Manniosides G-J, New Ursane- and Lupane-Type Saponins from Schefflera mannii (Hook.f.) Harms.

Four previously unreported triterpenoid saponins named 3β-hydroxy-23-oxours-12-en-28-oic acid 28- O -β- D -glucopyranosyl ester (mannioside G) ( 1 ), 23- O -acetyl-3β-hydroxyurs-12-en-28-oic acid 28- O -β- D -glucopyranosyl ester (mannioside H) ( 2 ), ursolic acid 28- O -[α- L -rhamnopyranosyl-(1→4)-β- D -glucopyranosyl-(1→6)-β- D -glucopyranosyl] ester (mannioside I) ( 3 ), and 3β-hydroxy-23-oxolup-20(29)-en-28-oic acid 28- O -β- D -glucopyranosyl ester (mannioside J) ( 4 ) were isolated as minor constituents from the EtOAc soluble fraction of the MeOH extract of the leaves of Schefflera mannii along with the known compounds 23-hydroxyursolic acid 28- O -β- D -glucopyranosyl ester ( 5 ), ursolic acid 28- O -β- D -glucopyranosyl ester ( 6 ), pulsatimmoside B ( 7 ) betulinic acid 28- O -[α- L -rhamnopyranosyl-(1→4)-β- D -glucopyranosyl-(1→6)-β- D -glucopyranosyl] ester ( 8 ), 23-hydroxy-3-oxo-urs-12-en-28-oic acid ( 9 ), hederagenin ( 10 ), ursolic acid ( 11 ), betulinic acid ( 12 ), and lupeol ( 13 ). Their structures were elucidated by a combination of 1D and 2D NMR analysis and mass spectrometry. The MeOH extract, the EtOAc and n -BuOH fractions, and some of the isolated compounds were evaluated for their antibacterial activity against four bacteria: Staphylococcus aureus ATCC1026, Staphylococcus epidermidis ATCC 35984, Escherichia coli ATCC10536, and Klepsiella pnemoniae ATCC13882. They were also screened for their antioxidant properties, but no significant results were obtained.