Analgesic activity of Gleditsia triacanthos methanolic fruit extract and its saponin-containing fraction.

CONTEXT: Gleditsia triacanthos L. (Leguminosae) pods are used in folk medicine for pain relief as anodyne and narcotic. OBJECTIVE: The objective of this study is to evaluate analgesic activity of Gleditsia triacanthos methanolic fruit extract (MEGT) and its saponin-containing fraction (SFGT). MATERIALS AND METHODS: Peripheral analgesic activity was assessed using the acetic acid-induced writhing model in mice at doses of 140, 280, and 560 mg/kg and formalin test in rats at 100, 200, and 400 mg/kg doses. Central analgesic activity was evaluated using the hotplate method in rats (100, 200, and 400 mg/kg). RESULTS: In the writhing test, six mice groups treated with MEGT and SFGT found ED50 values 268.2 and 161.2 mg/kg, respectively, displayed a significant decrease in writhing count compared with the group treated with standard drug indomethacin (14 mg/kg). SFGT (280 and 560 mg/kg) showed 64.94 and 70.78% protection, respectively, which are more than double % protection caused by indomethacin (31.82%). In the formalin test, MEGT and SFGT (ED50 values 287.6 and 283.4 mg/kg for phase I as well as 295.1 and 290.4 mg/kg for phase II, respectively) at 400 mg/kg showed significant % inhibition in both phase I (18.86 and 52.57%) and phase II (39.36 and 44.29%) with reference to 10 mg/kg indomethacin (56.0 and 32.29%). MEGT and SFGT caused significant delay in responses in hotplate model (ED50 values 155.4 and 200.6 mg/kg, respectively) compared with that of 10 mg/kg indomethacin at 30, 60, and 120 min. DISCUSSION AND CONCLUSION: Central and peripheral analgesic activities induced by Gleditsia triacanthos fruits might account for its uses in folk medicine.