Menthalactone, a new analgesic from Mentha cordifolia Opiz. Leaves.

* Author for correspondence and reprint requests Z. Naturforsch. 64c, 809-812 (2009); received May 7/July 23, 2009 Menthalactone, a new long-chain alkene with a bicyclic lactone moiety, was isolated as an analgesic constituent from the leaves of Mentha cordifolia Opiz. At a dosage of 100 mg/ kg mouse, it decreased the number of squirms induced by acetic acid by 67.3%. Statistical analysis using Kruskall Wallis one-way analysis of variance by ranks showed that menthalac-tone is different from the solvent control at alpha = 0.01 and approximates the analgesic activity of mefenamic acid at 0.001 level of significance.