Herbal gel formulation developed for anti-human immunodeficiency virus (HIV)-1 activity also inhibits in vitro HSV-2 infection

Abstract

Herpes simplex virus-2 (HSV-2) infection is the most common cause of genital ulcers. The impact of ulcers also demonstrates a strong link to the human immunodeficiency virus (HIV) infection. Complications, drug resistance, and side-effects of anti-viral drugs make the treatment of HSV-2 infection challenging. Herbal medicines have shown potential against HSV-2 and HIV infections. In this context, polyherbal gel formulation comprising 50% ethanolic extracts from Acacia catechu, Lagerstroemia speciosa, Terminalia chebula and Phyllanthus emblica has been developed. The gel formulation significantly exhibited virucidal activity against both HIV-1 and HSV-2 infections with IC 50 , 55.93 ± 5.30 µg/mL and 27.26 ± 4.87 µg/mL, respectively. It also inhibited HSV-2 attachment and penetration to the Vero cells with an IC 50 = 46.55 ± 1.25 µg/mL and 54.94 ± 2.52 µg/mL respectively, which were significantly lower than acyclovir. However, acyclovir is more potent in post-infection assay with an IC 50 = 0.065 ± 0.01 µg/mL whereas gel formulation showed an IC 50 = 469.05 ± 16.65 µg/mL under similar conditions. Gel formulation showed no inhibitory effect on the viability of lactobacilli, human vaginal keratinocyte cells (Vk2/E6E7), and the integrity of the Caco-2 cells monolayer. Gel formulation did not lead to any significant increase in the secretion of pro-inflammatory cytokines and mutagenic index. The proposed gel formulation may be a promising candidate microbicide for the prevention of sexually transmitted HIV-1 and HSV-2.