't necessarily confer tolerance. To decipher those mechanisms and have a better understanding on the contribution of different stress responses to the stress tolerance of a given species, we have carried out comparative studies on the responses to drought and salinity in a number of genetically related taxa with different tolerance potentials. Methodology The experimental approach was mostly based on i) establishing the relative tolerance to water and salt stress in the studied species from their distribution in nature (in the case of wild species) and through the relative inhibition of growth in the presence of stress, and ii) correlating changes in the levels of biochemical 'stress markers' associated to specific response pathways (ion transport, osmolyte accumulation¿) upon stress treatments, with the already established relative tolerance to stress. This strategy proved to be appropriate to distinguish mere general responses to stress from those mechanisms relevant for stress tolerance of the investigated species and cultivars. The work also sheds light on other aspects affected by salt stress, specifically regarding germination and reproductive success or anatomical changes in salt-stressed plants. The expression patterns of the gene NHX1, encoding a vacuolar Na+/H+ antiporter were also studied in the Plantago taxa, as a first step in the full characterisation of this ion transporter, that appears to play an important role in the mechanisms of salt tolerance in this genus. Conclusion The results obtained in this work contribute to a better understanding of general stress tolerance mechanisms in plants, and provides clear insights into the mechanisms conferring tolerance, specifically, to drought and salt stress in some wild species and crops. This work also shed more light on the highly efficient responses to stress in halophytes, plants that could be viewed as nature's answer to the aforementioned adverse environmental conditions via evolution and adaptation. Halophytes can therefore be considered as a suitable source - underutilized at present, in our opinion - of knowledge, genetic resources and biotechnological tools for the needed improvement of stress tolerance in crops.
[ES] Resumen Introducción La salinidad y la sequía son las condiciones de estrés ambiental más importantes, que reducen los rendimientos de los cultivos en todo el mundo y que limitan la distribución de las plantas silvestres en la naturaleza. La salinidad del suelo, especialmente la salinización secundaria causada por prácticas antropogénicas, como la irrigación prolongada, conducen a pérdidas importantes de rendimiento agrícola, especialmente en las regiones áridas y semiáridas. La sequía, provocada por la reducción de contenido de agua en el suelo, se produce debido a alteraciones en el ciclo del agua en la naturaleza, principalmente cuando la evapotranspiración excede la precipitación en un área determinada, hasta el punto que las reservas de agua del suelo ya no pueden soportar el crecimiento de la planta. La sequía y el estrés salino desencadenan la activación de una serie de mecanismos básicos de respuesta, que incluyen entre otros el control del transporte, la exclusión y la compartimentación de iones, así como la acumulación de solutos compatibles ('osmolitos'), y la activación de sistemas antioxidantes. Estos mecanismos están conservados en todas las plantas, tolerantes y sensibles a estrés por igual, y no confieren necesariamente tolerancia. Para descifrar estos mecanismos y conseguir una mejor comprensión de la contribución de diferentes respuestas a estrés a la tolerancia al estrés en una especie dada, hemos llevado a cabo estudios comparativos sobre las respuestas a la sequía y la salinidad, en un número de taxones relacionados genéticamente con diferentes potenciales de tolerancia. Metodología El enfoque experimental se basó principalmente en i) establecer la tolerancia relativa al estrés hídrico y al estrés salino en las especies estudiadas, a partir de su distribución en la naturaleza (en el caso de especies silvestres) y atendiendo a la inhibición relativa de su crecimiento en presencia de estrés, y ii) correlacionar cambios en los niveles de 'marcadores bioquímicos de estrés' asociados a vías específicas de respuesta (transporte de iones, acumulación de osmolitos ...) inducidos por los tratamientos de estrés, con la tolerancia relativa a estrés de las plantas, previamente establecido. Esta estrategia ha resultado ser apropiada para distinguir meras respuestas generales a estrés de los mecanismos relevantes para la tolerancia a estrés de las especies y cultivares investigados. El trabajo también arroja luz sobre otros aspectos afectados por el estrés salino, específicamente en relación con la germinación y el éxito reproductivo, o cambios anatómicos en las plantas tratadas con sal. También se estudiaron los patrones de expresión del gen NHX1, que codifica un antiportador vacuolar Na+/H+, en las especies de Plantago, como un primer paso en la caracterización completa de este transportador de iones, que parece desempeñar un papel importante en los mecanismos de tolerancia a sal en este género. Conclusión Los resultados obtenidos en este trabajo contribuyen a una mejor comprensión de los mecanismos generales de tolerancia al estrés en plantas, y proporcionan ideas claras sobre los mecanismos que confieren tolerancia, en concreto, a la sequía y al estrés salino, en algunas especies silvestres y cultivadas. Este trabajo también arroja más luz sobre las respuestas a estrés altamente eficientes en halófitas, plantas que podrían ser vistas como la respuesta de la naturaleza a las condiciones ambientales adversas antes mencionadas, a través de la evolución y la adaptación. Por lo tanto, las halófitas pueden ser consideradas como una fuente adecuada - infrautilizada en la actualidad, en nuestra opinión - de conocimiento, recursos genéticos y herramientas biotecnológicas para la necesaria mejora de la tolerancia al estrés en plantas cultivadas.
