クロモジ熱水抽出物の持続的な インフルエンザウィルス増殖抑制効果

摘要

Background Kuromoji (Lindera umbellata Thunb.) is a deciduous shi'ub of the Lauraceae with pleasant ai'oma, and has long been used as a material of stomach medicine. We found that a hot-water extract of branches of Kuromoji (Kuromoji extract) has suppressive effect on plaque formation caused by influenza viral infection. However, the persistence of protective effect of Kuromoji extract against viral infection has not been clarified. Methods Madin-Darby canine kidney cells were treated with Kuromoji extract simultaneously with or after infection with influenza virus strain (A/Puerto Rico/8/34, H1N1). The effect on influenza virus infection was evaluated by the observation of cytopathic effect and quantitative analysis of viral protein mRNA expression in cells. Results Kuromoji extract significantly suppressed the cytopathic effect caused by influenza virus. Expression of viral protein mRNA in cells was also significantly suppressed by the treatment with Kuromoji extract. The suppressive effect on viral mRNA expression was also observed in cells that had finished the treatment with Kuromoji extract 24 hours prior to viral infection. Conclusions Our study showed that Kuromoji extract has a sustained suppressive effect on the infection of influenza virus. We believe that Kuromoji extract becomes a useful food or medical material with protective effects against influenza infection.