Characterization and antinociceptive activity (in vivo) of kempferol-3,4′-di-O-α-L-rhamnopyranoside isolated from Dryopteris cycadina

Abstract

Compound 1, isolated from Dryopteris cycadina, was characterized as kempferol-3,4′-di-O-α-L-rhamnopyranoside on the basis of 1H and 13C NMR spectroscopic techniques. On the basis of preliminary screening data for this compound, its antinociceptive activity in different animal models was evaluated. Compound 1 displayed dose-dependent antinociceptive effects with maximum activity of 46.12 % at 10 mg/kg i.p. against acetic acid-induced writhing. In addition, it also showed dose-dependent blockade of noxious stimulation in both phases of formalin test with 40.78 and 43.44 % in the first and second phases at 10 mg/kg i.p., respectively. However, the injection of naloxone did not block the antinociceptive effect of compound 1 and thus ruled out the opioidergic involvement. It is, therefore, concluded with confidence that compound 1, isolated from D. cycadina, provoked strong antinociceptive activity and could be a lead analgesic drug candidate. Moreover, the mechanism of antinociceptive action by different flavonoids has also been investigated; results revealed that the bioactivity of compound 1 analogs should be discussed not only on the basis of flavonoids/biotarget interaction, but also on the basis of the catalytic activity of their bimetallic complexes.