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

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 HEp2 cells in vitro.

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 2,2-diphenyl-1- 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 Hep2 cells and antiviral activity of the extract on adenovirus were assessed by the MTT colorimetric method. The half-maximum cytotoxicity concentration (CC50) and the 50% inhibitory concentration (IC50) of the extract were calculated as well.

Phytochemical investigations showed that the IC50 of DPPH radical was 42.1 ± 3.2 μg/mL compared with butylated hydroxytoluene (IC50 of 33.5 ± 3.67 μg/mL). The TPC and TFC of the extract were 74.2 mg GAE/g and 16.3 mg RE/g of the dry extract, respectively. The extract demonstrated the highest amounts of syringic acid, gallic acid, 3,4-dihydroxybenzoic acid, and rutin levels (67.27, 20.12, 7.39, and 2.97 mg/g DW, respectively). Based on the results of cell culture, the CC50 and IC50 of GTE were 103.3 μg/mL and 25.16 μg/mL, respectively.

GTE with phenolic and flavonoid compounds can exert dose-dependent inhibitory effects on adenoviruses.