Letteratura scientifica selezionata sul tema "Endemic plants nutritional aspects south africa"

ABSTRACTKersting’s groundnut [Macrotyloma geocarpum(Harms) Marechal & Baudet] is a neglected indigenous African legume adapted to growth in N-deficient soils due to its ability to fix atmospheric N2via symbiosis with rhizobia. Despite its nutritional and medicinal uses, to date there is little information on the phylogeny and functional traits of its microsymbionts, aspects that are much needed for its conservation and improvement. This study explored the morphogenetic diversity, phylogenetic relationships, and N2-fixing efficiency of Kersting’s groundnut rhizobial isolates from contrasting environments in Ghana, South Africa, and Mozambique. BOX-PCR fingerprinting revealed high diversity among the rhizobial populations, which was influenced by geographic origin. Of the 164 isolates evaluated, 130 BOX-PCR types were identified at a 70% similarity coefficient, indicating that they were not clones. Soil pH and mineral concentrations were found to influence the distribution of bradyrhizobial populations in African soils. Phylogenetic analysis of 16S rRNA genes and multilocus sequence analysis of protein-coding genes (atpD,glnII,gyrB, andrpoB) and symbiotic genes (nifHandnodC) showed that Kersting’s groundnut is primarily nodulated by members of the genusBradyrhizobium, which are closely related toBradyrhizobium vignae7-2T,Bradyrhizobium kavangense14-3T,Bradyrhizobium subterraneum58-2-1T,Bradyrhizobium pachyrhiziPAC48T, the type strain ofBradyrhizobium elkanii, and novel groups ofBradyrhizobiumspecies. The bradyrhizobial populations identified exhibited high N2fixation and induced greater nodulation, leaf chlorophyll concentration, and photosynthetic rates in their homologous host than did the 5 mM KNO3-fed plants and/or the commercialBradyrhizobiumsp. strain CB756, suggesting that they could be good candidates for inoculant formulations upon field testing.IMPORTANCERhizobia play important roles in agroecosystems, where they contribute to improving overall soil health through their symbiotic relationship with legumes. This study explored the microsymbionts nodulating Kersting’s groundnut, a neglected orphan legume. The results revealed the presence of different bradyrhizobial populations with high N2-fixing efficiencies as the dominant symbionts of this legume across diverse agroecologies in Africa. Our findings represent a useful contribution to the literature in terms of the community of microsymbionts nodulating a neglected cultivated legume and its potential for elevation as a major food crop. The presence of potentially novel bradyrhizobial symbionts of Kersting’s groundnut found in this study offers an opportunity for future studies to properly describe, characterize, and delineate these isolates functionally and phylogenetically for use in inoculant production to enhance food/nutritional security.

Thesis (PhD)--University of Stellenbosch, 2010.
The aim of the study was to assess the importance of spatial and temporal variation in diet quality and abundance for determining sustainable stocking rates on commercial, communal and game ranches in a semi-arid savanna, with the ultimate goal of avoiding land degradation in the long term, to provide sustainable livelihoods in rangelands and to make policy that will help in managing the available natural resources in the rangelands. Thus, firstly the effects of grazing, fire, nitrogen and water availability on nutritional quality of grass in semi-arid savanna was assessed. Secondly, spatial and temporal variation in plant quantity and quality among management (commercial, communal and game) types and habitat types (open savanna, rocky, shrubby and pans) and stocking rates in different management types were determined. Thirdly, the quality and quantity of variation inside and outside herbivore exclosures among commercial, communal and game management and habitat types in the semi arid savanna were estimated. Fourthly, faecal profiling was used to assess the effects of different management types on diet quality in semi-arid savanna. Lastly, policy based on the results of the present study was formulated.

