Bioactive chromone constituents from Vitex negundo alleviate pain and inflammation

Background: Vitex negundo L. has been widely studied for its beneficial effect in inflammatory and pain conditions. The present study describes the isolation of two new bioactive chromone constituents from V. negundo and their in vivo evaluation for anti-inflammatory and antinociceptive activities. Methods: Two new chromone derivatives, namely, methyl 3-(2-(5-hydroxy-6-methoxy-4-oxo4H-chromen-2-yl) ethyl) benzoate (1) and 3-(1-hydroxy-2-(5-hydroxy-6-methoxy-4-oxo-4H-chromen-2-yl) ethyl) benzoic acid (2) were isolated from V. negundo and their structures were determined through various spectroscopic techniques including mass spectrometry, UV, IR, H-1 NMR, C-13 NMR, and two-dimensional-NMR like correlation spectroscopy and heteronuclear multiple bond correlation techniques. The isolated compounds (1-2) were tested for their prospective antinociceptive activity in acetic acid-induced abdominal constriction assay and anti-inflammatory activity in the carrageenan-induced paw edema assay in mice. Results: Significant attenuation (P<0.001) of tonic visceral nociception was demonstrated by compound 1 and 2 at doses of 50 and 100 mg/kg. At similar doses, these compounds (1-2) also showed potent amelioration (P<0.001) of carrageenan-induced paw swelling. Conclusion: The isolated chromone derivatives (1-2) from V. negundo are able to alleviate nociception and inflammation and the findings corroborated that V. negundo may be used as a potential source of antinociceptive and anti-inflammatory candidates.