Fig. 1

Chemical structures of saponins (1–4) isolated from n-BuOH extract of areal parts of M. elliptica. 1: 3-O-β-d-glucuronopyranosyl-oleanolic acid; 2: 3-O-β-d-glucuronopyranosyloleanolic acid 28-O-β-d-glucopyranosyl ester; 3: 3-O-β-d-glucopyranosyl(1 → 2)-β-d-glucuronopyranosyl oleanolic acid; 4: 3-O-β-d-glucopyranosyl(1 → 2)-β-d-glucuronopyranosyloleanolic acid 28-O-β-d-glucopyranosyl ester