Cytotoxic triterpenoid saponins from Vaccaria segetalis

Abstract

By the guidance of bioassay, one new cytotoxic triterpenoid saponin, 3-O-[β-d-galactopyranosyl-(1 → 2)-β-d-glucuronopyranosyl] quillaic acid 28-O-β-d-glucopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-[β-d-fucopyranosyl-(1 → 4)]-β-d-fucopyranoside (1), and five known cytotoxic triterpenoid saponins, vaccaroside E (2), vaccaroside G (3), vaccaroside B (4), segetoside H (5) and segetoside I (6), were isolated from Vaccaria segetalis. Their structures were established on the basis of ESI-MS, IR, extensive NMR (¹H NMR, ¹³C NMR, TOCSY, ¹H–¹H COSY, DEPT, HMQC, HMBC and ROESY) analyses, chemical degradation, and by comparing with previously reported data. Compounds 1–6 showed moderate cytotoxic activities against LNcap, P-388 and A-549 cell lines with IC₅₀ values in the range 0.1–12.9 μM.

Keywords:

• Vaccaria segetalis
• Vaccaria pyramidata
• Triterpenoid saponin
• Quillaic acid
• Vaccaroside I
• Cytotoxic activity