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Journal articles on the topic 'Natural Products (Structure - Determination)'

Author: Grafiati

Published: 4 June 2021

Last updated: 17 February 2022

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1

Biemann, Klaus. "Structure Determination of Natural Products by Mass Spectrometry." Annual Review of Analytical Chemistry 8, no. 1 (July 22, 2015): 1–19. http://dx.doi.org/10.1146/annurev-anchem-071114-040110.

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2

Chhetri, Bhuwan Khatri, Serge Lavoie, Anne Marie Sweeney-Jones, and Julia Kubanek. "Recent trends in the structural revision of natural products." Natural Product Reports 35, no. 6 (2018): 514–31. http://dx.doi.org/10.1039/c8np00011e.

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3

Li, Gao-Wei, Han Liu, Feng Qiu, Xiao-Juan Wang, and Xin-Xiang Lei. "Residual Dipolar Couplings in Structure Determination of Natural Products." Natural Products and Bioprospecting 8, no. 4 (June 25, 2018): 279–95. http://dx.doi.org/10.1007/s13659-018-0174-x.

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4

Linington, Roger G., Julia Kubanek, and Hendrik Luesch. "New methods for isolation and structure determination of natural products." Natural Product Reports 36, no. 7 (2019): 942–43. http://dx.doi.org/10.1039/c9np90023c.

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The Natural Product Reports themed issue on New Methods for Isolation and Structure Determination of Natural Products is introduced by the Guest Editors, Roger Linington, Julia Kubanek and Hendrik Luesch.

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5

Feng, Xidong, and Marshall M. Siegel. "FTICR-MS applications for the structure determination of natural products." Analytical and Bioanalytical Chemistry 389, no. 5 (August 14, 2007): 1341–63. http://dx.doi.org/10.1007/s00216-007-1468-8.

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6

Fun, Hoong Kun, Suchada Chantrapromma, and Nawong Boonnak. "Single Crystal X-Ray Structural Determination: A Powerful Technique for Natural Products Research and Drug Discovery." Advanced Materials Research 545 (July 2012): 3–15. http://dx.doi.org/10.4028/www.scientific.net/amr.545.3.

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Drug discovery from natural products resources have been extensively studied. The most important step in the discovery process is the identification of compounds with interesting biological activity. Single crystal X-ray structure determination is a powerful technique for natural products research and drug discovery in which the detailed three-dimensional structures that emerge can be co-related to the activities of these structures. This article shall present (i) co-crystal structures, (ii) determination of absolute configuration and (iii) the ability to distinguish between whether a natural product compound is a natural product or a natural product artifact. All these three properties are unique to the technique of single crystal X-ray structure determination.

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7

Berlinck, Roberto G. S., and Stelamar Romminger. "The chemistry and biology of guanidine natural products." Natural Product Reports 33, no. 3 (2016): 456–90. http://dx.doi.org/10.1039/c5np00108k.

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8

Zhang, Fan, Navid Adnani, Emmanuel Vazquez-Rivera, Doug R. Braun, Marco Tonelli, David R. Andes, and Tim S. Bugni. "Application of 3D NMR for Structure Determination of Peptide Natural Products." Journal of Organic Chemistry 80, no. 17 (August 21, 2015): 8713–19. http://dx.doi.org/10.1021/acs.joc.5b01486.

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9

Cordell, Geoffrey A., and A. Douglas Kinghorn. "One-dimensional proton—carbon correlations for the structure determination of natural products." Tetrahedron 47, no. 22 (January 1991): 3521–34. http://dx.doi.org/10.1016/s0040-4020(01)80866-8.

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10

Tarsis, Emily M., Ettore J. Rastelli, Sarah E. Wengryniuk, and Don M. Coltart. "The apratoxin marine natural products: isolation, structure determination, and asymmetric total synthesis." Tetrahedron 71, no. 31 (August 2015): 5029–44. http://dx.doi.org/10.1016/j.tet.2015.05.047.

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11

Karschin, Niels, Klaus Wolkenstein, and Christian Griesinger. "Magnetically Induced Alignment of Natural Products for Stereochemical Structure Determination via NMR." Angewandte Chemie 132, no. 37 (June 3, 2020): 15994–98. http://dx.doi.org/10.1002/ange.202004881.

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12

Fuwa, Haruhiko. "Structure determination, correction, and disproof of marine macrolide natural products by chemical synthesis." Organic Chemistry Frontiers 8, no. 14 (2021): 3990–4023. http://dx.doi.org/10.1039/d1qo00481f.

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13

Makarieva, Tatyana N., Natalia V. Ivanchina, and Valentin A. Stonik. "Application of Oxidative and Reductive Transformations in the Structure Determination of Marine Natural Products." Journal of Natural Products 83, no. 4 (February 24, 2020): 1314–33. http://dx.doi.org/10.1021/acs.jnatprod.9b01020.

