Flavonoids from Vietnamese Dalbergia oliveri and their Anti-inflammatory Activity

The ethyl acetate soluble fraction of Vietnamese Dalbergia oliveri was subjected to column chromatography using silica gel and Sephadex LH-20 to separate chemicals in order to evaluate the phytochemical components and their prevention of NO generation. From the heartwood of D. oliveri, nine secondary metabolites (1–9) were successfully extracted. The chemical structures of these compounds were identified as daidzein (1), formononetin (2), 3,7-dihydroxy-4¢-methoxyflavone (3), liquiritigenin (4), 3¢-methoxydaidzein (5), dalbergin (6), butin (7), sativanone (8), and isoliquiritigenin (9). The chemical structures of isolated compounds were identified by nuclear magnetic resonance data and comparison with previously reported literature. The compounds 1, 3, and 5–8 were isolated from D. oliveri for the first time. The anti-inflammation effects of the isolated compounds on the lipopolysaccharide (LPS)-induced NO production in RAW 264.7 cells were measured using the Griess reaction. Compounds 7 and 9 had the strongest inhibitory activity, with IC50 values of 7.6 and 11.2 M, respectively, and were followed by 3-6, which had IC50 values ranging from 19.6 to 28.7 M. The findings suggested that the NO-inhibiting properties of D. oliveri and its natural compounds may have anti-inflammatory benefits.