從結構生物學探討疏經活血湯對抗凝血劑之中西藥交互作用

Investigation of Interaction between Shu-Gin-Hwai-Shen-tang and Anticoagulant Warfarin from the Perspective of Structural Biology

中藥複方疏經活血湯主要功用為「疏經、活血、袪濕」，臨床檢驗顯示不直接影響凝血酶原的活性指標（INR）；但西藥抗凝血劑s-warfarin即直接作用抗凝血機制，該藥代謝為細胞色素P4502C9（CYP2C9）所作用排出。在臨床和動物試驗觀察到疏經活血湯與s-warfarin併用會影響抗凝血活性，此中西藥交互作用改變原先代謝或藥效是有極大危險性。本研究利用計算結構生物學的角度針對疏經活血湯中五個生物活性重要的指標成分：防己諾林鹼、金雀異黃酮、橙皮素、芍藥苷和粉防己分別在細胞色素CYP2C9對s-warfarin代謝作用活性區進行研究。此研究明顯觀察到疏經活血湯的生物活性成分橙皮素和西藥s-warfarin分別在CYP2C9的活性區和異位調節區彼此產生了中藥小分子和西藥小分子交互作用，其兩個分子間主要的作用力來自於氫鍵，進而影響橙皮素在細胞色素CYP2C9對s-warfarin代謝作用活性受其抑制。因此透過結構生物學更清楚闡明生物活性成分橙皮素參與在疏經活血湯併用西藥s-warfarin時增強抑制凝血作用的重要角色。

The major function of Chinese compound medicine Shu-Gin-Hwai-Shen-tang comprises channel coursing, blood circulation improvement and clearing damp. Animal study shows that Shu-Gin-Hwai-Shen-tang did not influence the activity index (INR) of prothrombin. However, anticoagulant s-warfarin is directly involved in the anticoagulation mechanism and is mainly metabolized by cytochrome P450 2C9 (CYP2C9). Clinical observations and animal models indicated that the co-administration of Shu-Gin-Hwai-Shen-tang and s-warfarin increased anticoagulation activity of warfarin. The changes of efficacy likely cause great danger in bleeding. The alteration of warfarin metabolism can be one of the potential factor. Our study employs the structural biology approach to investigate the effect of five major biologically active ingredients of Shu-Gin-Hwai-Shen-tang, namely fangchinoline, genistein, hesperetin, paeoniflorin and tetrandrine, on the active site of CYP2C9 for s-warfarin. Docking of ingredients to the active site of CYP2C9 revealed that the interaction is present between hesperetin and s-warfarin at the active regions and allosteric regulation regions of CYP2C9, and the primary force between the two molecules comes from hydrogen bond, which is involved in the inhibition of metabolism of s-warfarin by cytochrome CYP2C9 through hesperetin. Results from structural biology clearly illustrate the important role of hesperetin participating in the enhancement of coagulation inhibition when Shu-Gin-Hwai-Shen-tang is used together with s-warfarin.