Chemical Composition of Essential Oils from Origanum onites L. and Cymbopogon citratus, and Their Synergistic Effects with Acyclovir against HSV-1

Origanum onites L. and Cymbopogon citratus have a number of pharmacological activities such as antimicrobial, anti-inflammatory and antioxidant. In this study, we aimed to investigate the components and the synergistic effect of Origanum onites L. and Cymbopogon citratus and their combinations with acyclovir against HSV-1 on HEp-2 cell line. The main essential oil components of Origanum onites L. were Thymol (68,28%), γ-Terpinene (5,50%), p-Cymene (5,47%) and Linalool (4,40%) and for Cymbopogon citratus the main components were E-Citral (47,53%), Z-Citral (36,29%), β-Myrcene (9,31%). Initially, 100 TCID50 (Tissue Culture Infective Dose) of HSV-1 on HEp-2 was calculated in the study. Antiviral activity studies were carried out at the concentration of 1, 10 and 100 TCID50 of HSV-1. The antimicrobial efficacy of the Origanum onites L. and Cymbopogon citratus essential oils were assessed alone and in combination with acyclovir. In addition, the efficacy of acyclovir was determined on 100 TCID50 of HSV-1. In conclusion, the essential oils of Origanum onites L. and Cymbopogon citratus against HVS-1 were found to have a significant inhibitory effect on viral replication. We think that the essential oils of Origanum onites L. and Cymbopogon citratus may be a very important agent against herpesviruses. In particular, the essential oils of Cymbopogon citratus can be a very promising plant.