Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 16 2 2024 04 19 251 257 Mahsa Zamanian Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran Emad Asgari Department of Theriogenology, School of Veterinary Medicine, University of Tehran, Tehran, Iran Sahar Afaridoon Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran Tahmineh Akbarzadeh Department of Medicinal Chemistry, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; Persian Medicine and Pharmacy Research Center, Tehran University of Medical Sciences, Tehran, Iran Zohreh Sharifi Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran Mina Saeedi Persian Medicine and Pharmacy Research Center, Tehran University of Medical Sciences, Tehran, Iran; Medicinal Plants Research Center, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran 2023 07 31 2024 02 25 Background and Objectives: HSV-1 is known as a very contagious virus and the main cause of cold sores or fever blisters. Herein, the aqueous extract of Areca catechu L. was evaluated for its anti-HSV-1 activity, compared to the standard control (acyclovir). Also, the effect of extract on the expression of UL46 and US6 genes that accumulate late in viral infection, was studied. Materials and Methods: The aqueous extract was obtained by the maceration of powdered plant in boiling water. Its antiviral activity was evaluated on Vero cells infected with HSV-1 at different times: 2 h pre-infection, simultaneous infection, and 4 h post-infection, using MTT assay. The effect of extract on the expression of genes was investigated with quantitative real-time PCR. Results: The aqueous extract of A. catechu induced the inhibition of infection with the IC50 value of 110.52 ± 1.36 μg/ml. Also, it reduced the expression of UL46 when it was added 2 h pre-infection at 100 μg/ml. Moreover, reduction of expression of US6 was observed at the same concentration when the extract was used simultaneously with the occurrence of infection and 4 h post-infection. Conclusion: A. catechu can be considered an essential element of natural-based anti-HSV-1 agents. https://ijm.tums.ac.ir/index.php/ijm/article/view/4335 https://ijm.tums.ac.ir/index.php/ijm/article/download/4335/1662