Thesis (MScMedSc)--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: Introduction: Athrixia phylicoides is an aromatic, indigenous shrub with high antioxidant content and numerous indigenous medicinal properties inferred by ingestion of an herbal brew of the plant. Commercialization of “bush tea” (derived from A. phylicoides) holds economic and developmental potential for indigenous communities provided the safety and efficacy of the herbal tea is established. Recently A. phylicoides has been shown by McGaw et al. (2007) to have similar antioxidant activity to Rooibos tea, and a unique, new flavonol (i.e. a polyphenolic antioxidant plant metabolite) 5-hydroxy-6,7,8,3′,4′,5′-hexamethoxyflavon-3-ol, unique to A. phylicoides, was isolated by Mashimbye et al. in 2006. With changes in the socio-economic climate and a new trend in merging Western lifestyle with traditional practices, new interest has been shown in herbal/natural remedies. Study Aim: The aim of this study was to firstly, determine the in vitro effect of A. phylicoides aqueous extract on glucose metabolism in cell lines that mimic the three key organs implicated in glucose homeostasis. Secondly, the study aimed to determine the potential ex vivo antioxidant and anti-inflammatory effect of the extract in pancreatic β-cells and peripheral mononuclear cells respectively. Methods: Leaves and fine twigs of A. phylicoides were processed into an aqueous extract. C2C12, Chang and 3T3-L1 cells were cultured under standard conditions and acutely exposed to increasing concentrations of extract and water vehicle, as well as 1 μM insulin and metformin as positive controls. Glucose uptake from 8 mM glucose culture media was determined using a fluorimetric oxidase method. Radioactive 14C-glucose oxidation to 14CO2 and determination of glycogen content of cells were used to assess the fate of intracellular glucose. RT-PCR was used to assess the extract effect on insulin-signalling gene expression. The antioxidative effect of A. phylicoides extract in pancreatic β-cells isolated from Wistar rats was determined by measuring nitric oxide (NO) production in response to hyperglycemic conditions. NO was labelled with diaminofluorocein diacetate and fluorescence was measured using flow cytometry. Insulin secretion of pancreatic β- cells was measured using radio-immuno assay. The anti-oxidative effect of the extract in lipopolysaccharide-stimulated peripheral mononuclear cells isolated from Wistar rats was determined by measuring the production of TNF-α using an ELISA kit. Results: C2C12 myocytes showed maximal increased glucose uptake at the 0.05 μg/μl extract concentration (228.3% ± 66.2, p<0.001). In Chang cells, A. phylicoides extract maximally increased the amount of glucose taken up at the 0.05 μg/μl concentration (134.5% ± 2.5, p<0.05). In 3T3-L1 cells, the extract maximally increased the amount of glucose taken up at the 0.025 μg/μl concentration (143.5% ± 10.3, p<0.001). An extract-induced increase in insulin receptor and glucose transporter four expression was seen in C2C12 myocytes. The oxidation of 14C-glucose to 14CO2 by C2C12 myocytes was maximally increased following acute exposure to the extract at 0.1 μg/μl (2919.3 fmol/1x10^6 cells ± 428, p<0.01). The oxidation of 14C-glucose to 14CO2 by Chang cells was maximally increased following acute exposure to extract at 0.1 μg/μl (4476.7 fmol/1x10^6 cells ± 1620, p<0.05); as seen in the C2C12 cells. A. phylicoides extract increased glycogen storage at all three concentrations tested in Chang cells, but maximally at the 0.025 μg/μl concentration (13.6 μg/1x10^6 cells ± 0.7, p<0.05). A. phylicoides extract did not have any measurable effect on the oxidative status of β-cells or the anti-inflammatory status of peripheral mononuclear cells. The extract did show an increase in first phase insulin secretion of β-cells in hyperglycemic conditions, although it was not significant. Conclusion: Athrixia phylicoides aqueous extract stimulates in vitro glucose uptake and metabolism in an insulin-mimetic manner, suggesting that this extract could potentially be beneficial to type two diabetics as an adjunct therapy.