[CA] Resum Introducció La salinitat i la sequera són les condicions d'estrès ambiental més importants, que redueixen els rendiments dels cultius a tot el món i que limiten la distribució de les plantes silvestres en la naturalesa. La salinitat del sòl, especialment la salinització secundària causada per pràctiques antropogèniques, com la irrigació perllongada, condueixen a pèrdues importants de rendiment agrícola, especialment en les regions àrides i semiàrides. La sequera, provocada per la reducció de contingut d'aigua en el sòl, es produeix a causa d'alteracions en el cicle de l'aigua en la naturalesa, principalment quan la evapotranspiració excedeix la precipitació en un àrea determinada, fins al punt que les reserves d'aigua del sòl ja no poden suportar el creixement de la planta. La sequera i l'estrès salí desencadenen l'activació d'una sèrie de mecanismes bàsics de resposta, que inclouen entre uns altres el control del transport, l'exclusió i la compartimentació d'ions, així com l'acumulació de soluts compatibles ('osmolits'), i l'activació de sistemes antioxidants. Aquests mecanismes estan conservats en totes les plantes, tolerants i sensibles a estrès per igual, i no confereixen necessàriament tolerància. Per a desxifrar aquests mecanismes i aconseguir una millor comprensió de la contribució de diferents respostes a estrès a la tolerància a l'estrès en una espècie donada, hem dut a terme estudis comparatius sobre les respostes a la sequera i la salinitat, en un nombre de taxons relacionats genèticament amb diferents potencials de tolerància. Metodologia L'enfocament experimental es va basar principalment en i) establir la tolerància relativa a l'estrès hídric i a l'estrès salí en les espècies estudiades, a partir de la seua distribució en la naturalesa (en el cas d'espècies silvestres) i atenent a la inhibició relativa de el seu creixement en presència d'estrès, i ii) correlacionar canvis en els nivells de 'marcadors bioquímics d'estrès' associats a vies específiques de resposta (transport d'ions, acumulació d'osmolits ...) induïts pels tractaments d'estrès, amb la tolerància relativa a estrès de les plantes, prèviament establert. Aquesta estratègia ha resultat ser apropiada per a distingir meres respostes generals a estrès dels mecanismes rellevants per a la tolerància a estrès de les espècies i conreus investigats. El treball també llança llum sobre altres aspectes afectats per l'estrès salí, específicament en relació amb la germinació i l'èxit reproductiu, o canvis anatòmics en les plantes tractades amb sal. També es van estudiar els patrons d'expressió del gen NHX1, que codifica un anti-portador vacuolar Na+/H+, en les espècies de Plantago, com un primer pas en la caracterització completa d'aquest transportador d'ions, que sembla exercir un paper important en els mecanismes de tolerància a sal en aquest gènere. Conclusió Els resultats obtinguts en aquest treball contribueixen a una millor comprensió dels mecanismes generals de tolerància a l'estrès en plantes, i proporcionen idees clares sobre els mecanismes que confereixen tolerància, en concret, a la sequera i a l'estrès salí, en algunes espècies silvestres i conreades. Aquest treball també llança més llum sobre les respostes a estrès altament eficients en halòfites, plantes que podrien ser vistes com la resposta de la naturalesa a les condicions ambientals adverses abans esmentades, a través de l'evolució i l'adaptació. Per tant, les halòfites poden ser considerades com una font adequada - infrautilitzada en l'actualitat, en la nostra opinió - de coneixement, recursos genètics i eines biotecnològiques per a la necessària millora de la tolerància a l'estrès en plantes conreades.
Al Hassan, M. (2016). Comparative analyses of plant responses to drought and salt stress in related taxa: A useful approach to study stress tolerance mechanisms [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61985
TESIS

Um grande número de rochas de granulação grosseira tem valor agregado muito alto quando usadas como materiais de construção, as chamadas rochas exóticas. No entanto, existem problemas com a utilização desses materiais dado a sua fragilidade, que está relacionada com a sua textura muito heterogênea. No Brasil é empregado empiricamente um reforço (compósito) que utiliza resina epóxi e fibra de vidro para melhorar o desempenho mecânico de tais rochas quando empregadas como materiais de construção. Os objetivos da presente pesquisa foram estudar o reforço tradicional brasileiro (telagem) para determinar sua eficiência e, ao mesmo tempo, propor outras soluções de reforço alternativas e mais eficientes, e avaliá-las através da caracterização mecânica experimental. Foi proposto um critério denominado Declive Global para avaliar as tensões de serviço dos materiais pegmatíticos estudados, quando os reforços propostos foram aplicados. Para validar esse critério foi utilizado um sistema de correlação digital de imagem (CDI) para observar e medir o comportamento de deformação e fratura durante a realização de testes de flexão em 4 pontos. Tanto o critério proposto como a CDI mostraram que a propagação de fissuras ocorre muito antes do material atingir a carga máxima. O reforço alternativo proposto, que emprega resina epóxi e uma fibra de vidro 600 g/m² apresentou o melhor desempenho mecânico, elevando a carga de ruptura até 6x em comparação com as amostras onde nenhum reforço foi aplicado. Os resultados demonstrados pelos reforços propostos são promissores e aumentam a possibilidade de aplicar rochas exóticas frágeis como materiais de construção, além do critério proposto fornecer uma ferramenta importante para a compreensão mecânica prévia de produtos de rocha que utilizam reforços compósitos.
A great number of coarse-grained natural stones have very high added-value when used as building materials, the so called exotic stones. However, problems using these materials arise from its brittleness behavior, which are related to its very heterogeneous texture. Glass fiber-reinforced epoxy composite (GFRC) is being used to improve mechanical performance of such stones when employed as building materials. The objectives of this present investigation it were studying the Brazilian traditional reinforcement to determinate its efficiency and, at the same time, a number of alternative solutions were proposed and evaluated through experimental mechanical characterization. It was proposed a slope-based criterion to evaluate the useful service loads of pegmatitic materials when glass fiber-reinforcement is applied. To validate the proposed criterion, a digital image correlation (DIC) system was employed to observe and measure strain and fracture behavior during the realization of 4-point bending tests. Both proposed criterion and DIC show that crack propagation occurs long before the material reaches maximum load. GFRC acts as a crack inhibitor, raising the breaking load up to 6x in comparison with the specimens where no reinforcement was applied. The results from this study enhance the capability to apply such materials as building materials and provide an important tool to perform prior mechanical understanding of stone products using GFRC.

The valuation of an asset is one of the most important thing with accounting, though one of the most difficult thing as well. However, in deciding useful service life for an intangible asset and property, plant and equipment, there are quite a margin for the companies, which creates a difference between companies and industries. When computing the value of the inventories there are a few possibilities available for the companies, which also can generate differences

between companies and industries. Although these differences can occur, there might be some similarities in the companies’ estimates. Hence, the purpose of this essay is to establish whether there are any differences in how companies are assessing their useful service life of intangible assets, property, plant and equipment and deciding the value of inventories. To be able to accomplish the purpose, company’s annual reports were used along with other necessary sources, for instance books about accounting principles and theories. The study, furthermore, concluded that there are small differences between companies within the same industry and industries altogether, in their judgment on useful service life and the value of the inventories.

