Apoptotic and antiproliferative effects of Urtica dioica L. extract on K562 chronic myeloid leukemia cell line

Urtica dioica (stinging nettle) is an herb commonly in use as a medical supplement for its anticarcinogenic, antiinflammatory, analgesic, antifungal . In this study, phytochemical composition extract was analyzed and its apoptotic and antiproliferative effects were investigated in K562 cell line, a model cell line for chronic myeloid leukemia (CML). K562 cells exposed to different concentrations of Urtica dioica extract (0, 25, 50, 75 and 100 mg/ml) were tested for cell proliferation and appropriate methods and different phases of the cell cycle were analyzed using flow cytometry. Phenolic content of the plant was analyzed by LC–MS/MS. We showed that Urtica dioica ethanol extract has four phenolic compounds: caffeic acid, chlorogenic acid (major compound), malic acid and rutin. Urtica dioica significantly repressed proliferation of K562 cells compared to control mononuclear cells (PBMCs) isolated from the peripheral blood of healthy donors. Increase in Bax/Bcl-2 and PARP cleavage ratio, decrease in mitochondrial membrane potential indicated that the extract inhibited cell proliferation through an apoptosis-mediated process. Furthermore, cell cycle arrest at G0/G1 phase increased in a concentration dependent manner. Our results explicitly demonstrate that ethanol extract of to decrease in cell viability and proliferation, initiate apoptosis and induces G0/G1 cell cycle accumulation in this cell line. This study is the first to show antiproliferative and apoptotic effects of Urtica dioica on leukemia cell line in vitro.