Literature Search:

MEDLINE

A search of the MEDLINE database from 1966 through 1997 turns up 20 articles dealing with the use of saw palmetto (Serenoa repens) to treat BPH.

While some of these articles indicate the efficacy of saw palmetto in treating BHP in the highly technical language of medicine, note that not all of them do. Note too that most of these studies are in European journals, since saw palmetto is more widely used there than in the United States.

I have not yet been able to read most the original studies, many of which are not readily available even in large hospital libraries in the United States. If anyone has copies of any of them and will send them to me, I will make them available here.

A summary of the MEDLINE abstracts in chronological order (with the most recent first) follows:

Phytotherapy of benign prostatic hyperplasia [Translated from German].
Bracher F, Institut fur Pharmazeutische Chemie, Technische Universitat Braunschweig.
Urologe A 36 (1): 10-17 (Jan 1997)
Phytopharmaceutical agents have been used for a long time in the treatment of symptomatic benign prostatic hyperplasia (BPH). However, until recently, it has been questioned whether phytotherapy is superior to a placebo treatment. In this article, the most widely used phytopharmaceutical agents, such as saw palmetto berry extracts, Radix urticae extracts, pumpkin seeds, pollen extracts and different phytosterols, are described. In addition, both in vitro and in vivo studies are discussed in an attempt to explain a possible mechanism of action. There are several new clinical studies which demonstrate a significant benefit compared with placebo treatment. Based on these results, the use of phytopharmaceutical agents for the treatment of mild to moderate symptomatic BPH seems to be well justified. So far, no significant inhibition of further prostate growth has been demonstrated. For this, a careful follow-up of the patients is necessary so as not to miss a deterioration and perhaps the need for an operation.
Serenoa repens (Permixon). A review of its pharmacology and therapeutic efficacy in benign prostatic hyperplasia.
Plosker GL, Brogden RN, Adis International Limited, Auckland, New Zealand.
Drugs Aging 9 (5): 379-395 (Nov 1996)
Serenoa repens (Permixon) has been available for several years for the treatment of men with benign prostatic hyperplasia (BPH). The drug is the n-hexane lipidosterolic extract of the dwarf American palm (also known as Serenoa repens) and is a complex mixture of various compounds. A number of pharmacodynamic effects have been demonstrated with the lipidosterolic extract of Serenoa repens (LSESR), suggesting multiple mechanisms of action including in vitro inhibition of both type 1 and type 2 isoenzymes of 5 alpha-reductase and interference with binding of dihydrotestosterone to cytosolic androgen receptors in prostate cells. In controlled clinical trials in men with BPH, oral administration of Serenoa repens 160 mg twice daily for 1 to 3 months was generally superior to placebo in improving subjective symptoms, such as dysuria, as well as objective parameters. The frequency of nocturia was reduced by 33 to 74%, while urinary frequency during the day decreased by 11 to 43% and peak urinary flow rate increased by 26 to 50% with Serenoa repens. Corresponding values for placebo were 13 to 39%, 1 to 29% and 2 to 35%. The only large comparative trial conducted to date, in which > 1000 men with moderate BPH were randomised to receive Serenoa repens 160 mg twice daily or finasteride 5 mg once daily for 6 months, demonstrated similar efficacy between the two drugs. No statistically significant difference was demonstrated between treatment groups for improvement in patient self-rated quality-of-life scores and the primary end-point of objective symptom score; International Prostate Symptom Score improved by 37% with Serenoa repens compared with 39% with finasteride. In much smaller comparative trials, few significant differences were demonstrated between Serenoa repens and alpha 1-receptor antagonists, and larger randomised trials of adequate duration are required to better compare the clinical efficacy of these drugs. The most frequently reported adverse events in clinical trials with Serenoa repens have been minor gastrointestinal problems (e.g. nausea and abdominal pain). In conclusion, Serenoa repens is well tolerated and has greater efficacy than placebo and similar efficacy to finasteride in improving symptoms in men with BPH. Although there is a need for further comparative studies, particularly with alpha 2-receptor antagonists, available data indicate that Serenoa repens is a useful alternative to alpha 1-receptor antagonists and finasteride in the treatment of men with BPH.
