Inhibition of metabolism and DNA binding of polycyclic aromatic hydrocarbons (PAHs) by plant phenols in epidermis of SENCAR mice
Naturally occurring plant phenols such as tannic acid (TA), quercetin (QT), myricetin (MY) and anthraflavic acid (AA) have been shown to inhibit the mutagenicity of several bay-region diolepoxides of PAHs. Since skin is a target for PAH carcinogenesis, they investigated the effect of these plant phenols on epidermal aryl hydrocarbon hydroxylase (AHH) activity and the binding of PAHs to DNA in SENCAR mice. Each of the plant phenols tested was found to be an in vitro and in vivo inhibitor of epidermal AHH activity with I/sub 50/ values ranging from 4.4 x 10/sup -5/ - 12.4 x 10/sup -5/M in control and 3-methylcholanthrene (MCA) pretreated skin. On an equimolar basis TA was the most potent inhibitor with a Ki of 81 ..mu..M. Incubation of TA, QT, MY and AA with epidermal microsomes resulted in varying degrees of inhibition of enzyme mediated covalent binding of benzo(a)pyrene (BP) to calf thymus DNA. TA (25 ..mu..M) showed maximum inhibition (64%). A single topical application (12 ..mu..mol) of TA, QT, MY and AA resulted in significant decrease in the binding of BP, BP-7,8-diol and 7,12-dimethylbenz(a)anthracene to epidermal DNA. The formation of (+)-7..beta..,8..cap alpha..-dihydroxy-9..cap alpha..,10..cap alpha..-epoxy-7,8,9,10-tetrahydro-BP-deoxyguanine adduct in epidermis was significantly reduced (62-86%) following topical application of the plant phenols. Their results suggest that some of these plant phenols have substantial though variable potential to modify the risk of PAHs induced skin carcinogenicity.
- Research Organization:
- Case Western Reserve Univ., Cleveland, OH
- OSTI ID:
- 6962291
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHENOLS
BIOLOGICAL EFFECTS
POLYCYCLIC AROMATIC HYDROCARBONS
METABOLISM
MUTAGENESIS
BIOCHEMICAL REACTION KINETICS
COVALENCE
DNA
HYDROXYLASES
MICE
QUERCETIN
TANNIC ACID
ANIMALS
AROMATICS
CARBOXYLIC ACIDS
ENZYMES
FLAVENOIDS
FLAVONES
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROXY COMPOUNDS
KINETICS
MAMMALS
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDOREDUCTASES
POLYPHENOLS
PYRANS
REACTION KINETICS
RODENTS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology