title: Hydrolyzable tannins (chebulagic acid and punicalagin) target viral glycoprotein-glycosaminoglycan interactions to inhibit herpes simplex virus 1 entry and cell-to-cell spread.
abstract: Herpes simplex virus 1 (HSV-1) is a common human pathogen that causes lifelong latent infection of sensory neurons. Non-nucleoside inhibitors that can limit HSV-1 recurrence are particularly useful in treating immunocompromised individuals or cases of emerging acyclovir-resistant strains of herpesvirus. We report that chebulagic acid (CHLA) and punicalagin (PUG), two hydrolyzable tannins isolated from the dried fruits of Terminalia chebula Retz. (Combretaceae), inhibit HSV-1 entry at noncytotoxic doses in A549 human lung cells. Experiments revealed that both tannins targeted and inactivated HSV-1 viral particles and could prevent binding, penetration, and cell-to-cell spread, as well as secondary infection. The antiviral effect from either of the tannins was not associated with induction of type I interferon-mediated responses, nor was pretreatment of the host cell protective against HSV-1. Their inhibitory activities targeted HSV-1 glycoproteins since both natural compounds were able to block polykaryocyte formation mediated by expression of recombinant viral glycoproteins involved in attachment and membrane fusion. Our results indicated that CHLA and PUG blocked interactions between cell surface glycosaminoglycans and HSV-1 glycoproteins. Furthermore, the antiviral activities from the two tannins were significantly diminished in mutant cell lines unable to produce heparan sulfate and chondroitin sulfate and could be rescued upon reconstitution of heparan sulfate biosynthesis. We suggest that the hydrolyzable tannins CHLA and PUG may be useful as competitors for glycosaminoglycans in the management of HSV-1 infections and that they may help reduce the risk for development of viral drug resistance during therapy with nucleoside analogues.
authors.affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Liang-Tzung
authors.initials: LT
authors.lastname: Lin
authors.forename: Ting-Ying
authors.initials: TY
authors.lastname: Chen
authors.forename: Chueh-Yao
authors.initials: CY
authors.lastname: Chung
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Noyce
authors.forename: T Bruce
authors.initials: TB
authors.lastname: Grindley
authors.forename: Craig
authors.initials: C
authors.lastname: McCormick
authors.forename: Ta-Chen
authors.initials: TC
authors.lastname: Lin
authors.forename: Guey-Horng
authors.initials: GH
authors.lastname: Wang
authors.forename: Chun-Ching
authors.initials: CC
authors.lastname: Lin
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Richardson
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000302:isolation & purification / Q000378:metabolism*; D001578:Benzopyrans / Q000302:isolation & purification / Q000378:metabolism; D002460:Cell Line; D002522:Chlorocebus aethiops; D005960:Glucosides / Q000302:isolation & purification / Q000378:metabolism; D006023:Glycoproteins / Q000037:antagonists & inhibitors*; D006025:Glycosaminoglycans / Q000037:antagonists & inhibitors*; D018259:Herpesvirus 1, Human / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D047348:Hydrolyzable Tannins / Q000302:isolation & purification / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D029766:Terminalia / Q000737:chemistry; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000037:antagonists & inhibitors*; D038301:Virus Inactivation; D053586:Virus Internalization / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D001578:Benzopyrans; D005960:Glucosides; D006023:Glycoproteins; D006025:Glycosaminoglycans; D047348:Hydrolyzable Tannins; D014764:Viral Proteins; C076178:chebulagic acid; C115642:punicalagin