Abstract
Two new furanoflavonoids, retamasins A and B (1 and 2, resp.), along with five known flavonoids, 3-7, were isolated from the aerial parts of Retama raetam. Their structures were determined on the basis of extensive spectroscopic (IR, MS, and 1D- and 2D-NMR) analyses and by comparison with the literature data. This is the first report of the isolation of new furanoflavonoids 1 and 2 from Retama genus, while compounds 3, 5, and 6 were found for the first time from R. raetam. Antioxidant and anti-inflammatory activities of the isolated compounds were also evaluated. Compounds 2, 3, and 5-7 exhibited potent inhibitions of iNOS activity with IC50 values of 2.9, 5.0, 3.1, 1.2, and 4.8 mu g/ml, respectively. All compounds inhibited NF-kappa B except 1 and 5. Compound 6 was most active in inhibiting iNOS and NF-kappa B activity, as well as in decreasing oxidative stress.