BACKGROUND Cytochrome P450 1B1(CYP1B1) is an extrahepatic P450 isoenzyme that can participate in processes of undermining the effectiveness and safety of anti-cancer therapy. Ginsenosides are the main active ingredients in ginseng, which possesses rich pharmacological activities, including anti-cancer activity and organ protection. However, the effect of ginsenosides on the activity of CYP1B1 remains unclear. OBJECTIVE The present study aimed to investigate the inhibitory effect of ginsenosides on CYP1B1 and reveal the structure-inhibitory activity relationship. METHODS Firstly, recombinant CYP1B1 and EROD reactions were used to evaluate the inhibitory effect of ginsenosides. Secondly, molecular docking was used to simulate the interactions between ginsenosides and CYP1B1. Finally, the structure-inhibitory activity relationship was analyzed. RESULTS The ginsenosides, Rb2, Rd, and Rg3, significantly inhibited CYP1B1; the ginsenoside Rd showed the strongest inhibition effect, with a Ki value of 47.37 μM in non-competitive mode. Notably, ginsenoside Rd formed hydrogen bonds with two key amino acid residues of CYP1B1, and one bond was between the glycosyl in position 20 and ALA330, which also made ginsenoside Rd close to the heme iron of CYP1B1. In contrast, ginsenosides, Rb2 and Rg3, which showed weaker inhibition, interacted with only one CYP1B1 residue by the hydrogen bond, which was far away from the heme iron. Finally, the structure-inhibitory activity relationship analysis demonstrated that the number of glycosyls in position 20 and the type of sapogenins in the ginsenoside structure are the key factors determining inhibitory activity. Meanwhile, ALA330 was a vital amino acid in the potent inhibition of CYP1B1 by ginsenosides. CONCLUSION A structure-dependent inhibitory effect on CYP1B1 was revealed for ginsenosides, among which ginsenoside Rd showed the strongest inhibition due to its mono-glycosyl in position 20 of the ginsenoside parent structure. These findings would provide evidence for the synthesis of novel CYP1B1 inhibitors to augment the anti-cancer therapeutic effect.

中文翻译：

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揭示人参皂苷系列化合物对人细胞色素 P450 1B1 的结构依赖性抑制作用。

背景技术细胞色素P450 1B1(CYP1B1)是一种肝外P450同工酶，可参与破坏抗癌治疗的有效性和安全性的过程。人参皂苷是人参中的主要活性成分，具有丰富的药理活性，包括抗癌活性和器官保护活性。然而，人参皂甙对 CYP1B1 活性的影响仍不清楚。目的本研究旨在探讨人参皂苷对CYP1B1的抑制作用，并揭示其结构-抑制活性关系。方法首先采用重组CYP1B1和EROD反应评价人参皂苷的抑制作用。其次，利用分子对接模拟人参皂苷与CYP1B1的相互作用。最后，分析了结构-抑制活性关系。结果人参皂甙Rb2、Rd和Rg3显着抑制CYP1B1；人参皂苷Rd的抑制作用最强，非竞争模式下Ki值为47.37 μM。值得注意的是，人参皂甙Rd与CYP1B1的两个关键氨基酸残基形成氢键，其中20位的糖基与ALA330之间有一个键，这也使人参皂甙Rd与CYP1B1的血红素铁接近。相比之下，人参皂甙Rb2和Rg3的抑制作用较弱，仅通过氢键与一个CYP1B1残基相互作用，远离血红素铁。最后，结构-抑制活性关系分析表明，人参皂苷结构中20位糖基的数量和皂苷元的类型是决定抑制活性的关键因素。同时，ALA330 是人参皂苷有效抑制 CYP1B1 的重要氨基酸。结论人参皂苷对CYP1B1具有结构依赖性抑制作用，其中人参皂苷Rd由于其位于人参皂苷母体结构的20位单糖基而表现出最强的抑制作用。这些发现将为合成新型 CYP1B1 抑制剂以增强抗癌治疗效果提供证据。