Evaluation of anti-HSV-1 activity and toxicity of hydroethanolic extract of Tanacetum parthenium (L.) Sch.Bip. (Asteraceae).

BACKGROUND: Herpes simplex type 1 (HSV-1) is widely distributed throughout the world's population. The virus spreads through direct contact with an infected individual. After primary infection, the virus remains in a latent state, and the recurrence of herpetic lesions is common. Standard treatment is performed with nucleoside analogues, but the selection of resistant strains have occurred, thus requiring the continual search for new antiviral agents. Plant extracts, fractions, and isolated compounds are a good source for studying possible antiviral compounds. HYPOTHESIS: Among plants with antiviral activity, the crude extract of aerial parts of Tanacetum parthenium (L.) Sch.Bip. (Asteraceae) have previously shown to inhibit HSV-1 infection in vitro. METHODS: The present study investigated the chemical composition of a crude hydroethanolic extract (CHE) of T. parthenium, and in vivo safety and therapeutic efficacy against HSV-1 infection. RESULTS: Liquid chromatography-mass spectrometry showed that the CHE was composed of phenolic acids (chlorogenic acids) and sesquiterpene lactones (parthenolide). Acute and subchronic toxicity and genotoxicity tests in vivo showed that oral CHE administration did not result in signs of toxicity, with no genotoxic potential. The CHE was also safe for topical administration, in which no irritation of the epidermis was observed in treated animals. Tests of topical and oral therapeutic efficacy showed that the CHE was effective against HSV-1 infection. Topical administration was the most effective, the results for which were comparable to acyclovir. CONCLUSION: These findings indicate that the CHE from aerial parts of Tanacetum parthenium has in vivo anti-HSV-1 activity and is safe for oral and topical application.

Parthenolide Influences Herpes simplex virus 1 Replication in vitro.

BACKGROUND/AIMS: Parthenolide is a sesquiterpene lactone that is present in plants of the Tanacetum genus, for which many biological effects have already been reported, including antiherpetic activity. Although the effectiveness of parthenolide against Herpes simplex virus 1 (HSV-1) has already been demonstrated, such findings are still controversial. The objective of this study was to investigate the ways in which parthenolide exerts anti-HSV-1 activity. METHODS: The cytotoxicity and antiviral activity of parthenolide were determined by the MTT method and plaque reduction assay, respectively. The expression of cell and viral proteins during the treatment of infected cells was investigated by Western blot. RESULTS: Both strains of HSV-1 were sensitive to parthenolide, and parthenolide was active only after penetration of the virus into the host cell. The expression of p65 protein decreased, the expression of caspases 8 and 9 increased, and the expression of c-Jun N-terminal kinase (JNK) and p38 protein was altered in infected cells after parthenolide treatment, resulting in lower cell survival. The low expression of viral proteins gB, gD, and ICP0 confirmed the reduction of HSV-1 particle production. CONCLUSION: Parthenolide exerts anti-HSV-1 activity by impairing cell viability, which consequently interferes with the efficient infection and production of new viral particles.