Thesis (doctoral)--Université de Paris, 1921. / Includes bibliographical references (p. [131]-136) and index.

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

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.