[Status of phytotherapeutic drugs in treatment of benign prostatic hyperplasia] Stellenwert von Phytotherapeutika bei der Behandlung der benignen Prostatahyperplasie (BPH).
Dreikorn K; Schonhofer PS, Urologische Klinik, Zentralkrankenhaus Sankt-Jurgen-Strasse, Bremen.
Urologe A (GERMANY) Mar 1995, 34 (2) p119-29, ISSN 0340-2592
Languages: GERMAN Summary Languages: ENGLISH
Phytotherapeutic preparations are still commonly used for the treatment of symptomatic benign prostate hyperplasia (BPH) in Germany; in recent years there has even been an increase in their use, so that sales now amount to more than DM 220 millions per year. The preparations most frequently used are extracts of Hypoxis rooperi, the roots of the stinging nettle, the fruits of the saw palmetto, pumpkin seeds and rye pollen. The suggested mechanisms of action have not been documented by scientific observation. This applies especially to the blocking effect on 5 alpha-reductase postulated with the doses used. Moreover, a critical analysis of the data available suggests that the effects of phytotherapy are no better than those of placebo treatment. Further studies are urgently needed, to compare the effects of phytotherapy with those of chemically defined drugs (alpha 1-receptor antagonists, 5 alpha-reductase blocker) that seem to have a beneficial influence on the pathomechanism underlying symptomatic BPH. (77 Refs.)
Comparative effects of alfuzosin versus Serenoa repens in the treatment of symptomatic benign prostatic hyperplasia.
Grasso M; Montesano A; Buonaguidi A; Castelli M; Lania C; Rigatti P; Rocco F; Cesana BM; Borghi C, Department of Urology, Scientific Institute San Raffaele Hospital, Milan, Italy.
Arch Esp Urol (SPAIN) Jan-Feb 1995, 48 (1) p97-103, ISSN 0004-0614
Languages: ENGLISH
OBJECTIVES: Sixty-three patients suffering from benign prostatic hyperplasia (BPH) entered a double-blind, comparative, parallel-groups study lasting 3 weeks, carried out to compare the efficacy and safety of alfuzosin 2.5 mg tid (n = 32) vs serenoa repens 160 mg bid (n = 31) in BPH. METHODS: Efficacy was assessed both on clinical symptoms (Boyarsky's scale, visual analogue scale, clinical global impression), urinary flow rates (uroflowmetry) and residual urinary volume (transabdominal ultrasound). Events and reported signs were recorded throughout the entire study. RESULTS: Statistically significant and clinically relevant differences were found between the two treatments in favour of alfuzosin for Boyarsky's total score (decrease from 9.6 +/- 3.0 to 5.9 +/- 3.0, 38.8% for alfuzosin and from 9.3 +/- 2.5 to 6.8 +/- 2.8, 26.9% for serenoa repens) and obstructive score (decrease from 4.9 +/- 2.1 to 3.0 +/- 1.9, 37.8% for alfuzosin; from 4.4 +/- 1.7 to 3.4 +/- 1.8, 23.1% for Serenoa repens; p = 0.01 for both). Clinically relevant differences were found between the two treatments for visual analogue scale and overall clinical impression at the end of the study. Furthermore, the increase in quality of micturition was better with alfuzosin. The proportion of responders (increase on day 21 in peak flow rate of at least 25% relative to the baseline values) was in favour of alfuzosin (71.8% and 48.4% for alfuzosin and Serenoa repens, respectively; p = 0.057). Both treatments were well tolerated. No patient treated with alfuzosin complained of any adverse event at any time during the study. One patient in the Serenoa group complained of mild pruritus which cleared spontaneously. Systolic, diastolic blood pressure and heart rate did not show any clinically relevant change during treatment with alfuzosin. CONCLUSIONS: The findings confirm the efficacy and safety of alfuzosin in symptomatic BPH and indicate the superiority of alfuzosin over Serenoa repens in the treatment of urinary signs and symptoms of BPH.
Comparison of finasteride (Proscar) and Serenoa repens (Permixon) in the inhibition of 5-alpha reductase in healthy male volunteers.
Strauch G; Perles P; Vergult G; Gabriel M; Gibelin B; Cummings S; Malbecq W; Malice MP, Eclimed Pharmacologie Clinique, Hopital Universitaire Cochin, Paris, France.
Eur Urol (SWITZERLAND) 1994, 26 (3) p247-52, ISSN 0302-2838
Languages: ENGLISH
A total of 32 healthy male volunteers (age range 20-30 years) were enrolled in a 1-week open, randomized, placebo-controlled study comparing finasteride (Proscar), a 5 alpha-reductase inhibitor, with Permixon, the plant extract of Serenoa repens. The objective of the study was to evaluate the effect of single and multiple doses of the drugs on the inhibition of 5 alpha-reductase as assessed by serum dihydrotestosterone level determination. Following baseline measurements on day 1, the subjects were randomized to finasteride 5 mg once a day (n = 10), Permixon 80 mg x 2 twice a day (n = 11), or to placebo once a day (n = 11) for 7 days. Serum testosterone and dihydrotestosterone levels, were determined on day 1 (baseline and 12 h) and on days 2 (24 h), 3 (48 h), 4 (72 h), 6 (120 h), and 8 (168 h). After 12 h, a single dose of finasteride 5 mg reduced the serum dihydrotestosterone level by 65% (p = 0.01). The decreases ranged from -52 to -60% with multiple doses of finasteride 5 mg once a day (p = 0.01). As in the placebo group, there was no effect of Permixon on the serum dihydrotestosterone level. No significant difference was detected between finasteride and Permixon or between finasteride and placebo with respect to serum testosterone, except on days 3 and 6, respectively (p = 0.05). However, the corresponding serum testosterone levels remained within the normal ranges. These data confirm the efficacy of finasteride as inhibitor of 5 alpha-reductase.(ABSTRACT TRUNCATED AT 250 WORDS)
Plant extracts in BPH.
Di Silverio F; Flammia GP; Sciarra A; Caponera M; Mauro M; Buscarini M; Tavani M; D'Eramo G, Department of Urology U. Bracci, University of Rome La Sapienza, Rome.
Minerva Urol Nefrol (ITALY) Dec 1993, 45 (4) p143-9, ISSN 0393-2249
Languages: ENGLISH
In Italy plant extracts represent 8.6% of all pharmacological prescriptions for Benign Prostatic Hyperplasia (data from 1991). This review evaluates all the suggested mechanisms of action for plant extracts. Recently we demonstrated an antiestrogenic effect of Serenoa Repens in BPH patients. Clinical trials with plant extracts have yielded conflicting results. In a recent review by Dreikorn and Richter, only five placebo controlled studies were found. Moreover, as opposed to chemically defined drugs, it is possible that for these extracts the active ingredients are not known; consequently pharmacodynamic and pharmacokinetic data are often missing. The International Consultation of Benign Prostatic Hyperplasia (Paris, June 1991) concluded that, to date, phytotherapeutic agents must be considered as a symptomatic treatment. Now more adequate pharmacological and clinical studies, placebo controlled, should determine the exact role of these drugs in the treatment of BPH. (38 Refs.)
[Pharmacological combinations in the treatment of benign prostatic hypertrophy] Associations pharmacologiques dans le traitement de l'hypertrophie prostatique benigne.
Di Silverio F; D'Eramo G; Flammia GP; Buscarini M; Frascaro E; Mariani M; Sciarra A, Department of Urology, U. Bracci, University La Sapienza of Rome, V. Le Policlinico, Italy.
