Anti-viral Effect and Mechanism of Carvacrol on Herpes Simplex Virus Type 1

Background and Aims: Herpes simplex virus type 1 (HSV-1) belonging to herpes viridae family is a normal human pathogen with benign lesions in immunocompromised patients which creates serious problems. Acyclovir is used to treat herpetic infections. Because of developing drug-resistant strains, the use of medicinal plants and their related compounds with fewer side effects is considered for the treatment of patients. In this study the antiviral effect and mechanism of carvacrol, a medicinal compound, on HSV1 virus was studied. Materials and Methods: In this study, the maximum nontoxic concentration on vero cells was determined by MTT. The antiviral effect of the compound was determined by TCID50. The expression of early and late stages of viral replication (UL52 and UL27) was evaluated by real time polymerase chain reaction method. Results: The toxic concentration of carvacrol causing 50% cell death was 0.001%. The mechanism of action of the compound showed that pretreatment of HSV-1 with carvacrol prior to infection inhibits its ineffectivity approximately to 70%. The results also showed no reduction in the early and late gene expression of herpes virus replication. Conclusions: Overall, the findings demonstrated that the carvacrol has inhibitory effect on HSV-1 by direct inhibition of free virus particles.