AFRIKAANSE OPSOMMING: Inleiding: Athrixia phylicoides is 'n aromatiese, inheemse struik met 'n hoë antioksidant inhoud. Vele tradisionele medisinale eienskappe is gekoppel aan die ingestie van 'n kruie brousel van die plant, wat ook bekend as “bostee” is. Kommersialisering van “bostee” hou ekonomiese en ontwikkelings potensiaal in vir inheemse gemeenskappe mits die veiligheid en effektiwiteit van die kruietee bevestig kan word. McGaw et al. (2007) het onlangs bevind dat A. phylicoides se antioksidant aktiwiteit vergelykbaar is met die van rooibostee. 'n Unieke nuwe flavonol ('n polifenoliese antioksidant plant metaboliet) 5-hydroksie-6,7,8,3′,4′,5′-hexamethoksieflavon-3-ol, eie aan A. phylicoides, is deur Mashimbye et al. in 2006 geïsoleer. Met veranderings in die sosio-ekonomiese klimaat en 'n nuwe tendens om die westerse lewenstyl met tradisionele gebruike aan te vul word nuwe belangstelling in kruie/natuurlike rate ondervind. Studie Doelwitte: Die doelwitte van hierdie studie was eerstens om die in vitro effek van A. phylicoides waterekstrak op die glukosemetabolisme van drie sellyne wat die sleutel organe naboots wat glukosehomeostase beheer, te bepaal. Tweedens, is die potensiële ex vivo antioksidant en anti-inflammatoriese effek van die ekstrak op pankreatiese β-selle en perifere mononuklêere-selle onderskeidelik ondersoek. Metodes: n Waterige ekstrak is van die blare en fyn takkies van A. phylicoides berei. C2C12, Chang and 3T3-L1 selle is gekultuur onder standaard kondisies en akuut blootgestel aan stygende ekstrakkonsentrasies. Water het as kontrole gedien, met 1 μM insulien en metformien as positiewe kontroles. Glukose opname vanuit 8 mM glukose kultuurmedia is bepaal deur 'n fluorimetriese oksidase metode. Radioaktiewe 14C-glukose-oksidasie na 14CO2 en die bepaling van die glukogeen inhoud van selle is gebruik om die lot van intrasellulêre glukose te bepaal. RT-PKR is gebruik om die effek van die ekstrak op die insulien-seinpad geen-uitdrukking te ondersoek. Die antioksidant effek van A. phylicoides ekstrak in pankreatiese β-selle geïsoleer van Wistar rotte, is bepaal deur stikstofoksied (NO) produksie na aanleiding van hiperglukemiese kondisies. NO is met diaminofluorosien diasetaat gemerk en die fluoresensie gemeet deur vloeisitometrie. Insulien afskeiding deur die pankreatiese β-selle is deur radio-immuno metode bepaal. Die anti-oksidatiewe effek van die ekstrak op lipopolisakkaried-gestimuleerde perifere mononuklêere-selle afkomstig van Wistar rotte is bepaal deur die meting van TNF-α produksie met 'n ELISA kit. Resultate: C2C12 miosiete het 'n maksimale toename in glukoseopname by 'n 0.05 μg/μl ekstrakkonsentrasie (228.3% ± 66.2, p<0.001) gehad. Dieselfde ekstrakkonsentrasie het maksimale toename in glukoseopname in Chang selle (134.5% ± 2.5, p<0.05 getoon. In 3T3-L1 selle is maksimale toename in die glukoseopname by 'n konsentrasie van 0.025 μg/μl (143.5% ± 10.3, p<0.001) bereik. 'n Ekstrak-geinduseerde verhoging in die insulienreseptor en glukosetransporter vier ekspressie is in C2C12 miosiete waargeneem. Die oksidasie van 14C-glukose na 14CO2 deur C2C12 miosiete is maksimaal verhoog deur akute blootstelling aan die ekstrak by 'n konsentrasie van 0.1 μg/μl (2919.3 fmol/1x10^6 cells ± 428, p<0.01). Die oksidasie van 14C-glukose na 14CO2 deur Chang selle was maksimaal verhoog deur akute blootstelling aan die ekstrak by 'n konsentrasie van 0.1 μg/μl (4476.7 fmol/1x10^6 cells ± 1620, p<0.05) soos gevind in die C2C12 selle. Die ekstrak het glukogeenstoring verhoog teen al drie die konsentrasies waarteen getoets is in Chang selle, maar 'n maksimale effek is gevind by 'n konsentrasie van 0.025 (13.6 μg/1x10^6 cells ± 0.7, p<0.05). A. phylicoides ekstrak het nie 'n meetbare effek op die oksidatiewe status van β-selle of die anti-inflammatoriese status van perifere mononuklêere-selle gehad nie. Die ekstrak het wel 'n verhoging in die eerstefase insuliensekresie van β-selle in hyperglukemiese kondisies gehad, alhoewel die verhoging nie statisties betekenisvol was nie. Afleiding: Athrixia phylicoides waterekstrak stimuleer in vitro glukoseopname en metabolisme in 'n insulin-mimetiese manier, wat beteken dat die ekstrak potensiëel voordele vir tipe twee diabete kan inhou as aanvullingsterapie.

