Anti-inflammatory, antinociceptive and antipyretic properties of the aqueous extract of Clematis brachiata leaf in male rats.

Clematis brachiata Thunb. (Ranunculaceae) is used as a folk remedy for the treatment of pain, fever and inflammatory ailments. Aqueous extract of Clematis brachiata leaf was screened for its phytochemical constituents. The anti-inflammatory investigations were carried out using carrageenan and histamine-induced edema models; acetic acid writhing, formalin-induced pain and tail immersion models were used to evaluate antinociceptive activity while a Brewer's yeast-induced hyperthermia model was employed for the antipyretic experiment. Phytochemical screening of the extract revealed the presence of tannins, saponins, flavonoids and cardiac glycosides. The extract at 100, 200 and 400 mg/kg body weight significantly (P<0.05) reduced the edema paw volumes induced by carrageenan and histamine with the 400 mg/kg body weight extract being the most potent. On the antinociceptive front, while the extract reduced the writhing caused by acetic acid and the number of licks induced by formalin in a dose dependent manner, the increase in the reaction time by the extract in the tail immersion model was not dose-dependent. Again, there was significant (P<0.05) lowering of the Brewer's yeast-provoked elevated body temperature. The results suggest that the aqueous extract of Clematis brachiata leaves can be employed in the management of inflammation, pain and fever. These activities may be due in part to the flavonoid content of the extract.