Thesis (MScEng)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: Physical Asset Management (PAM) is becoming a greater concern for companies in industry today. The widely accepted British Standards Institutes’ specification for optimized management of physical assets and infrastructure is PAS55. According to PAS55, PAM is the “systematic and co-ordinated activities and practices through which an organization optimally manages its physical assets, and their associated performance, risks and expenditures over their life cycle for the purpose of achieving its organizational strategic plan”. One key performance area of PAM is Asset Care Plans (ACP). These plans are maintenance strategies which improve or ensure acceptable asset reliability and performance during its useful life. Maintenance strategies such as Condition Based Maintenance (CBM) acts upon Condition Monitoring (CM) data, disregarding the previous failure histories of an asset. Other maintenance strategies, such as Usage Based Maintenance (UBM), is based on previous failure histories, and does not consider CM data. Regression models make use of both CM data and previous failure histories to develop a model which represents the underlying failure behaviour of the asset under study. These models can be of high value in ACP development due to the fact that Residual Useful Life (RUL) can be estimated and/or the long term life cycle cost can be optimized. The objective of this thesis was to model historical failure data and CM data well enough so that RUL or optimized preventive maintenance instant estimations can be made. These estimates were used in decision models to develop maintenance schedules, i.e. ACPs. Several regression models were evaluated to determine the most suitable model to achieve the objectives of this thesis. The model found to be most suitable for this research project was the Proportional Hazards Model (PHM). A comprehensive investigation on the PHM was undertaken focussing on the mathematics and the practical implementation thereof. Data obtained from the South African mining industry was modelled with the Weibull PHM. It was found that the developed model produced estimates which were accurate representations of reality. These findings provide an exciting basis for the development of futureWeibull PHMs that could result in huge maintenance cost savings and reduced failure occurrences.
AFRIKAANSE OPSOMMING: Fisiese Bate Bestuur (FBB) is besig om ’n groter bekommernis vir maatskappye in die bedryf te word. Die Britse Standaarde Instituut se spesifikasie vir optimale bestuur van fisiese bates en infrastruktuur is PAS55. Volgens PAS55 is FBB die “sistematiese en gekoördineerde aktiwiteite en praktyke wat deur ’n organisasie optimaal sy fisiese bates, hul verwante prestasie, risiko’s en uitgawes vir die doel van die bereiking van sy organisatoriese strategiese plan beheer oor hul volle lewensiklus te bestuur”. Een Sleutel Fokus Area (SFA) van FBB is Bate Versorgings Plan (BVP) ontwikkeling. Hierdie is onderhouds strategieë wat bate betroubaarheid verbeter of verseker tydens die volle bruikbare lewe van die bate. Een onderhoud strategie is Toestands Gebasseeerde Onderhoud (TGO) wat besluite baseer op Toestand Monitering (TM) informasie maar neem nie die vorige falingsgeskiedenis van die bate in ag nie. Ander onderhoud strategieë soos Gebruik Gebasseerde Onderhoud (GGO) is gebaseer op historiese falingsdata maar neem nie TM inligting in ag nie. Regressiemodelle neem beide TM data en historiese falings geskiedenis data in ag ten einde die onderliggende falings gedrag van die gegewe bate te verteenwoordig. Hierdie modelle kan baie nuttig wees vir BVP ontwikkeling te danke aan die feit dat Bruikbare Oorblywende Lewe (BOL) geskat kan word en/of die langtermyn lewenssilus koste geoptimeer kan word. Die doelwit van hierdie tesis was om historiese falingsdata en TT data goed genoeg te modelleer sodat BOL of optimale langtermyn lewensiklus kostes bepaal kan word om opgeneem te word in BVP ontwikkeling. Hierdie bepalings word dan gebruik in besluitnemings modelle wat gebruik kan word om onderhoud skedules op te stel, d.w.s. om ’n BVP te ontwikkel. Verskeie regressiemodelle was geëvalueer om die regte model te vind waarmee die doel van hierdie tesis te bereik kan word. Die mees geskikte model vir die navorsingsprojek was die Proporsionele Gevaarkoers Model (PGM). ’n Omvattende ondersoek oor die PGM is onderneem wat fokus op die wiskunde en die praktiese implementering daarvan. Data is van die Suid-Afrikaanse mynbedryf verkry en is gemodelleer met behulp van die Weibull PGM. Dit was bevind dat die ontwikkelde model resultate geproduseer het wat ’n akkurate verteenwoordinging van realiteit is. Hierdie bevindinge bied ’n opwindende basis vir die ontwikkeling van toekomstige Weibull Proporsionele Gevaarkoers Modelle wat kan lei tot groot onderhoudskoste besparings en minder onverwagte falings.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Em engenharia, a modelagem computacional desempenha um papel importante na concepção de produtos e no desenvolvimento de técnicas de atenuação de ruído. Nesse contexto, esta tese investiga a intensidade acústica gerada pela radiação sonora de superfícies vibrantes. De modo específico, a pesquisa enfoca a identificação das regiões de uma fonte sonora que contribuem efetivamente para potência sonora radiada para o campo afastado, quando a frequência de excitação ocorre abaixo da frequência crítica de coincidência. São descritas as fundamentações teóricas de duas diferentes abordagens. A primeira delas, denominada intensidade supersônica (analítica) é calculada via transformadas de Fourier para fontes sonoras com geometrias separáveis. A segunda, denominada intensidade útil (numérica) é calculada através do método dos elementos de contorno clássico para fontes com geometrias arbitrárias. Em ambas, a identificação das regiões é feita pela filtragem das ondas não propagantes (evanescentes). O trabalho está centrado em duas propostas, a saber. A primeira delas, é a apresentação implementação e análise de uma nova técnica numérica para o cálculo da grandeza intensidade útil. Essa técnica constitui uma variante do método dos elementos de contorno (MEC), tendo como base o fato de as aproximações para as variáveis acústicas pressão e velocidade normal serem tomadas como constantes em cada elemento. E também no modo peculiar de obter a velocidade constante através da média de um certo número de velocidades interiores a cada elemento. Por esse motivo, a técnica recebe o nome de método de elemento de contorno com velocidade média (AVBEMAverage Velocity Boundary Element Method). A segunda, é a obtenção da solução forma fechada do campo de velocidade normal para placas retangulares com oito diferentes combinações de condições contorno clássicas. Então, a intensidade supersônica é estimada e comparada à intensidade acústica. Nos ensaios numéricos, a comparação da intensidade útil obtida via MEC clássico e via AVBEM é mostrada para ilustrar a eficiência computacional da técnica aqui proposta, que traz como benefício adicional o fato de poder ser utilizada uma malha menos refinada para as simulações e, consequentemente, economia significativa de recursos computacionais.
In engineering computational modeling plays an important role in product design and development techniques for noise attenuation. In such context, this thesis investigates the acoustic intensity generated by sound radiation from vibrating surfaces. Specifically, the research focuses on the identification that effectively contribute to the radiated sound power into the far-field, especially when the driven frequency occurs below the critical coincidence frequency. The theoretical formulations of two different approaches are described. The first one, called supersonic intensity (analytical) is calculated via Fourier transforms for noise sources with separable geometries. The second, called useful intensity (numerical) is calculated by the method of boundary elements to classic fonts with arbitrary geometries. In both, the identification of regions is done by filtering the non propagating waves (evanescent). The work is focused on the presentation, implementation and analysis of a new numerical technique for calculating the magnitude useful intensity. This technique is a variant of the method-boundary element (BEM), based on the fact that the approximations for the acoustic pressure and normal speed variables are taken as constant in each element. Also in particular way to obtain constant speed by mean of a number of speeds interior of each element. For this reason, the technique is called the Average Velocity Boundary Element Method . The closed form solution of the normal velocity field for rectangular plates in eight cases with distinct combinations of classical boundary conditions is also obtained. Then, the supersonic intensity is estimated and compared to the acoustic intensity. Numerical experiments are performed comparing to the useful intensity via the conventional BEM with theAVBEM in order to illustrate the positive computational features of the method. The numerical results indicate that the proposed method is much more computationally effcient than its standard BEM counterpart, it enabling the use of a coarser mesh.