The nutritional value of indigenous fodder plants has been reported to be high and constant throughout seasons as compared to grasses. The aim of this study was to evaluate the nutritional value of three tree species of the Combretum family, C. apiculatum, C. molle, C. zeyheri, and two other plant species, Colophospermum mopane and Pelthophorum africanum. This would be achieved through the determination of chemical composition (ash, dry matter (DM), organic matter (OM), CP, acid detergent fibre (ADF), acid detergent lignin (ADL), acid detergent indigestible nitrogen (ADIN), condensed tannins (CT) and ether extract (EE)), rumen degradability and in vitro digestibility of the leaves of these species were determined. The foliage of the tree species were collected in and north of Pretoria. After rinsing a portion of each species' samples, they were freeze-dried, prepared for analyses and stored as fresh samples pending analyses. The in situ analysis was done as blanket analysis over all the seasonal samples of each plant species excluding Mopane. This was done because the leaf materials collected were not enough to conduct a complete trial for each seasonal collection. Therefore sites were not considered for statistical analyses hence species were compared across seasons only. All the plant species exhibited a wider range of the chemical fractions. Their ash concentrations ranged from 30.3 g/kg DM for C. zeyheri to 85.8 g/kg DM forC. molle, NDF 270.3 g/kg DM for C. apiculatum to 410.1 g/kg DM for P africanum, ADF 208.1 g/kg DM P. africanum to 375.2 g/kg DM for C. molle. Their CP ranged from 62.9 g/kg DM for C. molle to 172 g/kg DM for Mopane, CT 65.6 mg sorghum tannin equivalent (STE)/g DM for C. zeyheri to 660.3 mg STE/g DM for Mopane, ADIN ranged from 1.2 g/kg DM for C. apiculatum to 3.3 g/kg DM in C. mopane. The range of some mineral concentrations of all the plants was not as wide as the other fractions. The concentrations of Ca ranged from 7.9 g/kg DM for Mopane to 16 g/kg DM for C. molle, K 1.2 g/kg DM Mopane to 7.8 g/kg DM for C. molle, Mg 1.4 g/kg DM for C. molle to 3.8 g/kg DM for C. apiculatum. The concentrations of Cu ranged from 7.8 mg/kg DM for C. molle to 66 mg/kg DM for C apiculatum, Fe 169 mg/kg DM for Mopane to 435 mg/kg DM for C. zeyheri. The in vitro dry matter digestibility (IVDOM) ranged from 52.6% for Mopane and C. zeyheri to 64.1% for C. apiculatum. The in situ degradability fractions for the Combretum species ranged as follows: soluble fraction was 4.02% for C. apiculatum to 25.4% for C. zeyheri; degradable fraction was 34% for C. zeyheri to 44% for C. apiculatum and the extent of nitrogen (N) degradation was 47% for C. apiculatum to 60% for C. zeyheri. The concentrations of the chemical fractions of all the plants did not show a particular seasonal trend. However significant and insignificant variations were observed. The CP concentrations were almost constant implying a better N supply to animals throughout the seasons. The CT concentrations were not high enough to adversely affect the digestibility of protein. The Combretum species showed reasonable N degradability in situ, C. zeyheri the most degradable. The plant's digestibility values were within the range of browse plants. These results cannot be conclusive on the eventual nutritional value of these plants to the animals. Further studies would be necessary to quantify the availability of the chemical fractions and the foliage's palatability to the animals.
