Rheum turkestanicum Induced Apoptosis Through ROS Without a Differential Effect on Human Leukemic Cells

Human myeloid leukemia is among the hematological cancers associated with arrested differentiation and continued proliferation in promyelocytes. Despite the widespread use of Rheum turkestanicum, as a medicinal plant, there is still a lack of information on its toxicity profile. In this research, the cytotoxic effect of hydroalcoholic extract of R. turkestanicum root was evaluated on leukemic cells.

We aimed to assess cellular oxidants, cytotoxicity, apoptosis, and differentiation caused by R. turkestanicum (60 - 500 µg/mL) and arsenic trioxide (50 µM) in leukemic and polymorph nuclear cells during 72 hours.

In order to determine cell viability, resazurin assay was carried out at 24, 48, and 72 hours following R. turkestanicum treatment (range, 60 - 500 µg/mL). Carboxy 2’, 7’-dichlorofluorescein diacetate was used to examine intracellular reactive oxygen species (ROS) via fluorimetry. For the analysis of apoptotic cells, propidium iodide (PI) flow cytometric assay was performed. Differentiation of cells was evaluated by Giemsa staining and nitro blue tetrazolium reduction.

R. turkestanicum inhibited viability and increased apoptosis of leukemic cells similar to the As2O3 group. R. turkestanicum did not induce differentiation of leukemic cells towards a granulocytic pattern. Based on the findings, no toxic effects were induced by the extract on polymorphonuclear cells.

The present study demonstrated that R. turkestanicum caused apoptosis dose- and time-dependently without causing any differential effects on leukemic cells. The precise signaling pathway by which R. turkestanicum induces apoptosis needs further research.