Nitric oxide production inhibitory activity of flavonoids contained in trunk exudates of Dalbergia sissoo.

Methanolic extracts of trunk exudates of Dalbergia sissoo yielded two new open-chain neoflavonoids (1, 2), a new flavonoid (3), a new flavanone (4), and 26 known compounds. Their structures were elucidated by detailed spectroscopic analyses. The ability of the isolated compounds to prevent nitric oxide (NO) production by LPS-stimulated J774.1 cells was also studied. All of the isolated compounds except 4, formononetin, and zenognosin B exhibited significant activity in a concentration-dependent manner. Compounds 2 and 3 were among the most potent NO production inhibitors, with IC50 values of 3.19 and 6.22 microM, respectively, and compound 1 had an IC50 of 31.6 microM.