Effects of Artesunate on the Growth and Chlorophyll Fluorescence of the Cyanobacterium Microcystis aeruginosa

Microcystis aeruginosa, a kind of cyanobacterium, can lead to water blooms under specific conditions and it is harmful to human and ecological security due to the toxins produced by certain strains. Artemisinin, which is derived from Artemisia annua Linn, has a strong allelopathic effect on algae. Artesunate is a water-soluble derivative of artemisinin. We investigated the effect of artesunate on M. aeruginosa, including growth and key photosynthetic parameters (Fv/Fm, φPSII). Our findings demonstrate that artesunate inhibits the growth of M. aeruginosa by damaging the photosynthetic center of photosystem II (PS II), and this inhibitory effect is enhanced with increasing concentration. At the concentration of 200 mol/L, the maximum inhibition rate was 41.62% for FACHB-315 and 43.19% for FACHB-927 after 96 h. After 24 h of exposure, the φPSII of the two strains decreased significantly (p < 0.01). These results could inform further studies on the use of artesunate to control cyanobacterial growth in water bodies and provide theoretical support for the application of artemisinin derivatives in treating water blooms.