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14

Tarsis, Emily M., Ettore J. Rastelli, Sarah E. Wengryniuk, and Don M. Coltart. "ChemInform Abstract: The Apratoxin Marine Natural Products: Isolation, Structure Determination, and Asymmetric Total Synthesis." ChemInform 46, no. 37 (August 27, 2015): no. http://dx.doi.org/10.1002/chin.201537241.

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15

Dawson, Simon, John P. Malkinson, David Paumier, and Mark Searcey. "Bisintercalator natural products with potential therapeutic applications: isolation, structure determination, synthetic and biological studies." Nat. Prod. Rep. 24, no. 1 (2007): 109–26. http://dx.doi.org/10.1039/b516347c.

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16

Köck, Matthias, Michael Reggelin, and Stefan Immel. "Model-Free Approach for the Configurational Analysis of Marine Natural Products." Marine Drugs 19, no. 6 (May 21, 2021): 283. http://dx.doi.org/10.3390/md19060283.

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The NMR-based configurational analysis of complex marine natural products is still not a routine task. Different NMR parameters are used for the assignment of the relative configuration: NOE/ROE, homo- and heteronuclear J couplings as well as anisotropic parameters. The combined distance geometry (DG) and distance bounds driven dynamics (DDD) method allows a model-free approach for the determination of the relative configuration that is invariant to the choice of an initial starting structure and does not rely on comparisons with (DFT) calculated structures. Here, we will discuss the configurational analysis of five complex marine natural products or synthetic derivatives thereof: the cis-palau’amine derivatives 1a and 1b, tetrabromostyloguanidine (1c), plakilactone H (2), and manzamine A (3). The certainty of configurational assignments is evaluated in view of the accuracy of the NOE/ROE data available. These case studies will show the prospective breadth of application of the DG/DDD method.

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17

Januar, Hedi Indra, Neviaty Putri Zamani, Dedi Soedharma, and Ekowati Chasanah. "Logic Structure Determination (LSD) as a Computer Assisted Structure Elucidation (Case) for Molecular Structure Determination of Cytotoxic Cembranoids from Soft Coral." Squalen Bulletin of Marine and Fisheries Postharvest and Biotechnology 11, no. 1 (May 19, 2016): 1. http://dx.doi.org/10.15578/squalen.v11i1.177.

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The tropical Indonesian soft corals are a valuable resources that produce pharmacological cytotoxic cembranoids. However, manual structure determination into these compounds requires adequate knowledge of organic chemistry. This study presents the application of Logic Structure Determination (LSD), as a freeware Computer Assisted Structure Elucidation (CASE) for automatic molecular structure determination of cembranoid compounds from soft corals species. 12 Nuclear Magnetic Resonance (NMR) dataset of cytotoxic cembranoids were used to evaluate the accuracy of LSD in generating the possible structures. Results of this study shows LSD generated numerous possible molecular structures, as the data input file derived only from 2D-NMR HMQC (Heteronuclear Multiple-Quantum Correlation), COSY (Homonuclear Correlation Spectroscopy), and HMBC (Heteronuclear Multiple Bond Correlation). The accuracy significantly enhanced (only 2-4 possible cembranoid structures from each NMR dataset) with addition of H2BC (Heteronuclear 2 Bond Correlation) experimental data. This may indicates that VLRC (Very Long-Range Correlations) affects significantly to LSD capability. Furthermore, LSD with direct 2 bond NMR experimental data is a reliable CASE technique for identification of cembranoid compounds. In general, this freeware-CASE is potential to be applied to other type of small molecule compounds and may serves as a potential solution for elucidation bottleneck step in Indonesian natural products studies.

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18

Kalesse, Markus, Jun Li, Jun Xing, Daniel Lücke, Dennis Lübken, Lucas Millbrodt, and Ruben Plentz. "The Structure Elucidation of Haprolid." Synthesis 50, no. 03 (November 24, 2017): 529–38. http://dx.doi.org/10.1055/s-0036-1591836.

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The assignment of two stereocenters of the natural product haprolid through the application of a profile hidden Markov model (HMM) and its confirmation through total synthesis of the natural product and of two of its diastereomers are reported. The structure elucidation of this polyketide-peptide hybrid natural product is a telling showcase of how difficult it can be to determine the absolute configuration of isolated stereocenters and the benefits of a gene cluster analysis for structure determination. The key steps of the synthesis are a selective epoxidation of a terminal olefin and the stereodivergent macrolactonization strategy. Furthermore, the biological evaluation of all products showed that all diastereomers are potent inhibitors of hepatocellular carcinoma cell lines.

