Nitric oxide production inhibitors from Polygonum multiflorum

Abstract

This study focuses on the anti-inflammatory activity-guided fractionation of the root of Vietnamese Polygonum multiflorum, resulting in the isolation of ten compounds (1–10). These compounds were identified as trans-resveratrol (1), methyl protocatechuate (2), methyl gallate (3), catechin (4), epicatechin (5), 4,6-dihydroxy-2-O-(β- D-glucopyranosyl)acetophenone (6), quercetin (7), apigenin (8), luteolin (9), and tricin (10). Compounds 2, 3, and 6 were isolated from P. multiflorum for the first time. All isolated compounds were tested against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in macrophage RAW264.7 cells to assess their anti-inflammatory potential. In vitro results revealed that compounds 7−9 exhibited significant NO production inhibition, with IC50 values of 12.0 ± 0.8, 17.8 ± 0.6, and 7.6 ± 0.3 μM, respectively. N(G)-monomethyl L-arginine (L-NMMA), a positive inhibitor, also effectively reduced LPS-induced NO production, with an IC50 value of 22.1 ± 0.1 μM. These findings indicate that compounds 7−9 isolated from P. multiflorum hold promise for further research and development of anti-inflammatory agents