Dissertation (M Inst. Agrar (Animal Production))--University of Pretoria, 2005.
Animal and Wildlife Sciences
unrestricted

MSCPNT
Department of Nutrition
Hypertension remains a major public health problem that needs different comprehensive health strategies to deal with it. Indigenous vegetables, Blackjack in particular, have been shown to possess anti-hypertensive properties that are attributed to bioactive chemical substances such as phytochemicals, fiber, antioxidants as well as micronutrients that include potassium, magnesium, calcium, vitamin C, zinc, iron and copper. The use of indigenous vegetables in combination with the conventional hypertension treatment may reduce hypertensive conditions; hence, the purpose of this study was to determine Blackjack nutritional knowledge and consumption by hypertensive patients. A cross-sectional study employing both quantitative and qualitative methods was conducted on 275 hypertensive participants at Mphambo and Mutale Health Centers, Vhembe District of Limpopo Province, South Africa. A questionnaire was used to collect data on participants’ Blackjack nutritional knowledge, Blackjack availability around their households as well as their Blackjack consumption patterns and nutritional status. The Blackjack nutritional knowledge data was triangulated with focus group discussions and participants’ nutritional status was assessed by anthropometric and dietary intake methods. The body mass index (BMI) was calculated and dietary intake frequency from selected foods was determined. Blood pressure was measured using Microlife automatic blood pressure monitor. The findings indicated that most hypertensive participants had poor knowledge of the nutritional importance of Blackjack and its associated medicinal contribution on hypertension management. Participants were unable to mention different diseases that can be prevented or managed by Blackjack, which was mostly consumed once a week with porridge during the summer season. Hypertensive patients were consuming high amounts of sodium and less amounts of minerals that are known to regulate blood pressure, such as potassium and magnesium. Hypertensive patients had high prevalence of overweight and obesity and most were either in hypertension stage 1 or stage 2. Lack of Blackjack nutritional knowledge may have contributed to a decreased consumption of Blackjack by hypertensive patients. The health professionals should promote the nutritional benefits of Blackjack in rural areas, particularly to hypertensive patients to raise awareness of Blackjack’s benefits in disease prevention and management.
NRF

South Africa has over 19 500 different indigenous plant species. Most of these are of ethnobotanical significance and are still used by local rural communities as medicine, food and for making beverages. The relatively little research that has been conducted on indigenous plant species has focused mainly on their medicinal potential. However, in view of the rapidly growing size of the global and local beverage industry and their constant search for new products, beverage-making indigenous plant species may have commercial development potential. To date, no detailed studies have been conducted on these plants, especially in the species-rich Limpopo province. The aim of this study was, therefore to evaluate the potential of indigenous plants for commercial beverage production. In order to achieve this, a survey was conducted in the Limpopo province to identify beverage-making plants and to document beverage preparation methods. Selected beverages were analysed and evaluated for their nutrient and sensory characteristics and a market product acceptability survey was conducted to identify those beverages with the greatest potential for development. Sixty three different beverage-plant species were identified in three study areas within the Limpopo province. These were used for the preparation of teas, fruit juices and alcoholic beverages. Plants that received further research attention were selected on the basis of their status as indigenous plants, frequency of use, nature of harvesting methods and availability. Some of the selected beverages were found to be rich in nutrients, especially with respect to vitamin C and mineral content. Furthermore, sensory analyses and market surveys indicated that four species, namely, Doyvalis caffra, Garcinia livingstonei, Grewia flavescens and Englerophytum magalismontanum have potential for further development for the beverage industry while Athrixia phylicoides has commercialisation potential as a herbal tea. However, further research is required to improve and refine preparation methods and to ensure compliance with quality standards. The availability of sufficient plant material for the industry must also be ensured. This research has indicated that South African indigenous plants have untapped market potential for the beverage industry which, if developed sustainably, could contribute to economic growth of the rural parts of South Africa.
