Antimalarial Activity of Brusatol Against Plasmodium Berghei Infected Mice and the Mechanism Revealed by Whole Transcriptome Sequencing (RNA-Seq) Analysis

Abstract BackgroundRecently, artemsinin-resistant malaria strains and clinical cases have appeared in Southeast Asia. Reportedly, there are malaria mutants in Africa that are resistant to artemisinin and its derivatives. Thus, it’s imminent to develop new antimalarial drugs. Brucea javanica is an effective antimalarial drug recorded in Chinese traditional medicine, which has been widely used in the folk for hundreds of years. Brusatol is the main active constituent of Brucea Javanica, thus we studied the effects of brusatol on prevention of malaria infection in vivo. MethodsTo determine the antiplasmodial activity of brusatol, a four-day suppressive test was used by dividing 56 mice into 7 groups of 8 mice each and given 4mg/kg, 3mg/kg, 2mg/kg, 1mg/kg, 0.5mg/kg of brusatol, the standard drug ((artesunate of 140 mg/kg) and the vehicle (normal saline). The best effective dose was used in the following test. The effects of brusatol to plasmodium berghei transcription were tested through RNA-seq and the results were confirmed by RT-qPCR. We also explored the expression of TNF -α, IFN-γ, IL-4, IL-12 to evaluate antimalarial mechanism of brusatol to host by ELISA.ResultsThe results showed that brusatol effectively inhibited plasmodium berghei infection, the best effective dose was 2mg/kg, and the side effects of brusatol to liver and kidney were slight and reversible. The expressions of GSK3β, ATP6A, ATP6B, ATP6M, MSP-2, EMP1, CTCS in plasmodium were significantly lower after brusatol treatment compared with control, while the expression of AMA-1 was significantly increased. The serum concentrations of IFN-γ, TNF-α and IL-4 in artesunate and brusatol group decreased significantly compared with the control group, while there was no statistical difference of the serum concentrations of IL-12.ConclusionsTaken together, these results demonstrated brusatol could be a priority candidate for antimalarial medicine development.