Inhibitory Potential of Herbal Medicines on Human Cytochrome P450-Mediated Oxidation: Properties of Umbelliferous or Citrus Crude Drugs and Their Relative Prescriptions

• Published in: Japanese journal of pharmacology Vol. 85; no. 4; pp. 399 - 408
• Main Authors: Guo, Lian-Qing, Taniguchi, Masahiko, Chen, Qiao-Yun, Baba, Kimiye, Yamazoe, Yasushi
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Pharmacological Society 2001
• Subjects: Aryl Hydrocarbon Hydroxylases; Citrus; Crude drug; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System - physiology; Cytochrome P450 3A; Drugs, Chinese Herbal - pharmacology; Enzyme Inhibitors - pharmacology; Furanocoumarin; Herbal Medicine; Humans; Inhibition; Microsomes, Liver - drug effects; Microsomes, Liver - enzymology; Oxidation-Reduction - drug effects; Oxidoreductases, N-Demethylating - antagonists & inhibitors; Oxidoreductases, N-Demethylating - physiology; Plant Extracts - pharmacology; Steroid Hydroxylases - antagonists & inhibitors; Traditional prescription
• ISSN: 0021-5198; 1347-3506
• DOI: 10.1254/jjp.85.399

To investigate the possible drug interaction with herbal medicine, hot water decoctions or 40% ethanol infusions of several Umbelliferous or Citrus crude drugs and their prescriptions were examined in vitro for their abilities to inhibit human cytochrome P450 3A (CYP3A). Addition of each decoction or infusion from Baizhi (Angelica dahurica and varieties), Qianghuo (Notopterygium incisum or N.forbesii), Duhuo (Angelica biserrata), Fangfeng (Saposhnikovia divaricata), Danggui (Angelica sinensis), Zhishi or Zhiqiao (Citrus aurantium) resulted in various degrees of human CYP3A inhibition as determined by microsomal testosterone 6β-hydroxylation. The inhibitory potency was consistent with the abundance of the hydrophobic components for each sample. Experiments on the infusion of a Japanese Baizhi (BZ1) showed the major role of furanocoumarins on human CYP3A inhibition. Some of the crude drugs and a related prescription showed increased inhibition after the preincubation, suggesting the involvement of a mechanism-based inhibition. Some formulated prescriptions, however, showed intense inhibition with their hydrophobic fractions rather than with their hydrophobic fractions, suggesting that components other than furanocou-marins in herbal prescriptions may also cause CYP3A inhibition. These results indicate the necessity of intensive investigations on the possible drug interaction with traditional medicines.