Abstract: To investigate the effects of Acalypha australis L.ethanol extract on influenza virus-induced lung inflammation in mice,activity of influenza virus neuraminidase and its antioxidant activities,the influenza virus infected lung inflammation model mice was established by intranasal inoculation,followed by the observation of pathological changes of lung tissue in mice.The inhibition activity of high,medium and low dosage groups on influenza virus neuraminidase were detected by the substrate of 2-(4-methylumbelliferyl)-α-D-N-acetylneuraminic acid (MUNANA),as well as its antioxidant activities were evaluated by Nitric Oxide,DPPH scavenging and β-carotene linoleic acid bleaching assays.The results showed that compared with the blank control group, in vivo, the normal tissues of alveolar and bronchioles in model group mice was destroyed.Compared with model group,oseltamivir group and the high,medium and low dose groups of A.australis ethanol extract can obviously promote the pathological damage of lung tissue of mice in dose-dependent manner.In the assay of influenza virus neuraminidase inhibiting activity,compared with model control group,the fluorescence value of A.australis ethanol extract groups significantly decreased (P<0.01) and the inhibition rate of high dose group reached 60.48%.In addition,the A.australis ethanol extract possessed potential antioxidant activities.In conclusion, A. australis ethanol extract can alleviate influenza virus-induced lung inflammation,which may be related to its inhibition activity on influenza virus neuraminidase and its antioxidant activities.

Key words: Acalypha australis L., influenza A virus, neuraminidase, antioxidation