Avaliação da atividade antiviral do extrato de Mikania glomerata Sprengel (guaco)

Abstract

Herpes is an infectious disease transmitted by type I (HSV-1) and type II (HSV-2) herpes simplex virus. The disease is characterized by the appearance of cold sores (HSV-1) and genital lesions (HSV-2). Mikania glomerata Sprengel (guaco) specie is a plant belonging to the Asteraceae family and is widely used in folk medicine. Coumarin, present in guaco leaves, have biological activity, such as decritas, antiedematogênica and bronchodilator effects spasmolytics. This study aimed to evaluate the antiviral effect of M. glomerata extract against the HSV-1 and HSV-2. It is noteworthy the promising potential of using guaco extract in the treatment of herpesvirus infections, since no published reports showing the activity of Mikania glomerata Sprengel against HSV-1 and HSV-2 herpesviruses were found. Cytotoxicity assessments of guaco dry extract and coumarin (2H-1-benzopyran-2-one) standard were performed in Vero cells culture (African green monkey‘s kidney cells) by observing morphology and viability. Based on this test, the maximum non-toxic concentration (MNTC) was determined. Subtoxic concentrations of guaco dry extract and 2H-1-benzopyran-2-one coumarin were employed to assess the anti-HSV-1 and HSV-2 activity by observing the reduction of viral titer. The results were expressed as percentage inhibition (PI). Guaco dry extract showed inhibitory activity against HSV-1 (PI=87.7%) and HSV-2 (PI=92.7%) viruses. The 2H-1-benzopyran-2-one coumarin standard was inactive against HSV-2 virus, but showed antiviral activity against HSV-1 virus (PI=68.4%). These results demonstrated the presence of other metabolites in the guaco dry extract that, either alone or in synergism, contributed to the higher antiviral activity. It is suggested to incorporate this extract in topical formulations for the purpose of provide an alternative treatment for herpetic infections.