EFECTO ANTIVIRAL DE TRES INFUSIONES VEGETALES (MENTHA PIPERITA, CINNAMOMUN ZEYLANICUM BLUME Y OCIMUM BASILICUM LINEO) EN UN MODELO MURINO DE INFECCION HERPETICA

There are many medicinal plants in Mexico, which have been traditionally used for treatment of several infections probably produced by viruses. On a previous study we analized in cells grown in vitro the antiviral properties of ten hot water extracts of several plants, selected by their empirical use for treatment of mucocutaneous infection perhaps caused by herpes simplex viruses. Eight of them shoed antiviral effect against herpes simplex viruses (HSV-1 and HSV-2), and the stronger activity was found in mint (Mentha piperita), cinnamon (Cinnamomum zeylanicum Blume) and basil (Ocimum basilicum Lineo). The aim of the present work was to evaluate the antiviral properties of the mint, cinnamon and basil on murine cutaneous HSV-2 infection as an experimental model for human herpes infection. To do this, Balb/c mice 6 to 7 weeks old were infected with 10^4.4TCID₅₀ of HSV-2 on depilated and scratched left middle flank. Lyophilized and rehydrated herb extracts were orally administered (300 mg/kg) 8 h before infection and twice daily after infection for 11 days. The development of skin lesions and body weight of infected mice were monitored every day. Viruses were recovered and titered from animals brain. The experiment with brasil was complemented with histopathological analysis and immunodetection of HSV-2 antigens in brain tissue. Mint and cinnamon water extracts did not modify the natural course of the cutaneous HSV-2 infection. When the infected animals were treated with the basil extract, the progression of lesions was retarded, the survival was prolonged (24-48 h), mortality rate was reduced to 75%, brain tissues showed less virus concentration per gram of brain tissue (log 3.38 ± 0.03 vs 4.08 ± 0.6), and no hemorrhagic signs were found. Nevertheless, there were not differences in the number of positive animals for HSV-2 antigens. To verify the antiviral activity showed by the basil hot water extract, a similar murine cutaneous infection was chosen, using the MacIntyre strain of HSV-1, which is less neurovirulent than the G HSV-2 strain. When basil extract was tested on HSV-1 infected mice, mortality rate was reduced at 0%, in comparison with 20% in nontreated animals. Basil treated animals did not show progress of lesions to a severe form, and viruses were not detected in the brain. These results demonstrated that the basil hot water extract has some antiviral effect against HSV-2 and HSV-1, mainly against the last one, by inducing a favorably change in the clinical course of the herpetic cutaneous infection.