Antiviral activity of theaflavin digallate against herpes simplex virus type 1

Abstract

Tea is the second most consumed drink in the world. The beneficial effects of tea have been mostly attributed to its catechin content. Black tea is derived from the leaves of Camellia sinensis plant, and it is rich in theaflavin polyphenols, in particular theaflavin (TF1), theaflavin-3-monogallate (TF2A), theaflavin-3'-monogallate (TF2B), and theaflavin-3,3'-digallate (TF3). Vero and A549 cells were used to evaluate the effect of purified individual black tea theaflavins as anti-herpes simplex virus 1 agents. With the rise of HSV resistant strains, there is a critical need to develop novel antiherpesviral treatments. Results of the cytotoxicity assay tested by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium] showed that TF1, TF2, and TF3 are not toxic to Vero and A549 cells at a concentration up to 75 μM. The antiviral activity of the individual theaflavins was tested by plaque reduction assay, MTS assay, flow cytometric analysis and confocal microscopy observations. The results showed that TF1, TF2, and TF3 exhibit potent, dose-dependent anti-HSV-1 effect, with TF3 being the most efficient in both Vero and A549 cells. A concentration of 50 μM TF3 and above was sufficient to inhibit >99% of the production of HSV-1 viral particles. The anti-HSV-1 effect of TF3 is due to a direct effect on the virions, and treating Vero or A549 cells with TF3 for 1h prior to infection, or treating the cells at different times post infection does not inhibit HSV-1 production. TF3 is stable at vaginal pH, indicating its potential to be a promising natural and affordable remedy against herpes simplex viral infections.

Antiviral effect of theaflavins against caliciviruses

“…They have many physiological activities, such as antiviral, antioxidant and antibacterial activities. 17,18,[25][26][27] To determine the antiviral mechanism of theaflavins, we examined antiviral activity when FCV was treated with theaflavin monogallates (mixture of TF2A and 2B) and TF3 before contact with the cells. A mixture of theaflavins and virus were filtered to remove the remaining compounds from the test solution, and then cells were infected with the treated virus.…”

Antiviral mechanism of tea polyphenols on porcine reproductive and respiratory syndrome virus

“…In our study, TPP inhibits the replication of PRRSV in multiple ways. Likewise, other polyphenols have also been described to present antiviral activity, such as proanthocyanidin A2 and thea avin [29,30]. Previous reports also indicate that replication of PRRSV in Marc-145 cells is inhibited by EGCG [20], which accounts for 60 to 80% of TPP.…”

Theaflavins, polyphenols of black tea, inhibit entry of hepatitis C virus

“…To understand the role of functional groups and galloyl moiety, further study is required through the approach of combinatorial and synthetic chemistry. It is interesting to note that theaflavins and EGCG have been described to inactivate the same viruses, HSV-1, HIV-1 and influenza virus (18–20,40). Taken together with the results presented here, it seems that these polyphenols from tea, black or green, have a very specific mode of action on enveloped viruses that could be more exploited in the context of antiviral therapy.…”