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Saw palmetto extracts potently and noncompetitively inhibit human ?1-adrenoceptors in vitro

1999; Wiley; Volume: 38; Issue: 3 Linguagem: Inglês

10.1002/(sici)1097-0045(19990215)38

1097-0045

Μ. Goepel, Ulrich Hecker, S. Krege, H. R�bben, Martin C. Michel,

Pharmacology and Obesity Treatment

The ProstateVolume 38, Issue 3 p. 208-215 Saw palmetto extracts potently and noncompetitively inhibit human α1-adrenoceptors in vitro Mark Goepel, Corresponding Author Mark Goepel mark.goepel@uni-essen.de Department of Urology, University of Essen, Essen, GermanyUrologische Klinik, Klinikum Essen, Hufelandstr. 55, 45122 Essen, GermanySearch for more papers by this authorUlrich Hecker, Ulrich Hecker Department of Medicine, University of Essen, Essen, GermanySearch for more papers by this authorSusanne Krege, Susanne Krege Department of Urology, University of Essen, Essen, GermanySearch for more papers by this authorHerbert Rübben, Herbert Rübben Department of Urology, University of Essen, Essen, GermanySearch for more papers by this authorMartin C. Michel, Martin C. Michel Department of Medicine, University of Essen, Essen, GermanySearch for more papers by this author Mark Goepel, Corresponding Author Mark Goepel mark.goepel@uni-essen.de Department of Urology, University of Essen, Essen, GermanyUrologische Klinik, Klinikum Essen, Hufelandstr. 55, 45122 Essen, GermanySearch for more papers by this authorUlrich Hecker, Ulrich Hecker Department of Medicine, University of Essen, Essen, GermanySearch for more papers by this authorSusanne Krege, Susanne Krege Department of Urology, University of Essen, Essen, GermanySearch for more papers by this authorHerbert Rübben, Herbert Rübben Department of Urology, University of Essen, Essen, GermanySearch for more papers by this authorMartin C. Michel, Martin C. Michel Department of Medicine, University of Essen, Essen, GermanySearch for more papers by this author First published: 20 January 1999 https://doi.org/10.1002/(SICI)1097-0045(19990215)38:3 3.0.CO;2-4Citations: 70AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract BACKGROUND We wanted to test whether phytotherapeutic agents used in the treatment of lower urinary tract symptoms have α1-adrenoceptor antagonistic properties in vitro. METHODS Preparations of β-sitosterol and extracts of stinging nettle, medicinal pumpkin, and saw palmetto were obtained from several pharmaceutical companies. They were tested for their ability to inhibit [3H]tamsulosin binding to human prostatic α1-adrenoceptors and [3H]prazosin binding to cloned human α1A- and α1B-adrenoceptors. Inhibition of phenylephrine-stimulated [3H]inositol phosphate formation by cloned receptors was also investigated. RESULTS Up to the highest concentration which could be tested, preparations of β-sitosterol, stinging nettle, and medicinal pumpkin were without consistent inhibitory effect in all assays. In contrast, all tested saw palmetto extracts inhibited radioligand binding to human α1-adrenoceptors and agonist-induced [3H]inositol phosphate formation. Saturation binding experiments in the presence of a single saw palmetto extract concentration indicated a noncompetitive antagonism. The relationship between active concentrations in vitro and recommended therapeutic doses for the saw palmetto extracts was slightly lower than that for several chemically defined α1-adrenoceptor antagonists. CONCLUSIONS Saw palmetto extracts have α1-adrenoceptor-inhibitory properties. If bioavailability and other pharmacokinetic properties of these ingredients are similar to those of the chemically defined α1-adrenoceptor antagonists, α1-adrenoceptor antagonism might be involved in the therapeutic effects of these extracts in patients with lower urinary tract symptoms suggestive of benign prostatic obstruction. Prostate 38:208–215, 1999. © 1999 Wiley-Liss, Inc. Citing Literature Volume38, Issue315 February 1999Pages 208-215 RelatedInformation