Metabolic Pharmacokinetics of Polygonum cuspidatum and Its Effects on the Pharmacokinetics of Methotrexate

• Main Authors: Meng-Hao Wu, 吳孟壕
• Other Authors: 李珮端
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/04677778734197217851

碩士 === 中國醫藥大學 === 中國藥學研究所碩士班 === 95 === Polygoni Cuspidati (PC) Rhizoma is the stems and roots of Polygonum cuspidatum SIEB. et ZUCC. (Polygonaceae). Resveratrol and emodin are the major phenolic components in PC. Polyphenols are usually present as glycosides or aglycones in nature. We investigated the contents of resveratrol and emodin in PC decoction before and after acidic hydrolysis. Resveratrol was found mainly as aglycones and emodin as glycosides. The blood of rats withdrawn via cardiopuncture at specific time after oral administration of PC decoction. The concentrations of resveratrol and emodin were determined by HPLC method after treatments with sulfatase/glucuronidase and glucuronidase, respectively. The results indicated that the parent forms of resveratrol and emodin were not detected in blood. Resveratrol was present as sulfates and glucuronides, and emodin mainly as glucuronides. Methotrexate (MTX), a folate antagonist, is commonly used as immunosuppressant but with narrow therapeutic window. We investigated X the effects of two doses of PC decoction and different coadministration time on the pharmacokinetics of MTX. The results showed that coadministration of PC decoction (2 g/kg) 30 min before MTX significantly inhibited both the absorption and elimination of MTX, whereas PC decoction (1 g/kg) only inhibited its absorption. Coadministration of PC decoction at 1.5 hr after MTX also markedly inhibited the elimination of MTX. Therefore, coadministration with PC decoction with MTX should be avoided at the same period to ensure the efficacy and safty of MTX.