Phytochemical properties and antiviral effect of green tea (Camellia sinensis) extract on adenovirus in vitro

Background and aims: The lack of effective antiviral drugs for adenoviruses is one of the most important problems in this area. The aim of this study was to investigate the phytochemical properties and antiviral effect of the green tea extract (GTE) on adenovirus in HEp۲ cells in vitro. Methods: In this experimental study, dried leaves of green tea were extracted by maceration. Total phenolic content (TPC), total flavonoid content (TFC), and antioxidant capacity of the extract were measured by Folin-Ciocalteu, aluminum chloride, and ۲,۲-diphenyl-۱- picrylhydrazyl (DPPH) colorimetric methods, respectively. The amounts of some phenolic compounds in the extract were also determined using high-performance liquid chromatography. The toxicity of the extract on Hep۲ cells and antiviral activity of the extract on adenovirus were assessed by the MTT colorimetric method. The half-maximum cytotoxicity concentration (CC۵۰) and the ۵۰% inhibitory concentration (IC۵۰) of the extract were calculated as well. Results: Phytochemical investigations showed that the IC۵۰ of DPPH radical was ۴۲.۱ ± ۳.۲ μg/mL compared with butylated hydroxytoluene (IC۵۰ of ۳۳.۵ ± ۳.۶۷ μg/mL). The TPC and TFC of the extract were ۷۴.۲ mg GAE/g and ۱۶.۳ mg RE/g of the dry extract, respectively. The extract demonstrated the highest amounts of syringic acid, gallic acid, ۳,۴-dihydroxybenzoic acid, and rutin levels (۶۷.۲۷, ۲۰.۱۲, ۷.۳۹, and ۲.۹۷ mg/g DW, respectively). Based on the results of cell culture, the CC۵۰ and IC۵۰ of GTE were ۱۰۳.۳ μg/mL and ۲۵.۱۶ μg/mL, respectively. Conclusion: GTE with phenolic and flavonoid compounds can exert dose-dependent inhibitory effects on adenoviruses.

Keywords:

Adenovirus , Camellia sinensis , Antiviral effect , Green tea