Chem Biol Interact. 1980 Oct;32(1-2):101-10.  

Inhibition of cytochrome P-448 mixed function oxidase activity following
administration of 9-hydroxyellipticine to rats.

Delaforge M, Ioannides C, Parke DV.

The in vitro inhibitor of mixed-function oxidation, 9-hydroxyellipticine,
non-competitively inhibited the binding of the type II substrate, aniline, to
cytochrome P-448 of hepatic microsomal preparations from rats pretreated with
3-methylcholanthrene. In contrast, 9-hydroxyellipticine did not inhibit the
binding of aniline to cytochrome P-450 of hepatic microsomal preparations from
rats pretreated with phenobarbitone, nor did it inhibit the binding of the type
I substrate, hexobarbitone to either cytochrome P-450 or cytochrome P-448.
Following the pretreatment of rats intraperitoneally with 9-hydroxyellipticine
and phenobarbitone, the cytochrome P-448-specific enzyme activity,
ethoxyresorufin O-deethylase, was 50% inhibited in vitro but cytochrome P-450,
cytochrome P-450 reductase, and other mixed function oxidase activities were
unaffected. With rats pretreated with 9-hydroxyellipticine and
3-methylcholanthrene, inhibition of ethoxyresorufin O-deethylase was 90%, and
cytochrome P-450/P-448, cytochrome P-450 reductase, biphenyl 2- and
4-hydroxylase were inhibited by 30, 15, 50 and 40% respectively. It is concluded
that 9-hydroxyellipticine administered in vivo markedly inhibits mixed-function
oxidations which are specific to cytochrome P-448, but has no effect on
cytochrome P-450-catalysed microsomal oxidation.

PMID: 7428105 [PubMed - indexed for MEDLINE]