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19

Oishi, Tohru. "Structure Determination, Chemical Synthesis, and Evaluation of Biological Activity of Super Carbon Chain Natural Products." Bulletin of the Chemical Society of Japan 93, no. 11 (November 15, 2020): 1350–60. http://dx.doi.org/10.1246/bcsj.20200151.

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20

Bross-Walch, Nadja, Till Kühn, Detlef Moskau, and Oliver Zerbe. "Strategies and Tools for Structure Determination of Natural Products Using Modern Methods of NMR Spectroscopy." Chemistry & Biodiversity 2, no. 2 (February 2005): 147–77. http://dx.doi.org/10.1002/cbdv.200590000.

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21

Sadler, I. H. "The use of n.m.r. spectroscopy in the structure determination of natural products: one-dimensional methods." Natural Product Reports 5, no. 2 (1988): 101. http://dx.doi.org/10.1039/np9880500101.

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22

Derome, A. E. "The use of n.m.r. spectroscopy in the structure determination of natural products: two-dimensional methods." Natural Product Reports 6, no. 2 (1989): 111. http://dx.doi.org/10.1039/np9890600111.

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23

Plainchont, Bertrand, Jean-Marc Nuzillard, Gilberto V. Rodrigues, Marcelo J. P. Ferreira, Marcus T. Scotti, and Vicente P. Emerenciano. "New Improvements in Automatic Structure Elucidation Using the LSD (Logic for Structure Determination) and the SISTEMAT Expert Systems." Natural Product Communications 5, no. 5 (May 2010): 1934578X1000500. http://dx.doi.org/10.1177/1934578x1000500517.

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This article describes the integration of the LSD (Logic for Structure Determination) and SISTEMAT expert systems that were both designed for the computer-assisted structure elucidation of small organic molecules. A first step has been achieved towards the linking of the SISTEMAT database with the LSD structure generator. The skeletal descriptions found by the SISTEMAT programs are now easily transferred to LSD as substructural constraints. Examples of the synergy between these expert systems are given for recently reported natural products.

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24

Fukui, Hiroki, and Isamu Shiina. "Total Synthesis of Botcinolides and Botcinins; Determination of the Structure of Natural Products Isolated from Botrytis cinerea." Journal of Synthetic Organic Chemistry, Japan 67, no. 6 (2009): 628–42. http://dx.doi.org/10.5059/yukigoseikyokaishi.67.628.

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25

Vogler, B., I. Klaiber, G. Roos, C. U. Walter, W. Hiller, P. Sandor, and W. Kraus. "Combination of LC−MS and LC−NMR as a Tool for the Structure Determination of Natural Products." Journal of Natural Products 61, no. 2 (February 1998): 175–78. http://dx.doi.org/10.1021/np970416z.

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26

Karschin, Niels, Klaus Wolkenstein, and Christian Griesinger. "Innenrücktitelbild: Magnetically Induced Alignment of Natural Products for Stereochemical Structure Determination via NMR (Angew. Chem. 37/2020)." Angewandte Chemie 132, no. 37 (August 10, 2020): 16387. http://dx.doi.org/10.1002/ange.202009650.

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27

Deev, Sergey L., Alexander S. Paramonov, Tatyana S. Shestakova, Igor A. Khalymbadzha, Oleg N. Chupakhin, Julia O. Subbotina, Oleg S. Eltsov, et al. "15N-Labelling and structure determination of adamantylated azolo-azines in solution." Beilstein Journal of Organic Chemistry 13 (November 29, 2017): 2535–48. http://dx.doi.org/10.3762/bjoc.13.250.

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Determining the accurate chemical structures of synthesized compounds is essential for biomedical studies and computer-assisted drug design. The unequivocal determination of N-adamantylation or N-arylation site(s) in nitrogen-rich heterocycles, characterized by a low density of hydrogen atoms, using NMR methods at natural isotopic abundance is difficult. In these compounds, the heterocyclic moiety is covalently attached to the carbon atom of the substituent group that has no bound hydrogen atoms, and the connection between the two moieties of the compound cannot always be established via conventional 1H-1H and 1H-13C NMR correlation experiments (COSY and HMBC, respectively) or nuclear Overhauser effect spectroscopy (NOESY or ROESY). The selective incorporation of 15N-labelled atoms in different positions of the heterocyclic core allowed for the use of 1H-15N (J HN) and 13C-15N (J CN) coupling constants for the structure determinations of N-alkylated nitrogen-containing heterocycles in solution. This method was tested on the N-adamantylated products in a series of azolo-1,2,4-triazines and 1,2,4-triazolo[1,5-a]pyrimidine. The syntheses of adamantylated azolo-azines were based on the interactions of azolo-azines and 1-adamatanol in TFA solution. For azolo-1,2,4-triazinones, the formation of mixtures of N-adamantyl derivatives was observed. The J HN and J CN values were measured using amplitude-modulated 1D 1H spin-echo experiments with the selective inversion of the 15N nuclei and line-shape analysis in the 1D 13С spectra acquired with selective 15N decoupling, respectively. Additional spin–spin interactions were detected in the 15N-HMBC spectra. NMR data and DFT (density functional theory) calculations permitted to suggest a possible mechanism of isomerization for the adamantylated products of the azolo-1,2,4-triazines. The combined analysis of the J HN and J CN couplings in 15N-labelled compounds provides an efficient method for the structure determination of N-alkylated azolo-azines even in the case of isomer formation. The isomerization of adamantylated tetrazolo[1,5-b][1,2,4]triazin-7-ones in acidic conditions occurs through the formation of the adamantyl cation.