As a consequence of the recent deregulation in the electrical power production industry, there has been a shift in the traditional ownership of power plants and the way they are operated. To hedge their business risks, the many new private entrepreneurs enter into long-term service agreement (LTSA) with third parties for their operation and maintenance activities. As the major LTSA providers, original equipment manufacturers have invested huge amounts of money to develop preventive maintenance strategies to minimize the occurrence of costly unplanned outages resulting from failures of the equipments covered under LTSA contracts. As a matter of fact, a recent study by the Electric Power Research Institute estimates the cost benefit of preventing a failure of a General Electric 7FA or 9FA technology compressor at $10 to $20 million. Therefore, in this dissertation, a two-phase data analytics approach is proposed to use the existing monitoring gas path and vibration sensors data to first develop a proactive strategy that systematically detects and validates catastrophic failure precursors so as to avoid the failure; and secondly to estimate the residual time to failure of the unhealthy items. For the first part of this work, the time-frequency technique of the wavelet packet transforms is used to de-noise the noisy sensor data. Next, the time-series signal of each sensor is decomposed to perform a multi-resolution analysis to extract its features. After that, the probabilistic principal component analysis is applied as a data fusion technique to reduce the number of the potentially correlated multi-sensors measurement into a few uncorrelated principal components. The last step of the failure precursor detection methodology, the anomaly detection decision, is in itself a multi-stage process. The obtained principal components from the data fusion step are first combined into a one-dimensional reconstructed signal representing the overall health assessment of the monitored systems. Then, two damage indicators of the reconstructed signal are defined and monitored for defect using a statistical process control approach. Finally, the Bayesian evaluation method for hypothesis testing is applied to a computed threshold to test for deviations from the healthy band. To model the residual time to failure, the anomaly severity index and the anomaly duration index are defined as defects characteristics. Two modeling techniques are investigated for the prognostication of the survival time after an anomaly is detected: the deterministic regression approach, and parametric approximation of the non-parametric Kaplan-Meier plot estimator. It is established that the deterministic regression provides poor prediction estimation. The non parametric survival data analysis technique of the Kaplan-Meier estimator provides the empirical survivor function of the data set comprised of both non-censored and right censored data. Though powerful because no a-priori predefined lifetime distribution is made, the Kaplan-Meier result lacks the flexibility to be transplanted to other units of a given fleet. The parametric analysis of survival data is performed with two popular failure analysis distributions: the exponential distribution and the Weibull distribution. The conclusion from the parametric analysis of the Kaplan-Meier plot is that the larger the data set, the more accurate is the prognostication ability of the residual time to failure model.

Made available in DSpace on 2016-04-25T18:39:35Z (GMT). No. of bitstreams: 1 Dalgi Sequeira Santos.pdf: 459515 bytes, checksum: 067388b08d48c23b142f655159808db8 (MD5) Previous issue date: 2010-11-12
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The objective of this study is to check compliance of the depreciation rates used by the companies, in conformity with the explanatory notes of property, plant and equipment included in their annual reports, with the concept of depreciation described in the Accounting Theory. The depreciation rates suggested by the Brazilian income tax regulation were utilized to compare the depreciation rates used in the balance sheets published. Based on this objective, three questions were raised: (i) is the accounting standard effective in Brazil, as regards depreciation rate, in accordance with the Accounting Theory?; (ii) is the accounting practice followed by the companies, with regard to depreciation rate, consistent with the definitions of the standard?; and (iii) did the new accounting legislation lead to the adoption of depreciation rates different from those recommended by the Tax Authorities? In order to obtain answers to the questions above, three hypotheses were corroborated, namely: (i) I the Brazilian accounting standard is in conformity with the Accounting Theory as regards the concepts of useful life of assets; (ii) II assets submitted to different conditions and systems to explore their benefits will have various economic useful lives. However, in hypothesis III, it is expected that, according to hypotheses I and II, and considering the definition of useful life of assets given by the Accounting Theory, the depreciation rates used be determined in accordance with the useful life of the asset and, therefore, be different, depending on their use and lines of business. Accordingly, for the same asset different depreciation rates will be used in different businesses, which means that not always the depreciation suggested by the Tax Authorities can be adopted as a rule. That hypothesis was refuted, based on the empirical surveys. The research adopted three methods to obtain the necessary information and data: (i) bibliographic research for the theoretical basis; (ii) documental research for surveying the standards in effect; and (iii) empirical research for surveying the data in primary sources
O objetivo deste estudo é verificar a aderência das taxas de depreciação utilizadas pelas empresas, conforme as notas explicativas de ativo imobilizado contidas em seus relatórios anuais, com o conceito de depreciação da Teoria da Contabilidade. Para comparação das taxas de depreciação utilizadas nos balanços publicados, utilizaram-se as taxas de depreciação sugeridas pela legislação brasileira de imposto de renda. Com base neste objetivo, foram levantadas três questões: (i) a norma contábil vigente no Brasil, no tocante à taxa de depreciação, está de acordo com a Teoria Contábil?; (ii) a prática contábil observada nas empresas, no tocante à taxa de depreciação, está coerente com as definições da norma?; e (iii) a nova legislação contábil levou à adoção de taxas de depreciação diferentes das recomendadas pelo Fisco? A fim de obter as respostas às questões anteriores, três hipóteses foram corroboradas, a saber: (i) I a norma brasileira de contabilidade está alinhada com a Teoria da Contabilidade no que se refere aos conceitos de vida útil do ativo; (ii) II ativos submetidos a diferentes condições e regimes de exploração de seus benefícios terão diversas vidas útil-econômicas. No entanto, na hipótese III, espera-se que, de acordo com as hipóteses I e II e considerando a definição de vida útil do ativo dada pela Teoria da Contabilidade, as taxas de depreciação utilizadas sejam estipuladas segundo a vida útil-econômica do ativo e, dessa forma, sejam diferentes conforme seu uso e em diversos ramos de negócios. Assim, para um mesmo ativo, diferentes taxas de depreciação serão utilizadas em negócios diversos, afastando-se da depreciação sugerida pelo Fisco. A referida hipótese foi refutada com base nos levantamentos empíricos. A pesquisa foi empreendida com a utilização de três métodos para obter as informações e os dados necessários: (i) pesquisa bibliográfica para a base teórica; (ii) pesquisa documental para o levantamento das normas vigentes; e (iii) pesquisa empírica para o levantamento dos dados em fonte primária

