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Effect of phytochemicals on cytochrome P450‐linked alkoxyresorufin O‐dealkylase activity
Author(s) -
Teel Robert W.,
Huynh Huong
Publication year - 1998
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/(sici)1099-1573(199803)12:2<89::aid-ptr193>3.0.co;2-j
Subject(s) - cytochrome p450 , microsome , cyp1a2 , biochemistry , catechin , chemistry , hamster , metabolism , polyphenol , biology , enzyme , antioxidant , microbiology and biotechnology
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 μ M and 0.5 μ M was incubated with 0.2 mg hamster liver microsomal protein and 0.5 μmole 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. © 1998 John Wiley & Sons, Ltd.