J Urol (Paris) (FRANCE) 1993, 99 (6) p316-20, ISSN 0248-0018
Languages: FRENCH Summary Languages: ENGLISH
In the development of the obstructive symptomatology of benign prostatic hypertrophy (BPH), two components may be identified, mechanical and dynamic. In the mechanical component, the interaction of a stromal and a epithelial compartment determines prostatic mass growth. The dynamic component involves smooth muscle tone in the prostate and urethra. The consideration that prostatic disease is not only epithelial in origin, but also stromal, leads to the association of an antiandrogen (which acts on the epithelial component) and an antiestrogen (active on the stromal component) in the medical therapy of BPH. In 1985 we carried out a randomized study on 256 BPH patients treated with Cyproterone acetate (CPA) plus Tamoxifen (TAM). Recently, we performed a multicenter double blind study on BPH patients treated with the association CPA plus Serenoa Repens. A statistically significant difference in prostate volume reduction between the groups treated with the combinations and those with the monotherapies was observed. The development of new compounds, such as 5 alpha reductase and aromatase inhibitors, consents to introduce a combination therapy with less side effects. A second pharmacological association may be obtained with drugs acting on the mechanical and others acting on the dynamic (alpha blockers) component of BPH. This combination may associate the early symptomatic effect of alpha blockers with the long term results of a 5 alpha reductase inhibitor, antiestrogen or aromatase inhibitor. (25 Refs.)
Inhibition of the activity of 'basic' 5 alpha-reductase (type 1) detected in DU 145 cells and expressed in insect cells.
Delos S; Iehle C; Martin PM; Raynaud JP, Laboratoire de Cancerologie Experimentale, Faculte de Medecine, Secteur Nord, Marseille, France.
J Steroid Biochem Mol Biol (ENGLAND) Mar 1994, 48 (4) p347-52, ISSN 0960-0760
Languages: ENGLISH
The purpose of this study was 2-fold: (1) to identify the 5 alpha-reductase (5 alpha-R) isozyme(s) present in DU 145 cells, a human cell-line of low androgen sensitivity derived from a cerebral metastasis of an epithelial prostate cancer; and (2) to compare the inhibitory potencies of three compounds on the 'basic' 5 alpha-R isozyme expressed in a baculovirus-directed insect cell system. Conversion of testosterone (T) into 5 alpha-dihydrotestosterone (DHT) in DU 145 cells was measured by HPLC coupled to a Flo-one HP radioactivity detector. DU 145 cells exhibited 5 alpha-R activity (21 pmol DHT/min/mg protein) at pH 7.4 which disappeared at pH 5.5 suggesting that, of the two genomically distinct human isozymes identified so far, type 1 5 alpha-R is expressed in DU 145 cells. This was confirmed by at least two observations: first, 5 alpha-R activity in DU 145 cells was inhibited with much higher potency by 4-MA than by finasteride which is known to be a very poor competitor of the 'basic' enzyme (IC50s = 2.8 +/- 0.2 and 264 +/- 55 nM, respectively). Second, only the type 1 5 alpha-R cDNA and not type 2 5 alpha-R cDNA hybridized with DU 145 RNA. A high potency differential was also recorded for the inhibition of 'basic' type 1 5 alpha-R expressed in a baculovirus-directed-insect cell system by these two compounds, 4-MA being considerably more active than finasteride (Ki = 8.4 +/- 2.3 and 330 +/- 9 nM, respectively). This inhibition was competitive. On the other hand, inhibition by an n-hexane lipid/sterol extract of Serenoa repens (LSESr) was non-competitive and, when expressed in terms of recommended therapeutic doses, was 3-fold greater for LSESr than for finasteride. These studies suggest that LSESr might exert a regulatory inhibitory activity due to its specific lipid/sterol composition.
Lack of effects of a lyposterolic extract of Serenoa repens on plasma levels of testosterone, follicle-stimulating hormone, and luteinizing hormone.
Casarosa C; Cosci di Coscio M; Fratta M, Division of Urology, Hospital Riuniti S. Chiara, Pisa, Italy.