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28

Köck, Matthias, Bernd Reif, William Fenical, and Christian Griesinger. "Differentiation of HMBC two- and three-bond correlations: A method to simplify the structure determination of natural products." Tetrahedron Letters 37, no. 3 (January 1996): 363–66. http://dx.doi.org/10.1016/0040-4039(95)02206-6.

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29

Carter, Guy T. "NP/MS since 1970: from the basement to the bench top." Nat. Prod. Rep. 31, no. 6 (2014): 711–17. http://dx.doi.org/10.1039/c3np70085b.

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This Highlight explores the evolution of applications of mass spectrometric technologies in the context of natural products research since the 1970's. The central themes are the analysis of mixtures, dereplication and structure determination. An example of sequential analysis of fragment ions (MS/MS) to provide detailed structural information on muraymycins is presented.

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30

Suzuki, Keisuke. "Synthetic study of ravidomycin, a hybrid natural product." Pure and Applied Chemistry 72, no. 9 (January 1, 2000): 1783–86. http://dx.doi.org/10.1351/pac200072091783.

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Strategies and tactics associated with the total synthesis of hybrid natural products are discussed. The target is ravidomycin (2), one of the gilvocarcin-class antitumor antibiotics with an aryl C-glycoside structure. The first total synthesis of 2, which was achieved along similar lines of that of gilvocarcin V (1), served for the determination of the relative as well as the absolute stereochemistry of 2. Also revealed was a limitation of the synthetic scheme so long as the amino sugar congener was concerned. A preliminary result is discussed on the [2+2+2] approach that relies on the ready availability of various benzocyclobutene derivatives via regioselective [2+2] cycloaddition of α-alkoxybenzynes and ketene silyl acetals.

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31

Rodrigues, Gilberto do V., Ivan P. de Arruda Campos, and Vicente de P. Emerenciano. "Applications of artificial intelligence to structure determination of organic compounds. XX*. Determination of groups attached to the skeleton of natural products using13C nuclear magnetic resonance spectroscopy." Spectroscopy 13, no. 3 (1997): 191–200. http://dx.doi.org/10.1155/1997/657194.

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A procedure for the identification of substituent groups (viz. angelate, tiglate, etc.) attached to any of the atoms in the conventional skeleton of a natural product is described. It consists in the use of the program MACRONO, which was developed for finding subspectra due to the carbons in the said substituent groups amid the raw13C NMR spectroscopic data from any given natural product (by means of comparisons of all possible subsets of the observed chemical shifts with those contained in an apposite database, built with literature13C NMR spectroscopic data regarding those groups). This procedure enables one to expunge the chemical shifts not due to skeletal carbons from the initial dataset, which then can be input to the expert system SISTEMAT, for skeletal identification.

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32

Miles, Christopher O., Alistair L. Wilkins, Ian Garthwaite, Richard M. Ede, and Sarah C. Munday-Finch. "Immunochemical techniques in natural products chemistry: Isolation and structure determination of a novel indole-diterpenoid aided by TLC-ELISAgram." Journal of Organic Chemistry 60, no. 19 (September 1995): 6067–69. http://dx.doi.org/10.1021/jo00124a016.

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33

Veijanen, A., J. Paasivirta, and M. Lahtiperä. "Structure and Sensory Analyses of Tainting Substances in Finnish Freshwater Environments." Water Science and Technology 20, no. 8-9 (August 1, 1988): 43–48. http://dx.doi.org/10.2166/wst.1988.0223.

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GC/MS/SNIFF/TASTE methods have been used in Finland to identify the causes of three tainting problems in water and one in fish nets. Structure determination was often verified by comparison with authentic compounds. Algal growth was implicated to be the source of geosmin and MIB in river water in Northern Finland and was associated with the appearance of tainting problems in raw water and reservoir water in Åland county. Terpenoids (e.g. camphor), degradation products of natural lipids (e.g. aldehydes, ketones and unsaturated aliphatic compounds) and volatile organohalogen compounds were frequently found in contaminated water but showed minor tainting effects compared to geosmin and MIB. Di-tert.-butyl-p-cresol and chlorobenzene also produced only minor tainting effects.

