Biotransformation of artemisinin by human intestinal fungi and cytotoxicity against breast cancer cells of its metabolites.

Artemisinin widely exists in the Artemisia annua L. and is the front-line of antimalarial drugs. In this study, microbial transformation of artemisinin was performed based on seventeen human intestinal fungal species. Our findings revealed that isomerization and deoxygenation were the most prevalent metabolic pathways in fungi. Incubation of artemisinin with Rhizopus microspores (PT2906) and Candida boidinii (M7017B) afforded three new compounds (P3, P5 and P6) along with seven known metabolites which were elucidated by extensive spectroscopic data analysis. All metabolites were evaluated for their cytotoxicity against MCF-7 cells, and the results showed that 3β-hydroxydeoxyartemisinin (P5) suppressed the growth of MCF-7 cells better than artemisinin. In addition, ten artemisinin isomers were found in the feces of antibiotic-treated mice after M7017B transplantation, demonstrating that human intestinal fungi have the potential to participate in the in vivo intestinal transformation of artemisinin.