Characterization of Secondary Metabolites from Natural Sources

Natural products have contributed for many years to the development of new medicines for the treatment of diseases. Their structural diversity and complexity have inspired chemists to produce interesting compounds with pharmaceutical use. Although many pharmaceutical companies have eliminated or scaled down their natural products research, they still remain an important source of new drugs. This thesis is a review of the results obtained from the study of natural products produced for two fungi species and three medicinal plants. To this effect, one chapter describes the structural elucidation of three new sesquiterpenes from Ripartites tricholoma and Ripartites metrodii, and one new cyclopeptide from Cylindrocarpon sp. Their antimicrobial and cytotoxic activities are discussed as well. Finally, the isolation and structural elucidation of natural products produced for three medicinal plants from Mexico are discussed in the last chapter. Two nor-isoprenoids and one terpene lactone were isolated from Heliotropium angiospermum. The study of the organic extract of Bourreria pulchra yielded fifteen metabolites; of these two benzochromene derivatives and one trimeric caffeic acid derivative are new metabolites. In addition, one glucosylated flavonoid was isolated from the leaves of Syderoxylon foetidissimum