title: In vitro inhibition of herpes simplex virus type 1 replication by Mentha suaveolens essential oil and its main component piperitenone oxide.
abstract: Several essential oils exert in vitro activity against bacteria and viruses and, among these latter, herpes simplex virus type 1 (HSV-1) is known to develop resistance to commonly used antiviral agents. Thus, the effects of the essential oil derived from Mentha suaveolens (EOMS) and its active principle piperitenone oxide (PEO) were tested in in vitro experimental model of infection with HSV-1. The 50% inhibitory concentration (IC50) was determined at 5.1μg/ml and 1.4μg/ml for EOMS and PEO, respectively. Australian tea tree oil (TTO) was used as control, revealing an IC50 of 13.2μg/ml. Moreover, a synergistic action against HSV-1 was observed when each oil was added in combination with acyclovir. In order to find out the mechanism of action, EOMS, PEO and TTO were added to the cells at different times during the virus life-cycle. Results obtained by yield reduction assay indicated that the antiviral activity of both compounds was principally due to an effect after viral adsorption. Indeed, no reduction of virus yield was observed when cells were treated during viral adsorption or pre-treated before viral infection. In particular, PEO exerted a strong inhibitory effect by interfering with a late step of HSV-1 life-cycle. HSV-1 infection is known to induce a pro-oxidative state with depletion of the main intracellular antioxidant glutathione and this redox change in the cell is important for viral replication. Interestingly, the treatment with PEO corrected this deficit, thus suggesting that the compound could interfere with some redox-sensitive cellular pathways exploited for viral replication. Overall our data suggest that both EOMS and PEO could be considered good candidates for novel anti-HSV-1 strategies, and need further exploration to better characterize the targets underlying their inhibition.
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
authors.forename: Livia
authors.initials: L
authors.lastname: Civitelli
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Panella
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Marcocci
authors.affiliation: Department of Drug Chemistry and Technologies, Sapienza University of Rome, Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: De Petris
authors.affiliation: Department of Drug Chemistry and Technologies, Sapienza University of Rome, Rome, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Garzoli
authors.affiliation: Department of Drug Chemistry and Technologies, Sapienza University of Rome, Rome, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Pepi
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Vavala
authors.affiliation: Department of Drug Chemistry and Technologies, Sapienza University of Rome, Rome, Italy.
authors.forename: Rino
authors.initials: R
authors.lastname: Ragno
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Nencioni
authors.affiliation: Department of Public Health and Infectious Diseases, Institute Pasteur Cenci Bolognetti Foundation, Sapienza University of Rome, Rome, Italy; San Raffaele Pisana Scientific Institute for Research, Hospitalization and Health Care, Rome, Italy.
authors.forename: Anna Teresa
authors.initials: AT
authors.lastname: Palamara
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy. Electronic address: letizia.angiolella@uniroma1.it.
authors.forename: Letizia
authors.initials: L
authors.lastname: Angiolella
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002522:Chlorocebus aethiops; D006566:Herpesviridae Infections / Q000188:drug therapy / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D020128:Inhibitory Concentration 50; D008297:Male; D027541:Mentha / Q000737:chemistry*; D039821:Monoterpenes / Q000494:pharmacology*; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology; D020947:Tea Tree Oil / Q000494:pharmacology; D014709:Vero Cells; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D039821:Monoterpenes; D009822:Oils, Volatile; D010936:Plant Extracts; D020947:Tea Tree Oil; C044956:piperitenone
keywords: Essential oil; Glutathione; Herpes simplex; Tea tree oil; Viral activity