Abstract

• Leaves of Croton oblongifolius R. (Thetyin-gyi) have been known to use in Myanmar traditional medicine concerning antioxidant, anti-arthritis and antimicrobial activities. Therefore, locally grown C. oblongifolius has been chosen for this study. This research aimed to investigate the anti-arthritis activities of the leaves of C. oblongifolius (Thetyin-gyi). In the present work, anti-arthritis activity and cytotoxicity of the Thetyin-gyi leaves have been determined. The sample was collected from the campus of Inya hostel in Yangon University. The cytotoxicity of watery and ethanol extracts evaluated by brine shrimp cytotoxicity bioassay gave LD50 values as 921 µg/mL and 884.5 µg/mL, respectively. The LD50 value of K2Cr2O7 was 1.5 µg/mL and its cytotoxicity values were between 1 and 10 µg/mL. In vitro anti-arthritic activity of ethanol and watery extracts of leaves of Thetyingyi was investigated by protein denaturation method by using bovine serum albumin and egg albumin. In both methods, the ethanol extract has shown significant activity at the concentrations of 500 µg/mL and the effects were compared with the standard drug diclofenac potassium. So, the ethanol extract of C. oblongifolius have higher anti-arthritic activity than watery extract.