Effect of phytochemicals on cytochrome P450-linked alkoxyresorufin O-dealkylase activity

✍ Scribed by Robert W. Teel; Huong Huynh

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 201 KB
• Volume: 12
• Category: Article
• ISSN: 0951-418X
• DOI: 10.1002/(sici)1099-1573(199803)12:2<89::aid-ptr193>3.0.co;2-j

✦ Synopsis

Eight compounds of plant origin with potential chemopreventive properties were studied for their effects on hamster liver microsome-mediated alkoxyresorufin O-dealkylase activity. The phytochemicals investigated were ()-catechin, chlorophyllin, crocetin, curcumin, diallyl sulphide, (-)-epigallocatechin gallate (EGCG), d-limonene and tannic acid. Each phytochemical at concentrations of 0.25 mM and 0.5 mM was incubated with 0.2 mg hamster liver microsomal protein and 0.5 mmole benzyloxyresorufin, methoxyresorufin and ethoxyresorufin. The resorufins serve as substrates for measurements of the activity of isoforms of cytochrome P450 (CYP). Benzyloxyresorufin O-dealkylase (BROD), methoxyresorufin demethylase (MROD) and ethoxyresorufin deethylase (EROD) are linked to CYP 2C11, CYP 1A2 and CYP 2C6, respectively. Chlorophyllin, curcumin, EGCG and tannic acid were all potent inhibitors of BROD, MROD and EROD activity. ()-Catechin and diallyl sulphide inhibited BROD and EROD but not MROD activity. Crocetin and d-limonene inhibited BROD activity more than MROD and EROD. These results indicate that the enzymatic activity of cytochrome P450 isoforms 2C11, 1A2 and 2C6 can be altered by phytochemicals and that phytochemicals can affect the metabolism of substrates for these isoforms.