The aim of this study was to investigate drug interactions of L-dopa/carbidopa with catechin and green tea essence in rabbits following the simultaneous administration via an intramuscular injection of catechin or via an intragastric route for green tea essence with L-dopa/carbidopa. The results indicated that catechin at doses of 10, 20 and 50 mg/kg increased the area under the plasma concentration–time curve from time zero to the time of the last quantifiable concentration (AUC_0–t) of L-dopa by about 69, 78 and 42%, respectively. The metabolic ratios of the AUC_0–t for 3-O-methyldopa (3-OMD)/L-dopa significantly decreased by about 56, 68 and 76% (P < 0.05), respectively. In addition, a single dose of 5/1.25 mg/kg L-dopa/carbidopa was co-administrated with 150 mg/kg green tea essence via an intragastric route with an oral-gastric tube. Comparing the related pharmacokinetic parameters of L-dopa, the clearance and metabolic ratio of L-dopa decreased by 20 and 19% (P < 0.05), respectively. In conclusion, catechin and green tea essence can significantly affect the metabolism of L-dopa by the catechol-O-methyltransferase (COMT) metabolic pathway. Catechin can enhance L-dopa bioavailability, and both catechin and green tea essence decreased 3-OMD formation. Therefore, catechin and green tea essence may increase L-dopa efficacy for Parkinson's disease treatment.

中文翻译：

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儿茶素和绿茶香精商业制剂对左旋多巴在兔体内药代动力学的影响

本研究的目的是研究左旋多巴/卡比多巴与儿茶素和绿茶香精在兔体内的药物相互作用，即通过肌内注射儿茶素或绿茶香精与左旋多巴/卡比多巴的胃内途径同时给药。结果表明，10、20 和 50 mg/kg 剂量的儿茶素使血浆浓度-时间曲线下面积从零时间到L-多巴的最后可量化浓度 (AUC _{0– t} )的时间增加了约 69 ，分别为 78% 和 42%。AUC的代谢比率_0-吨为3- ø -methyldopa（3- OMD）/左旋多巴显著减少了约56，68和76％（P < 0.05)，分别。此外，单剂量 5/1.25 mg/kg L-多巴/卡比多巴与 150 mg/kg 绿茶香精通过胃内途径与口腔胃管共同给药。比较左旋多巴的相关药代动力学参数，左旋多巴的清除率和代谢率分别降低了20%和19%（P  < 0.05）。总之，儿茶素和绿茶精可以通过儿茶酚-O-甲基转移酶（COMT）代谢途径显着影响左旋多巴的代谢。儿茶素可以提高左旋多巴的生物利用度，儿茶素和绿茶精华都减少了 3-OMD 的形成。因此，儿茶素和绿茶精华可能会增加左旋多巴治疗帕金森病的疗效。