In vitro antiviral activity of Mentha cordifolia plant extract in HIV-1 latently infected cells using an established human cell line.

Emergence of drug resistance demands new therapeutic strategies against the human immunodeficiency virus (HIV). Currently, there is an increasing research focus on targeting gene expression- the crucial step wherein new viruses and new viral strains are amplified. Moreover, natural products are also being considered as potential candidates for new antivirals. We screened the extract obtained from a Philippine medicinal plant, Mentha cordifolia (Mc). In this study, we demonstrated that Mc ammonium sulfate extract has antiretroviral activity against HIV. HIV-1 latently infected cells (OM10.1) were pre-treated with Mc extract and activated with TNFα. In treated cells, viral replication was inhibited in both cell culture supernatant and whole cell lysates. The level of viral production, as measured by the viral p24 protein concentration, was very much inhibited under noncytotoxic concentrations to the similar level without addition of TNFα. Luciferase assays, however, showed that Mc does not inhibit the HIV-1 LTR driven gene expression. IκBα degradation and p65 nuclear translocation was also not affected as visualized through Western blot and immunofluorescence. These observations demonstrated that Mc possessed an antiviral component against HIV-1 and warrant further work to explore its target of action at a later step of gene expression. Our study introduces a potential source of a lead compound that targets steps in the HIV life cycle.