Son çalışmalarda, Gamma Linoleic Asit (GLA), Alpha Linolenic Asit (ALA), ve Linoleic Asit 5-Alpha Reductase'ın 1.Tip ve 2.Tip formunda en güçlü inhibitör olduğu ve lokal olarak uygulandığında Dehidrotestesteron (DHT) seviyelerinin düşmesinde çok etkili olduğu görülmüştür. Daha da önemlisi bu işi hiçbir sistematik etkiyi etkilemeden başarmaktadır

Daha ileri çalışmalar bu yağ asitlerinin, kalıp halinde saç dökülmesi, akne ve kadınlarda aşırı tüylenme (hirsuitism) gibi dehidrotestestorana bağlı düzensizliklerinin tedavsinde faydalı olduğunu öne sürmektedir.

Gamma-linolenic ve 5-Alpha Reductase engelleyici diğer yağ asitlerinin lokal olarak uygulanması ile hamster farelerin yan uzuvlarında büyüme baskısı.

Androjen Hareketi: Moleküler mekanizma ve medikal uygulama.

Özel alifatik doymamış yağ asitleri tarafından steroid 5-Alpha Reductase'ın engellenmesi.

Bu makale İngiliz Dermatoloji Dergisi'nde yayınlanmıştır ve Azelaik asitin, Çinko Sülfat'in ve Vitamin B6'nin çok düşük seviyelerdeki konsantrasyondaki birleşimini göstermiştir. ALpha Reductase'ın %90 oraninda durdurulması başarılmıştır.

Çinko ve Azelaik asit ile insan derisindeki 5 alpha-reductase'ın aktivitesinin durdurulması

Aşağıdaki araştırmalarda Saw Palmetto özünün alpha-reductase tip 1 ve tip 2 formlarının ikisinin de Finasteride'den daha iyi engellediği gösterilmiştir (Finasteride ve Propecia sadece tip 2'yi engeller)ve Testesteron ve DHT'nin çeşitli hücrelerdeki reseptörlerine olan bağının etkisini azaltmıştır. Aşağıdaki araştırmalardaki Saw Palmetto özünün Permixon veya Serenoa repens'in lipido-sterol özüne sevk edilmiş olduğuna lütfen dikkat edin.(LSESr)

İnsan prostatik steroid 5 alpha-reductase izoformu--seçmeli inhibitörlerin karşılaştırmalı araştırması.

Birincil kültürlerde testesteron metabolizması veya insan prostat epitel hücreleri ve fibroblastlar.

Androjen reseptörlerindeki Permixon etkisi.

Aşağıdaki araştırmalarda, Procyanidin Oligomerlerinin saç köklerinin büyümesini aktif hala getirdiği gösterilmektedir.

Procyanidin B2'nin saç büyütücü etken olarak potensiyelini ilk kez kilinik ortamda araştırma deneyi.

Procyanidin Oligomerleri, deneysel ortamda seçici ve yoğun olarak fare saç epitel hücrelerinin üremesini destekler ve canlı ortamda saç köklerinin uzamasını aktif hale getirir.

Üzüm tohumundaki Proanthocyanidins, deneysel ortamda fare saç kök hücrelerinin üremesini destekler ve canlı ortamda saç dönüşümünü sağlar.

Growth suppression of hamster flank organs by topical application of gamma-linolenic and other fatty acid inhibitors of 5 alpha-reductase.

Liang T; Liao S

Journal of Investigational Dermatology: 1997 Aug; 109 (2): 152-7

Certain unsaturated aliphatic fatty acids, such as gamma-linolenic acid, inhibit 5alpha-reductase activity in vitro and in vivo. Hamster flank organ growth, as measured by the increase in the area of pigmented macule, is dependent on androgen. When one of the paired flank organs of a castrated hamster was treated topically with testosterone, the treated organ, but not the contralateral flank organ, became larger and darker. Topical application of gamma-linolenic acid to the testosterone-treated flank organ suppressed this testosterone effect. Other fatty acids that were not inhibitors of 5alpha-reductases were not active. Topical treatment of hamster flank organs with 5alpha-dihydrotestosterone also stimulated the growth of the organ. This 5alpha-dihydrotestosterone-dependent activity, however, was not significantly affected by gamma-linolenic acid, suggesting that flank organ growth was dependent on 5alpha-dihydrotestosterone and that gamma-linolenic acid acted by inhibiting 5alpha-reductase. With intact male hamsters, the endogenous androgen-dependent growth of flank organs is also suppressed by topical treatment with gamma-linolenic acid. The effect of gamma-linolenic acid is localized at the site of its application; topical application of gamma-linolenic acid did not affect the androgen-dependent growth of other organs such as testis, epididymis, seminal vesicle, and prostate. gamma-Linolenic acid, with low toxicity and absence of systemic effect, therefore may be potentially useful for treatment of androgen-dependent skin disorders.

