Grape seed extract a natural aromatase inhibitor

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Old 10-27-2006, 06:28 PM
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Default Grape seed extract a natural aromatase inhibitor

In my research for safe alternatives to drug aromatase inhibitors, I discovered that grape seed extract both inhibits aromatase & downregulates its expression:

Grape seed extract is an aromatase inhibitor and a suppressor of aromatase expression.Kijima I, Phung S, Hur G, Kwok SL, Chen S.
Department of Surgical Research, Beckman Research Institute of the City of Hope, Duarte, California, USA.

Aromatase is the enzyme that converts androgen to estrogen. It is expressed at higher levels in breast cancer tissues than normal breast tissues. Grape seed extract (GSE) contains high levels of procyanidin dimers that have been shown in our laboratory to be potent inhibitors of aromatase. In this study, GSE was found to inhibit aromatase activity in a dose-dependent manner and reduce androgen-dependent tumor growth in an aromatase-transfected MCF-7 (MCF-7aro) breast cancer xenograft model, agreeing with our previous findings. We have also examined the effect of GSE on aromatase expression. Reverse transcription-PCR experiments showed that treatment with 60 mug/mL of GSE suppressed the levels of exon I.3-, exon PII-, and exon I.6-containing aromatase mRNAs in MCF-7 and SK-BR-3 cells. The levels of exon I.1-containing mRNA, however, did not change with GSE treatment. Transient transfection experiments with luciferase-aromatase promoter I.3/II or I.4 reporter vectors showed the suppression of the promoter activity in a dose-dependent manner. The GSE treatment also led to the down-regulation of two transcription factors, cyclic AMP-responsive element binding protein-1 (CREB-1) and glucocorticoid receptor (GR). CREB-1 and GR are known to up-regulate aromatase gene expression through promoters I.3/II and I.4, respectively. We believe that these results are exciting in that they show GSE to be potentially useful in the prevention/treatment of hormone-dependent breast cancer through the inhibition of aromatase activity as well as its expression.

PMID: 16740737 [PubMed - indexed for MEDLINE]
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Old 10-27-2006, 06:38 PM
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Default Re: Grape seed extract a natural aromatase inhibitor

Andrew- is there a date and journal name for that abstract. Looks good.
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Old 10-27-2006, 06:43 PM
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Default Re: Grape seed extract a natural aromatase inhibitor

i wonder if the grapeseed oil i use in my brews would be good too .. for aromatase that is, already know it's very good for health
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Old 10-27-2006, 07:12 PM
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Default Re: Grape seed extract a natural aromatase inhibitor

It looks like the original research showed grape seed extract probably inhibited aromatase in tumors only and not in the rest of the body. May not be any help to high estrogen men.
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Old 10-27-2006, 08:05 PM
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Default Re: Grape seed extract a natural aromatase inhibitor

Here's another study I found on medline. This was done in 2003. The study above was done in June 2006.

Suppression of estrogen biosynthesis by procyanidin dimers in red wine and grape seeds.Eng ET, Ye J, Williams D, Phung S, Moore RE, Young MK, Gruntmanis U, Braunstein G, Chen S.
City of Hope Graduate School of Biological Science,Department of Surgical Research, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA.

In breast cancer, in situ estrogen production has been demonstrated to play a major role in promoting tumor growth. Aromatase is the enzyme responsible for the conversion of androgen substrates into estrogens. This enzyme is highly expressed in breast cancer tissue compared with normal breast tissue. A wine extract fraction was recently isolated from red wine that exhibited a potent inhibitory action on aromatase activity. Using UV absorbance analysis, high-performance liquid chromatography profiling, accurate mass-mass spectrometry, and nanospray tandem mass spectrometry, most of the compounds in our red wine fraction were identified as procyanidin B dimers that were shown to be aromatase inhibitors. These chemicals have been found in high levels in grape seeds. Inhibition kinetic analysis on the most potent procyanidin B dimer has revealed that it competes with the binding of the androgen substrate with a K(i) value of 6 micro M. Because mutations at Asp-309, Ser-378, and His-480 of aromatase significantly affected the binding of the procyanidin B dimer, these active site residues are thought to be important residues that interact with this phytochemical. The in vivo efficacy of procyanidin B dimers was evaluated in an aromatase-transfected MCF-7 breast cancer xenograft model. The procyanidin B dimers were able to reduce androgen-dependent tumor growth, indicating that these chemicals suppress in situ estrogen formation. These in vitro and in vivo studies demonstrated that procyanidin B dimers in red wine and grape seeds could be used as chemopreventive agents against breast cancer by suppressing in situ estrogen biosynthesis.

PMID: 14679019 [PubMed - indexed for MEDLINE]
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Old 10-28-2006, 03:04 AM
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Default Re: Grape seed extract a natural aromatase inhibitor

Quote:
Originally Posted by Andrew Androgen
In my research for safe alternatives to drug aromatase inhibitors, I discovered that grape seed extract both inhibits aromatase & downregulates its expression:

Grape seed extract is an aromatase inhibitor and a suppressor of aromatase expression.Kijima I, Phung S, Hur G, Kwok SL, Chen S.
Department of Surgical Research, Beckman Research Institute of the City of Hope, Duarte, California, USA.

Aromatase is the enzyme that converts androgen to estrogen. It is expressed at higher levels in breast cancer tissues than normal breast tissues. Grape seed extract (GSE) contains high levels of procyanidin dimers that have been shown in our laboratory to be potent inhibitors of aromatase. In this study, GSE was found to inhibit aromatase activity in a dose-dependent manner and reduce androgen-dependent tumor growth in an aromatase-transfected MCF-7 (MCF-7aro) breast cancer xenograft model, agreeing with our previous findings. We have also examined the effect of GSE on aromatase expression. Reverse transcription-PCR experiments showed that treatment with 60 mug/mL of GSE suppressed the levels of exon I.3-, exon PII-, and exon I.6-containing aromatase mRNAs in MCF-7 and SK-BR-3 cells. The levels of exon I.1-containing mRNA, however, did not change with GSE treatment. Transient transfection experiments with luciferase-aromatase promoter I.3/II or I.4 reporter vectors showed the suppression of the promoter activity in a dose-dependent manner. The GSE treatment also led to the down-regulation of two transcription factors, cyclic AMP-responsive element binding protein-1 (CREB-1) and glucocorticoid receptor (GR). CREB-1 and GR are known to up-regulate aromatase gene expression through promoters I.3/II and I.4, respectively. We believe that these results are exciting in that they show GSE to be potentially useful in the prevention/treatment of hormone-dependent breast cancer through the inhibition of aromatase activity as well as its expression.

PMID: 16740737 [PubMed - indexed for MEDLINE]
This is interesting and potentially useful information.
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  #7  
Old 10-28-2006, 04:15 AM
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Default Re: Grape seed extract a natural aromatase inhibitor

Quote:
Originally Posted by Naturdoc
It looks like the original research showed grape seed extract probably inhibited aromatase in tumors only and not in the rest of the body. May not be any help to high estrogen men.
I think it would still be of benefit. As you see in the study, the procyanidin dimers are potent inhibitors of aromatase. Its ability to down-regulate aromatase gene expression would also be very useful.
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