New prenylflavonol glycosides with xanthine oxidase inhibitory activity from the leaves of Cyclocarya paliurus.

• Eight new and five known prenylflavonol glycosides were isolated from the leaves of Cyclocarya paliurus. • Prenylflavonol glycosides were discovered in Cyclocarya paliurus for the first time. • The compounds were evaluated for the inhibitory effects on xanthine oxidase activity. • Compounds 2 and 7 exhibited significant inhibition on xanthine oxidase activity. Eight new prenylflavonol glycosides (1 – 8), along with five known analogues (9 – 13) were isolated from the n -butanol extract of the dried leaves of Cyclocarya paliurus (family Juglandaceae) for the first time. The structures of these compounds were characterized by comprehensive analysis of 1D, 2D NMR, HRESIMS, UV data and acid hydrolysis. In bioassay, all these thirteen prenylflavonol glycosides exhibited inhibitory effects on xanthine oxidase (XOD) activity. Especially compounds 2 and 7 , showed outstanding IC 50 values of 31.81 ± 2.20 and 29.71 ± 3.69 μM, respectively. [ABSTRACT FROM AUTHOR]