Protective effects of quercetin during influenza virus-induced oxidative stress

Oxidative stress was found to have a role in many viral diseases including AIDS, hepatitis and influenza. In the present study the pathology of influe nza viral infection in the lungs, which may lead to oxidative stress, was i nvestigated and an attempt was made to study the efficacy of anti-oxidants as therapeutic agents. Adult male mice of Swiss albino type were infected w ith influenza virus (A/Hong Kong/8/68) and studied for the anti-oxidant sta tus in the lungs by evaluating the lung enzymatic anti-oxidant system inclu ding superoxide dismutase and catalase. Superoxide radical generation, whic h might increase by the activated alveolar macrophages, was estimated by ni troblue-tetrazolium reduction assay. We have also estimated lipid peroxidat ion levels in lung through thiobarbutiric acid reactive substances assay. W e also examined the ability of flavonoid quercetin in protecting from influ enza virus-induced oxidative stress. The influenza-infected group showed de creased levels of superoxide dismutase and catalase; however, anti-oxidant supplemented groups showed these activities to be the same as in the contro l group. The lipid peroxide levels were increased in virus-infected mice. A dministration of quercetin lowered the lipid peroxide levels significantly. Formazan positive cells were increased by 80% in the virus-infected group and supplementation with quercetin reduced their number to 44%.