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34

Martin, Gary E., Radhika Sanduja, and Maktoob Alam. "Two-dimensional NMR studies of marine natural products. 2. Utilization of two-dimensional proton double quantum coherence NMR spectroscopy in natural products structure elucidation on - determination of long-range couplings in plumericin." Journal of Organic Chemistry 50, no. 13 (June 1985): 2383–86. http://dx.doi.org/10.1021/jo00213a039.

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35

Uemura, Daisuke. "Preface." Pure and Applied Chemistry 79, no. 4 (January 1, 2007): vi. http://dx.doi.org/10.1351/pac20077904vi.

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Natural products chemistry primarily involves research on organic compounds produced by plants, animals, and microorganisms, and focuses not only on the determination of chemical structures and biosynthesis, but also on chemical synthesis and the development of stereoselective chemical reactions. In recent years, developments have spread to the field of molecular biology in particular, as indicated by the investigation of the relationship between the structure and activity of biologically active substances, in addition to the elucidation of the mechanisms of biological effects at the molecular level. These achievements have facilitated corresponding progress in other related sciences, and have contributed significantly to developments in pharmaceutical, agrochemical, and other industries.Meanwhile, the science of biodiversity focuses on objectives such as the search for active ingredients in organisms and the preservation of species and diversity, from a scientific perspective. These two fields are closely related in their respective focuses on the diversity of organisms and the diversity of metabolic products, and it is for this reason that the respective conferences on biodiversity and natural products chemistry have come to be merged, starting with the preceding event in the series, held in India. I believe that this joint approach is highly beneficial, and sincerely hope that this conference has provided opportunities for exchange of a diverse range of information between the respective researchers and has contributed to further global development of these fields.This conference was held at the Kyoto International Conference Hall on 23-28 July 2006, and was officially sponsored by IUPAC and hosted by the Science Council of Japan jointly with the Chemical Society of Japan, the Pharmaceutical Society of Japan, and the Japan Society for Bioscience, Biotechnology, and Agrochemistry. In addition to 17 plenary speakers, lectures were also delivered by 77 invitees of various generations, and 580 posters were presented, primarily by younger delegates, of which 72 were supplemented by oral presentations. In order to broadly examine various topics relating to each aspect of the field of natural products chemistry, discussions were conducted by classifying this diverse field into the following eight themes, thereby promoting interactions between researchers and cooperation between related fields.- Isolation and Structure Elucidation of Natural Products- Synthesis of Natural Products and their Models- Biosynthesis and Genetic Engineering on Natural Products- Spectroscopy in Natural Products Chemistry- Molecular Mode of Action on Natural Products and Drugs- Chemical Biology and Related Areas- Chemistry and Biochemistry Related to Biodiversity- Drug Diversity and DevelopmentsApproximately 1200 participants from 31 countries and regions attended this conference, and exhibits from a total of 26 companies were presented in the concurrently held exhibition. In addition, pre- and post-symposia were held in Nagoya, Tokushima, Sapporo, Sendai, Fukuoka, and Tokyo, and the 48th Symposium of a regular series on the Chemistry of Natural Products (in Sendai) also took advantage of the opportunity to promote more diverse and closer interactions. I would like to express my deepest gratitude to the aforementioned hosts, co-hosts, and many other organizations and individuals for their support, without which this conference would not have been possible. Finally, it is my sincere hope that this conference has provided opportunities for the future advancement of natural products chemistry and biodiversity science.Daisuke UemuraChairman, Organizing Committee

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36

MILES, C. O., A. L. WILKINS, I. GARTHWAITE, R. M. EDE, and S. C. MUNDAY-FINCH. "ChemInform Abstract: Immunochemical Techniques in Natural Products Chemistry: Isolation and Structure Determination of a Novel Indole-Diterpenoid Aided by TLC- ELISAgram." ChemInform 27, no. 6 (August 12, 2010): no. http://dx.doi.org/10.1002/chin.199606201.

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37

Karschin, Niels, Klaus Wolkenstein, and Christian Griesinger. "Inside Back Cover: Magnetically Induced Alignment of Natural Products for Stereochemical Structure Determination via NMR (Angew. Chem. Int. Ed. 37/2020)." Angewandte Chemie International Edition 59, no. 37 (August 10, 2020): 16247. http://dx.doi.org/10.1002/anie.202009650.

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38

Medvedev, Andrey, Ekaterina Bobrova, Alexey Poserenin, and Ervand Zarmanyan. "Evaluation of mineral fiber properties using x-ray fluorescence analysis and measurement of natural radioactivity." MATEC Web of Conferences 170 (2018): 03018. http://dx.doi.org/10.1051/matecconf/201817003018.

