ABSTRACT
Fourteen compounds were isolated from the n-butanol fraction of the 95% aqueous ethanol extract of the stems and twigs of Strychnos cathayensis by D101 macroporous resin, silica gel, ODS, Sephadex LH-20 column chromatography, and semipreparative RP-HPLC. Their structures were elucidated as ethyl 4-O-β-D-allopyranosyl-vanillate (1), n-butyl 4-O-β-D-allopyranosyl-vanillate (2), n-butyl 4-O-(6′-O-syringoyl)-β-D-allopyranosyl-vanillate (3), n-butyl 4-O-(6′-O-vanilloyl)-β-D-allopyranosyl-vanillate (4), n-butyl 4-O-(6′-O-syringoyl)-β-D-glucopyranosyl-vanillate (5), n-butyl 4-O-α-L-rhamnopyranosyl-syringate (6), methyl 3-methoxy-4-(β-D-allopyranosyloxy) benzoate (7), pseudolaroside B (8), butyl syringate (9), glucosyringic acid (10), methyl syringate (11), methyl 4-hydroxy-3-methoxybenzoate (12), clemochinenoside C (13), and clemoarmanoside A (14), respectively, on the basis of spectroscopic data interpretation and by comparison with literature information. Compounds 1-6 are artificial products of phenolic acid esterified by ethanol or n-butanol. It is noted that the precursors (4-O-(6′-O-syringoyl)-β-D-allopyranosyl-vanillic acid and 4-O-(6′-O-vanilloyl)-β-D-allopyranosyl-vanillic acid) of compounds 3 and 4 are new compounds. The hepatoprotective, anti-inflammatory, antioxidant and cytotoxic activities of compounds 1-13 were evaluated in vitro at a concentration of 10 μmol·L-1. Compounds 1, 2 and 6-10 exhibited potential hepatic protection effects with cell survival rates ranging from 53.6% to 55.5% (acetaminophen, 45.4% at 8 mmol·L-1). Compound 4 demonstrated anti-inflammatory activity with nitric oxide inhibitory rate of 74.6%. Compounds 3 and 5 showed potential antioxidant activities with malondialdehyde inhibitory rates of 53.2% and 56.1%, respectively.