Four new prenylflavonol glycosides from the leaves of Cyclocarya paliurus

Four new prenylflavonol glycosides (1-4) along with two known analogues (5-6) were isolated from the leaves of Cyclocarya paliurus for the first time. The structures of these compounds were characterized by comprehensive analysis of 1 D, 2 D NMR, HRESIMS, UV data and enzymatic hydrolysis. In bioassays, compounds 1-4 were evaluated for inhibitory effects on xanthine oxidase (XOD) and effects on the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS) induced RAW264.7 cells. Moreover, compounds 1 and 2 showed outstanding XOD inhibitions with IC₅₀ values of 18.16 ± 3.91 and 37.65 ± 5.67 µM, and exhibited inhibitions against LPS-induced NO production with IC₅₀ values of 80.50 ± 3.09 and 82.28 ± 2.87 µM.

Keywords: Cyclocarya paliurus; RAW264.7 cells; nitric oxide; prenylflavonol glycosides; xanthine oxidase.