Jundishapur J Nat Pharm Prod. 2019 November; 14(4):e12198. Published online 2019 September 18. doi: 10.5812/jjnpp.12198. Research Article Rheum turkestanicum Induced Apoptosis Through ROS Without a Diﬀerential Eﬀect on Human Leukemic Cells Maliheh Moradzadeh 1 , Arezoo Rajabian 2 , Azita Aghaei 2 , Azar Hosseini 2, 3, * and Hamid Reza Sadeghnia 2, 3, 4, ** 1 Golestan Rheumatology Research Center, Golestan University of Medical Sciences, Gorgan, Iran 2 Pharmacological Research Center of Medicinal Plants, Mashhad University of Medical Sciences, Mashhad, Iran 3 Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 4 Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran * Corresponding author: Pharmacological Research Center of Medicinal Plants, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Tel: +98-5138828566, Fax: +98-5138828567, Email: hoseiniaz@mums.ac.ir ** Corresponding author: Pharmacological Research Center of Medicinal Plants, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Tel: +98-5138828566, Fax: +98-5138828567, Email: sadeghniahr@mums.ac.ir Received 2017 April 27; Revised 2018 April 22; Accepted 2018 July 01. Abstract Background: Human myeloid leukemia is among the hematological cancers associated with arrested diﬀerentiation and contin- ued 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. Objectives: 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. Methods: In order to determine cell viability, resazurin assay was carried out at 24, 48, and 72 hours following R. turkestanicum treat- ment (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. Results: R. turkestanicum inhibited viability and increased apoptosis of leukemic cells similar to the As2 O3 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. Conclusions: 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. Keywords: Rheum turkestanicum, Leukemia, Apoptosis, Diﬀerentiation, ROS 1. Background Acute promyelocytic leukemia (APL) is one of the most threatening hematological malignant cancers (1). Promye- locytes exhibit a failure of myeloid diﬀerentiation. Arsenic trioxide (As 2 O 3 ) is used clinically in the treatment of APL. Apoptosis induction, growth inhibition, and promotion of diﬀerentiation constitute the major anticancer mecha- nism. High doses of As 2 O 3 causes various side eﬀects and toxicity; however replacement or combination of this drug with other anti-cancer compounds can reduce the dose and side eﬀects of As 2 O 3 (2-4). Development of combination treatments require lower concentrations of As 2 O 3 can be favorable for APL patients (5). Therefore, the search for novel anti-cancer agents is currently receiving great attention. Natural prod- ucts, especially medicinal plants, have been recognized for as long as potential sources for anti-cancer drugs (6, 7). For example, paclitaxel is used to treat various malignant diseases such as lung and breast cancers and was discov- ered by isolating the compound from the Paciﬁc yew tree, Taxusbrevifolia (8-10). Therefore, the search for potent anticancer drugs, isolated from plants, is in progress. The recent studies have shown that some medicinal plants such as Spirulina platensis, pomegranate fruit, Cuscuta campestris, Ferula gummosa gum, Epigallocatechin-3- Copyright © 2019, Jundishapur Journal of Natural Pharmaceutical Products. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.