Biography
Biography: Stephen Hsu
Abstract
Tea is the second most popular beverage in the world next to water. Benefits of tea polyphenols, especially the polyphenols
from unfermented green tea leaves, have been studies extensively. While the antioxidant, anticancer, and anti-inflammatory
activities of green tea extracts have been well-documented, the antimicrobial activities of green tea and its extracts were only
scientifically investigated in recent years. Many groups around the globe reported promising results regarding the antibacterial
and antiviral properties of green tea polyphenols, especially epigallocatechin-3-gallate (EGCG), the most abundant polyphenol
from green tea. However, due to the water-soluble and chemically unstable nature of these antioxidant compounds, green
tea polyphenols in their original forms are difficult to incorporate into practical products for antimicrobial use, such as
topical formulations, disinfectants, and sanitizers. To overcome these obstacles, we have focused on certain modified green
tea polyphenols that have lipid-solubility and stable activity against microbes that are resistent to conventional disinfectant
methods. We discovered that the lipid-soluble tea polyphenols (LTP) possess potent virucidal activities against many viruses,
including alcohol-resistant nonenveloped viruses such as poliovirus and norovirus. Both In vitro and clinical studies have
demonstrated that LTP, in the form of EGCG-esters, are effective against herpes simplex viruses and related symptoms such
as herpes labialis, without adverse effect. These findings lead to recently created topical applications for treating herpes labialis
and alcohol-based hand sanitizer formulations containing LTP. We are currently investigating the sporicidal mechanism of
LTP to develop strategies of using these nontoxic compounds to better protect populations from microbial infections.