Synthesis and biological evaluation of 3-tetrazolo steroidal analogs: Novel class of 5α-reductase inhibitors

A chemoenzymatic process for preparation of highly purified dehydroepiandrosterone in high space-time yield

Dehydroepiandrosterone (DHEA) is an important neurosteroid hormone to keep human hormonal balance and reproductive health. However, DHEA was always produced with impurities either by chemical or biological method and required high-cost purification before the medical use. To address this issue, a novel chemoenzymatic process was proposed and implemented to produce DHEA. An acetoxylated derivate of 4-androstene-3,17-dione (4-AD) was generated by chemical reaction and converted into DHEA by an enzyme cascade reaction combining a hydrolysis reaction with a reduction reaction. The hydrolysis reaction was catalyzed by a commercial esterase Z03 while the reduction reaction was catalyzed by E. coli cells co-expressing a 3β-hydroxysteroid dehydrogenase SfSDR and a glucose dehydrogenase BtGDH. After the condition optimization, DHEA was synthesized at a 100 mL scale under 100 mM of substrate loading and purified as white powder with the highest space-time yield (4.80 g/L/h) and purity (99 %) in the biosynthesis of DHEA. The successful attempt in this study provides a new approach for green synthesis of highly purified DHEA in the pharmaceutical industry.

Novel and Predictive QSAR Model for Steroidal and Nonsteroidal 5α- Reductase Type II Inhibitors

AIMS AND OBJECTIVE

In this study, a novel quantitative structure activity relationship (QSAR) model has been developed for inhibitors of human 5-alpha reductase type II, which are used to treat benign prostate hypertrophy (BPH).

METHODS

The dataset consisted of 113 compounds-mainly nonsteroidal-with known inhibitory concentration. Then 3D structures of compounds were optimized and molecular structure descriptors were calculated. The stepwise multiple linear regression was used to select descriptors encoding the inhibitory activity of the compounds. Multiple linear regression (MLR) was used to build up the linear QSAR model.

RESULTS

The results obtained revealed that the descriptors which best describe the activity were atom type electropological state, carbon type, radial distribution function (RDF), barysz matrix and molecular linear free energy relation. The suggested model could achieve satisfied square correlation coefficient of R² = 0.72, higher than of many previous studies, indicating its superiority. Rigid validation criteria were met using external data with Q² ˃ 0.5 and R² = 0.75, reflecting the predictive power of the model.

CONCLUSION

The QSAR model was applied for screening botanical components of herbal preparations used to treat BPH, and could predict the activity of some, among others, making reasonable attribution to the proposed effect of these preparations. Gamma tocopherol was found to be an active inhibitor, in consistence with many previous studies, anticipating the power of this model in the prediction of new candidate molecules and suggesting further investigations.

Crystal structure, Hirshfeld surface analysis and computational studies of 5-[(prop-2-en-1-yl)sulfan-yl]-1-[2-(tri-fluoro-meth-yl)phen-yl]-1H-tetra-zole

The title compound was synthesized from 2-(tri­fluoro­meth­yl)aniline by a multi-step reaction and is constructed from a pair of aromatic rings [2-(tri­fluoro­meth­yl)phenyl and tetra­zole], which are turned by 76.8 (1)° relative to each other because of significant steric hindrance of the tri­fluoro­methyl group at the ortho position of the benzene ring·In the crystal, very weak C—H⋯N and C—H⋯F hydrogen bonds and aromatic π–π stacking inter­actions link the mol­ecules into a three-dimensional network.

The title compound, C₁₁H₉F₃N₄S, was synthesized from 2-(tri­fluoro­meth­yl)aniline by a multi-step reaction. It crystallizes in the non-centrosymmetric space group Pna2₁, with one mol­ecule in the asymmetric unit, and is constructed from a pair of aromatic rings [2-(tri­fluoro­meth­yl)phenyl and tetra­zole], which are twisted by 76.8 (1)° relative to each other because of significant steric hindrance of the tri­fluoro­methyl group at the ortho position of the benzene ring. In the crystal, very weak C—H⋯N and C—H⋯F hydrogen bonds and aromatic π–π stacking inter­actions link the mol­ecules into a three-dimensional network. To further analyse the inter­molecular inter­actions, a Hirshfeld surface analysis, as well as inter­action energy calculations, were performed.

Synthesis and evaluation of novel D-ring substituted steroidal pyrazolines as potential anti-inflammatory agents

To identify new potential anti-inflammatory agents, a number of novel steroidal derivatives with nitrogen heterocyclic side chains 4a-4l were synthesized and evaluated for their anti-inflammatory effects in activated RAW 264.7 macrophage cells. The synthesis scheme involves two steps, Claisen-Schmidt condensation with the corresponding pregnenolone and aromatic aldehydes as the first step followed by nucleophilic addition of thiosemicarbazide across an α, β-unsaturated carbonyl as a later step. Compound structures were confirmed by ¹H NMR, ¹³C NMR, HRMS, and IR. The compounds were assayed to test their anti-inflammatory effects in activated RAW 264.7 cells. Compound 4g, 3β-hydroxy-pregn-5-en-17β-yl-5'-(m-fluorophenyl)-4', 5'-dihydro-1'-carbothioic acid amido pyrazole, was identified as the most potent anti-inflammatory agent of the analysed compounds, with an IC₅₀ value of 0.86 µM on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cells for 24 h compared to dexamethasone (IC₅₀ = 0.62 µM) and low cytotoxicity against RAW 264.7 cells. Compound 4g significantly inhibited NO produced by LPS-induced RAW 264.7 cells. Further studies showed that compound 4g markedly inhibited the expression of pro-inflammatory factors, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2) in LPS-induced RAW 264.7 cells. These results indicate that derivatives bearing pyrazoline structure might be considered for further research and scaffold optimization in designing anti-inflammatory drugs and compound 4g might be a promising therapeutic anti-inflammatory drug candidate.

Tetrazole hybrids with potential anticancer activity

Cancer is one of the main causes of death throughout the world. The anticancer agents are indispensable for the treatment of various cancers, but most of them currently on the market are not specific, resulting in series of side effects of chemotherapy. Moreover, the emergency of drug-resistance towards cancers has already increased up to alarming level in the recent decades. Therefore, it's imperative to develop novel anticancer candidates with excellent activity against both drug-susceptible and drug-resistant cancers, and low toxicity as well. Tetrazole is the bioisoster of carboxylic acid, and its derivatives demonstrated promising anticancer activity. Hybridization of tetrazole with other anticancer pharmacophores may provide novel candidates with anticancer potency. The present review described the anticancer activity of tetrazole hybrids, and the structure-activity relationship (SAR) is also discussed to provide an insight for rational designs of tetrazole anticancer candidates with higher efficiency.