Modified Green Tea Polyphenol, EGCG-ester, as a Novel Approach to Inhibit Herpes Simplex Virus Infections

HSV-1 DNA with the green fluorescent protein (GFP) introduced into the UL46 gene was used to investigate the effects of green tea polyphenols on the virus. Two different green tea extracts have been isolated and modified, EGCG and EGCG-ester. These extracts with concentration of 12.5, 25, 50, 75 and 100uM were used to determine its effects on cell morphology, cell proliferation and cell viability. The results indicated that the maximum non-toxic concentration is 75uM for both polyphenols. GFP expression, DAPI DNA stain and Lysosome activation stain were also used to observe the morphological, and cellular changes in the infected cells. The results suggested that EGCG-ester treated infected cultures did not show any changes compared with noninfected cells. Each extract was further used to study its effect on HSV1, by plaque forming unit (PFU) assay and GFP expression. EGCG treated virus had a titer that is ten fold lower than the control, and EGCG-ester completely inhibited the PFU. Quantitative study using RT-PCR indicated that EGCG-ester at 75uM inhibited 99.46% of infection when compared to the control