Antipyretic, analgesic and muscle relaxant activities of pueraria isoflavonoids and their metabolites from Pueraria lobata Ohwi-a traditional Chinese drug.

We evaluated the antipyretic, analgesic, and muscle relaxant activities of Pueraria isoflavonoids and their metabolites in mice. The glycosides daidzin and genistin significantly reduced fever induced by lipopolysaccharide (LPS). Their metabolites, daidzein and p-ethylphenol, also significantly reduced fever induced by LPS. In addition, daidzin, daidzein, dihydrodaidzein, and p-ethylphenol showed analgesic activity as assessed by the acetic acid-induced writhing test. Furthermore, equol and p-ethylphenol showed muscle relaxant activity in the rotarod and horizontal wire test. These results suggest that these compounds play a major role in the therapeutic activity of Pueraria isoflavonoids.