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.