Euromed, 08100 Mollet del Vallès, Barcelona, Spain.
Adv Ther. 2010 Aug;27(8):555-63. doi: 10.1007/s12325-010-0041-6. Epub 2010 Jul 10.
The nicotinamide adenine dinucleotide phosphate (NADPH)-dependent membrane protein 5alpha-reductase irreversibly catalyses the conversion of testosterone to the most potent androgen, 5alpha-dihydrotestosterone (DHT). In humans, two 5alpha-reductase isoenyzmes are expressed: type I and type II. Type II is found primarily in prostate tissue. Saw palmetto extract (SPE) has been widely used for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH). The mechanisms of the pharmacological effects of SPE include the inhibition of 5alpha-reductase, among other actions. Clinical studies of SPE have been equivocal, with some showing significant results and others not. These inconsistent results may be due, in part, to varying bioactivities of the SPE used in the studies.
The aim of the present study was to determine the in vitro potency of a novel saw palmetto ethanol extract (SPET-085), an inhibitor of the 5alpha-reductase isoenzyme type II, in a cell-free test system. On the basis of the enzymatic conversion of the substrate androstenedione to the 5alpha-reduced product 5alpha-androstanedione, the inhibitory potency was measured and compared to those of finasteride, an approved 5alpha-reductase inhibitor.
SPET-085 concentration-dependently inhibited 5alpha-reductase type II in vitro (IC(50)=2.88+/-0.45 microg/mL). The approved 5alpha-reductase inhibitor, finasteride, tested as positive control, led to 61% inhibition of 5alpha-reductase type II.
SPET-085 effectively inhibits the enzyme that has been linked to BPH, and the amount of extract required for activity is very low compared to data reported for other extracts. It can be concluded from data in the literature that SPET-085 is as effective as a hexane extract of saw palmetto that exhibited the highest levels of bioactivity, and is more effective than other SPEs tested. This study confirmed that SPET-085 has prostate health-promoting bioactivity that also corresponds favorably to that reported for the established prescription drug standard of therapy, finasteride.
烟酰胺腺嘌呤二核苷酸磷酸（NADPH）依赖性膜蛋白 5α-还原酶不可逆地催化睾酮转化为最强的雄激素，5α-二氢睾酮（DHT）。在人类中，表达两种 5α-还原酶同工酶：I 型和 II 型。II 型主要存在于前列腺组织中。锯棕榈提取物（SPE）已广泛用于治疗良性前列腺增生（BPH）引起的下尿路症状。SPE 的药理作用机制包括抑制 5α-还原酶等。SPE 的临床研究结果不一致，有些显示出显著的效果，有些则没有。这些不一致的结果可能部分归因于研究中使用的 SPE 的不同生物活性。
本研究旨在确定新型锯棕榈乙醇提取物（SPET-085）的体外效力，SPET-085 是一种 5α-还原酶同工酶 II 型抑制剂，在无细胞测试系统中。基于底物雄烯二酮向 5α-还原产物 5α-雄烷二酮的酶促转化，测量并比较了其抑制效力与已批准的 5α-还原酶抑制剂非那雄胺。
SPET-085 浓度依赖性地抑制了体外 5α-还原酶 II 型（IC50=2.88+/-0.45μg/mL）。作为阳性对照测试的已批准的 5α-还原酶抑制剂非那雄胺导致 5α-还原酶 II 型的 61%抑制。
SPET-085 有效地抑制了与 BPH 相关的酶，与文献中报道的其他提取物相比，所需的提取物量非常低。根据文献中的数据可以得出结论，SPET-085 与表现出最高生物活性的锯棕榈正己烷提取物一样有效，并且比其他测试的 SPE 更有效。本研究证实，SPET-085 具有促进前列腺健康的生物活性，这与已确立的处方药物标准疗法非那雄胺的报道相当。
