Evaluation of anti-inflammatory and antinociceptive activity of methanol extract of Calotropis gigantea root

Abstract

Objective: Extracts of the root of Calotropis gigantea (family: Apocynaceae) have been used as a natural therapeutic agent in traditional medicine to treat inflammation and pain. This study aims to evaluate the anti-inflammatory and analgesic activity of methanol extract of C. gigantea root (MECG). Materials and Methods: The analgesic activity of MECG was evaluated using formalin-induced pain and glutamate-induced paw licking models. Antagonism of opioid receptors using naloxone was used to determine the involvement of central pathways of pain. The acute inflammation was measured by carrageenan and dextran-induced paw edema models. Cyclooxygenase (COX) assay was carried out to determine the action of MECG on prostaglandins (PGs). Results: MECG 200 mg/kg dose was found to produce a significant (P < 0.001) and dose-dependent analgesic activity in the models used. MECG caused significant inhibition of edema in the carrageenan and dextran-induced inflammation tests. MECG was found to reduce the expression of COX, thus confirming the inhibitory action of MECG on PGs. Conclusion: The findings suggest that MECG possesses analgesic and anti-inflammatory activity mediated through peripheral and central mechanisms. The results justify its traditional use in the treatment of inflammation and pain.