Analgesic Potential of Opuntia dillenii and Its Compounds Opuntiol and Opuntioside Against Pain Models in Mice

Opuntia dillenii (Nagphana) traditionally used against inflammation and also possess analgesic effect. Thus in the present study analgesic properties of O. dillenii cladode methanol extract, its fractions obtained via vacuum liquid chromatography along with isolated α-pyrones, opuntiol and its glucoside, opuntioside were analyzed. The acetic acid-induced writhes were reduced by O. dillenii test agents with opuntioside being most effective (IC 50 26 ± 0.9 mg/kg) and equipotent to diclofenac and β-sitosterol. Consistently, it also elicited most potent effect (IC 50: 28 ± 1.1 and 24 ± 1.2 mg/kg) during early and late phases of formalin-induced paw licking, producing effect similar to diclofenac and indomethacin. It was also most effective in hot plate test. Naloxone (opioid antagonist) reversed the analgesic effects of extract and fractions but failed to antagonize the opuntiol and opuntioside analgesic effects. In conclusion, edible O. dillenii extract, its fractions, opuntiol and opuntioside reduced peripheral and centrally mediated pain via opioid dependent and independent systems. Among them opuntioside emerged as most effective analgesic possibly due to the presence of glucose moiety at position 7 of its α-pyrone ring. This is the first report of opuntiol and opuntioside analgesic effect which may serve as lead compounds in designing of new analgesics.