[Chemical constituents of leaves of Diospyros kaki (Ⅲ)].

Diospyros kaki leaves were separated and purified using various chromatographic methods, including polyamide chromatography, microporous resin(MCI) chromatography, C_(18) reversed-phase chromatography, and silica gel column chromatography. The isolated compounds were identified through spectral data analysis and comparison with literature. Ten monomeric compounds were obtained from D. kaki leaves:(Z)-hex-3-en-1-ol-(α-L-rhamnopyranosyl)-(1→3)-(4-O-trans-p-coumaroyl)-β-D-glucopyranoside(1), benzyl 2-O-β-glucopyranosyl-2,6-dihydroxybenzoate(2), ligurobustoside C(3), eugenol-O-β-glucopyranoside(4), osmanthuside B_6(5), β-(p-hydroxyphenyl)ethyl-O-α-L-rhamnopyranosyl-(1→3)-6-O-cis-p-coumaroyl-β-D-glucopyranpside(6), eugenol-β-rutinoside(7), amarusine A(8), osmanthuside D(9), and osmanthuside B(10). Among them, compound 1 is a new compound, while compounds 2-10 were isolated from this plant for the first time. The antioxidant activities of the compounds were evaluated by DPPH and ABTS radical scavenging assays, with water-soluble vitamin E as the positive control. The IC_(50) values of compounds 2, 3, and 5 for ABTS radical scavenging were 8.2, 5.7, and 9.9 μg·mL~(-1), respectively, which were comparable to that of the positive control(5.9 μg·mL~(-1)), indicating that compounds 2, 3, and 5 possess strong antioxidant activity.