Foram avaliados vários métodos de extração para os extratos hidroalcoólicos das folhas de "guaco" (Mikania glomerata Spreng.): maceração, maceração com ultra-som, infusão e extração por fluido supercrítico. Dentre os métodos estudados, a maceração com ultra-som proporcionou os melhores resultados, especialmente considerando-se a relação rendimento da extração/ tempo de extração. A cromatografia líquida de alta eficiência (CLAE) foi utilizada para determinar a concentração de cumarina nos extratos hidroalcoólicos das folhas de "guaco". A metodologia de análise desenvolvida utilizando CLAE mostrou ser sensível e reprodutível. Methods for preparation of hydroalcoholic extracts of "guaco" (Mikania glomerata Spreng.) leaves were compared: maceration, maceration under sonication, infusion and supercritical fluid extraction. Evaluation of these methods showed that maceration under sonication had the best results, when considering the ratio extraction yield/extraction time. A high performance liquid chromatography (HPLC) procedure for the determination of coumarin in these hydroalcoholic extracts of "guaco" leaves is described. The HPLC method is shown to be sensitive and reproducible.

Aqueous infusions of Brazilian Maytenus leaves are used as beverages, foodstuffs, and phytomedicines. Previously, we isolated two new flavonoid tetrasaccharides from the infusion of Maytenus aquifolium leaves that showed antiulcer activity. In this investigation a new flavonoid tetrasaccharide, kaempferol-3-O-alpha-L-rhamnopyranosyl (1-->6)-O-[alpha-L-arabinopyranosyl (1-->3)-O-alpha-L-rhamnopyranosyl (1-->2)]-O-beta-D-galactopyranoside (3), was isolated, together with kaempferol tri- and disaccharides and quercetin trisaccharides from the aqueous infusion of Maytenus ilicifolia leaves. All structures were elucidated by ES-MS and NMR spectroscopic methods. The quantitative analysis of the flavonoid glycosides from Maytenus ilicifolia and M. aquifolium has been performed by HPLC.