Vol. 3, Issue 11, Part F (2017)

Abstract
Thespesia populnea (L.) belongs to Malvaceae family, known as Poovarasu in Siddha literature, is a large avenue tree found in tropical and coastal region in Srilanka and India. The root bark, leaves, flower and fruits are useful in medical therapy such as scabies, psoriasis, eczema and ring worm infestation. The leaves are externally applied for the anti-inflammatory effect for condition like swollen joints. The purpose of the research is to find out the in vitro antioxidant potential and membrane stabilizing effect of T. populnea extract in human RBC model. Powdered samples (10 g) were extracted with 100 ml of solvents (hexane, ethyl acetate, methanol, ethanol and water) for 3 h at room temperature. The solvent was evaporated using a rotovapor and dry extract was obtained. The extract was then re-dissolved in water at 100 mg / ml ratio and used for the analysis of antioxidant activity through DPPH free radical scavenging assay. RBC membrane stabilization potential of plant extracts were investigated using human RBC model. Blood (2 ml) was drawn from volunteer in a heparinised tube and centrifuged at 2000 rpm for 10 min. The pellet (RBC cells) was washed twice with PBS (9 ml) and finally the pellet was re-suspended in 10 ml of PBS. The extract (500 µl) were added to 1 ml PBS, 1 ml of 3% H₂O₂ and incubated for 30 min. The contents were centrifuged and the supernatant was analyzed spectropmetrically. Based on the absorbance, the percentage of RBC membrane damage and inhibition of membrane damage were calculated. From the results, it is concluded that the aqueous extract of T. populnea bark showed appreciable antioxidant and ferric reducing capacities and effective in preventing RBC membrane damage.