Synthesis and biological evaluation of a series of non-hemiacetal ester derivatives of artemisinin

• Synthesis of a series of non-hemiacetal ester derivatives of artemisinin.
• Evaluation of antimalarial and anticaner activities and cytotoxicity of series.
• Thermal stability evaluation through TGA.
• Most active derivatives thermally more stable than clinical artemisinins.
• Benzoate; most promising derivative is equipotent to dihydroartemisinin but no anticancer hit found.

In an attempt to improve the efficacy and stability of current, clinically used artemisinins, a series non-hemiacetal ester derivatives of artemisinin were synthesized and evaluated for their in vitro antiplasmodial and anticancer activities as well as cytotoxicities. These esters were synthesized through the reaction of acid anhydrides, or acid chlorides with artemisinin derived alcohol. In vitro antiplasmodial activity assessments were conducted against intraerythrocytic NF54 and Dd2 Plasmodium falciparum strains. Cytotoxicities were assessed, using normal human fetal lung fibroblast (WI-38) and Chinese hamster ovarian (CHO) mammalian cell lines, while anticancer activities were tested by using panels with three cell lines, consisting of renal (TK10), melanoma (UACC62) and breast (MCF7) cancer cells. Most compounds were found active against the breast cancer cell line. Since antiplasmodial activities for most compounds were found comparable only to that of artesunate, this study did not yield any esters with significantly improved antimalarial efficacies, nor did it deliver any promising antitumor hits. However, from the outcomes of this study, compounds with good safety profiles and increased thermal stabilities, compared to the clinically used artemisinins, were identified. The benzoate derivative 11 was found to have antimalarial activity, comparable to that of dihydroartemisinin and was it subsequently identified as a candidate for further investigation in the urgent search for new, safe and effective antimalarial drugs.

In this study, a series non-hemiacetal esters of artemisinin were synthesized and screened in vitro for antimalarial activity against both CQS (NF54) and CQR (Dd2) strains of Plasmodium falciparum and their cytotoxicity, anticancer activity as well as thermal stability were assessed.Figure optionsDownload as PowerPoint slide