2.7.2. Assessment of formalin-induced paw oedema

The method was carried out according to [22] with slight modifications. For this, five groups of four A.W. rats and weight (170–180 g) of both sexes were also formed and treated by gavage. Also, two control groups (positive and negative batches) received prednisolone (10 mg/kg.b.w) and tween-80 (1%; 10 ml/kg.b.w) respectively, whereas the test batches received increasing concentrations of EAF (50 mg/kg.b.w, 100 mg/kg.b.w, and 200 mg/kg.b.w). After a respective observation of 30 min (for control batches) and 1 h (for test batches), a subcutaneous injection of the mouse paw was performed with 45 μL of formalin (3%). Inhibition of edema formation is estimated by the surface area of the foot before formalin injection and after 1h; 2h; 3h and 4h after injection. The formula below is used to estimate the inhibition of edema induced by formalin:

Where, (P_I %) = Percentage of inhibition of edema, C = paw edema of control at different time interval, D = paw edema of treatment at different time interval.