Phytochemical Screening and in vivo Evaluation of Analgesic Activity of Methanolic Leaf Extract of Calotropis gigantea from Butwal, Nepal

Abstract

Introduction: Calotropis gigantea (Apocynaceae) is a medicinal shrub widely used in South Asian traditional medicine for treating pain and inflammation. However, scientific validation of its analgesic properties remains limited. Methods: Leaves, flowers, and latex of C. gigantea were collected from Butwal, Nepal. The methanol leaf extract (MLE) was prepared by cold maceration and subjected to qualitative phytochemical screening. Analgesic activity was evaluated in Wistar rats using the hot plate and acetic acid-induced writhing tests. Diclofenac sodium served as the standard, and saline as the control. Results: Phytochemical screening confirmed the presence of secondary metabolites, including alkaloids, flavonoids, tannins, saponins, and glycosides. MLE at doses of 200 and 400 mg/kg significantly (p<0.01) increased reaction latency in the hot plate test by 56.77% and 69.6%, respectively—the same doses reduced acetic acid-induced writhing by 37.76%, indicating both central and peripheral analgesic activity.  Conclusion: The methanol leaf extract of Calotropis gigantea possesses significant analgesic potential, validating its traditional use in pain management and suggesting the presence of bioactive compounds with pharmacological relevance.