Poria cocos WOLF is a parasite commonly found on roots of pine trees, it grows naturally in China, Korea, Japan, and North America. Dried sclerotia of P. cocos WOLF are used in the Chinese drug Hoelen and are used in combination with other drugs in more than 52 traditional Chinese prescriptions as a diuretic, sedative, and tonic medicine.1) Poria cocos WOLF consists of 90% b-glucan and 10% various terpenes by dry weight. The predominant triterpenes in P. cocos WOLF are pachymic acid, tumulosic acid and eburicoic acid, which are the lanostane type of triterpene acids.2) Pachymic acid also has been isolated from the European fungus Fomitopsis pinicola.3) Pachymic acid and dehydrotumulosic acid isolated from P. cocos WOLF actively inhibited phospholipase A2 from snake venom.4) The sclerotia of P. cocos WOLF are usually prescribed as an antipalpitation drug. Kaminaga et al. demonstrated that triterpenes of P. cocos WOLF have a potent inhibitory effect on tumor promotion in mice skin two-stage carcinogenesis and on 12-o-tetradecanoyl phobol-13-acetateinduced inflammation in mice. 5,6) Tai et al. reported that triterpenes extracted from P. cocos WOLF with an exomethylene group at C-24, such as pachymic acid, exhibited antiemetic activity in frogs.7) Until this study there has been no report concerning the antidiabetic effect of P. cocos WOLF.In a previous study, we established preadipose cell line ST 13 from adult ddN mice and discovered the physiological modulator or pharmacological agent that controls terminal differentiation of preadipocytes.8) We also demonstrated that Ciglitazone (ADD4743) prostaglandins D2, F2a, A 2 , E1, and E2 induce ST 13 adipose conversion.9,10) Of these adipose inducers, the most potent adipose promoter is Ciglitazone (ADD4743), which was originally synthesized as an oral antidiabetic drug by Takeda Chemical Industries Ltd. (Japan). Retinoids and 1,25-dehydroxyvitamin D 3 , the active form of vitamin D 3 , inhibited ST 13 and 3T3 L1 preadipocyte differentiation at physiological concentrations. 11,12) Furthermore, we demonstrated the presence of nuclear vitamin D 3 receptors in both preadipose cell lines.
12)Peroxisome proliferator-activated receptor g (PPAR g), which belongs to the nuclear receptor superfamily, is expressed at high levels in the adipose tissue and functions as a master regulator of adipocyte differentiation.13) Recent studies show that the ability of thiazolidinedions to bind and activate PPAR g correlate with their ability to reduce hyperglycemia in animal models of noninsulin-dependent diabetes mellitus (NIDDM) and obesity. 14,15) We found that a methanol extractive fraction of P. cocos WOLF is a potent inducer of adipocyte differentiation. We attempted to identify the active component from P. cocos WOLF and tested whether this compound activates PPAR g or reduces plasma glucose in animal models of NIDDM and obesity.There are two possible mechanisms of action in insulinsensitizing drug. One mechanism is the activation of PPAR as induced by thiazolidinediones, and another ...