Minthostachys verticillata essentials oil and its major components: antiherpetic selective action in HEp-2 cells

Abstract

The medicinal herb Minthostachys verticillata was studied in various fields of natural medicine. Numerous studies were made to evaluate its antimicrobial properties. This work emphasizes in the analysis of the antiviral capacity of its Essential Oil (EO). The aim of this study was to determine the Therapeutic Index (TI) of the EO and its main chemical components. Suid herpesvirus type 1 or Pseudorabies virus (Prv) was proliferated in HEp-2 cells in presence of non-toxic concentrations of the oily samples. Antiviral action was quantified by reducing the number of plaques of lysis. Previously, the cytotoxicity of the samples was evaluated and 50% Cytotoxic Concentration values (CC50) were determined. The TI was calculated by relating the cytotoxic concentrations of each sample vs. those concentrations active against the virus. The results showed that the major components of the EO were pulegone, menthone and limonene, with CC50 of 352, 835 and 1155 μg/mL respectively vs. the CC50 of EO: 613 μg/mL. The antiviral action was exerted by pulegone and the EO at concentrations 20 to 30 times lowers than the toxic concentrations. These IT values show the possible applicability of these compounds because they exert selective antiviral action.