Carrageenan-induced rat paw edema
The EtOH extract and fractions of Boesenbergia longiflora rhizomes were tested in animal model, carrageenan-induced rat paw edema, as described by Winter et al. (1962). Briefly, male Wistar rats (180–200 g) were randomly divided into seven groups. For the EtOH extract and its fractions, 24 animals were divided into 4 doses treatment groups, each comprised of 6 animals. The control group (group 1) was treated with vehicle (10 ml/kg, Tween 80: DMSO: water=2.5:2.5:95) and the positive control group (group 2) was treated by indomethacin (10 mg/kg). The EtOH extract (group 3) and its fractions (groups 4–7) of Boesenbergia longiflora at various doses (50–500 mg/kg) were administered orally to rats for 30 min before subcutaneous injection of 0.1 ml of 1% (w/v) carrageenan in normal saline into the subplantar surface of the right-hind paw. The measurements of paw volume were taken before carrageenan injection and in every 0.5, 1, 2, 3, 4 and 5 h using a plethysmometer (UGO Basile 7140). The volume of hind paw was evaluated for anti-inflammatory activity and was expressed as % inhibition of the hind paw volume. The percentage of inhibition was determined for each experimental group as following equation and the half maximal effective dose (ED50) values were determined graphically (N=6).