Since prehistoric times medicinal plants have been an invaluable source of medicinal preparations to mankind due to their respective chemical constituents. The family of the Mesembryanthemaceae is almost entirely endemic to southern Africa, and the subfamily Mesembryanthemoideae is a key source of previous reports of plants with traditional uses, both medicinal and culinary. In this thesis, phytochemical investigations were performed on a representative sample of the Mesembryanthemaceae genera and species, with emphasis on the subfamily Mesembryanthemoideae. The aims of this study were to record all ethnobotanical information on the medicinal and culinary uses of the Mesembryanthemaceae, and to isolate and identify alkaloids from selected taxa (especially those of medicinal interest) with specific emphasis on mesembrane alkaloids A review on the structural classification, biosynthesis and biological properties of the mesembrane alkaloids is presented in this dissertation. Experimentally, extracts of the 67 plants encompassing 15 genera and approximately 26 species which were investigated were prepared using one of two alkaloid extraction procedures, following which the extracts were screened for the presence of alkaloids by thin-layer chromatography. The extracts in which alkaloids were detected were analysed further using gas chromatography/mass spectrometry. Where possible, pure alkaloids were isolated from the crude alkaloid extracts and the pure compounds characterised using 1H and 13C nuclear magnetic resonance spectroscopy. Six of the mesembrane alkaloids as well as the tyrosine-derived non-mesembrane alkaloid hordenine were found to be distributed amongst the various genera and species of the Mesembryanthemoideae. The mesembrane alkaloids detected include mesembrine, mesembrenone, mesembrenol, mesembranol, 4’-Omethylsceletenone and 4,5-dihydro-4’-O-methylsceletenone. Within the genus Sceletium mesembrine, mesembrenone, mesembrenol, mesembranol and hordenine were identified. Mesembrine, mesembrenone, mesembranol and hordenine were also detected in Aridaria. The sceletenone derivatives 4’-Omethylsceletenone and 4,5-dihydro-4’-O-methylsceletenone as well as hordenine were identified as the major alkaloid constituents of the genus Aptenia. No alkaloids were detected in the species of Brownanthus and Prenia investigated in this study. Amongst the genera Mesembryanthemum, Phyllobolus and Psilocaulon, a random distribution of the alkaloid hordenine was observed. During the course of this study, the isolation and characterisation of 4’-O-methylsceletenone and 4,5-dihydro-4’-O-methylsceletenone from both Aptenia cordifolia and Aptenia lancifolia, as well as the non-mesembrane alkaloid hordenine from a number of species, was achieved. The two mesembrane alkaloids have been prepared synthetically, but this is the first report of the presence of the compounds in a natural source.
Prof. F.R. van Heerden

MSc (Microbiology)
Department of Microbiology
BACKGROUND: Medicinal plants form an important part of the Southern African cultural heritage. Indigenous populations, for example the Vha-Venda people, tend to use medicinal plants in formulations rather than western medicines for health and survival. In order to certify and give scientific credibility to the use of medicinal plants formulations used by Vha-Venda people for the treatment of diseases, several assays were carried out. The present study was aimed at assessing phytochemical content, antimicrobial, antioxidant and cytotoxic activities of four indigenous Venda medicinal plants in a formulation and compare their activity with each plant used individually. METHODS: Peltophorum africanum (roots), Pterocarpus angolensis (bark), Terminalia sericea (roots) and Ximenia caffra (roots) were collected from the Thohoyandou area. The collected plant parts were extracted with methanol and water respectively. Individual plant extracts and Five designed formulations were tested for their antimicrobial activity against Staphylococcus aureus ATCC 25923 (Methicillin Resistant), Staphylococcus aureus ATCC 33591(Methicillin Susceptible), beta lactamase producing Klebsiella pneumonia (ATCC 700603) and extended spectrum beta lactamase producing E. coli (ATCC 35218), four clinical isolates of Candida spp and Cryptococcus neoformans using the Broth dilution method. Minimum bactericidal concentration (MBC) of the extracts was determined by culturing the contents of minimum inhibitory concentration (MIC) on nutrient agar. Similarly, minimum fungicidal concentration (MFC) was also determined by culturing contents of MIC in sabouraud dextrose agar (SDA). Extracts were further assessed for their total phenolic content, total flavonoid content and Qualitative phytochemical analysis. The antioxidant ability of the plants extracts and formulations to scavenge free radical DPPH was also determined. The plant formulations were assessed for their anti-HIV activity using the reverse transcriptase colorimetric assay kit. Cytotoxicity against human lymphatic endothelial cells (HLEC) was determined using MTT assay. RESULTS: Methanolic and aqueous extracts of T. sericea exhibited the best antifungal and antibacterial activities whilst P. angolensis and X. caffra showed poor activities. Methanolic plant formulations showed good activities compared to aqueous formulations. However, Fractional Inhibition Concentration Index showed that there was 1 synergistic interaction, 25 additive interactions and 14 antagonistic interactions between the plant extracts. The methanolic formulation 3 showed the best overall phenolic content at 11.85±0.109 mgGAE/g whilst aqueous X. caffra extract showed the least content at 4.546±0.104 mgGAE/g. Higher total flavonoid contents were seen in methanolic formulation 4 at 2.75±0.02 mgQE/g. Qualitative phytochemical analysis revealed the presence of flavonoids, phenolics, terpenoids, tannins, saponins and steroids in 80% of the tested plant extracts and formulations. All plant extracts and formulations exhibited good antioxidant activity against DPPH. The methanolic formulation showed the best antioxidant activity with IC50 of 0.094 ± 0.33μg/ml. For anti- HIV inhibition, all formulations at 200μg/ml exhibited higher percentage of HIV-1 reverse transcriptase inhibition with methanolic mixture 3 being the best overall at 97.5% activity whilst aqueous mixture5 was the least active with 63.03% inhibition activity. Moreover, the best anti-HIV activity at 100μg/ml was exhibited by methanolic mixture 3 at 71% inhibition. Furthermore, aqueous X. caffra, mixture 2 inhibited 26% and 51% at 12.5mg/ml and 3.125mg/ml respectively. Peltophorum africanum and mixture 5 inhibited 34%, 54% and 43% at 3.125mg/ml, 6.25mg/ml and 12.5 mg/ml respectively of Human Lymphatic Endothelial cells growth. CONCLUSIONS: The results from the study indicated that most of the commonly used traditional medicinal Plants in the Venda region when mixed together have merit for use in traditional medical practice as they have shown good antimicrobial activities, good antioxidant xviii activities, good phytochemical activities and good cell proliferation activity. However some formulations showed antagonistic interaction against bacteria. Some Individual medicinal plants showed toxicity at higher concentrations against immune cells. Whereas formulations promoted cell proliferation, therefore, the use of such individual plants in the treatment of infections should be highly monitored as they may pose a health threat to normal immune cells. Generally, plants are potential pharmacological agents which needs to be preserved and harvested with care.
