The effect of medicinal plants used in Chinese folk medicine on RANTES secretion by virus-infected human epithelial cells

The accumulation of inflammatory cells in the infective sites has been reported to play a crucial role in the progression of chronic inflammation and multiple sclerosis after viral infection. In the present study, nine ethanol extracts of Forsythia suspensa Vahl. (Oleaceae), Lonicera japonica Thunb. (Caprifoliaceae), Isatis indigotica Fort. (Cruciferae), Strobilanthes cusia (Ness.) O. Kuntze (Acanthaceae), Astragalus membranaceus (Fisch.) Bge. (Leguminosae), Hedysarum polybotrys Hand.-Mazz. (Leguminosae), Andrographis paniculata (Burm. f.) Ness. (Acanthaceae), Glycyrrhiza uralensis Fischer. (Leguminosae) and Ligusticum wallichii Franch. (Umbelliferae), medicinal plants traditionally used in China for treating conditions likely to be associated with inflammation and viral infection, were screened for their effect on RANTES secretion by influenza A virus (H1N1)-infected human bronchial epithelial cells (A549). With exception of Lonicera japonica, Isatis indigotica, Astragalus membranaceus and Hedysarum polybotrys, all plants tested at concentration of 200 μg/ml possessed more than 50% suppressing effect on RANTES secretion by H1N1-infected A549 bronchial epithelial cells. Among the plants tested, Andrographis paniculata showed the most promising property to inhibit RANTES secretion with an IC50 of 1.2 ± 0.4 μg/ml while the next two were Glycyrrhiza uralensis and Forsythia suspensa (IC50 ranging from 35 to 48 μg/ml).