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5155034 
Journal Article 
The red clover (Trifolium pratense) isoflavone biochanin A modulates the biotransformation pathways of 7,12-dimethylbenz[a]anthracene 
Chan, HY; Wang, H; Leung, LK 
2003 
Yes 
British Journal of Nutrition
ISSN: 0007-1145
EISSN: 1475-2662 
90 
1 
87-92 
English 
12844379 
WOS:000184159400011 
Several flavonoids have shown their anti-carcinogenic effects in various models. The soyabean isoflavone genistein was demonstrated earlier in our laboratory to be an effective inhibitor of dimethylbenz[a]anthracene (DMBA)-induced DNA damage in MCF-7 cells by curbing cytochrome P450 (CYP) 1 enzymes. The red clover (Trifolium pratense) isoflavone biochanin A is a methylated derivative of genistein, and its anti-mutagenic effect in bacterial cells has been shown previously. Because of its protection against chemical carcinogenesis in an animal model, biochanin A was selected for testing in our established MCF-7 cell system. From the results obtained in the semi-quantitative reverse transcription-polymerase chain reaction and xenobiotic response element (XRE)-luciferase reporter assays, biochanin A could reduce xenobiotic-induced CYP1A1 and -1B1 mRNA abundances through the interference of XRE-dependent transactivation. Enzyme kinetic studies also indicated that biochanin A inhibited both CYP1A1 and -1B1 enzymes with inhibition constant (Ki) values 4.00 and 0.59 microm respectively. Since the biotransformation of DMBA was dependent on CYP1 enzyme activities, biochanin A was able to decrease the DMBA-DNA lesions. The present study illustrated that the red clover isoflavone could protect against polycylic aromatic hydrocarbon-induced DNA damage. 
7,12-Dimethylbenz[a]anthracene-DNA lesion; Biochanin A; Cytochrome P450 1A1; Cytochrome P450 1B1