Suresh Thareja

An overview on 5α-reductase inhibitors

Benign prostatic hyperplasia (BPH) is the noncancerous proliferation of the prostate gland associated with benign prostatic obstruction and lower urinary tract symptoms (LUTS) such as frequency, hesitancy, urgency, etc. Its prevalence increases with age affecting around 70% by the age of 70 years. High activity of 5alpha-reductase enzyme in humans results in excessive dihydrotestosterone levels in peripheral tissues and hence suppression of androgen action by 5alpha-reductase inhibitors is a logical treatment for BPH as they inhibit the conversion of testosterone to dihydrotestosterone. Finasteride (13) was the first steroidal 5alpha-reductase inhibitor approved by U.S. Food and Drug Administration (USFDA). In human it decreases the prostatic DHT level by 70-90% and reduces the prostatic size. Dutasteride (27) another related analogue has been approved in 2002. Unlike Finasteride, Dutasteride is a competitive inhibitor of both 5alpha-reductase type I and type II isozymes, reduced DHT levels >90% following 1 year of oral administration. A number of classes of non-steroidal inhibitors of 5alpha-reductase have also been synthesized generally by removing one or more rings from the azasteroidal structure or by an early non-steroidal lead (ONO-3805) (261). In this review all categories of inhibitors of 5alpha-reductase have been covered.

Protein Tyrosine Phosphatase 1B Inhibitors: A Molecular Level Legitimate Approach for the Management of Diabetes Mellitus

Diabetes mellitus is a systemic disease responsible for morbidity in the western world and is gradually becoming prevalent in developing countries too. The prevalence of diabetes is rapidly increasing in industrialized countries and type 2 diabetes accounts for 90% of the disease. Insulin resistance is a major pathophysiological factor in the development of type 2 diabetes, occurring mainly in muscle, adipose tissues, and liver leading to reduced glucose uptake and utilization and increased glucose production. The prevalence and rising incidence of diabetes emphasized the need to explore new molecular targets and strategies to develop novel antihyperglycemic agents. Protein Tyrosine Phosphatase 1B (PTP 1B) has recently emerged as a promising molecular level legitimate therapeutic target in the effective management of type 2 diabetes. PTP 1B, a cytosolic nonreceptor PTPase, has been implicated as a negative regulator of insulin signal transduction. Therefore, PTP 1B inhibitors would increase insulin sensitivity by blocking the PTP 1B‐mediated negative insulin signaling pathway and might be an attractive target for type 2 diabetes mellitus and obesity. With X‐ray crystallography and NMR‐based fragment screening, the binding interactions of several classes of inhibitors have been elucidated, which could help the design of future PTP 1B inhibitors. The drug discovery research in PTP 1B is a challenging area to work with and many pharmaceutical organizations and academic research laboratories are focusing their research toward the development of potential PTP 1B inhibitors which would prove to be a milestone for the management of diabetes.

Pharmacology and chemistry of diabetes mellitus and antidiabetic drugs: a critical review.

Diabetes mellitus, an epidemic metabolic disorders characterized by high blood glucose level associated with various macrovascular and microvascular complications, is one of the main causes of human suffering across the globe. Researchers around the world mainly focused on insulin, insulin analogues, oral hypoglycemic agents and various other complementary and alternate medicines to control the blood glucose levels in diabetes. The present review summarizes the disorders associated with elevation of blood glucose level, biochemical & endocrinological aspects and the current strategies to control. The emphasis has been laid in particular on the new potential biological targets and the possible treatment as well as the current ongoing research status on new generation hypoglycemic agents.

3D-QSAR studies on unsaturated 4-azasteroids as human 5α-reductase inhibitors: A self organizing molecular field analysis approach

Azasteroids have been reported as inhibitors of human 5alpha-reductase enzyme. These were designed by substitution of one carbon atom of steroidal A ring by heteroatom nitrogen. Due to lack of information on the crystal structure of human 5alpha-reductase, 3D-QSAR study has been performed on a series of unsaturated 4-azasteroids using Self Organizing Molecular Field Analysis (SOMFA) for rationalizing the molecular properties and human 5alpha-reductase inhibitory activities. The statistical results having good cross-validated r(2)(cv) (0.783), non cross-validated r(2) (0.806) and F-test value (87.282), showed satisfied predictive ability. Analysis of SOMFA models through electrostatic and shape grids provide useful information for the design and optimization of new steroidal human 5alpha-reductase inhibitors.

Self organizing molecular field analysis on a series of human 5α-reductase inhibitors: Unsaturated 3-carboxysteroid

Steroidal 5alpha-reductase is a NADPH dependent enzyme that catalyzes the irreversible conversion of 4-en-3-oxo-steroid testosterone to the corresponding 5alpha-H-3-oxo-steroid dihydrotestosterone thus involved in Benign Prostatic Hyperplasia (BPH). As the crystal structure of target enzyme is not available; we have carried out ligand based designing using Self Organizing Molecular Field Analysis (SOMFA). SOMFA, a novel 3D-QSAR methodology used in present case to study the correlation between molecular properties and human 5alpha-reductase inhibitory activities of a series of unsaturated 3-carboxysteroid. The statistical results, good cross-validated r(2)(cv) (0.693) and non cross-validated r(2) (0.732), showed satisfied predictive ability. All analysis of SOMFA model may provide some useful information in the design of human steroidal 5alpha-reductase inhibitors with better spectrum of activity.

