DEVELOPMENT OF ANTIVIRAL THERAPEUTIC AGENTS FROM TRADITIONAL MEDICINES

Traditional medicines contain various metabolites derived from nucleic acid, protein, and lipid metabolism. Some of these specific metabolit es may recongnize the differences between viral and host metabolism re sulting in antiviral activity; hence traditional medicines may be usef ul sources for new antiviral agents. Traditional medicines can be chea ply obtained and have been orally administered as hot-water extracts. Therefore, they may be used for the prophylactic and therapeutic treat ment of viral infection by drinking them, such as coffee or tea. Here are describe how the antiviral activity of traditional medicines was s creened in vitro and how their therapeutic antiviral activities were v erified in vivo, to obtain traditional antiviral medicines that can be clinically used. Therefore, we have selected 12 herbal extracts, from more than 250 herbal medicines, that exhibit therapeutic activities a gainst cutaneous herpes simplex virus (HSV) type 1 (HSV-1) infection i n mice. Four of the 12 augmented the therapeutic efficacy of acyclovir (ACV) in mice and showed potent anti-HSV activity against infection w ith ACV-resistant HSV-1 mutants in mice. These herbal extracts selecti vely inhibited viral DNA synthesis and showed a different mode of anti -HSV-1 action from that of ACV. They were also effective against both recurrent HSV and cytomegalovirus infections, without toxicity. Such p rophylactic and therapeutic antiviral activities of the traditional me dicines were verified by the purification of major active compounds. W e could show new indications of traditional medicines as antiviral age nts. Thus, the drinking of the extracts, in a daily tea or coffee, may be used for prophylaxis and therapy of diseases caused by herpes viru s infection and improve the quality of life.