Environmental Sciences
D. Ed. (Environmental Management)

This study was undertaken to redress the scant knowledge regarding the chemistry and mode of action of pregnancy-related traditional medicines, or isihlambezo (Zulu), which are used by 60 to 80% of women in South Africa. The three selected plants are among the six most frequently cited species from the approximately 90 used by traditional healers. The purpose of the study was to identify components which could cause uterine contractions, those with nutritional value for the foetus and mother, and those with any toxic effects. Plant root extracts were purified via silica gel column chromatography and bioassays were carried out on the fractions, using isolated rat uterine tissue. Purified compounds were identified via spectral techniques, and some were characterised by comparison to authentic standards using HPLC, and others by matching their GC-MS spectra to library standards. Thirty-eight compounds were identified in total, the majority of these being novel to the species concerned. Those isolated from Combretum kraussii were 1 sitosterol, 2 combretastatin, 3 3',4-tri-O-methylellagic acid, 4 combretastatin B-1, 5 combretastatin A-1, 6 3,3'-di-O-ellagic acid lactone, 7a ellagic acid lactone, 7b ellagic acid, 8 and 9 a mixture of combretastatin B-1 and A-1 glucosides, 10 and 11 partly characterised glucosides of ellagic acid. Those isolated from Gunnera perpensa were 12 3',4-tri-methylellagic acid, 13 ellagic acid lactone, 14 1,1'-biphenyl-4,4'-diacetic acid, 15 p-hydroxybenzaldehyde, 16 Z-methyl lespedezate, 17 and 18 partly characterized higher glucosides of Z-methyllespedezate. Those isolated rom Rhoicissus tridentata were 19 (-)-epigallocatechin, 20 (+)-gallocatechin, 21 procyanidin B3, 22 procyanidin B4, 23 (+)-catechin hydrate, 24 (+)-mollisacacidin, 25 (+)-epicatechin, 26 fisetinidol-(4a-8) catechin, 27 (-)-fisetinidol, 28 fisetinidol-(4b-8)catechin, 29 gallic acid, 30 epicatechin-3-0-gallate, 31 partly characterized hydrogel of glucose, 32 sitosterol, 33 sitosterolin, 34 y-sitosterol, 35 oleanolic acid, 36 lupen-3-one, 37 20-epi-y-taraxastananol and 38 triacontanol. The compounds with the greatest in vitro uteroactivity were predominantly proanthocyanidins or phenolic glucosides. It is proposed that effects of phenolic glucosides could be due to the interaction of the sugar moiety as well as the phenolic moiety with the receptor site in muscle tissue. The corresponding phenolic aglycones isolated were only moderately uterotonic, or unreactive by comparison. Non-polar compounds such as sitosterol and sitosterolin showed minimal enhancement of the uterine response at low concentrations, and inhibition at higher concentrations. Aqueous root extracts of the plants were all found to be non-toxic according to cell-viability tests using monkey vero cells and human fibroblasts. Extracts are therefore considered safe for human consumption, although it is recommended that Rhoicissus tridentata be used with caution because it showed the lowest cell viability of the three species, and uterine hyperstimulation has been attributed to this species, as well as CNS depression and respiratory arrest. Ions which could be nutritionally beneficial in pregnancy, calcium, iron, and phospate, were present in low in aqueous extracts. Levels of calcium and potassium ions were considered to be too low to directly stimulate uterine muscle. Proanthocyanidins, combretastatins, ellagic acid derivatives and phytosterols, with health-promoting properties, were also identified.
Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2004.