Self-organizing molecular field analysis on pregnane derivatives as human steroidal 5α-reductase inhibitors

Normal growth and development of human prostate is regulated by the androgens which balances cell proliferation and apoptosis. Testosterone (T) and dihydrotestosterone (DHT) are the two key androgens that stimulate most of the androgen action in prostate. Testosterone is converted to DHT by the membrane bound NADPH-dependent 5alpha-reductase enzyme. As a consequence of the important observation that progesterone and deoxycortisone inhibits the synthesis of DHT by competing with 4-en-3-one function of the testosterone for the 5alpha-reductase enzyme a number of pregnane derivatives were synthesized and have been reported as inhibitors of human 5alpha-reductase enzyme. Due to lack of information on the crystal structure of human 5alpha-reductase, ligand-based 3D-QSAR study has been performed on pregnane derivatives using self-organizing molecular field analysis (SOMFA) for rationalizing the molecular properties and human 5alpha-reductase inhibitory activities. The statistical results having good cross-validated r(cv)(2) (0.881), non-cross-validated r(2) (0.893) and F-test value (175.527), showed satisfied predictive ability r(pred)(2) (0.777). Analysis of SOMFA models through electrostatic and shape grids provide useful information for the design and optimization of steroidal structure as novel human 5alpha-reductase inhibitors.

Self-organizing molecular field analysis of 2,4-thiazolidinediones: A 3D-QSAR model for the development of human PTP1B inhibitors.

Thiazolidinediones (TZDs) have been recently developed to treat diabetic patients that can reverse insulin resistance by activation of gamma isoform of peroxisome proliferator-activated receptor (PPAR-gamma). Self-Organizing Molecular Field Analysis (SOMFA) has been performed on TZD scaffold having h-PTP1B inhibitory activities for the development and optimization of lead. The master grids obtained from SOMFA models indicated significant electrostatic and shape potential contributions. These can be mapped back onto structural features relating to the trends in activities of the molecules. The robustness of generated SOMFA models was evidenced by various statistical measures. Overall, the present SOMFA study investigated the indispensable structural features of substituted TZDs which can be exploited for further structural modifications in order to optimize h-PTP1B inhibitors.

Synthesis and biological evaluation of novel unsaturated carboxysteroids as human 5α-reductase inhibitors: a legitimate approach.

In the present study, novel steroidal 17a-substituted 3-cyano-17a-aza-D-homo-3,5-androstadien-17-ones (12-19) and 17a-substituted 17-oxo-17a-aza-D-homo-3,5-androstadien-3-oic acids (20-26) were synthesized from dehydroepiandrosterone acetate (6) along with 17-oxo-19-nor-3,5-androstadien-3-oic acid (30) through a multistep synthesis. Compounds were evaluated for their in vitro 5α-reductase inhibitory activity by measuring the conversion of [(3)H] androstenedione in human embryonic kidney (HEK) cells. In vivo 5α-reductase inhibitory activity was also determined using rat prostate weighing method. Compounds 21-23 and 25 showed potent inhibition of 5α-reductase II enzyme with IC(50) values of 54.1 ± 9.5, 22.1 ± 2.4, 72.8 ± 2.3 and 26.5 ± 4.4 nM respectively as compared to Finasteride (30.3 nM) along with a significant (p < 0.05) reduction in rat prostate weight.

3D-QSAR Studies on a Series of 5-Arylidine-2, 4-Thiazolidinediones as Aldose Reductase Inhibitors: A Self-Organizing Molecular Field Analysis Approach.

Aldose Reductase (AR), the key enzyme of the polyol pathway catalyzes the reduction of glucose to sorbitol using nicotinamide adenine dinucleotide phosphate as an essential cofactor, has been demonstrated to play an important role in the pathogenesis of diabetic complications. Self Organizing Molecular Field Analysis (SOMFA), a novel three-dimensional quantitative structure activity relationship (3D-QSAR) method has been used in present case to study the correlation between the molecular properties and the aldose reductase inhibitory activities on a series of 5-arylidine-2, 4-thiazolidinedione. SOMFA calculations for both shape and electrostatic potentials were carried out. The master grid maps derived from the best model has been used to display the contribution of electrostatic potential and shape molecular field. The statistical results showed good cross-validated r(2)(CV), non cross-validated r(2), F-test set and significant predictive ability indicated by r(2)(pred). All analysis of SOMFA model may provide useful information in the design of new aldose reductase inhibitors with improved spectrum of activity for management of diabetic complications.

Saxagliptin: a new drug for the treatment of type 2 diabetes.

Saxagliptin (BMS-477118) has been recently FDA approved drug for the management of T2DM developed by Bristol-Myers Squibb and AstraZeneca under the trade name Onglyza. Saxagliptin is a nitrile-containing selective, potent, reversible and durable DPP IV inhibitor developed as an alternative second-line adds on to Metformin in place of a sulphonylurea. Saxagliptin increases and prolongs the action of incretin hormones by inhibiting the DPP IV enzyme that inactivates incretins usually within minutes. Saxagliptin is well absorbed and has low plasma protein binding and displays slow-binding properties to DPP IV. Saxagliptin is metabolized in vivo to form an active metabolite (BMS-510849), which is twofold less potent than the parent molecule. The X-ray crystallography revealed that Saxagliptin is covalently bound to the DPP IV active site. In drug-native patients with T2DM and inadequate glycemic control, once-daily Saxagliptin monotherapy for 24 wks demonstrated clinically meaningful with no weight gain and generally well tolerated.