Androgen action: molecular mechanism and medical application.

Liao S

Journal of Formos Medical Association: 1994 Sep; 93 (9): 741-51

Androgen action in many organs, such as prostate and skin, is dependent on the conversion of testosterone by 5 alpha-reductase to 5 alpha-dihydrotestosterone. 5 alpha-Dihydrotestosterone then binds to the androgen receptor to regulate specific gene expression. Inhibitors of 5 alpha-reductase are useful for the selective treatment of prostatic cancer, benign prostate hyperplasia, acne, baldness and female hirsuitism, without affecting spermatogenesis, sexual behavior and smooth muscle growth, that do not require the conversion of testosterone to 5 alpha-dihydrotestosterone. Certain unsaturated fatty acids, such as gamma-linolenic acid, are potent 5 alpha-reductase inhibitors, suggesting a linkage between unsaturated fatty acids and androgen action. Mutations in androgen receptor genes are responsible for many cases of androgen-insensitivity. In some prostate cancer cells, some antiandrogens may act like androgens in stimulating the proliferation of the cancer cells because these antiandrogens can bind to a mutated androgen receptor and transactivate target genes. Prostate cancers are usually androgen-dependent initially but can lose dependency and responsiveness. Tumor cells which are resistant to endocrine therapy ultimately proliferate. Androgen-independent or androgen-repressive cells can arise from androgen-sensitive prostate cancer cells by changes in specific gene expression over time in a clonal isolate. This change in androgen responsiveness was accompanied by a change in androgen receptor expression and transcriptional activity as well as expression of some oncogenes.

Inhibition of steroid 5 alpha-reductase by specific aliphatic unsaturated fatty acids.

Liang T; Liao S

Journal of Biochemistry, 1992 Jul 15, 285 ( Pt 2):, 557-62

Human or rat microsomal 5 alpha-reductase activity, as measured by enzymatic conversion of testosterone into 5 alpha-dihydrotestosterone or by binding of a competitive inhibitor, [3H]17 beta-NN-diethulcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one ([3H]4-MA) to the reductase, is inhibited by low concentrations (less than 10 microM) of certain polyunsaturated fatty acids. The relative inhibitory potencies of unsaturated fatty acids are, in decreasing order: gamma-linolenic acid greater than cis-4,7,10,13,16,19-docosahexaenoic acid = cis-6,9,12,15-octatetraenoic acid = arachidonic acid = alpha-linolenic acid greater than linoleic acid greater than palmitoleic acid greater than oleic acid greater than myristoleic acid. Other unsaturated fatty acids such as undecylenic acid, erucic acid and nervonic acid, are inactive. The methyl esters and alcohol analogues of these compounds, glycerols, phospholipids, saturated fatty acids, retinoids and carotenes were inactive even at 0.2 mM. The results of the binding assay and the enzymatic assay correlated well except for elaidic acid and linolelaidic acid, the trans isomers of oleic acid and linoleic acid respectively, which were much less active than their cis isomers in the binding assay but were as potent in the enzymatic assay. gamma-Linolenic acid had no effect on the activities of two other rat liver microsomal enzymes: NADH:menadione reductase and glucuronosyl transferase. gamma-Linolenic acid, the most potent inhibitor tested, decreased the Vmax. and increased Km values of substrates, NADPH and testosterone, and promoted dissociation of [3H]4-MA from the microsomal reductase. gamma-Linolenic acid, but not the corresponding saturated fatty acid (stearic acid), inhibited the 5 alpha-reductase activity, but not the 17 beta-dehydrogenase activity, of human prostate cancer cells in culture. These results suggest that unsaturated fatty acids may play an important role in regulating androgen action in target cells.

Inhibition of 5alpha-reductase activity in human skin by zinc and Azelaic acid.

Stamatiadis, D; Bulteau-Portois, MC; Mowszowicz, I.

British Journal of Dermatology, 1988 Nov, 119(5):627-32.

The effects of zinc sulfate and azelaic acid on 5 alpha-reductase activity in human skin were studied using an in vitro assay with 1,2[3H]-testosterone as substrate. When added at concentrations of 3 or 9 mmol/l, zinc was a potent inhibitor of 5-alpha-reductase activity. At high concentrations, zinc could completely inhibit the enzyme activity. Azelaic acid was also a potent inhibitor of 5 alpha-reductase; inhibition was detectable at concentrations as low as 0.2 mmol/l and was complete at 3 mmol/l. An additive effect of the two inhibitors was observed. Vitamin B6 potentiated the inhibitory effect of zinc, but not of azelaic acid, suggesting that two different mechanisms are involved. When the three substances were added together at very low concentrations which had shown to be ineffective alone, 90% inhibition of 5 alpha-reductase activity was obtained. If this inhibition is confirmed in vivo, zinc sulfate combined with azelaic acid could be an effective agent in the treatment of androgen related pathology of human skin.

