Abstract

1. We developed an assay system to evaluate the cytochrome P450 (CYP) 3A4-inhibitory activity of compounds, taking account of their cellular permeability, using intestine-derived cell lines pre-treated with the CYP3A4 inducer 1α,25-dihydroxy-vitamin D₃ (250 nM).

2. Ketoconazole (KTZ), saquinavir (SQV), naringin, naringenin (NGE), bergamottin (BG), 6',7'-dihydroxybergamottin (DHBG), epigallocatechin gallate (EGCG), and resveratrol (RES) were evaluated as known CYP3A4 inhibitors. The apparent IC₅₀ (IC_50,app) values of known inhibitors were determined in Caco-2 cells with 10 µM midazolam as a CYP3A4 substrate, and compared with the IC₅₀ values in a human liver microsome assay.

3. SQV and BG with high lipophilicity and good membrane permeability show similar concentrations inside and outside the cells, and consequently IC_50,app and IC₅₀ are similar.

4. KTZ, EGCG, DHBG, NGE, and RES showed a difference between IC₅₀ and IC_50,app. This is considered to result from a difference between the intracellular and extracellular concentrations of the compound, which is likely due to the involvement of efflux and/or influx transporters.

5. This method to evaluate CYP inhibition taking account of membrane permeation should be helpful to assess the potential clinical relevance of drug-drug or drug-food interactions in the gastrointestinal tract.

摘要

1. 我们开发了一种分析系统来评估化合物的细胞色素 P450 (CYP) 3A4 抑制活性，同时考虑到它们的细胞渗透性，使用经 CYP3A4 诱导剂 1α,25-二羟基维生素 D ₃预处理的肠源细胞系（ 250 纳米）。

2. 酮康唑 (KTZ)、沙奎那韦 (SQV)、柚皮素、柚皮素 (NGE)、佛手柑素 (BG)、6',7'-二羟基佛手柑素 (DHBG)、表没食子儿茶素没食子酸酯 (EGCG) 和白藜芦醇 (RES) 被评估为已知的 CYP3A4 抑制剂. 已知抑制剂的表观 IC ₅₀ (IC _50,app ) 值在 Caco-2 细胞中测定，​​使用 10 µM 咪达唑仑作为 CYP3A4 底物，并与人肝微粒体试验中的 IC ₅₀值进行比较。

3. 具有高亲脂性和良好膜渗透性的SQV和BG在细胞内外表现出相似的浓度，因此IC _50,app和IC ₅₀相似。

4. KTZ、EGCG、DHBG、NGE 和 RES 显示出 IC ₅₀和 IC _50,app之间的差异。这被认为是由于化合物的细胞内和细胞外浓度之间的差异造成的，这可能是由于外排和/或内流转运蛋白的参与。

5. 这种考虑膜渗透来评估 CYP 抑制的方法应该有助于评估胃肠道中药物-药物或药物-食物相互作用的潜在临床相关性。