Triterpenoid saponins from Sesbania vesicaria

Nine oleanane saponins including three new and six known were isolated from the seeds of Sesbania vesicaria. The new saponins were established as 3-O-α-l-rhamnopyranosyl-(1 → 3)]-β-d-glucuronopyranosyl-3β,29-dihydroxy-olean-12-en-28-oic acid, 3-O-α-l-rhamnopyranosyl-28-O-β-d-glucopyransoyl-3β-hydroxy-olean-12-en-23-al-28-oate, and 3-O-α-l-rhamnopyranosyl-28-O-β-d-glucopyransoyl-3β,23-dihydroxy-olean-12-en-28-oate. All isolated saponins were assayed for their DNA topoisomerase I inhibition ability and cytotoxicity against A549 human lung adenocarcinoma epithelial cells with no positive activity detected (IC₅₀ > 312 μM and GI₅₀ > 25 μM, respectively).