title: Antiherpesvirus activity and mode of action of SP-303, a novel plant flavonoid.
abstract: SP-303, a natural plant flavonoid polymer of molecular weight 2,100 daltons, was found to have antiviral activity against two strains of type 1 herpes-type simplex virus, including a thymidine-kinase-deficient strain, and a strain of type 2 herpes simplex virus. The 50% effective concentrations (EC50s) were 1-2 microM. Acyclovir, which was run in parallel, had values of 4-28 microM. Surprisingly, the compound was inactive against human cytomegalovirus. SP-303 was also virucidal at 50 microM. Interferon was not induced. The mode of antiviral action of this biopolymer was through inhibition of virus penetration into cells (EC50 = 2.1 +/- 0.2 microM). SP-303 also significantly reduced lesion formation in a mouse vaginal model when applied topically at 5-10%.
authors.affiliation: Institute for Antiviral Research, Utah State University, Logan.
authors.forename: D L
authors.initials: DL
authors.lastname: Barnard
authors.forename: D F
authors.initials: DF
authors.lastname: Smee
authors.forename: J H
authors.initials: JH
authors.lastname: Huffman
authors.forename: L R
authors.initials: LR
authors.lastname: Meyerson
authors.forename: R W
authors.initials: RW
authors.lastname: Sidwell
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001704:Biopolymers / Q000494:pharmacology*; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D006561:Herpes Simplex / Q000517:prevention & control; D007372:Interferons / Q000096:biosynthesis; D051379:Mice; D012307:Risk Factors; D018139:Simplexvirus / Q000187:drug effects* / Q000254:growth & development; D044945:Proanthocyanidins
chemical_list: D000998:Antiviral Agents; D001704:Biopolymers; D002392:Catechin; D007372:Interferons; C546704:crofelemer; D044945:Proanthocyanidins