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Topic Title: Research article--polyphenols and 5alpha reductase
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Created On: 06/19/2002 07:12 PM
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 06/19/2002 07:12 PM
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I know that there is a great deal of interest in green tea and other antioxidants in this forum, so for those keeping a file of articles at home...I'm not sure if this has been posted already.

TI: Title
Structure-activity relationships for inhibition of human 5alpha-reductases by polyphenols.

AU: Author
Hiipakka RA; Zhang HZ; Dai W; Dai Q; Liao S

AF: Author Affiliation
Department of Biochemistry and Molecular Biology, The Ben May Institute for Cancer Research, and The Tang Center for Herbal Medicine Research MC6027, University of Chicago, 5841 S. Maryland, Chicago, IL 60637, USA.

SO: Source
Biochemical pharmacology, 2002 Mar 15, 63(6):1165-76


AB: Abstract

The enzyme steroid 5 alpha-reductase (EC catalyzes the NADPH-dependent reduction of the double bond of a variety of 3-oxo-Delta(4) steroids including the conversion of testosterone to 5 alpha-dihydrotestosterone. In humans, 5 alpha-reductase activity is critical for certain aspects of male sexual differentiation, and may be involved in the development of benign prostatic hyperplasia, alopecia, hirsutism, and prostate cancer. Certain natural products contain components that are inhibitors of 5 alpha-reductase, such as the green tea catechin (-)-epigallocatechin gallate (EGCG). EGCG shows potent inhibition in cell-free but not in whole-cell assays of 5 alpha-reductase. Replacement of the gallate ester in EGCG with long-chain fatty acids produced potent 5 alpha-reductase inhibitors that were active in both cell-free and whole-cell assay systems. Other flavonoids that were potent inhibitors of the type 1 5alpha-reductase include myricetin, quercitin, baicalein, and fisetin. Biochanin A, daidzein, genistein, and kaempferol were much better inhibitors of the type 2 than the type 1 isozyme. Several other natural and synthetic polyphenolic compounds were more effective inhibitors of the type 1 than the type 2 isozyme, including alizarin, anthrarobin, gossypol, nordihydroguaiaretic acid, caffeic acid phenethyl ester, and octyl and dodecyl gallates. The presence of a catechol group was characteristic of almost all inhibitors that showed selectivity for the type 1 isozyme of 5 alpha-reductase. Since some of these compounds are consumed as part of the normal diet or in supplements, they have the potential to inhibit 5 alpha-reductase activity, which may be useful for the prevention or treatment of androgen-dependent disorders. However, these compounds also may adversely affect male sexual differentiation.

Edited: 06/19/2002 at 07:19 PM by Hair Loss Help Moderator
 06/20/2002 01:39 PM
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Continuing the insanity, I found that one can get quercitin from many health food stores. Here is the description from the Twin Lab product:

"A high potency, synergistic combination of quercetin, a non-citrus bio-active bioflavonoid derived from blue-green algae, and corn free vitamin C, which is derived from sago palm. Quercetin is more potent than common bioflavonoid complexes and contains no citrus allergens. It is a natural antioxidant and an active derivative of the bioflavonoid rutin."
 06/20/2002 10:23 PM
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Green tea is very good. From what I hear to receive optimal benefits of green tea one must drink 9-10 cups of it a day. There are ways to receive the polyphenol extract which can be equivalent to 9-10 cups of green tea. Otherwise the tea is supposed to maintain your hair color, health, vigor, youthfulness, etc. Does anybody know where I can get the polyphenal extract, as it would be a convenient addition to my regimen rather than drinking green tea itself.

I would like to switch from my daily lipton tea to a quality green tea. Otherwise the AC serum and spray contain green tea.
 06/26/2002 09:46 PM
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Research on flavenoids presented in 2001 that might be relevant:

Quercetin Inhibits the Expression and Function of the Androgen Receptor in LNCaP Prostate Cancer Cells

Nianzeng Xing, Yi Chen, Susan Mitchell, Charles YF Young, Mayo Clinic, Rochester, MN.

The androgen receptor (AR) is involved in the development and progression of prostate cancer. In order to find new chemicals which may present novel mechanisms to attenuate the function of AR, we investigated the effect of a natural flavonoid chemical, quercetin, on androgen action in an androgen-responsive LNCaP prostate cancer cell line. Western blot analysis showed that AR protein expression was inhibited by quercetin in a dose-dependent manner. To demonstrate that the repression effects on AR expression can actually reduce its function, we found that quercetin inhibited the secretion of the prostate specific, androgen regulated tumor markers, PSA and hK2. The mRNA levels of androgen regulated genes such as PSA, NKX3.1 as well as ornithine decarboxylase (ODC) were down-regulated by quercetin. Transient transfections further showed that quercetin inhibited AR-mediated PSA expression at the transcription level. Finally, it was demonstrated that quercetin could repress the expression of AR gene at the transcription level. Our result suggests that quercetin can attenuate the function of AR by repressing its expression and has the potential to become a chemopreventive and/or chemotherapeutic agent for prostate cancer.

From the Proceedings of the AACR, Vol. 42, March 2001.
Copyright © 2001 by the American Association for Cancer Research.
Online Publication Date: February 27, 2001.
DOI: 10.1158/010101.

 06/27/2002 06:31 AM
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The best pharmacuetical grade green tea extract can be found at
 07/24/2002 04:49 PM
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<< The best pharmacuetical grade green tea extract can be found at >>

Question: what is the equivalancy in cups of drinking green tea to taking green tea extract(such as the one you speak of)?

If someone where to drink green tea as if it were coffee about four full mugs are equal to 8 0r 9 cups. I drink, on average, 2 mugs of green tea a day. I know it has helped my health in other areas but I haven't really been keeping tabs as far as its effect on my hair.

Also, is anyone out there taking pharmacuetical grade cod liver oil? Barry Sears wrote a new book about the amazing benefits of taking it. Sounds like enternal emu oil for inflammation.
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