Cytotoxicity of ethanolic extracts of Artemisia annua to Molt-4 human leukemia cells.

Although dihydroartemisinin (DHA) and other artemisinin derivatives have selective toxicity towards cancer cells, Artemisia annua (A. annua) extracts containing artemisinin have not been evaluated for their anticancer potential. Our main goal was to assess the anticancer effect of ethanolic leaf extracts of A. annua from Brazilian and Chinese origins (with DHA as a comparison) on normal and cancer cells. Leukocytes and leukemia (Molt-4) cells were counted at 0, 24, 48, and 72 hr after treatment with extracts having artemisinin concentrations of 0, 3.48, 6.96, and 13.92 µg/mL. Also, we assessed the antioxidant capacity of these extracts using the oxygen radical absorbance capacity (ORAC) test. Both extracts had high antioxidant capacity and toxicity towards Molt-4 cells. DHA was significantly more potent (p < 0.05) in killing Molt-4 cells than Brazilian extract at 48 and 72 hr and Chinese extract at 72 hr. In Molt-4 cells, LD₅₀ values for Brazilian and Chinese extracts were comparable at all time points and not significantly different from DHA at 24 hr. In leukocytes, DHA, Chinese extract, and Brazilian extract had LD₅₀ values of 760.42, 13.79, and 28.23 µg/mL of artemisinin, respectively, indicating a better safety index for the Brazilian extract compared to that of the Chinese extract at 24 hr. However, at 48 and 72 hr, the toxicity in leukocytes for any of the treatment groups was not significantly different. These experiments suggest that these extracts may have potential application in cancer treatment.