Induction and inhibition of cytochromes P450 by the St. John's wort constituent hyperforin in human hepatocyte cultures
Induction and inhibition of cytochromes P450 by the St. John's wort constituent hyperforin in human hepatocyte cultures
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DOI：
10.1124/dmd.32.5.512
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发表时间：
2004-05-01
影响因子：
3.9
通讯作者：
Venkataramanan, R
中科院分区：
文献类型：
--
作者：
Komoroski, BJ;Zhang, SM;Venkataramanan, R
贯叶连翘属植物贯叶连翘(Hypericum perperatum L.)是美国最常用的草药之一。临床报道的优势表明，四逆解毒丸可提高细胞色素P450 3A4酶活性，降低某些药物的血药浓度。虽然生姜丸对细胞色素P3A4有明显的诱导作用，但也有报道表明生姜丸成分可能具有一定程度的酶抑制作用。因此，我们试图在人肝细胞模型上研究四君子汤成分对细胞色素P3A4的诱导和抑制作用。此外，大多数研究都集中在SJW对细胞色素P3A4的诱导，而对其他重要的药物代谢酶如细胞色素P1A2、细胞色素P450_2C9和细胞色素P450_2D6的研究较少。以金丝桃素和金丝桃素为主要成分，观察四逆汤对肝细胞色素P450 1A2、细胞色素P450 2 C9、细胞色素P2 2 D6和细胞色素P3 A4的影响。用金丝桃素或金丝桃素处理的肝细胞暴露在探针底物中，以确定酶活性以及蛋白质和RNA的收获。金丝桃素处理后，细胞色素P3A4和细胞色素P450 2C9的mRNA、蛋白和活性显著增加，而对细胞色素P1A2和细胞色素P450 2 D6的活性无明显影响。在探针底物出现前1h，5um和10um时给予金丝桃素可抑制细胞色素P3A4的活性。金丝桃素对所测试的任何酶都没有影响。这些结果表明，在慢性暴露条件下，四逆汤对药物代谢酶的诱导作用占主导地位，人肝细胞培养是筛选中药制品对细胞色素P450酶影响的通用工具。
St. John's wort extract (SJW) (Hypericum perforatum L.) is among the most commonly used herbal medications in the United States. The predominance of clinical reports indicates that SJW increases the activity of cytochrome P450 3A4 (CYP3A4) enzyme and reduces plasma concentrations of certain drugs. Although the inductive effect of SJW on CYP3A4 is clear, other reports indicate that SJW constituents may have, to a small degree, some enzyme inhibitory effects. Therefore, we sought to study the induction and inhibition effects of the constituents of SJW on CYP3A4 in the human hepatocyte model. Moreover, most research has focused on the induction of CYP3A4 by SJW with little attention paid to other prominent drug-metabolizing enzymes such as CYP1A2, CYP2C9, and CYP2D6. To examine the effects of SJW on CYP1A2, CYP2C9, CYP2D6, as well as CYP3A4, hepatocytes were exposed to hyperforin and hypericin, the primary constituents of SJW extract. Hepatocytes treated with hypericin or hyperforin were exposed to probe substrates to determine enzyme activity and protein and RNA harvested. Hyperforin treatment resulted in significant increases in mRNA, protein, and activity of CYP3A4 and CYP2C9, but had no effect on CYP1A2 or CYP2D6. Acute administration of hyperforin at 5 and 10 muM 1 h before and along with probe substrate inhibited CYP3A4 activity. Hypericin had no effect on any of the enzymes tested. These results demonstrate that with chronic exposure, the inductive effect of SJW on drug-metabolizing enzymes predominates, and human hepatocyte cultures are a versatile in vitro tool for screening the effect of herbal products on cytochrome P450 enzymes.