Clin Ther (UNITED STATES) 1988, 10 (5) p585-8, ISSN 0149-2918
Languages: ENGLISH
Twenty men, aged 50 to 75 years (mean, 67 years), suffering from benign prostatic hypertrophy received 160 mg of a lyposterolic extract of Serenoa repens, twice daily for 30 days. Before and at the end of treatment, plasma levels of testosterone, follicle-stimulating hormone, and luteinizing hormone were determined. No changes in plasma hormone levels occurred as a result of treatment. It is concluded that Serenoa extract, which is useful in the treatment of benign prostatic hypertrophy, does not act via systemic changes of hormone levels.
Evidence that Serenoa repens extract displays an antiestrogenic activity in prostatic tissue of benign prostatic hypertrophy patients.
Di Silverio F; D'Eramo G; Lubrano C; Flammia GP; Sciarra A; Palma E; Caponera M; Sciarra F, Department of Urology U. Bracci, University of Rome La Sapienza, Italy.
Eur Urol (SWITZERLAND) 1992, 21 (4) p309-14, ISSN 0302-2838
Languages: ENGLISH
A double-blind placebo-controlled study was performed in 35 benign prostatic hypertrophy (BPH) patients never treated before. The patients were randomized into two groups, the 1st (18 cases) receiving Serenoa repens extract (160 mg t.d.) for 3 months up to the day before the operation of transvesical adenomectomy and the 2nd (17 cases) receiving placebo. Steroid receptors were evaluated in the nuclear (n) and cytosolic (c) fraction using the saturation analysis technique (Scatchard analysis or single saturating-dose assay) for androgen (AR) and estrogen (ER) receptors and the enzyme immunoassay (EIA) for ER and progesterone receptors (PgR). Scatchard analysis of ERc and ERn revealed the presence of two classes of binding sites, one with high-affinity low-capacity binding and the other with low-affinity high-capacity binding. In the untreated BPH group, ER were higher in the n than in the c fraction: ERn were positive in 14 cases and ERc in 12 of 17 cases. In the BPH group treated with S. repens extract on the contrary, ERn were negative for both binding classes in 17 cases and ERc in 6 of 18 cases. Using EIA, ERn and ERc were detected in all 15 samples examined, but in the treated group, ERn were significantly (p less than 0.01) lower than in the untreated group, whilst ERc remained almost unchanged. Similar results were obtained measuring PgR: the n fraction of the treated group prostatic samples was significantly (p less than 0.01) lower than that of the untreated group.(ABSTRACT TRUNCATED AT 250 WORDS)
[Symptomatic treatment of benign hypertrophy of the prostate. Comparative study of prazosin and serenoa repens] Tratamiento sintomatico de la hipertrofia benigna de prostata. Estudio comparativo entre Prazosin y Serenoa repens.
Adriazola Semino M; Lozano Ortega JL; Garcia Cobo E; Tejeda Banez E; Romero Rodriguez F, Servicio de Urologia, Hospital Rio Carrion, Palencia, Espana.
Arch Esp Urol (SPAIN) Apr 1992, 45 (3) p211-3, ISSN 0004-0614
Languages: SPANISH Summary Languages: ENGLISH
Forty-five patients diagnosed as having BPH and clinically diagnosed micturition disorders were entered in a therapeutic protocol. Twenty-five patients received Prazosin and the remaining 20 patients were treated with Serenoa Repens for a period of 12 weeks. The symptomatology was assessed by flowmetry and the patients were questioned as to the irritative symptoms. It can be concluded from the study that Prazosin is slightly more effective in controlling the irritative symptoms produced by BPH.
[Anti-inflammatory activity of sabal fruit extracts prepared with supercritical carbon dioxide. In vitro antagonists of cyclooxygenase and 5-lipoxygenase metabolism] Antiphlogistische Wirkung eines mit hyperkritischem Kohlendioxid gewonnenen Sabalfrucht-Extraktes. In-vitro-Hemmung des Cyclooxygenase-und 5-Lipoxygenase-Metabolismus.
