Novel antiviral activity of mung bean sprouts against respiratory syncytial virus and herpes simplex virus-1: an in vitro study on virally infected Vero and MRC-5 cell lines

Background: New sources for discovering novel antiviral agents are desperately needed. The current antiviral products are both expensive and not very effective. Methods: The antiviral activity of methanol extract of mung bean sprouts (MBS), compared to Ribavarin and Acyclovir, on respiratory syncytial virus (RSV) and Herpes Simplex virus -1 (HSV-1) was investigated using cytotoxicity, virus yield reduction, virucidal activity, and prophylactic activity assays on Vero and MRC-5 cell lines. Moreover, the level of antiviral cytokines, IFN beta, TNF alpha, IL-1, and IL-6 was assessed in MBS-treated, virally infected, virally infected MBS-treated, and control groups of MRC-5 cells using ELISA. Results: MBS extract showed reduction factors (RF) 2.2 x 10 and 0.5 x 10(2) for RSV and HSV-1, respectively. The 2 h incubation virucidal and prophylactic selectivity indices (SI) of MBS on RSV were 14.18 and 12.82 versus Ribavarin SI of 23.39 and 21.95, respectively, and on HSV-1, SI were 18.23 and 10.9 versus Acyclovir, 22.56 and 15.04, respectively. All SI values were >10 indicating that MBS has a good direct antiviral and prophylactic activities on both RSV and HSV-1. Moreover, interestingly, MBS extract induced vigorously IFN beta, TNF alpha, IL-1, and IL-6 cytokines in MRC-5 infected-treated group far more than other groups (P < 0.05) and induced TNF alpha and IL-6 in treated group more than infected group (P < 0.05). Conclusions: MBS extract has potent antiviral and to a lesser extent, prophylactic activities against both RSV and HSV-1, and in case of HSV-1, these activities were comparable to Acyclovir. Part of the underlying mechanism(s) of these activities is attributed to MBS potential to remarkably induce antiviral cytokines in human cells. Hence, we infer that MBS methanol extract could be used as such or as purified active component in protecting and treating RSV and HSV-1 infections. More studies are needed to pinpoint the exact active components responsible for the MBS antiviral activities.