Anti-nociceptive Effect of 7-methoxy Coumarin from Eupatorium Triplinerve vahl (Asteraceae)

AIM: To evaluate the anti-nociceptive activity of 7-methoxy coumarin isolated from ethyl acetate fraction of the alcoholic extract of Eupatorium triplinerve Vahl. MATERIALS AND METHODS: The shade dried leaves of E. triplinerve were extracted with ethyl alcohol and the extract was condensed. This extract was fractionated with n-hexane, ethyl acetate, and n-butanol. The ethyl acetate fraction was subjected to column chromatography which yielded a crystalline compound-A, which was investigated for spectral characteristics. PHARMACOLOGICAL STUDIES: The isolated compound-A was subjected to behavioral studies and anti-nociceptive evaluation in mice by acetic acid induced writhing and formalin induced nociception. RESULTS: The spectral studies indicated that the structure of compound-A complies with 7- methoxy coumarin. Pre-treatment with 7-methoxy coumarin reduced the number of abdominal constrictions in mice and decreased the time spent in paw licking and biting response in formalin assay. There were no significant behavioral changes. CONCLUSION: A dose dependent anti-nociceptive action of 7- methoxy coumarin was revealed by the present experiments which support the traditional use of E. triplinerve in pain and inflammatory disorders. SUMMARY: Bio-guided fractionation of alcoholic extract of E. triplinerve yielded 7-methoxy coumarin. 7-methoxy coumarin was evaluated for its anti-nociceptive potential by acetic acid induced writhing and formalin induced nociception assays. 7-methoxy coumarin exhibited significant inhibition of acetic acid induced writhing response and the second phase of formalin nociception. The anti-nociceptive action of 7-methoxy coumarin revealed by the present experiments supports the traditional use of E. triplinerve in pain and inflammatory disorders. Abbreviation used: TLC-Thin layer chromatography, Kg-kilogram, g-gram, TXB(2)-Thromboxane B2, UV-Ultraviolet, IgE-Immunoglobulin E, s.c-subcutaneous, p.o-oral route