Anti-dengue fever activity of a polyherbal extract from medicinal plants of Vietnam.

This study investigated the anti - dengue hemorrhagic fever (DHF) and anti-dengue virus (DENV) properties of an extract containing six Vietnamese medicinal plants (HemoShield - HE). HE in water (WE) and in 25 % ethanol (EE) exhibited anti-DENV activity against all four tested DENV serotypes (1, 2, 3, and 4), with the strongest effect observed with DENV2. Moreover, HE demonstrated apparent inhibitory activity against NS2B-NS3pro enzyme responsible for viral replication with an IC50 value of 48.5 ± 2.3 μg/mL. In the thrombocytopenia rats, HE-treated group showed a significant increase in platelet count (approximately 33.62 %; p < 0.05). Additionally, the bleeding time of 0.74  g/kg treatment group was significantly reduced by 33.4 % (p < 0.05). Antipyretic activity of HE in rabbits after 3-h treatment showed a significant reduction in body temperature (38.8 %; ΔT: 0.4 ± 0.1 °C) at a dose of 0.31 g/kg. Thus, our findings provided new in vitro and in vivo evidence demonstrating the effect of HE in alleviating DHF.