NRF

The aim of the study was to find benefits derived from the natural propagation and the use of guava plants and fruit by people living in rural areas of KwaZulu-Natal, looking at guava as a source of food, income, medicinal uses, shade, a source of fuel and use for agricultural purposes like fencing; and also assessing Conservation of the Agricultural Resource Act (CARA), Act 43 of 1983 relating to guava plant as invasive species. The Act states that all alien invader species and weeds should be controlled or removed depending on the category. CARA states that plants in category one are declared as alien invasive plants and are not allowed to grow on the land or appear on the water surface. Plants under this category may not be transported or allowed to disperse e.g. Psidium x durbanensis (Durban guava). Category two plants are invader species that have a potential value, plants that are used by the people as a source of income and food. These species can be retained if they grow in special areas demarcated for the purpose (an orchard). If these species are found outside demarcated areas they are to be removed e.g. Psidium guava (guava). Category three species are mostly plants with ornamental value which are not allowed to occur anywhere unless they were already in existence when the regulation came into effect e.g. Psidium guineense (brazillian guava) and Psidium cattleianum (strawberry guava). The study focused on selected areas of KwaZulu-Natal,: Umgungundlovu district municipality (Richmond local municipality) and Uthungulu district municipality. Richmond represented the midlands areas and Uthungulu the coastal areas to reflect two different areas of KwaZulu-Natal. To investigate this study the researcher used telephonic interviews with 23 Extension officials, questionnaires to guide focus group discussions which were conducted with 28 community groups that were involved in guava usage. Informal observation surveys were also carried out with five markets (stall holders) selling guava and guava products. Informal observations in two supermarkets and two home industries were also conducted. The results showed that people in rural areas still use this resource (guava) as a source of fuel (wood), medicine (especially the leaves and bark), fruit for own consumption (either processed or raw) and income generation. The impact of the legislation on rural poor communities is negative as guavas sustain livelihoods and the costs of applying for permits are prohibitive. People are illiterate yet they have to apply for special permits to plant this useful species because the regulation stipulates that guava plants must be controlled if dispersed outside demarcated areas.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

MSc (Botany)
Department of Botany
Since time immemorial plants have traditionally been used for various purposes in many parts of the world including Vhembe district, Limpopo province of South Africa. The use of C. abbreviata plants at Matsa village of Vhembe district also contributes significantly to the livelihood of the community. However, little work has been made in the past to properly document and promote the knowledge. The purpose of the present study was to record and analyse the ethnobotanical knowledge of C. abbreviata within the people of Matsa village around Nzhelele in Vhembe district. Semi-structured questionnaires were administered on 50 informants from different households selected randomly to gather data regarding the local name of C. abbreviata, the uses and its availability. Significantly higher number of medicinal use was reported by elderly people including both men and women as compared to middle-aged, younger people. Other use categories included firewood, furniture and joinery production and shade for people in the area. Awareness on the importance of the species should therefore be created amongst the people, especially the young ones. Understanding the ethnobotanical knowledge of indigenous species within an area is crucial towards development of its management plan.
NRF

MSc (Chemistry)
Department of Chemistry
Rauvolfia caffra Sond, a species of evergreen trees and shrubs in the dogbane family, (Apocynaceae), is used as a medicinal plant among traditional communities in many countries for the treatment of malaria, diabetes, coughs, gastrointestinal disturbances, skin infections, impotence, insomnia, diarrhoea, dysentery, scabies, worm infections, and both parasitic and microbial infections. Phytochemical studies have revealed that indole alkaloids are the major constituents of the stem bark. However, there are limited studies linking the compounds with the ethnomedicinal uses. The aim of this study is to isolate and characterize bioactive compounds from Rauvolfia caffra Sond. The highest phenolic content found in a fraction was 16.06±0.125 mg GAE/g, while the highest flavonoid content measured was 9.453±0.081 mg QE/g. In the DPPH free radical scavenging activity and reducing power tests, a lowest IC50 value of 0.022±0.003 μg/mL and IC0.5 value 0.518±0.044 μg/mL, respectively, was found. Six compounds were isolated from the stem bark, including lupeol, a pentacyclic tri-terpenoid isolated for the first time from the genus Rauvolfia; raucaffricine, a rare glycoalkaloid of the monoterpenoid indole class; N-methylsarpagine, an indole alkaloid isolated for the time from R. caffra and spegatrine, an indole alkaloid isolated for the first time from R. caffra, respectively. Concerning antimicrobial activity, the highest activity of a fraction was against B. cereus with MIC values as low as 12.5 mg/mL. One fraction at the tested concentration (250 μg/mL) decreased the viability of Plasmodium falciparum (4.149±6.979 %) with an IC50 value of 6.533 μg/mL. The crude extract and some fractions affected the viability of the Trypanosomes at the tested concentration (250 μg/mL), giving -0.133 ± 0.206 %, 11.334 ± 2.692 %, 1.026 ± 0.143 % and 20.769 ± 9.054 % with IC50 values of 18.50 μg/mL, 14.15 μg/mL, 15.58 μg/mL and 34.71 μg/mL, respectively. Furthermore, the fractions did not show significant cytotoxic effects at a concentration of 50 μg/mL.
