Abstract

This study was designed to investigate the antiherpetic activities of the crude methanolic extracts of the aerial parts of three species of Hypericum growing in Turkey (Hypericum neurocalycinum Boiss. & Heldr., Hypericum salsugineumRobson & Hub.-Mor. and Hypericum kotschyanum Boiss.). For this purpose, firstly, the cytotoxicity potential of the extracts against Vero cells were assessed using MTT [3-(4,5-dimethylthiazol–2-yl) - 2,5-diphenyltetrazolium bromide] colorimetric assay. The 50% cytotoxic dose (CD₅₀) corresponded to the concentration required to kill 50% of the Vero cells for each extract was calculated by nonlinear regression analysis using GraphPad Prism software. Additionally, the maximum non-cytotoxic concentrations (MNCCs) were determined as the maximal concentration of the extracts that did not exert a toxic effect. Later, the values of the maximum non-toxic concentration obtained (50.00, 100.00 and 25.00 µg/ml for the methanolic extracts ofH. neurocalycinum, H. salsugineum and H. kotschyanum, respectively) were used in antiherpetic activity determination of the extracts using MTT assay. Nevertheless, it was determined that none of the extracts have antiherpetic activity in tested maximum non-toxic concentrations.

Key words:  Hypericum species, antiherpetic activity, colorimetric MTT assay.

Abbreviation

MTT, 3-(4,5-Dimethylthiazol–2-yl) - 2,5-diphenyltetrazolium bromide;MNCCs, maximum non-cytotoxic concentrations.