Triterpenoids from Brazilian Ilex species and their in vitro antitrypanosomal activity.
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Resumo
From the leaves of Ilex affinis and Ilex buxifolia, two adulterant species of "erva mate" (Ilex paraguariensis), three new triterpenoid glycosides were isolated. Affinoside 1 (3beta-O-[beta-D-glucopyranosyl-(1-->3)-[2-O-acetyl-(1-->2]]-alpha-L-arabinopyranosyl pomolic acid 28-O-beta-D-glucopyranosyl ester, 1) was isolated from I. affinis, while buxifolioside I (28-O-beta-D-glucopyranosyl ester of (20S)-3alpha,19alpha-dihydroxyurs-12-ene-23,28-dioic acid, 7) and buxifolioside II (28-O-beta-D-glucopyranosyl ester of (20S)-3beta,19alpha-dihydroxyurs-12-en-24,28-dioic acid, 8) were isolated from I. buxifolia. Along with these new compounds, ilexoside II (2), ursolic acid (3), 28-nor-ursolic acid (4), 3beta-O-acetylursolic acid (5), and uvaol (6) were also isolated. The observed results confirm the structural specificity of the I. paraguariensis triterpenoids and reinforce a previous proposal to detect mate adulteration by triterpenoid analysis. In addition, the in vitro antitrypanosomal activity of some Ilex triterpenoids is also reported.