葛根 (Pueraria Radix; PR) 為豆科植物Pueraria lobata (Leguminosae) 之根，含豐富異黃酮，包括 puerarin、daidzin、daidzein 等。本研究探討大鼠口服葛根濃縮散劑、葛粉與乙醇萃取物後之異黃酮代謝動力學及組織分佈、葛根與治療指數狹窄的西藥 methotrexate (MTX) 及 valproic acid (VPA) 之交互作用，以及對大鼠海馬迴乙醯膽鹼釋放之影響。 利用高效液相層析法分析葛根製劑中puerarin、daidzin、daidzein之含量，發現各種製劑中均以puerarin之含量最高；之後進行葛根之代謝動力學及組織分佈研究。大鼠口服葛根製劑，於特定時間以心臟穿刺採血，血清未經水解或分別以β-glucuronidase及sulfatase水解後，利用高效液相層析法定量。結果顯示，血液中、腦及睪丸，均無法測得daidzein free form，至於肝臟、腎臟與脾臟則可測得；因此異黃酮以daidzein sulfates及glucuronides存在於血中及組織中，並以sulfates為主要代謝物，且經重量校正後，以腎臟之daidzein結合態代謝物含量最高，肝臟次之。而血中daidzein sulfates及glucuronides濃度，多次給藥後於第四天達血中之穩定狀態。另外，為驗證文獻中葛根異黃酮成分原形於體內活性之真實性，利用口服葛根與直接輸注葛根含藥血清之方式，評估葛根製劑對大鼠海馬迴乙醯膽鹼 (acetylcholine; Ach) 釋出之影響，結果顯示並未增加乙醯膽鹼之釋出。 西藥與中藥併用為臺灣嚴重的社會醫療問題。西藥MTX與VPA為羧類藥物，為多重抗藥性蛋白 (multidrug resistant proteins; MRPs) 及有機陰離子運輸蛋白 (organic anion transporters; OATs) 之受質。葛根異黃酮口服吸收後於體內代謝成sulfates與glucuronides，許多研究報導sulfates及glucuronides為MRPs 與 OATs之受質。葛根異黃酮代謝物與MTX、VPA於體內應會相互競爭運輸蛋白。本研究以大鼠為模型，利用螢光偏極免疫法 (monoclonal fluorescence polarization immunoassay; FPIA) 定量血中藥物濃度。結果顯示，大鼠併服葛根水煎劑時，對口服MTX之血藥面積及滯留時間皆顯著提高，對口服VPA之血藥面積顯著提高，而二者之Cl/F亦顯著降低，且延長靜脈注射MTX與VPA之半衰期及滯留時間，至於清除率則顯著降低，顯示交互作用發生於排除期。因此建議盡量避免同期服用羧類藥物與葛根。 本研究另以免疫抑制劑環孢靈為模型藥物，代表CYP3A4與 P-glycoprotein (P-gp) 的受質，以大鼠為模型動物，分別單獨口服環孢靈及併服常用中藥，包括人參、西洋參、三七、冬蟲夏草與薑汁等，給藥後於特定時間採血，利用具特異性之螢光偏極免疫法，分析環孢靈之血中濃度。結果顯示，這些中藥除三七外，皆使口服環孢靈之生可用率顯著降低，且即使提前一或二小時給藥亦具顯著降低之作用，而對靜脈注射環孢靈的動力學無顯著影響，顯示交互作用發生在吸收期；因此建議病人盡量避免同期服用此些中藥與環孢靈，以保障療效。但這些中藥對於P-gp對Rhodamine 123外排之作用並無顯著影響，顯見交互作用之發生應與P-gp無關，其交互作用發生之機轉尚待進一步研究。 總之，以代謝動力學的方法可以探索中藥在完整動物活體內的命運，甚至可以進一步發現具潛在風險的中西藥交互作用。; Pueraria Radix (PR), the roots of Pueraria lobata OWHI is an isoflavone-rich Chinese herb and also a food in oriental countries. Puerarin, daidzin and daidzein are bioactive isoflavone constituents of PR. The aims of this study were (1) to investigate the metabolic pharmacokinetics of isoflavones after oral administrations of commercial and ethanol extract of PR in rats, (2) to measure the effects of PR decoction on the pharmacokinetics of methotrexate (MTX) and valproic acid (VPA), and (3) to measure the effect of PR in extracellular acetylcholine release on rat hippocampus. Rats were given commercial and ethanol extract of PR and blood samples were withdrawn via cardiopuncture and assayed by HPLC method after enzymatic hydrolysis with β-glucuronidase and sulfatase, respectively. Daidzein sulfates were found predominantly in the bloodstream, whereas daidzein glucuronides presented in less amount. Microdialysis technique was used for pharmacodynamic study of PR, the effect of PR after oral dosing on the extracellular acetylcholine release in rat hippocampus was not significant. MTX and VPA are two western medicines with narrow therapeutic index, and thus were used as model drugs to explore the herb - drug interaction which is an important public health issue in Taiwan. MTX and VPA are carboxylic acids and being substrates of multidrug resistance proteins (MRPs) and organic anion transporters (OATs). The isoflavones of PR were metabolized into sulfates and glucuronides in the body, both metabolites are also reported as substrates of MRPs and OATs. These metabolites may compete the transporters with MTX and VPA. This study investigated the effects of PR decoction on the pharmacokinetics of MTX and VPA in rats. The blood concentrations of MTX and VPA were determined by monoclonal fluorescence polarization immunoassay (FPIA) method. The systemic exposure of MTX and VPA were significantly increased after oral coadministration of PR decoction. In addition, when MTX and VPA were given intravenously, the coadministration of PR decoction significantly decreased the clearance of MTX and VPA. Therefore, the enhanced of exposure of MTX and VPA by coadministration of PR can be ascribed to the decreased elimination of MTX and VPA. In order to ensure safety, concurrent intake of MTX or VPA with PR should be discouraged. Cyclosporin (CsA) is a widely used immunosuppressant with narrow therapeutic range. CsA was used as a model d