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The article analyzes the factors affecting the longevity of insu-lating systems and the operational resistance of products based on mineral fibers. It is emphasized that the ratio of acid oxides contained in the charge to the main oxides is the main factor influencing the operational resistance of mineral fibers, as well as the energy intensity of their production. A hy-pothesis has been put forward and confirmed that the operational resistance of a fiber depends on the content of heavy metals (their oxides) in the ini-tial charge. Determination of the elemental composition of stone wool samples was carried out by X-ray fluorescence analysis. Conducted sam-ples with a different acidity module of the study, show, that the fibers are safe by radiation indices, and their operational resistance can be affected by heavy metal oxides. It is substantiated that the durability of building systems in which mineral wool products are used as thermal insulation is determined by the properties of mineral wool products, the literacy of de-sign solutions and the quality of installation. The properties of mineral wool products, including their operational resistance, depend on the prop-erties of mineral fibers and the observance of technological regimes both on the fact of the most complete curing of the binder and on the features of formation of the volume-oriented structure of the mineral wool carpet.

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39

Zeynep DUMANOĞLU. "A Study on the Determination of Some Physical and Physiological Properties of Seeds of Two Different Jute Varieties (Corchorus capsularis L. and Corchorus olitorius L.)." ISPEC Journal of Agricultural Sciences 5, no. 2 (June 2, 2021): 456–62. http://dx.doi.org/10.46291/ispecjasvol5iss2pp456-462.

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In recent years, the production of natural and recyclable, environmentally friendly products has come to the fore rather than textile and textile products produced from petroleum resources. One of the materials used in the production of these products is the Jute plant. This study was carried out in a laboratory environment under controlled conditions between 2019 and 2020. In the study, some physical (shape-size, surface area, average arithmetic-geometric diameter, sphericity, thousand grain weight) and physiological properties (germination percentage and time, average shoot-root lengths) of seeds belonging to two different varieties of Jute plant (Corchorus capsularis L. and Corchorus olitorius L.) were determined. According to the data obtained; It has been determined that C. capsularis variety has a short and oval structure, while C. olitorius variety has a medium and oval structure. Furthermore, the germination rate was determined as 74.5% in C. capsularis seeds and 63.5% in C. olitorius seeds.

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40

Ellestad, George, Arie Zask, and Nina Berova. "The enduring legacy of Koji Nakanishi's research on bioorganic chemistry and natural products. Part 1: Isolation, structure determination and mode of action." Chirality 32, no. 5 (March 10, 2020): 632–51. http://dx.doi.org/10.1002/chir.23214.

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41

Chuluunbaatar, Bayar, Zoltán Béni, Miklós Dékány, Bernadett Kovács, András Sárközy, Zsolt Datki, Lilla Mácsai, János Kálmán, Judit Hohmann, and Attila Ványolós. "Triterpenes from the Mushroom Hypholoma lateritium: Isolation, Structure Determination and Investigation in Bdelloid Rotifer Assays." Molecules 24, no. 2 (January 15, 2019): 301. http://dx.doi.org/10.3390/molecules24020301.

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Twelve compounds (1–12) were isolated from the methanol extract of brick cap mushroom (Hypholoma lateritium (Schaeff.) P. Kumm.). The structures of the compounds were elucidated using extensive spectroscopic analyses, including NMR and MS measurements. Lanosta-7,9(11)-diene-12β,21α-epoxy-2α,3β,24β,25-tetraol (1) and 8-hydroxy-13-oxo-9E,11E-octa-decadienoic acid (2) were identified as new natural products, together with ten known compounds, from which 3β-hydroxyergosta-7,22-diene (4), demethylincisterol A2 (5), cerevisterol (6), 3β-O-glucopyranosyl-5,8-epidioxyergosta-6,22-diene (7), fasciculol E (9), and uridine (12) were identified in this species for the first time. The isolated triterpenes (1, 3–11) were investigated for their toxicity in vivo using bdelloid rotifer assays. Most of the examined steroids in general showed low toxicity, although the effects of the compounds varied in a wider range from the non-toxic lanosta-7,9(11)-diene-12β,21α-epoxy-2α,3β,24β,25-tetraol (1) to the significantly toxic cerevisterol (6), with substantial dependence in some cases on the presence of nutrient in the experimental environment.

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Riccio, R., Giuseppe Bifulco, Paola Cimino, Carla Bassarello, and Luigi Gomez-Paloma. "Stereochemical analysis of natural products. Approaches relying on the combination of NMR spectroscopy and computational methods." Pure and Applied Chemistry 75, no. 2-3 (January 1, 2003): 295–308. http://dx.doi.org/10.1351/pac200375020295.

