Two new dihydroamentoflavone glycosides from Cycas revoluta

Abstract

Phytochemical investigation of the ethyl acetate extract of Cycas revoluta Thunb. leaflets afforded five compounds including two new dihydroamentoflavone glucosides, (2S)-I-(2,3)-dihydro-I-7-O-β-D-glucopyranosylamentoflavone (1) and (2S)-I-(2,3)-dihydro-I-7,II-7-di-O-β-D-glucopyranosylamentoflavone (2), in addition to the known compounds prunin (3), vitexin-2″-rhamnoside (4) and protocatechuic acid (5). Compounds (3) and (4) being reported for the first time in this plant. The structures of these compounds were established by the detailed analysis of their spectroscopic data, mainly 1D NMR, 2D NMR, CD and HR-MSD-TOF. The ethyl acetate extract showed weak cytotoxicity against HepG2 (IC50 = 207.6 μg/mL) and RAW 264.2 cells (IC50 = 160.8 μg/mL). Compound 4 showed significant activity towards Leishmania donavani (IC50 = 13.8 μM, IC90 = 34.6 μM). The isolated compounds showed weak antimicrobial activity (IC50>10 μg/mL).