NRF

PhD (Botany)
Department of Botany
Brackenridgea zanguebarica Oliv. (Ochnaceae) commonly known as “Yellow Peeling Plane”, is an important medicinal plant species, and one of the most threatened tree species that is endemic to Thengwe village in Vhembe District, South Africa. It is widely harvested for traditional purposes and difficult to propagate sexually and asexually. Nowadays, it has become threatened and this unique plant population is believed to be declining in the Brackenridgea Nature Reserve (BNR). According to the Red List of South African plants, B. zanguebarica is considered a critically endangered medicinal plant. All these facts combined with a lack of knowledge on the conservation of this species prompted this study on its conservation. To ascertain the effective conservation and proper management of this multipurpose tree, this study was conducted with the aim to improve its conservation strategy by investigating current threats to the existence of B. zangueberica, the chemical constituents from the different plant parts, the propagation methods of the species, and the factors delaying the germination of its seeds. In this study, an assessment of the current population threats was important as a first step in conservation; this would update the status of the species in its natural habitat. The current status of Brackenridgea zanguebarica was conducted through an extensive field survey in the Brackenridgea Nature Reserve (BNR), where a belt transect method was deployed to record quantitative information, while the harvesting damage was estimated using a sliding scale from 0 to 5. The structure of the populations in terms of the stem diameter size classes showed a bell shape vi pattern. About 60% of individuals showed some signs of plant parts extraction as the stem bark was reported to be the main plant part harvested. The population structure, however, was dominated by juvenile plants due to the selective harvesting of mature individuals; this hinders fruit production leading to poor or slow seed production. The present study aimed to compare the chemical constituents and the antimicrobial activities of some parts of this plant species. The extracts were screened for phytochemicals using standard methods. Thin-layer chromatography (TLC) was carried out to compare the chemical constituents using various solvent systems of varying polarity. Agar well diffusion and broth microdilution methods were used to evaluate the antimicrobial activity and the minimum inhibitory concentrations (MIC) of plant extracts respectively, against three bacteria and four fungi. The phytochemical analysis revealed a close similarity of various phytoconstituents of the three plant parts (stem bark, twigs and leaves). TLC analysis showed a slight difference in the acetone extract of different plant parts with more bands on the leaves than the stem bark and twigs. Acetone extracts of the three plant parts exhibited varying degrees of antimicrobial activity against Staphylococcus aureus and Candida glabrata, while none of the extracts showed any activity against Escherichia coli, Klebsiella pneumonia, Candida albicans, C. krusei, and C. parapsilosis. However, analysis of the antibacterial activity of various extracts revealed that the best inhibitory activity was produced by the stem bark extract compared to the leaf and twig extract. vii The sustainable way to meet the growing demand of Brackenridgea zanguebarica is to increase its availability through propagation practices. Unfortunately, the conservation of B. zanguebarica is hampered by lack of information on how it can be propagated. Sexual and asexual propagations were conducted to determine an efficient method to increase the number of individuals of this plant species. Seed propagation was carried out to study the effect of various pre-treatments on germination, in order to understand the germination requirements; vegetative propagation was conducted to assess if B. zanguebarica could be successfully propagated via stem cuttings if the appropriate growth hormones and growing media were applied. Brackenridgea zanguebarica seed did not germinate at all under any of the conditions tested. However, the results, showed the potential of propagating this species from stem cutting despite the poor results obtained. Thus B. zanguebarica was found to be difficult to propagate sexually and asexually. Seeds serve as a means of reproduction and a vital element to ensure the survival of plant species. Seed germination is controlled by a number of factors. The propagation of B. zanguebarica via seed is very difficult and research has not been undertaken to understand possible factors that may delay its germination. This study was aimed to investigate and describe both the morphological and anatomical features of B. zanguebarica seed, in order to identify structural features implicated in its poor germination. To achieve this goal, a morphological and anatomical study was conducted based on the observation of seeds under a scanning electron microscope (SEM) and light microscopy (LM). Water uptake potential was assessed by the increase in seed mass. The morpho-anatomical analysis indicated that some structures of the seed, such as seed coat, and the presence of endosperm viii surrounding the embryo that consisted of two prominent cotyledons, seem to greatly hinder the germination of this species. The research findings provided information regarding the seed structure which is one important step in identifying useful techniques to improve seed germination for conservation purposes.
NRF

MSCAGR ( Plant Production)
Many high valued tree species of medicinal significance in the Limpopo Province, South Africa exhibit seed dormancy, and also contain aromatic oils which inhibit rooting of their stem cuttings. These plant species are under pressure due to human over-exploitation. The main objective of this study was to investigate effects of rooting hormones on the rooting ability that will help in domesticating some of the selected high valued medicinal plants, Elaeodendron transvaalense (bushveld saffron), Brackenridgea zanguebarica (yellow peeling plane), and Warburgia salutaris (pepper-bark tree). Stem cuttings of these plant species were prepared and treated with various concentrations (500, 1000 and 2000 ppm) of IBA, IAA and NAA in different growth media (Natural soil, farm soil and hygromix) at a nursery house. 180 experimental units were sown and arranged in Randomized Complete Block Design (RCBD), each treatment replicated five times and then monitored for a period of three months. Data were only obtained from Brackenridgea zanguebarica as other species dried up two weeks after sprouting. The two variables measured from the experiments were sprouted stems and number of leaves. The data obtained were subjected to analysis of variance and least significant difference (LSD) at 5% probability level was used to compare treatment using STATISTICA software analysis package. The hormone, hormone concentration, growth media and their interactions had effect on sprouted stems and number of leaves produced on Brackenridgea zanguebarica cuttings, with no record of rooting ability. IBA (500 ppm and 1000 ppm) and control (without rooting hormone) showed high significant results with natural soil and farm soil in terms of leaf production compared to the hygromix, which is significantly lower from others. IBA at the various concentrations (500, 1000 and 2000 ppm) and the control gave the highest percentage sprouted stem on both natural soil and farm soil as compared with other hormones at the same
NRF

PhD (Chemistry)
Department of Chemistry
