Triterpenoids from Brazilian Ilex species and their in vitro antitrypanosomal activity.

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.