Evaluation of the Antiviral Activity of Cistus laurifolius L. Leaf Extracts against Respiratory Syncytial Virus (RSV)

As an effort to search for new antiviral agents from traditional medicine, the methanol, and aqueous extracts of Cistus laurifolius L. were investigated in vitro antiviral activities against respiratory syncytial virus (RSV) with a XTT-based colorimetric assay. The antiviral activity of EC50 was defined as the concentration achieved 50% cyto-protection against virus infection and the selectivity index (SI) was determined by the ratio of CC50 (concentration of 50% cellular cytotoxicity) to EC50. As a result of the study, it was determined that the methanol extract (EC50 = 0.504 μg/ml; SI = 188.91) had anti-RSV activity more than ribavirin (EC50 = 4.19 μg/ml, SI = 27.92) which has been used positive control against RSV. On the other hand, antiviral activity could not be determined in aqueous extract. This study is the first report to assess the anti-RSV activity of Cistus laurifolius. Keywords : Cistus laurifolius, methanolic and aqueous extracts, antiviral activity, respiratory syncytial virus DOI : 10.7176/JSTR/6-10-09