New Potent 5α- Reductase and Aromatase Inhibitors Derived from 1,2,3-Triazole Derivative.

This work describes the utility of pyrazole-4-carbaldehyde 1 as starting material for the synthesis of a novel potent series of 5α-reductase and aromatase inhibitors derived from 1,2,3-triazole derivative. Condensation of 1 with active methylene and different amino pyrazoles produced the respective Schiff bases 2-4, 8 and 9. On the other hand, 1 was reacted with ethyl cyanoacetate and thiourea in one-pot reaction to afford the pyrazolo-6- thioxopyridin-2-[3H]-one (10). Moreover, α-ß unsaturated chalcone derivative 11 was prepared via the reaction of compound 1 with P-methoxy acetophenone, which in turn reacted with each of ethyl cyanoacetate, malononitrile, hydrazine hydrate, and thiosemicarbazide to afford the corresponding pyridine and pyrazole derivatives 13, 14, 17, and 20. The structure of newly synthesized compounds was characterized by analytical and spectroscopic data (IR, MS and NMR). All new compounds were evaluated against 5α-reductase and aromatase inhibitors and the results showed that many of these compounds inhibit 5α-reductase and aromatase activity; compound 13 was found to be the highest potency among the tested samples comparing with the reference drugs.

Serenoa repens extracts: In vitro study of the 5α-reductase activity in a co-culture model for Benign Prostatic Hyperplasia.

OBJECTIVES: Benign Prostatic Hyperplasia (BPH) is a form of benign tumor that occurs in humans mainly with ageing. It affects more than 50% of over 50 years old males and it is characterized by an increased synthesis of dihydrotestosterone (DHT), due to the 5α-reductase activity. The BPH therapeutic approach mainly uses 5α-reductase inhibitors, such as the active compounds present in the extracts deriving from species Serenoa repens. Many lipidosterolic extracts are available on the market, which are obtained with different solvents, among them ethanol is recognized as non-toxic and has less handling risks than hexane. The purpose of the present experimental study was to investigate in-vitro the potency of an ethanol extract of S. repens comparing it with an n-hexane one. MATERIALS AND METHODS: Two different lipido-sterolic extracts of S. repens have been tested: ethanol extract and n-hexane extract, two batches for each one. The inhibitory action of the extract was evaluated estimating in-vitro the activity of enzyme 5α-reductase type I (5α-RI), which was mainly active under the experimental condition of pH 7.5. DHT amount, synthesized from testosterone (1 µM), was evaluated in a co-culture model of epithelial cells and fibroblasts resulting from prostatic biopsy of a patient with BPH. RESULTS: The analysis of the resulting dose-response curves showed that the entire S. repens extracts inhibited the 5α-RI showing no difference between the two kinds of extract or between the batches. The resulting IC50 values were the following: 8.809 (95% CI = 5.133-15.56) and 9.464 (95% CI = 5.094- 18.27) for ethanol extracts; 11.08 (95% CI = 6.389-19.98) and 12.72 (95% CI = 7.758-21.53) for n-hexane extracts. CONCLUSIONS: The potency of ethanol extracts of S. repens was comparable with the one of n-hexane extracts.

Synthesis of new derivatives of 21-imidazolyl-16-dehydropregnenolone as inhibitors of 5α-reductase 2 and with cytotoxic activity in cancer cells.

The aim of this study was to synthesize several 16-dehydropregnenolone derivatives containing an imidazole ring at C-21 and a different ester moiety at C-3 as inhibitors of 5α-reductase 1 and 2 isoenzymes. Their binding capacity to the androgen receptor (AR) was also studied. Additionally, we evaluated their pharmacological effect in a castrated hamster model and their cytotoxic activity on a panel of cancer cells (PC-3, MCF7, SK-LU-1). The results showed that only the derivatives with an alicyclic ester at C-3 showed 5α-R2 enzyme inhibition activity, the most potent of them being 21-(1H-imidazol-1-yl)-20-oxopregna-5,16-dien-3ß-yl-cyclohexanecarboxylate with an IC50 of 29nM. This is important because prostatic benign hyperplasia is directly associated with the presence of 5α-R2. However, all the derivatives failed to inhibit 5α-R1 or bind to the AR. These alicyclic ester derivatives decreased the weight and size of androgen-dependent glands in the hamster, indicating they are very active in vivo and are not toxic. In addition, the 21-(1H-imidazol-1-yl)-20-oxopregna-5,16-dien-3ß-yl-acetate derivative showed the highest cytotoxic activity on the three cancer cell lines studied. It is therefore important in the synthesis of steroidal compounds to consider the size of the ester moiety at C-3 of the steroid skeleton, which is key in obtaining biological activity, as observed in this experiment.

Combination therapy with dutasteride and tamsulosin for the treatment of symptomatic enlarged prostate.

Benign prostatic hyperplasia (BPH) is a frequent cause of lower urinary symptoms, with a prevalence of 50% by the sixth decade of life. Hyperplasia of stromal and epithelial prostatic elements that surround the urethra cause lower urinary tract symptoms (LUTS), urinary tract infection and acute urinary retention. Medical treatments of symptomatic BPH include; 1) the 5alpha-reductase inhibitors, 2) the alpha1-adrenergic antagonists, and 3) the combination of a 5alpha-reductase inhibitor and a alpha1-adrenergic antagonist. Selective alpha1-adrenergic antagonists relax the smooth muscle of the prostate and bladder neck without affecting the detrussor muscle of the bladder wall, thus decreasing the resistance to urine flow without compromising bladder contractility. Clinical trials have shown that alpha1-adrenergic antagonists decrease LUTS and increase urinary flow rates in men with symptomatic BPH, but do not reduce the long-term risk of urinary retention or need for surgical intervention. Inhibitors of 5alpha-reductase decrease production of dihydrotestosterone within the prostate resulting in decreased prostate volumes, increased peak urinary flow rates, improvement of symptoms, and decreased risk of acute urinary retention and need for surgical intervention. Interim results of the ongoing Combination of Avodart and Tamsulosin (CombAt) study have shown combination therapy with the 5alpha-reductase inhibitor dutasteride and the alpha1-adrenergic antagonist tamsulosin offer significant improvements from baseline compared with either drug alone.

Biocatalytic synthesis of 4-pregnen-20,21-diol-3-one, a selective inhibitor of human 5alpha-reductase type II.

Biocatalysis, the conversion of substrates into valuable products by the use of enzymes, has some striking advantages in comparison to standard organic chemistry for drug synthesis. By biocatalysis, substrates that contain several identical reactive groups at different positions can be converted with high regio-selectivity and enantio-selectivity. In this study, an E. coli isolate (E132) was identified which was able to convert the steroid desoxycorticosterone into the product 4-pregnen-20,21-diol-3-one in real terms. The product was purified from the cell culture supernatant by HPLC and its structure was demonstrated by mass spectrometry and NMR spectroscopy. It was tested on inhibition of human 5alpha-reductases type I and type II. At a concentration of 10 microM, inhibition was 49.0% for type I and 81.8% for type II, whereas there was no inhibition of human aromatase (CYP19) at 20 microM and human 17alpha-hydroxylase-C17,20-lyase (CYP17) at 2.5 microM detectable. The IC50 value of 4-pregnen-20,21-diol-3-one for human 5alpha-reductase type II was determined to be 1.56 microM.