Abstract

• Spatholobus suberectus (Kyathway-pannwe-pin) stem was chosen to evaluate some biological activities such as antioxidant, antimicrobial, cytotoxic, anti-arthritic, and anti-diabetic. The DPPH assay revealed that both watery and ethanol extracts exhibited antioxidant activity, with IC50 values of 2.01 μg/mL and 2.66 µg/mL, respectively. The antimicrobial activity of pet-ether, ethyl acetate, ethanol, and watery extracts was tested on eight microorganisms by the agar-well diffusion method. Among all these extracts, the ethanol extract exhibited potent activity, with inhibition zone diameters ranging from about 20 mm and above. The cytotoxicity of the watery and ethanol extracts was evaluated through a brine shrimp lethality bioassay. The results did not indicate any cytotoxic effects for either extract at concentrations up to 1000 μg/mL. In vitro anti arthritic activity determined by the egg albumin denaturation method showed that the IC50 values of ethanol and watery extracts were found to be 35.92 μg/mL and 108.89 μg/mL. The anti-diabetic activity of ethanol and watery extracts was screened with an in vitro α-amylase inhibition assay. The IC50 values of ethanol extract (23.97 μg/mL) have higher inhibition than that of the watery extract (81.64 μg/mL).