Cytotoxic and antiviral activities of the essential oils from Tunisian Fern, Osmunda regalis

This study was undertaken to assess the in vitro cytotoxic and antiviral activities of the essential oil (EO) from Tunisian fern, Osmunda regalis. The essential oil was obtained by hydrodistillation and its chemical composition was determined by gas chromatography and mass spectrometry (GC-FID and GC–MS) analyses that allowed detecting 85.35% of the components. The main compounds were hexahydrofarnesyl acetone (11.82%), 2,4-di-t-butylphenol (6.80%), and phytol (6.46%). Cytotoxicity of the essential oil was assessed on HEp-2 cell line using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Antiviral activity was also evaluated in vitro against Coxsackievirus B4 (CV-B4), an enterovirus implicated in a variety of diseases such as myocarditis, type 1 diabetes and central nervous system diseases, by measuring cell viability following viral infection (using MTT) and appreciating the reduction of cytopathic effect (CPE). Hence, the 50% cytotoxic concentration (CC50), 50% inhibitory concentration (IC50) and selectivity index (SI) were determined. The essential oil turned out to be non-toxic against the tested cell line (CC50 = 1772.41 ± 0.95) μg/mL, have a relevant anti-Coxsckievirus B4 activity (IC50 = 2.24 ± 0.99) μg/mL and a high SI (789.66). Results presented here suggest that O. regalis EO is a potentially promising new source as active antiviral agent.