Antioxidative oligostilbenes from Caragana sinica

Two new oligostilbenes, caragasinins A (5) and B (10), and eight known compounds, kobophenol A (1), (+)-α-viniferin (2), (+)-ampelopsin F (3), pallidol (4), (+)-isoampelopsin F (6), miyabenol C (7), carasinaurone (8) and caraphenol B (9) were isolated from the ethylacetate-soluble extract of the roots of Caragana sinica. The structures of the isolates were determined on the basis of extensive spectroscopic analysis including 1D, 2D NMR and HRESI-MS. These compounds were assessed for antioxidant activities. Caragasinin A (5), caraphenol B (9), and caragasinin B (10) showed moderate DPPH scavenging activity and lipid peroxidation inhibitory activities with IC50 values ranging from 34.7 ± 1.0 to 89.1 ± 2.3 μM.