Analgesic and anti-inflammatory activities of total extract and individual fractions of Chinese medicinal ants Polyrhachis lamellidens.

The ethanol extract of Chinese medicinal ants Polyrhachis lamelliden was evaluated for its analgesic and anti-inflammatory activities in mice. It was shown that the extract significantly inhibited acetic acid-induced writhing response and increased hot-plate pain threshold of mice at doses of 1.5 and 3.0 g crude drug/kg. Meanwhile, the extract significantly inhibited the increase in vascular permeability induced by acetic acid and in ear edema induced by xylene in mice. However, it had no obvious effect on leukocyte migration induced by carboxymethylcellulose sodium (CMC-Na). The ethanol extract suspended in water was partitioned with diethyl ether, ethyl acetate and n-butanol successively to yield four fractions including water fraction. Among these fractions, diethyl ether and ethyl acetate fractions were found to increase hot-plate pain threshold and to inhibit acetic acid-induced writhing response in mice. Water fractions markedly inhibited acetic acid-induced writhing response and reduced the dye leakage to the peritoneal cavity induced by acetic acid and ear edema induced by xylene. These results suggest that P. lamellidens presents remarkable analgesic and anti-inflammatory activity, which supported the traditional use of the medicinal ants in the treatment of various diseases associated with inflammation. The diethyl ether fraction has greater contribution to the overall analgesic activity, whereas the water fraction showed the greatest anti-inflammatory and peripheral analgesic activities.