Inhibition of aromatase activity by flavonoids

Jeong, Hyun Ja; Shin, Young Geun; Kim, Il Hyuk; Pezzuto, John M.

doi:10.1007/bf02976369

Cited by 125 publications

(97 citation statements)

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“…Prior laboratory research suggests that flavonoids may inhibit breast cancer development by decreasing estrogen production (1,2), inhibiting breast cancer cell proliferation (3), and decreasing reactive oxygen species production (4,5). Several population-based studies (6)(7)(8), including analyses from the Long Island Breast Cancer Study (LIBCSP; ref.…”

Section: Introductionmentioning

confidence: 99%

Dietary Flavonoid Intake and Breast Cancer Survival among Women on Long Island

Fink

Steck

Wolff

et al. 2007

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Background: Laboratory research and a growing number of epidemiologic studies have provided evidence for a reduced risk of breast cancer associated with dietary intake of certain classes of flavonoids. However, the effects of flavonoids on survival are not known. In a population-based cohort of breast cancer patients, we investigated whether dietary flavonoid intake before diagnosis is associated with subsequent survival. Methods: Women ages 25 to 98 years who were newly diagnosed with a first primary invasive breast cancer between August 1, 1996, and July 31, 1997, and participated in a population-based, case-control study (n = 1,210) were followed for vital status through December 31, 2002. At the case-control interview conducted shortly after diagnosis, respondents completed a FFQ that assessed dietary intake in the previous 12 months. All-cause mortality (n = 173 deaths) and

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Section: Introductionmentioning

confidence: 99%

Dietary Flavonoid Intake and Breast Cancer Survival among Women on Long Island

Fink

Steck

Wolff

et al. 2007

Cancer Epidemiology, Biomarkers &Amp; Prevention

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“…Apigenin was found to possess anticarcinogenic, 8) anti-tumor promoter, 9) antioxidative, free radical scavenging and anti-inflammatory activities. 10) Both chrysin and apigenin were found to be potent inhibitors of enzyme aromatase and can protect against breast cancer [11][12][13] and were not mutagenic in the Ames test. [14][15][16] Previous mammalian metabolic studies of chrysin and apigenin in rat showed that they are conjugated at the C-7 hydroxyl group to produce ethereal sulfates and glucuronides, although no structures were provided, and that chrysin is hydroxylated to apigenin.…”

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confidence: 99%

Biotransformation of Chrysin and Apigenin by Cunninghamella elegans

Ibrahim

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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In a previous publication, the sulfation of the hydroxyl group at C-7 of naringenin by the filamentous fungus Cunninghamella elegans was reported. 1) Metabolism of quercetin with this organism produced quercetin-4Ј-sulfate. The same results were obtained with flavanones, methoxylated at C-7. 2) Preliminary studies of flavones such as kaempferol and morin as well as the flavanones hesperitin and dihydroquercetin showed that they were converted to polar metabolites by this fungus, which were hydrolyzed by mild acid at room temperature to the respective substrates. The potential of flavonoid sulfates as therapeutically useful agents, 3,4) as standards to study flavonoid conjugation by mammals, 5) and for comparison with natural products 6) requires the preparation of flavonoids sulfated at specific sites.Chemical synthesis usually provides mixtures of flavonoid sulfates with sulfate groups randomly allocated 6) and may be difficult to purify. Thus the use of microorganisms to introduce sufalte groups at specific positions of the flavonoid nucleus seems interesting. Many microbial enzymes were found to possess broad substrate specificity, yet they catalyze reactions with high degree of regio and stereospecificity. 7) In order to check the breadth of substrate specificity of C. elegans sulfating enzyme(s), two biologically active flavones: chrysin (5,7-dihydoxyflavone) and apigenin (5,7,4Ј-trihydroxyflavone) were subjected to metabolic studies using a culture of the same microorganism. Apigenin was found to possess anticarcinogenic, 8) anti-tumor promoter, 9) antioxidative, free radical scavenging and anti-inflammatory activities. 10) Both chrysin and apigenin were found to be potent inhibitors of enzyme aromatase and can protect against breast cancer 11-13) and were not mutagenic in the Ames test. [14][15][16] Previous mammalian metabolic studies of chrysin and apigenin in rat showed that they are conjugated at the C-7 hydroxyl group to produce ethereal sulfates and glucuronides, although no structures were provided, and that chrysin is hydroxylated to apigenin. 17) Luteolin and apigenin were also obtained from incubation of apigenin and chrysin, respectively with rat liver microsomes. 18) Only glucuronide and sulfate conjugates of apigenin were obtained from incubation with HepG 2 cells, which emphasizes the importance of phase II conjugation reactions in the metabolism of flavonoids. 19) Fungi are eukaryotic organisms possessing similar metabolic machinery to those of mammals and the outcome of xenobiotic metabolism in both systems is expected to be closely related. 20) Since microorganisms are known to hydroxylate flavonoids at the C-4Ј position, 21) an additional goal of this work was to convert chrysin to the far more expensive and important apigenin. No microbial biotransformation studies on chrysin or apigenin have previously been reported. Results and DiscussionMicrobial transformation studies, using C. elegans, have indicated the capability of this microorganism to simulate metabolic reactions of drugs perf...

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“…The flavonoid chrysin (5,7-dihydroxyflavone) is present at high levels in honey and propolis (Siess et al, 1996) and in many plant extracts (Williams et al, 1997). In addition to its reported anticarcinogenic (Cardenas et al, 2006), antiviral (Critchfield et al, 1996), antioxidant (Lapidot et al, 2002), and anti-inflammatory (Cho et al, 2004) activities, chrysin has been shown as a potent inhibitor of aromatase (Jeong et al, 1999), an enzyme responsible for the conversion of androstenedione and testosterone into estrone and estradiol, respectively (Meinhardt and Mullis, 2002). As such, chrysin acts as a testosterone-boosting agent and is currently available as dietary supplements used for increasing lean body mass.…”

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confidence: 99%