Breu W; Hagenlocher M; Redl K; Tittel G; Stadler F; Wagner H, Institut fur Pharmazeutische Biologie, Ludwig-Maximilians-Universitat Munchen.
Arzneimittelforschung (GERMANY) Apr 1992, 42 (4) p547-51, ISSN 0004-4172
Languages: GERMAN Summary Languages: ENGLISH
The extract SG 291 (Talso, Talso uno) from the fruits of Sabal serrulata (syn.: Serenoa repens) prepared by supercritical fluid extraction with carbon dioxide is used for the treatment of benign prostatic hyperplasia (BPH) and non bacterial prostatitis. In the present work, the Sabal extract SG 291 was analyzed by gas chromatography and investigated for its inhibitory influence on the biosynthesis of inflammatory arachidonic acid metabolites. The extract SG 291 was found in vitro to be a dual inhibitor of the cyclooxygenase (IC50-value: 28.1 micrograms/ml) and 5-lipoxygenase pathway (IC50-value: 18.0 micrograms/ml). By alkaline hydrolysis, ether extraction and preparative thin layer chromatography the extract SG 291 was separated in three fractions containing acid lipophilic compounds (A), fatty alcohols (B) and sterols (C) as main components. Fraction A inhibited the biosynthesis of cyclooxygenase (CO) and 5-lipoxygenase (5-LO) metabolites in the same intensity as the native extract SG 291, while the fractions B, C and beta-sitosterol showed no inhibitory effect on both enzymes of the arachidonic acid pathways. Therefore, the CO and 5-LO inhibiting principle of Sabal serrulata extract SG 291 must be localized in the acidic lipophilic fraction (SLF). The CO and 5-LO inhibitory effects may give an explanation for the in vivo observed antiphlogistic and antiedematous activity of the lipophilic Sabal serrulata extract SG 291.
The effect of Permixon on androgen receptors.
el-Sheikh MM; Dakkak MR; Saddique A, Department of Obstetrics and Gynaecology, King Khalid University Hospital, Riyadh, Saudi Arabia.
Acta Obstet Gynecol Scand (SWEDEN) 1988, 67 (5) p397-9, ISSN 0001-6349
Languages: ENGLISH
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.
[Our experience with a hexane extract of Serenoa repens in the treatment of benign prostatic hypertrophy] Nuestra experiencia con extracto hexanico de Serenoa repens en el tratamiento de la hipertrofia benigna de prostata.
Olle Carreras J
Arch Esp Urol (SPAIN) Jun 1987, 40 (5) p310-3, ISSN 0004-0614
Languages: SPANISH Summary Languages: ENGLISH
[Treatment of obstructive symptomatology caused by prostatic adenoma with an extract of Serenoa repens. Double-blind clinical study vs. Placebo] Trattamento della sintomatologia ostruttiva da adenoma prostatico con estratto di Serenoa repens. Studio clinico in doppio cieco vs. Placebo.
Tasca A; Barulli M; Cavazzana A; Zattoni F; Artibani W; Pagano F
Minerva Urol Nefrol (ITALY) Jan-Mar 1985, 37 (1) p87-91, ISSN 0393-2249
Languages: ITALIAN Summary Languages: ENGLISH
A double-blind trial of an extract of the plant Serenoa repens in benign prostatic hyperplasia.
Champault G; Patel JC; Bonnard AM
Br J Clin Pharmacol (ENGLAND) Sep 1984, 18 (3) p461-2, ISSN 0306-5251
Languages: ENGLISH
[Anti-edematous action of a hexane extract of the stone fruit of Serenoa repens Bartr.] Action anti-oedemateuse d'un extrait hexanique de drupes de Serenoa repens Bartr.
Tarayre JP; Delhon A; Lauressergues H; Stenger A; Barbara M; Bru M; Villanova G; Caillol V; Aliaga M
Ann Pharm Fr (FRANCE) 1983, 41 (6) p559-70, ISSN 0003-4509
Languages: FRENCH Summary Languages: ENGLISH
Binding of Permixon, a new treatment for prostatic benign hyperplasia, to the cytosolic androgen receptor in the rat prostate.
