In vitro anti-herpes simplex virus-2 activity of Salvia desoleana Atzei & V. Picci essential oil

Salvia desoleana Atzei & V. Picci is an indigenous species in Sardinia island used in folk medicine to treat menstrual, digestive and central nervous system diseases. Nowadays, it is widely cultivated for the pleasant smell of its essential oil (EO), whose antimicrobial and antifungal activities have already been screened. This study evaluated the in vitro anti-Herpes Simplex Virus-2 (HSV-2) activity of S. desoleana EO, fractions and main components: linalyl acetate, alpha terpinyl acetate, and germacrene D. Phytochemical composition of S. desoleana EO was studied by GC-FID/MS analysis and the active fraction(s) and/or compounds in S. desoleana EO were identified with a bioassay-guided fractionation procedure through in vitro assays on cell viability and HSV-2 and RSV inhibition. S. desoleana EO inhibits both acyclovir sensitive and acyclovir resistant HSV-2 strains with EC50 values of 23.72 μg/ml for the former and 28.57 μg/ml for the latter. Moreover, a significant suppression of HSV-2 replication was observed with an EC50 value of 33.01 μg/ml (95% CI: 26.26 to 41.49) when the EO was added post-infection. Among the fractions resulting from flash column chromatography on silica gel, the one containing 54% of germacrene D showed a similar spectrum of activity of S. desoleana EO with a stronger suppression in post-infection stage. These results indicated that S. desoleana EO can be of interest to develop new and alternative anti-HSV-2 products active also against acyclovir-resistant HSV-2 strains.