Flavonoids from Millettia nitida var. hirsutissima with their anticoagulative activities and inhibitory effects on NO production.

Two new compounds, (2R)-7,3'-dihydroxy-6,4'-methoxyflavan (1) and (3R)-7,4'-dihydroxy-2'-methoxyisoflavan (2), along with 12 known flavonoids (3-14), were isolated from the vine stems of Millettia nitida var. hirsutissima. The structures of the isolated compounds were elucidated based on spectroscopic analyses and comparison of literature data. All of the isolates were evaluated for their effects on in-vitro anticoagulative assay and on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated RAW264.7 macrophages. As a result, all compounds showed weak antiplatelet aggregation activities and compounds 4, 5, 7, 8 and 9 demonstrated antithrombin activity with a good dose-effect relationship from 5 to 100 μg mL⁻¹ in rabbit plasma. Compounds 8, 9, 10 and 14 exhibited inhibitory effects on LPS-induced NO production in RAW264.7 macrophages with IC₅₀ values of 4.79 ± 0.20, 8.23 ± 0.35, 5.23 ± 0.11 and 6.30 ± 0.30 μg mL⁻¹, respectively.