Carilla E; Briley M; Fauran F; Sultan C; Duvilliers C
J Steroid Biochem (ENGLAND) Jan 1984, 20 (1) p521-3, ISSN 0022-4731
Languages: ENGLISH
The benign hyperplasia of the prostate is a manifestation of aging, involving the accumulation, within the gland, of dihydrotestosterone, the probable mediator of the hyperplasia. Binding studies were performed on the cytosolic androgenic receptor of the rat prostate using [3H]methyltrienolone as a ligand. The binding of [3H]methyltrienolone at 5 nM, was inhibited by various drugs, such as methyltrienolone and cyproterone acetate. Permixon, a liposterolic extract of the plant, Serenoa Repens B, inhibits competitively the binding to the cytosolic receptor of the rat prostate. Various vegetable and mineral oils, the plant steroid: beta sitosterol and the antiprostatic drug: Tadenan, were all found to be inactive. The antiprostatic activity of Permixon shown in animal studies and controlled clinical trials, may thus result from a direct action at the cytosolic receptor.
Inhibition of androgen metabolism and binding by a liposterolic extract of "Serenoa repens B" in human foreskin fibroblasts.
Sultan C; Terraza A; Devillier C; Carilla E; Briley M; Loire C; Descomps B
J Steroid Biochem (ENGLAND) Jan 1984, 20 (1) p515-9, ISSN 0022-4731
Languages: ENGLISH
We previously suggested [Steroids 33, (1979) 3; Steroids 37, (1981) 6] that cultured genital skin fibroblasts should prove useful for screening of potential antiandrogens in human and living target cells. "Serenoa repens" lipidic extract (S.R.E.) was recently reported (Br. J. Pharmacol., in press) to inhibit androgen action in animals. The present investigation was designed to study the antiandrogenicity of this compound in human cells: we therefore analyzed the effects of S.R.E. on the intracellular conversion of testosterone (T) to 5 alpha-reduced derivatives, and we investigated interaction of S.R.E. with the intracellular androgen-receptor complex. Since the chemical structure of the active component of S.R.E. is still unknown, results are expressed in U/ml (one unit is defined as the amount of S.R.E. required to inhibit 50% of the specific binding (IC50) of [3H]1881 to rat prostate cytosol). S.R.E. at different dilutions (5.7 to 28.6 U/ml) is added to culture media containing [3H]T or [3H]dihydrotestosterone (DHT) and incubated at 37 degrees C with cultured fibroblasts. 28.6 U/ml S.R.E. significantly alters the formation of DHT and strongly inhibits 3 ketosteroid reductase mediated conversion of DHT to 5 alpha-androstane-3 alpha, 17 beta-diol, characterized radiochemically by thin-layer chromatography. S.R.E. is a good competitor for the whole cell androgen receptor: 7.1 U/ml S.R.E. gives 50% inhibition of the binding of 2 X 10(-9) M [3H]DHT to its receptor. Competitive binding assays after cell fractionation indicate that S.R.E. is less potent in nuclear than in cytosol receptors. Sucrose gradient centrifugation of the radioactive cell lysate of fibroblasts demonstrates that 28.6 U/ml S.R.E. abolishes 70% of the 3.6 S receptor-complex radioactive peak. The present studies show that S.R.E. inhibits 5 alpha-reductase, 3-ketosteroid reductase and receptor binding of androgens in cultured human foreskin fibroblasts. As the search for the ideal antiandrogen continues, S.R.E. appears to be a new type of antiandrogenic compound as therapeutics for the treatment of benign prostatic hypertrophy, hirsutism and so forth.
Activity and isolated phytoestrogen of shrub palmetto fruits (Serenoa repens Small), a new estrogenic plant.
Elghamry MI; Hansel R
Experientia (SWITZERLAND) Aug 15 1969, 25 (8) p828-9, ISSN 0014-4754
Languages: ENGLISH

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