Antioxidant and Anti-Inflammatory Constituents from Rhamnus crenata

A new naphthalene derivative, 7-acetyl-8-hydroxy-3-methoxy-6-methylnaphthalen-1-yl acetate ( 1 ), has been isolated from the stem of Rhamnus crenata , together with eight known compounds 2–9 . The structure of new compound 1 was determined through spectroscopic and MS analyses. Among the isolates, emodin ( 3 ), physcion ( 4 ), quercetin 3-O- α -L-rhamnopyranoside ( 5 ), and quercetin 7-O- α -L-rhamnopyranoside ( 6 ) showed potent inhibition with IC 50 values of 33.18 ± 2.73, 35.52 ± 3.27, 28.05 ± 1.85, and 26.41 ± 3.01 μM, respectively, against LPS-induced NO generation. In addition, compounds 3 , 5 , and 6 also showed potent DPPH radical scavenging activities with IC 50 values of 95.47 ± 6.18, 68.27 ± 5.38, and 66.25 ± 4.20 μM, respectively.