柑橘屬水果與中草藥中 furanocoumarins 成分之分析及其對肝臟代謝酵素細胞色素 P450 3A4 （ CYP3A4 ）活性影響之評估

1. 柑橘屬水果與中草藥中furanocoumarins成分之分析及其對肝臟代謝酵素細胞色素P450 3A4（CYP3A4）活性影響之評估 • 本研究以葡萄柚、西施柚、白柚和文旦等四種柑橘屬水果果汁與十種中草藥白芷、羌活、獨活、防風、當歸、黃芩、甘草、茵陳蒿、葛根和陳皮等之水萃取液和酒精萃取液進行五種已知之主要furanocoumarin的成分分析，以及進行體外之代謝酵素抑制試驗，由此了解柑橘屬水果與中藥所含furanocoumarin之成分及含量與其對於代謝酵素 CYP3A4之抑制作用之間的關係。首先，利用高效液相層析法（high performance liquid chromatography，HPLC）建立一簡單、快速且具有良好的靈敏度與再現性的分析方法來分析五個已知之主要的furanocoumarin成分包括bergaptol、psoralen、bergapten、6’, 7’-dihydroxybergamottin（DHBG）和bergamottin。利用此經過確效之分析方法進行四種柑橘屬水果果汁與十種中草藥之水萃取液和酒精萃取液中furanocoumarin成分的分析。結果顯示，四種柑橘屬水果中，葡萄柚、西施柚和白柚皆含有除了bergapten外的其它四個furanocoumarin成分，其中以葡萄柚果汁中的furanocoumarin成分含量最高。而在十種中草藥中，除了葛根和茵陳蒿未分析出含有此五種furanocoumarin成分外，其他均測出含有不同種類及含量之furanocoumarin成分。另外，分別將此四種柑橘屬水果果汁與十種中草藥之水萃取液和酒精萃取液，以nifedipine為CYP3A4之受質，進行體外之代謝酵素抑制試驗。實驗結果顯示，四種柑橘屬水果果汁均具有抑制代謝酵素CYP3A4的作用。在十種中草藥中以黃芩之抑制作用最強，而繖形科之白芷、羌活和獨活亦具有非常明顯之抑制CYP3A4作用的表現。整體而言，對於主要成分為furanocoumarin的柑橘屬水果及繖形科中草藥，我們可藉由其所含furanocoumarin成份的種類數目及含量多寡預測其在體內對代謝酵素CYP3A4可能造成的影響。然而，對於只含有微量或無法偵測到furanocoumarin成分之黃芩和其他非繖形科之中草藥，可能還有本實驗中未進行分析的dimeric form之furanocoumarin成分或其他flavonoid之成分，造成其抑制代謝酵素CYP3A4的作用。

2. Determination of Furanocoumarins in Citrus Fruits and Herbal Medicines and Their Inhibitory Potential on Cytochrome P450 3A4（CYP3A4）Activity • In this study, the composition of five furanocoumarins in four Citrus fruit (grapefruit, pomelo I, pomelo II, and shaddock) juices and ten Chinese herbal medicine (Bai-Zhi, Qiang-Huo, Du-Huo, Fang-Feng, Dang-gui, Huang-Qin, Gan-Cao, Ge-Gen, Yin-Chen-Hao, and Chen-Pi) extracts in water or alcohol have been investigated.A rapid and sensitive high-performance liquid chromatography (HPLC) method for quantitation of five major furanocoumarins (bergamottin, DHBG, bergapten, bergaptol and psoralen) was developed and validated. This method was applied to analyze the composition of five furanocoumarins in four Citrus fruit juices and ten Chinese herbal medicine extracts in water or alcohol. Results showed that five major furanocoumarins except bergapten were detected in grapefruit, pomelo I and pomelo II and the highest amount of these components found in the grapefruit juice. In the ten Chinese herbal medicines, five furanocoumarins were not detected in Ge-Gen and Yin-Chen-Hao, while the rest of herbs contained various compositions and amounts of furanocoumarins.Furthermore, the inhibitory effects on nifedipine dehydrogenation by CYP3A4 were evaluated for the four Citrus fruit juices and ten Chinese herbal medicines extracts in water or alcohol. Results show that all Citrus fruits juices exhibited CYP3A4 inhibitory effects on the metabolism of nifedipine. Among ten herbal medicines, both water and alcohol extracts of Huang-Qin demonstrated the greatest inhibition on CYP3A4 activity. In addition, Umbelliferous herbs including Bai-Zhi, Qiang-Huo, and Du-Huo also showed significant inhibitory potencies on CYP3A4 activity.Our results indicated that the inhibitory potency is in direct proportional to the abundant and different composition of the furanocoumarins in Citrus fruit juices and Umbelliferous herbs. However, the content of furanocoumarins were found to be very low or even undetectable in Huang-Qin and herbs not belong to Umbelliferae family, their inhibitory effect could be attributed to the dimeric forms of furanocoumarins or other unidentified components (eg. flavonoid).