Evaluation of the effect of hydro alcoholic extract of cinnamon on herpes simplex virus-1

Background: Long‑term treatments of herpes simplex with drugs such as acyclovir, the side effects to such drugs including limited usage during the lactation period, and concerns for the emergence of drug‑resistant strains have given rise to a need for new medications with fewer complications. Nowadays, there is an increasing usage of herbal medicines throughout the world due to their higher effectiveness and safety. The present study aims to assess the effects of hydroalcoholic cinnamon extract on herpes simplex virus type 1 (HSV‑1) in culture with vero cells. Materials and Methods: In this in vitro study Hydroalcoholic extract of cinnamon was extracted through percolation. To assess cell survival rates, the 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide assay was employed, and the tissue culture infective dose 50 assay was used to quantify the virus. Effects of the extract were evaluated in three stages, including before, during, and after viral inoculation into the culture medium. Two‑way ANOVA and Post hoc analysis the test was performed in 1, 0.5, and 0.25 mg/ml concentrations of cinnamon extract in every stage (P < 0.05). Results: Over 50% of the cells survived in the 0.25 mg/ml extract concentration. Results of our viral quantification showed a viral load of 105. The cinnamon extract was able to reduce the viral titer in all concentrations under study. Conclusion: Hydroalcoholic extract of cinnamon was effective in reducing the viral titer of HSV‑1. This effect could have been caused by prevention of viral attachment to cells; however, further research is required to determine the exact mechanisms at play.