Antiviral Activity of a Arisaema Tortuosum Leaf Extract and Some of its Constituents against Herpes Simplex Virus Type 2.

Infections caused by HSV-2 are a public health concern worldwide, and there is still a great demand for the discovery of novel anti-herpes virus agents effective against strains resistant to current antiviral agents. In this context, medicinal plants represent an alternative source of active compounds for developing efficient antiviral therapies. The aim of this study was to evaluate the antiviral activity of Arisaema tortuosum, a plant used in the traditional medicine of India. A chloroform soluble fraction of the leaves exhibited anti-HSV-2 activity with a selectivity index of 758. The extract was also active against acyclovir-resistant HSV-2 and HSV-1. The mechanism of action of the extract was investigated evidencing inhibition of both early and late events of the HSV-2 replicative cycle. A HPLC-PDA-MS/MS analysis showed the presence of flavonoids including apigenin and luteolin in the chloroform extract (CE). Apigenin and luteolin showed a high inhibitory activity with EC₅₀ values of 0.05 and 0.41 µg/mL, respectively. Both compounds exhibited antiviral activity when added up to 6 h post infection and were able to reduce the viral progeny production. In addition, apigenin interfered with cell-to-cell virus spread.