RESUMO
BACKGROUND: We evaluated the anti-malarial activity of Heracleum persicum individually and in combination with chloroquine. METHODS: This study was conducted at the School of Public Health, Tehran University of Medical Sciences, Tehran, Iran in 2015-2016. The Peter's method was used for determining fifty percent effective dose (ED50) of the H. persicum extract and chloroquine individually against chloroquine sensitive P. berghei in small white mice. Six experimental groups for H. persicum and 6 groups for chloroquine and two control group (positive and negative) were considered for determination of ED50. Interaction between H. persicum and chloroquine also was evaluated based on fixed ratios method. Ratios of 0/100, 20/80, 40/60, 60/40, 80/20, 100/0 of ED50 of chloroquine and H. persicum respectively were tested against the parasite. Then inhibitory effects of two drugs were calculated and plotted in the relevant graphs. RESULTS: Overall, 1500 mg/kg, and 1000 mg/kg concentrations of H. persicum against P. berghei resulted in ED50 and ED74 respectively. ED50 of chloroquine against the parasite was obtained as 1.4 mg/kg of mouse body weight. Moreover, combination of H. persicum and chloroquine showed a weak potentiation in ratios of 40/60 (chloroquine +H. persicum) with 64% inhibition, but not in other ratios. CONCLUSION: Although H. persicum individually showed a reasonable antimalarial efficacy against chloroquine sensitive P. berghei, in combination with chloroquine it showed additive or antagonism result except in ratios of 40%CQ+60%HP.