Evaluation on antimalarial activity of 3 artemisinin drugs using SYBR green I and flow cytometry in vitro

Objective To evaluate the antimalarial activity against Plasmodiumfalciparum in vitro by SYBR green Ⅰ and flow cytometry.Methods SYBR green Ⅰ was used to evaluate the inhibition to proliferation of Plasmodium falciparum in vitro treated by artimisinin(ART),artemether(AM) and dihydroartemisinine(DHA) at different concentrations.The intervention concentrations of ART,AM and DHA were 6,6×10-1,6×10-2,6×103,6×10-4μmol/L,4,4×10-1,4×10-2,4×10-3,4×10-4 μmol/L,and 3×10-1,3×10-2,3×10-3,3×10-4,3×10-5 μmol/L respectively,a blank control group was set up.After 72 h of drug intervention in vitro,the inhibition rate was measured using SYBR green Ⅰ,the 50％ inhibitory concentration (IC50) and 95％ inhibition concentration (IC95) were used to reflect the inhibition activity,then compared with the changes of DNA content of malaria parasites measured by flow cytometry.Results SYBR green Ⅰ showed the inhibition rates increased as dose of ART increased,The IC5o values of ART,AM and DHA were 11.29,3.32,0.66 nmol/L; IC95 values were 42.55,17.89,4.02 nmol/L respectively.At the same time,the results of the flow cytometry showed the content of DNA decreased with the increase of drug concentration,agreeing with the results of SYBR green Ⅰ and being objectively perceived.Conclusion The sensitivity of SYBR green Ⅰ and intuitiveness of flow cytometry could meet the requirements of evaluation on antimalarial activity of artemisinin-based antimalarial drugs against Plasmodiumfalciparum in vitro; The order from high to low of antimalarial activity is DHA＞AM＞ART. Key words: SYBR green Ⅰ ;  Flow cytometry ;  Artimisinin ;  Artemether;  Dihydroartemisinine ;  Plasmodium falciparum