Terminalia sericea Burch. ex. DC (Combretaceae) is one of the 50 most popular medicinal plants in Africa. The fruit, leaves, stems and roots are commonly used for the treatment of cough, skin infections, diabetes, diarrhoea, venereal diseases and tuberculosis. However, the roots are most commonly used in the preparation of traditional medicines. Pharmacological studies have revealed that the crude root extracts display antibacterial activity against several Gram-positive and Gram-negative bacteria. Anolignan b, termilignan b and arjunic acid are reported to be the major antibacterial constituents present in the roots. Other compounds isolated from the roots include resveratrol-3-rutinoside, sericic acid, sericoside and arjunglucoside I. Authorities worldwide, including the Medicines Control Council of South Africa, have begun to regulate herbal drugs sold in the form of commercial formulations. Quality control of herbal drugs is challenging, since the chemical profiles of the raw materials may vary, depending on the origin of the plant material and the way that it was handled and processed. The chemistry, in turn, impacts on the safety and efficacy of the plant material. To date, there are no available data on parameters that can be used to standardise the quality of T. sericea raw materials. The aim of this study was therefore to provide information on the variation of the chemical constituents that contribute to the biological effects of the roots of T. sericea and also establish its safety. Since the compounds previously isolated from the roots were not commercially available, isolation of the major constituents of the roots was undertaken to obtain analytical standards. A crude dichloromethane:methanol (1:1) extract was initially fractionated using silica gel column chromatography, where after, some of the fractions were further purified using silica gel and Sephadex LH-20 column chromatography. Final purification of the enriched fractions was achieved using preparative high performance liquid chromatography coupled with mass spectrometry (prep-HPLC-MS). The structures of these compounds were subsequently elucidated using one- and two- dimensional nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry and identified as sericic acid (340 g), sericoside (500 g), resveratrol-3-rutinoside (240 mg) and arjunglucoside I (74 mg). The chemical variation within the crude root extracts of samples (n = 42) from ten populations in the Limpopo Province of South Africa, was determined using ultra performance liquid chromatography-mass spectrometry (UPLC-MS). A method was developed for the simultaneous determination of sericic acid, resveratrol-3-rutinoside, sericoside and arjungluicoside I in the extracts using UPLC with photodiode array detection (PDA). The method was validated according to the guidelines of the International Council for Harmonisation (ICH). A regression coefficient (R2) of 0.998 was obtained for sericic acid, resveratrol-3- rutinoside and arjunglucoside I, while the R2 value for sericoside was 0.999, indicating a linear relationship between the concentration and the detector response. Satisfactory limits of detection for sericic acid (25.2 ng/mL), sericoside (11.6 ng/mL), resveratrol-3-rutinoside (23.3 ng/mL) and arjunglucoside I (8.81 ng/mL) were determined. Recoveries of 98 % and 80% were obtained for samples spiked with 12.5 μg/mL and 25 μg/mL of resveratrol-3-rutinoside, respectively, indicating that the method is accurate. The intra- and inter-day variation in resveratrol-3-rutinoside concentration, measured over three days, indicated excellent analytical precision, since all the relative standard deviations were below 0.70 %. The quantitative data revealed that sericic acid (1.59 to 8.45 mg/g), sericoside (2.07 to 20.17 mg/g), resveratrol-3-rutinoside (0.65 to 29.82 mg/g) and arjunglucoside I (0.86 to 8.44 mg/g dry weight) were the major constituents of the root samples, but their concentrations were highly variable. Chemometric analysis of the aligned UPLC-MS data was used to investigate similarities and differences in the chemical profiles of the samples using an untargeted approach. A principal component analysis (PCA) model was constructed and subsequently hierarchical cluster analysis (HCA) indicated the presence of two main groups, which were found to be independent of the populations to which the samples belong. Classes, based on the HCA class identifiers, were subsequently assigned to the samples, and an orthogonal projection to latent structures-discriminant analysis (OPLS-DA) model was then constructed, (R2 cum = 0.996 and Q2 cum = 0.967). The corresponding loadings plot allowed sericic acid, sericoside and resveratrol-3-rutinoside to be identified as biomarkers associated with the first group. Quantitative, rather than qualitative differences were responsible for the observed clustering pattern. Techniques that could be applied in quality control protocols for T. sericea root were investigated. High performance thin layer chromatography (HPTLC) analysis of the root extracts was optimised by testing different developing solvents and visualization reagents. The presence of the sericic acid (Rf = 0.80), sericoside (Rf = 0.49) and resveratrol-3-rutinoside (Rf = 0.36) were clearly visible on the plates. There were visible variations in the concentrations of resveratrol-3-rutinoside in representative samples from the 10 populations, corresponding to the UPLC results. The powdered samples were then analysed by mid-(MIR) infrared spectroscopy. Chemometric analysis of the data revealed no definitive clustering pattern. Partial least squares-discriminant analysis (PLS-DA) calibration models were established from the MIR spectral data combined with the accurate UPLC-values, for the prediction of the sericoside (R2Y = 0.848, Q2 = 0.757, RMSEP = 2.70 mg/g) and resveratrol-3-rutinoside (R2Y = 0.794, Q2 = 0.695, RMSEP = 4.37 mg/g) concentrations in powdered root samples. The antibacterial activities of the root extracts, column fractions and isolated compounds were determined using three Gram-positive and five Gram-negative bacteria, all selected due to their ability to cause intestinal and skin disorders. Extracts and fractions containing high concentrations of sericic acid exhibited the highest activities against Klebsiella pneumoniae (ATCC 13883), Pseudomonas aeruginosa (ATCC 27858), Salmonella typhimurium (ATCC 14028), Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12223) and Shigella sonnei (ATCC 9292). The pure compound (sericic acid) was highly active against S. sonnei (MIC 0.078 μg/mL), a Gram- negative bacterium. There were no variations in the activity of the crude extracts against B. cereus and P. aeruginosa, while the MIC values obtained against S. typhi were variable and ranged from 0.25 to 1.0 mg/mL. Sericoside and resveratrol-3-rutinoside did not display any activity. The anti-oxidant activities were evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) and reducing power assays. The anti-oxidant assays revealed that resveratrol-3- rutinoside exhibited lower activity (DPPH = 186 μg/mL; RP = 184 μg/mL) compared to the crude extract (DPPH = 22.3 μg/mL; RP = 24.4 μg/mL) and ascorbic acid (DPPH = 11.3 μg/mL, RP = 145 μg/mL). Sericic acid and sericoside did not display any anti- oxidant activities. The variation in the anti-oxidant activities (4.58 to 26.0 μg/mL) of the samples from different populations was an indication of chemical variability. A toxicity study of the raw powdered plant material was conducted using vervet monkeys (Chlorocebus pygerythrus). Biochemical analysis (liver function tests, kidney function tests and hematology), physical and physiological examinations were conducted. The subjects were fed a normal diet supplemented with T. sericea root powder (2.14 g/kg per day) for 120 days, where after the diet was returned to normal (washout) for another 30 days. The treatment groups presented with elevated serum enzymes at Week 4, followed by the reduction of the elevated serum enzymes levels at Week 12. These results indicate short-term hepatotoxic effects, followed by hepatoprotective activity. Reduction of the serum glucose at Week 4 suggests hypoglycemic potential. However, elevated serum creatinine levels indicated possible nephrotoxicity. In conclusion, this study has indicated the variability in the chemical constituents of the roots of T. sericea, which affects the antibacterial and anti-oxidant activities. Sericic acid, resveratrol-3-rutinoside, and sericoside were, for the first time, identified as biomarkers that can be used for the quality control of raw root material to be used in herbal products. Sericic acid was also found to be the main antibacterial constituent of the roots. The hepatoprotective, nephrotoxic and hematotoxic effects observed in monkeys to which the root powder had been administered is cause for concern.
NRF