Studies on the Chemical Constituents of Japanese Buckeye Seed (Aesculus turbinata)Part Ⅱ * Isolation and Identification of Escin IVc and Isoescins Ia, Ib / 中草药

ABSTRACT

Three triterpenoid saponins were isolated from 90％ ethanolic extract of the seeds of Aes-culus turbinata Bl.. Their structures were identified on the basis of spectral data as escin IVc22α-O-tigloyl-28-O-acetylprotoaescigenin 33-O-[β-D-glucopyranosyl (1→2)][β-D-glucopyranosyl (1→4)]-β-D-glucopyranosiduronic acid (Ⅰ), isoescin Ia 21β-O-tigloyl-28-O-acetylprotoaescigenin-3β-O-[β-D-glucopy-ranosyl (1→2)][β-D-glucopyranosyl (1→4)]-β-D-glucopyranosiduronic acid (Ⅳ), and isoescin Ib21β-O-angeloyl-28-O-acetylprotoaescigenin-3β-O-[β-D-glucopyranosyl (1→2)][β-D-glucopyr anosyl (1→4)]-β-D-glucopyranosiduronic acid (Ⅴ). Escin IVc and isoescins Ia, Ib were obtained for the first time from thisplant. Escins Ia, Ib, IVc and isoescins Ia, Ib had inhibitory effect against recombinant HIV-1 protease atconcentration of 100 μmol/L in vitro.