Triterpenoids and Their Glycosides from Glinus Oppositifolius with Antifungal Activities against Microsporum Gypseum and Trichophyton Rubrum.

Four new triterpenoids, 3β,12β,16β,21β,22-pentahydroxyhopane (1), 12β,16β,21β,22-tetrahydroxyhopan-3-one (2), 3-oxo-olean-12-ene-28,30-dioic acid (3), and 3β-hydroxyoleana-11,13(18)-diene-28,30-dioic acid 30-methyl ester (4); 21 new triterpenoid saponins, glinusopposides A-U (5-25); and 12 known compounds (26-37) were isolated from the whole plants of Glinus oppositifolius. The structures of the new compounds were elucidated based on the analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and mass spectrometry (MS) data. All compounds from the plants were measured for antifungal activities against Microsporum gypseum and Trichophyton rubrum. Glinusopposide B (6), glinusopposide Q (21), glinusopposide T (24), and glinusopposide U (25) showed strong inhibitory activities against M. gypseum (MIC₅₀ 7.1, 6.7, 6.8, and 11.1 μM, respectively) and T. rubrum (MIC₅₀ 14.3, 13.4, 11.9, and 13.0 μM, respectively). For those active compounds with an oleanane skeleton, glycosylation (21-26) or oxidation (3) of 3-OH was helpful in increasing the activity; replacement of the 30-methyl group (29) by a carboxymethyl group (26) enhanced the activity; the presence of 11,13(18) double bonds (20) decreased the activity.