Iehlé C; Délos S; Guirou O; Tate R; Raynaud JP; Martin PM

J Steroid Biochem Mol Biol, 54: 5-6, 1995 Sep, 273-9

The present study describes the independent expression of the type 1 and 2 isoforms of human 5 alpha-reductase in the baculovirus-directed insect cell expression system and the selectivity of their inhibition. The catalytic properties and kinetic parameters of the recombinant isozymes were consistent with published data. The type 1 isoform displayed a neutral (range 6-8) pH optimum and the type 2 isoform an acidic (5-6) pH optimum. The type 2 isoform had higher affinity for testosterone than did the type 1 isoform (Km = 0.5 and 2.9 microM, respectively). Finasteride and turosteride were selective inhibitors of the type 2 isoform (Ki (type 2) = 7.3 and 21.7 nM compared to Ki (type 1) = 108 and 330 nM, respectively). 4-MA and the lipido-sterol extract of Serenoa repens (LSESr) markedly inhibited both isozymes (Ki (type 1) = 8.4 nM and 7.2 micrograms/ml, respectively; Ki (type 2) = 7.4 nM and 4.9 micrograms/ml, respectively). The three azasteroids were competitive inhibitors vs substrate, whereas LSESr displayed non-competitive inhibition of the type 1 isozyme and uncompetitive inhibition of the type 2 isozyme. These observations suggest that the lipid component of LSESr might be responsible for its inhibitory effect by modulating the membrane environment of 5 alpha-reductase. Partially purified recombinant 5 alpha-reductase type 1 activity was preserved by the presence of lipids indicating that lipids can exert either stimulatory or inhibitory effects on human 5 alpha-reductase.

Délos S; Carsol JL; Ghazarossian E; Raynaud JP; Martin PM

J Steroid Biochem Mol Biol, 55: 3-4, 1995 Dec, 375-83

We compare testosterone (T) metabolism in primary cultures of epithelial cells and fibroblasts separated from benign prostate hypertrophy (BPH) and prostate cancer tissues. In all cultures, androstenedione (delta 4) formed by oxidation of T by 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) represented 80% of the metabolites recovered. The amounts of 5 alpha-dihydrotestosterone (DHT), formed by reduction of T by 5 alpha-reductase (5 alpha-R), were small: 5 and 2% (BPH) and 8 and 15% (adenocarcinoma) for epithelial cells and fibroblasts, respectively. Northern blot analysis of total RNA from epithelial cells (BPH or adenocarcinoma) attributed the reductive activity to the 5 alpha-reductase type 1 isozyme and oxidative activity to the 17 beta-HSD type 2. In cancer fibroblasts, only little 17 beta-HSD type 2 mRNA was detected. The 5 alpha-reductase inhibitors, 4-MA (17 beta-(N,N-diethyl)carbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one) and finasteride, inhibited DHT formation with a preferential action of 4-MA on epithelial cells (BPH or adenocarcinoma) and of finasteride on fibroblasts from adenocarcinoma. Neither inhibitor acted on delta 4 formation. On the other hand, the lipido-sterol extract of Serenoa repens (LSESr, Permixon, Saw Palmetto) inhibited the formation of all the T metabolites studied [IC50 S = 40 and 200 micrograms/ml (BPH) and 90 and 70 micrograms/ml (adenocarcinoma) in epithelial cells and fibroblasts, respectively]. These results have important therapeutic implications when selecting appropriate treatment options for BPH.

el-Sheikh MM; Dakkak MR; Saddique A

Acta Obstet Gynecol Scand, 67: 5, 1988, 397-9

Permixon, the liposterolic extract of the plant Serenoa Repens is a recently introduced drug for the treatment of benign prostatic hyperplasia. The effect of Permixon on dihydrotestosterone and testosterone binding by eleven different tissue specimens was tested. The drug reduced the mean uptake of both hormones by 40.9% and 41.9% respectively in all tissue specimens. Since hirsutism and virilism are among other gynecological problems caused either by excessive androgen stimulation or excess endorgan response, we suggest that Permixon could be a useful treatment in such conditions and recommend further investigations of the possible therapeutic values of the drug in gynecological practice.

The first clinical trial of topical application of procyanidin B-2 to investigate its potential as a hair growing agent.

