Anti-inflammatory and analgesic effects of Daphne retusa Hemsl

Daphne retusa Hemsl. belongs to the genus Daphne, a member of Thymelaeaceae family. The barks and stems of Daphne retusa are used as a folkloric medicine 'Zhu Shi Ma' in Western China because of its effects of detumescence and acesodyne. In this paper, we investigate the anti-inflammatory and analgesic effects of the 75% ethanol extract of the stems and barks of Daphne retusa and different fractions partitioned with petroleum ether, methylene chloride, ethyl acetate and n-butanol, respectively. The anti-inflammatory effects were evaluated using xylene-induced ear oedema in mice and carrageenan-induced paw oedema in rats, while the acetic acid-induced writhing test and hot-plate test as models for evaluating the centrally and peripherally analgesic activity. The results showed the plant has significant anti-inflammatory and analgesic effects (P<0.05-0.01). Meanwhile, the result of the acute toxicity test at which the MTD was above 5g/kg indicates that the plant extract is relatively safe in, and/or non-toxic to, mice. The findings of these experimental animal studies indicate that the Daphne retusa ethanol extract possesses anti-inflammatory and analgesic properties, and thus provide pharmacological support to folkloric, ethnomedical uses of 'Zhu shima' in the treatment and/of management of anti-inflammatory and painful conditions in China.