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The stereochemical study of flexible stereogenic carbon chains, such as those of many novel natural products, is a particularly challenging task. Recent applications of our group on the so-called "J-based approach", a methodology relying on a detailed analysis of homonuclear (H-H) and heteronuclear (C-H) 2,3J couplings, include the study of the sphinxolide family of antitumor macrolides, a group of molecules characterized by a flexible macrocyclic framework bearing a number of oxygenated and methylated undetermined stereocenters, and of ascaulitoxin, a nitrogen-containing phytotoxin with herbicidal activity produced by a phytopathogenic fungus. An extension of the original procedure, relying on a Hartree-Fock (HF) ab initio calculation of conformational equilibrium and an estimate of the Boltzmann averaged 2,3JHH and 2,3JCH couplings, has been applied to the stereochemical study of sapinofuranone A, where the conformational equilibrium among existing rotamers had initially led to controversial results. 13C NMR chemical shifts are additional useful parameters in the study of complex organic molecules. Along these lines, we have lately proposed the use of Hartree–Fock gauge including atomic orbitals (GIAO) calculated 13C NMR chemical shift values as a supporting tool for the validation of the structure of new natural products and the determination of the relative stereochemistry of diastereomeric flexible compounds that are characterized by multiple conformer equilibria.

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Ciornei, N., I. Facaoaru, and V. Cetean. "NON-DESTRUCTIVE METHOD FOR RAPID "IN SITU" CHARACTERIZATION OF ROCKS." Bulletin of the Geological Society of Greece 36, no. 4 (January 1, 2004): 1912. http://dx.doi.org/10.12681/bgsg.16674.

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The effective determination of the field and place of application of the products resulting from stone working is a compulsory requirement in the building activity and is solved by laboratory analyses. This article presents details on the determination, by non-destructive method, of the compression strength of the rocks, both "in situ" (in the deposit) and in a laboratory. The originality of the method consists in simplifying the determination process of this parameter, a method that is in agreement with the systems proposed to be applied in the European Community. The method has the advantage of being applicable in quarries, where knowledge of this parameter leads to a rationalizing of the working and more especially to a selection of the blocks by quality criteria. The method is applicable to all categories of natural consolidated hard rocks, being a viable alternative for deposits with an inhomogeneous composition as to quality and structure.

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König, Gabriele M., and Anthony D. Wright. "Concerted application of a shift reagent and 2D NOESY to the structure determination of new natural products from the tropical brown algaDictyopteris delicatula." Magnetic Resonance in Chemistry 33, no. 3 (March 1995): 178–83. http://dx.doi.org/10.1002/mrc.1260330305.

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Mukharlyamova, Aisylu Z., Aleksandr M. Saifutdinov, Elvira R. Rakhmetova, Aygul G. Mukhammetshina, and Igor M. Fitsev. "Comparison of the efficiency of photoionization at atmospheric pressure and electrospray ionization on the example of some aflatoxins and trichothecenes." Butlerov Communications 64, no. 12 (December 31, 2020): 113–19. http://dx.doi.org/10.37952/roi-jbc-01/20-64-12-113.

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The article presents the results of comparing the effectiveness of modern ionization methods used in chromatomass spectrometric analysis: photoionization at atmospheric pressure (APPI) and electrospray ionization (ESI) for the determination of aflatoxin B1 and T-2 toxins related to the main natural pollutants of agricultural feed, food raw materials and food products. Aflatoxin B1 is a member of the aflatoxin family, which in their chemical structure are derivatives of substituted coumarins or furocoumarins. The peculiarity of aflatoxins is that in the process of technological or culinary processing, they are practically not destroyed, while being the strongest hepatocancerogens that cause irreversible liver damage. T-2 toxin refers to trichothecene mycotoxins, in the structure of which there is a trichothecene ring containing a multiple bond and an epoxy group. Most trichothecene mycotoxins are slightly toxic compounds, but T-2 toxin is deadly, having a negative effect on immunocompetent organs, hematopoietic organs, and the gastrointestinal tract, increasing the risk of internal hemorrhage. Due to the impossibility of preventing contamination of agricultural feed, food raw materials and food products with mycotoxins, their strict control is necessary. Chromatomass spectrometry is one of the methods that provide high sensitivity and reliability for the determination of mycotoxins Methods of ionization sources, such as electrospray and photoionization at atmospheric pressure during mass spectrometric detection of mycotoxins by high-performance liquid chromatography (HPLC-MS/MS), are evaluated. In order to increase the sensitivity of the determinations, the optimal conditions of the quadrupole-time-of-flight mass spectrometric detector were selected and the maximum intensity responses of the analytes were obtained. During the experiment, it was found that the intensity of the signal with a photoionization source obtained by analyzing the T-2 toxin is higher than the signal obtained by using an electrospray ionization source.