Takahashi T, Kamimura A, Yokoo Y, Honda S, Watanabe Y.

Tsukuba Research Laboratories, Kyowa Hakko Kogyo Co., 2, Miyukigaoka, Tsukuba, Ibaraki 305-0841, Japan.

Procyanidin B-2 is a compound we have identified in apple which acts as a growth-promoting factor on murine hair epithelial cells. This report describes our investigation of the hair-growing effects of 1% procyanidin B-2 tonic after sequential use for 4 months. A double-blind clinical trial was performed, involving a total of 29 subjects (procyanidin B-2, 19 men; placebo, 10 men). No adverse side effects were observed in either group. In the procyanidin B-2 group, 78.9% showed an increased mean value of hair diameter, whereas only 30.0% in the placebo group showed any increase (p < 0.02, Fisher's exact probability test). The increased ratio of hairs measuring more than 40 microm in diameter after 4 months of procyanidin B-2 treatment was significantly higher than that of the placebo controls (p < 0.05, two-sample-t-test). The increase in number of total hairs in the designated scalp area (0.25 cm(2)) of procyanidin B-2 subjects after a 4 month trial was significantly greater than that of the placebo controls (procyanidin-B-2, 3.67 +/- 4.09 (mean +/- SD)/0.25 cm(2); placebo, -2.54 +/- 4.00/0.25 cm(2); p < 0.001, two-sample t-test). Procyanidin B-2 therapy shows potential as a promising cure for male pattern baldness. Copyright 2001 John Wiley & Sons, Ltd.

Procyanidin Oligomers selectively and intensively promote proliferation of mouse hair epithelial cells in vitro and activate hair follicle growth in vivo.

Acta Derm Venereol 1998 Nov;78(6):428-32

Takahashi T, Kamiya T, Yokoo Y

Tsukuba Research Laboratories, Kyowa Hakko Kogyo Co., Ibaraki, Japan.

For the purpose of discovering natural products which possess hair growing activity, we examined about 1000 kinds of plant extracts concerning growth-promoting activity with respect to hair follicle cells. After an extensive search, we discovered that proanthocyanidins extracted from grape seeds promote proliferation of hair follicle cells isolated from mice by about 230% relative to controls (100%); and that proanthocyanidins possess remarkable hair-cycle-converting activity from the telogen phase to the anagen phase in C3H mice in vivo test systems. The profile of the active fraction of the proanthocyanidins was elucidated by thiolytic degradation and tannase hydrolysis. We found that the constitutive monomers were epicatechin and catechin; and that the degree of polymerization was 3.5. We demonstrated the possibility of using the proanthocyanidins extracted from grape seeds as agents inducing hair growth.
PMID: 9833041, UI: 99050235

Proanthocyanidins from grape seeds promote proliferation of mouse hair follicle cells in vitro and convert hair cycle in vivo.

J Invest Dermatol 1999 Mar;112 (3):310-6

Takahashi T, Kamiya T, Hasegawa A, Yokoo Y

Tsukuba Research Laboratories, Kyowa Hakko Kogyo, Ibaraki, Japan.

We have previously reported that proanthocyanidins extracted from grape seeds possess growth-promoting activity toward murine hair epithelial cells in vitro and stimulate anagen induction in hair cycle progression in vivo. This report constitutes a comparison of the growth-promoting activity of procyanidin oligomers and the target cells of procyanidins in the skin. Results show that procyanidin dimer and trimer exhibit higher growth-promoting activity than the monomer. The maximum growth-promoting activity for hair epithelial cells with procyanidin B-2, an epicatechin dimer, reached about 300% (30 microM) relative to controls (= 100%) in a 5 d culture. Optimum concentration of procyanidin C-1, an epicatechin trimer, was lower than that of procyanidin B-2; the maximum growth-promoting activity of procyanidin C-1 was about 220% (3 microM). No other flavonoid compounds examined exhibit higher proliferative activities than the procyanidins. In skin constituent cells, only epithelial cells such as hair keratinocytes or epidermal keratinocytes respond to procyanidin oligomers. Topical application of 1% procyanidin oligomers on shaven C3H mice in the telogen phase led to significant hair regeneration [procyanidin B-2, 69.6% +/- 21.8% (mean +/- SD); procyanidin B-3, 80.9% +/- 13.0%; procyanidin C-1, 78.3% +/- 7.6%] on the basis of the shaven area; application of vehicle only led to regeneration of 41.7% (SD = 16.3%). In this paper, we demonstrate the hair-growing activity of procyanidin oligomers both in vitro and in vivo, and their potential for use as agents to induce hair growth.
PMID: 10084307, UI: 99181798