Evaluation of antiviral effect of Epigallocatechin gallate, Epigallocatechin, Epicatechin gallate and Green tea extract against fowl adenovirus-4

Abstract

Tea is the second most consumed drink globally after water. Green tea is the non-fermented form of tea prepared from the buds of Camellia senensis plant. Green tea extract (GTE) and its isolated compounds epigallocatechin gallate (EGCG), epicatechin gallate (ECG) and epigallocatechin (EGC) were evaluated for their capacity to inhibit fowl adenovirus type 4 (FAdV-4) in-vitro through plaque reduction assay, its virucidal effect and its cytotoxicity was evaluated to normal cells through 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl tetrazoliumbromide (MTT) assay. In-vivo study was conducted in broiler chicks to evaluate its protective efficacy against challenge of FAdV-4. Plaque reduction assay GTE at dose rate of 100mg/ml was shown maximum inhibition of plaque in-vitro followed by EGCG, EGC and ECG. In virus reduction assay, the test compounds were added to infected cells and harvest the virus at 8, 24 and 36 hours of post infection. The harvested virus was subjected to plaque assay and maximum inhibition in virus yield was observed at 100 mg/ml of GTE at 24 hours of post infection against FAdV-4 with (EC50) 34.80μg with a 50% CC50 109.23μg having SI 3.195 showed strong antiviral effects with minimum CC50 toward normal cells. Maximum cell inhibition was shown by EGCG, EGC, and ECG at 120 μM and 180 μM and 200 μM respectively while GTE showed minimum cell inhibition at different concentration. In-vivo study, GTE was shown maximum protection in broiler chicks against challenge which was shown survival rate of more than 90% at 100 mg/ml GTE. Gross and histopathological lesion score was minimum in GTE treated group followed by EGCG, EGC and ECG. GTE was showed promising antiviral activity against FAdV-4 in cell culture which was evaluated in in-vivo and was a candidate agent to uaed in poultry for this virus infection.