Evaluation of Cytotoxic Potential of Classical Siddha Medicine Padikara Parpam in Human Monocytic Leukemic Cell Lines (THP-1)

Abstract:

Introduction: Padikara Parpam (PP), is one among the highly regarded Siddha medicine that is been traditionally claimed for its anti-proliferating and anti-carcinogenic properties. Objectives: In the present work, we investigated the cytotoxic effects of PP in a cellular model of Human leukemia (Human monocytic cell lines (THP-1). Materials and Methods: Determination of cell viability was assessed by the 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide (MTT) assay and by using Confocal Laser Scanning Microscope (CLSM). Fluorescence-activated single cell sorting (FACS), and 2'-7'-Dichloro-Dihydro-Fluorescein Diacetate (DCFH-DA) mediated intracellular Reactive Oxygen Species (ROS) measurements were also carried out to understand the effect of PP on THP-1 cells. Results: PP induced cytotoxic effects against THP-1 in a concentration-dependent manner (6.02%–92.7%), with the highest cytotoxicity at 0.5 mg/mL concentration of PP. The IC₅₀ values of PP in THP-1 cell lines were 0.115 mg/mL. The result from the MTT assay was further confirmed by CLSM reports. The images of Acridine orange/Ethidium bromide stained THP-1 cells treated with PP (IC₅₀ concentration) indicated red fluorescence compared to the control cells which showed only green fluorescence. The images indicated the induction of apoptosis by the study drug. FACS and DCFH-DA based intracellular ROS measurements indicated the ability of PP to increase intracellular ROS levels in a concentration dependent manner. Thereby indicating at a possible ROS mediated apoptotic mechanism of action. Conclusion: These results suggest that with further clinical studies, PP could be used as an economic and effective anti-leukemic drug in patients suffering from leukemia.

Keywords: Siddha medicine, Padikara Parpam, Human Monocytic cell lines, Cytotoxic effects, Confocal Laser Scanning Microscope, MTT assay, Intracellular ROS assay.