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Kaklauskas, A. "IMPROVEMENT OF CRITERIA SIGNIFICANCE DETERMINATION/KRITERIJŲ REIKŠMINGUMŲ NUSTATYMO TOBULINIMAS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 2, no. 5 (March 31, 1996): 64–70. http://dx.doi.org/10.3846/13921525.1996.10531549.

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Having determined the significances of criteria by expert methods, we learn how much one of the criteria is more significant over another one. However, having determined by these methods the significances of technical-economical criteria (TEC) (they can be expressed in monetary or natural form: price and production costs of products, maintenance costs, construction time, labour expenditures, etc.), we do not find out everything we need. For instance, quantitative chracteristics of TEC in this case are not fully evaluated. Therefore a method should be developed enabling realistic and accurate assessment of these quantitative changes. The paper presents the method suggested by the author for significance determination of criteria, taking into account their quantitative and qualitative characteristics.

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Emerenciano, Vicente de P., Lilian D. Melo, Gilberto do V. Rodrigues, and Jean P. Gastmans. "Application of artificial intelligence in organic chemistry. Part XIX*. Pattern recognition and structural determination of flavonoids using13C‒NMR spectra." Spectroscopy 13, no. 3 (1997): 181–90. http://dx.doi.org/10.1155/1997/967406.

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This essay describes another improvement to the expert system named SISTEMAT. The purpose of such improvement is to help chemists who work with natural products to figure out chemical structures. SISTEMAT uses Nuclear Magnetic Resonance (NMR)13C data to ensemble compatible substructures according to related spectra. The system also is able to suggest a list of probable carbon skeletons. Those will work as models to structure generating programs, reducing the combinatorial explosion problem. This is the first essay from our research group which shows our system applications to aromatic compounds. A database with 700 NMR13C spectra of flavonoids obtained from the literature was used. We applied heuristic SISTEMAT in order to discover ranges of chemical shifts that characterise several skeleton types. The diversity of flavonoid structures is due to several oxidation patterns at rings A and B. This phenomenon causes a great complexity in the absorptions at the aromatic region. Heuristic SISTEMAT was able to discover more accurate rules that differentiate specific patterns of oxidation for some skeleton types. The performance of the software was checked against a higher complex structure of a dimeric flavonoid recently isolated. The system gives only two possibilities of skeleton types (among 70 others). Both substructures found by the program showed correct linkages between carbons 2 and 7″and 4 and 8″of the monomers.

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KOMORI, Tetsuya. "Our Investigation on the Chemistry of Biologically Active Natural Products. With the Object of Exploitation for Structure Determination Methods, and Elucidation of Vital Function." YAKUGAKU ZASSHI 113, no. 3 (1993): 198–236. http://dx.doi.org/10.1248/yakushi1947.113.3_198.

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Boon, M. A., and S. Tesfamichael. "DETERMINATION OF THE PRESENT VEGETATION STATE OF A WETLAND WITH UAV RGB IMAGERY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W2 (November 15, 2017): 37–41. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w2-37-2017.

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The compositional and structural characteristics of wetland vegetation play a vital role in the services that a wetland supplies. Apart from being important habitats, wetland vegetation also provide services such as flood attenuation and nutrient retention. South Africa is known to be a water scarce country. The protection and continuous monitoring of wetland ecosystems is therefore important. Factors such as site transformation and disturbance may completely change the vegetation of a wetland and the use of Unmanned Aerial Vehicle (UAV) imagery can play a valuable role in high-resolution monitoring and mapping. This study assessed if the use of UAV RGB imagery can enhance the determination of the present vegetation state of a wetland. The WET-Health level two (detailed on-site evaluation) methodology was followed for the vegetation assessment, where wetland health is a measure of the deviation of a wetland’s structure and function from its natural reference condition. The mapping of the disturbances classes was then undertaken using ultra-high resolution orthophotos, point clouds and digital surface models (DSM). The WET-Health vegetation module completed with the aid of the UAV products still indicates that the vegetation of the wetland is largely modified (“D” PES Category) and that the vegetation of the wetland will further deteriorate (change score). These results are the same as determined in the baseline study. However a higher impact (activities taking place within the wetland) score were determined. The assessment of various WET-Health vegetation indicators were significantly enhanced using the UAV imagery and derived products. The UAV products provided an accurate vantage point over the wetland and surroundings, and assisted to easily refine the assessment of the disturbance classes and disturbance units.

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Matsumori, Nobuaki, Daisuke Kaneno, Michio Murata, Hideshi Nakamura, and Kazuo Tachibana. "Stereochemical Determination of Acyclic Structures Based on Carbon−Proton Spin-Coupling Constants. A Method of Configuration Analysis for Natural Products." Journal of Organic Chemistry 64, no. 3 (February 1999): 866–76. http://dx.doi.org/10.1021/jo981810k.

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