Polyphenon
Polyphenon is a series of high grade green tea polyphenol extracts manufactured by the Mitsui Norin Co., Ltd. of Japan. The extracts are in part the result of a water based extraction method which begins with green tea leaves, and then involves successive steps which concentrate the catechins thought to be responsible for the health benefits of green tea. As of October 2016, 20 clinical trials have been published for Polyphenon E (16 oral and 4 topical). In 2006 the U.S. Food and Drug Administration approved as a drug an ointment containing 15% Polyphenon E for the treatment of  genital and perianal warts. The product name is Veregen. To date, no oral use of the product has been approved. Many dietary supplement companies sell green tea extracts as supplements, but as such, are not allowed to make any disease treatment or prevention claims.