Manniosides B-F, five new triterpenoid saponins from the leaves of Schefflera mannii (Hook.f.) Harms.

Fifteen triterpenoid saponins including five new compounds (Mannioside B: 3β-[(β-d-glucopyranosyl)oxy]urs-12-en-28-oic acid α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (1), mannioside C: 3β-[(β-d-glucopyranosyl)23-dioxy]urs-12-en-28-oic acid α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (2), mannioside D: 3β,23-dihydroxyurs-12-en-28-oic acid β-d-glucopyranosyl-(1 → 6)- β-d-glucopyranosyl ester (3), mannioside E: 3β-hydroxy-23-oxolup-20(29)-en-28-oic acid α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (4) and mannioside F: (22S)-27β-[(β-d-glucopyranosyl)oxy]-22-hydroxyprotosta-12,24-dien-3β-yl β-d-glucopyranoside (5)) were isolated from the leaves of Schefflera mannii (Hook.f.) Harms. Their structures were established on the basis of 1D and 2D NMR data, mass spectrometry and chemical methods. The major isolated compounds were tested for their antiproliferative activity on human malignant epithelial (HeLa) cells but were not efficient at the concentration of 33 mM.