Abstract: In this experiment,a crude extract named as AWE was extracted by water extraction from Acalypha wilkesiana leaves,and then a polyphenol-enriched fraction was prepared by macroporous resin,designated as AWF.Based on the results of free radical scavenging activities of AWE and AWF in vitro,the hepatoprotective effects of AWF and the underlying mechanisms were further investigated by APAP-induced acute liver injury mice model.Results showed that the polyphenol contents in AWE and AWF reached 224.9±1.5 and 608.7±16.4 μg GAE/mg extract,respectively.AWF exhibited strong scavenging abilities on DPPH and ABTS free radicals,the IC₅₀s were 4.46 and 41.25 μg/mL,respectively.AWF (200 and 400 mg/kg·bw) pretreatment significantly alleviated APAP-induced acute liver injury,as evidenced by the decreased serum levels of ALT,AST,LDH,and MDA (P<0.05 or P<0.001),and the elevated activities of SOD,CAT,and GSH-Px (P<0.01or P<0.001),the results of which were further confirmed by the histopathological analysis.Moreover,AWF remarkably inhibited the activation of MAPKs and proapoptotic protein caspase-3/9,down-regulated the expression level of proapoptotic protein Bax and restored the expression level of antiapoptotic protein Bcl2.These results indicate that AWF possesses hepatoprotective effects against APAP-induced liver injury,which may be attributed to the antioxidant and antiapoptotic effects through the modification of MAPKs/apoptosis cascade reaction.

Key words: Acalypha wilkesiana leaves, acute liver injury, antioxidant, antiapoptotic effect