Studies on novel D-ring substituted steroidal pyrazolines as potential anticancer agents

Diverse Pharmacological Potential of different Substituted Pyrazole Derivatives

The chemistry of heterocyclic compounds has been a topic of research interest. Some five-membered heterocyclic compounds have been the subject of extensive research due to their different types of pharmacological effects. The five-membered nitrogen-containing heterocyclic compounds pyrazole, pyrazoline, and pyrazolone derivatives have a lot of interest in the fields of medical and agricultural chemistry due to their diverse spectrum of therapeutic activities. Various substituted pyrazole, pyrazoline, and pyrazolone compounds exhibited diverse pharmacological effects like Anti-microbial, anti-inflammatory, anti-tubercular, anti-fungal, anti-malarial, anti-diabetic, diuretic, anti-depressant, anticonvulsant, antioxidant, anti-leishmanial, antidiabetic, and antiviral, etc. In recent decades, the synthesis of numerous pyrazole, pyrazoline, and pyrazolone derivatives by different synthetic methods as well as research into their chemical and biological behavior have become more important. This review focuses on synthetic methods of the pyrazole, pyrazoline, and pyrazolone derivatives, which have significant biological properties and a variety of applications.

Tandem Addition/Cyclization/Halogenation Reaction of Difluoromethylated N-Acylhydrazones with Allyltrimethylsilanes

As novel difluoromethyl building blocks, difluoromethylated N-acylhydrazones react with allyltrimethylsilanes and the halogen source via a tandem addition/cyclization/halogenation strategy, which produces various difluoromethylpyrazoline compounds in good yields. The method features mild reaction conditions, broad substrate scopes, and a transition metal-free process with easy operation. It also proves that difluoromethylated N-acylhydrazones are useful difluoromethyl building blocks for the construction of difluoromethylated nitrogen heterocycles.

Spirocyclization and Michael addition of 3-benzylidene succinimides: route to spirocyclopentapyrrolidine-tetraones and benzylidene N-arylpyrrolidine-diones

Reactions of 3-benzylidene succinimides with 2-substituted 2-hydroxy-indane-1,3-diones and unsaturated pyrazolones are carried out under basic conditions to afford spirocyclized derivatives and Michael adducts, respectively, with high regio- and stereo-selectivities. The most notable aspect of the reaction is the ability of highly reactive benzylidene succinimide to act as both an electrophile and a nucleophile causing spirocyclization. The reaction proceeded under mild and metal-free conditions and products were isolated in good to high yields. The current strategy utilizes simple and easily accessible precursors, and provides functionally rich products of medicinal interest with two to four contiguous stereogenic centres and complete regioselectivity with excellent diastereoselectivity.

Discovery and biological evaluation of pregnenolone selenocyanoamides with potential anticancer and antimicrobial activities

Starting with pregnenolone, a 20-carbonyl group was converted into an amino group through a series of chemical reactions. This amino group was further converted into selenocyanoalkylamide, leading to the synthesis of six pregnenolone selenocyanoalkylamide derivatives. These compounds were then screened for antitumor activity in vitro, yielding promising results. Compounds 4b-4f show higher inhibitory activity than the positive control abiraterone and 2-methoxyestradiol, with IC50 values lower than 10 μmol/L against breast, ovarian, and cervical cancer cell lines that closely related to human hormone expression levels. The Annexin V assay of compound 4f revealed that compounds inhibited tumor cell proliferation primarily through the induction of programmed apoptosis. The zebrafish test results indicated that compound 4d had significant inhibitory activity against MCF-7 cell xenografts in vivo. Moreover, the antibacterial test indicated that compounds 4a and 4d-4e had better inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) than the positive controls vancomycin and ampicillin. These results suggest that these compounds may hold promise as novel antitumor agents or antimicrobial agents for further study.

Synthesis, In Vitro Biological Evaluation of Antiproliferative and Neuroprotective Effects and In Silico Studies of Novel 16E-Arylidene-5α,6α-epoxyepiandrosterone Derivatives

Steroids constitute an important class of pharmacologically active molecules, playing key roles in human physiology. Within this group, 16E-arylideneandrostane derivatives have been reported as potent anti-cancer agents for the treatment of leukemia, breast and prostate cancers, and brain tumors. Additionally, 5α,6α-epoxycholesterol is an oxysterol with several biological activities, including regulation of cell proliferation and cholesterol homeostasis. Interestingly, pregnenolone derivatives combining these two modifications were described as potential neuroprotective agents. In this research, novel 16E-arylidene-5α,6α-epoxyepiandrosterone derivatives were synthesized from dehydroepiandrosterone by aldol condensation with different aldehydes followed by a diastereoselective 5α,6α-epoxidation. Their cytotoxicity was evaluated on tumoral and non-tumoral cell lines by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Furthermore, the assessment of the neuroprotective activity of these derivatives was performed in a dopaminergic neuronal cell line (N27), at basal conditions, and in the presence of the neurotoxin 6-hydroxydopamine (6-OHDA). Interestingly, some of these steroids had selective cytotoxic effects in tumoral cell lines, with an IC50 of 3.47 µM for the 2,3-dichlorophenyl derivative in the breast cancer cell line (MCF-7). The effects of this functionalized epoxide on cell proliferation (Ki67 staining), cell necrosis (propidium iodide staining), as well as the analysis of the nuclear area and near neighbor distance in MCF-7 cells, were analyzed. From this set of biological studies, strong evidence of the activation of apoptosis was found. In contrast, no significant neuroprotection against 6-OHDA-induced neurotoxicity was observed for the less cytotoxic steroids in N27 cells. Lastly, molecular docking simulations were achieved to verify the potential affinity of these compounds against important targets of steroidal drugs (androgen receptor, estrogen receptor α, and 5α-reductase type 2, 17α-hydroxylase-17,20-lyase and aromatase enzymes). This in silico study predicted a strong affinity between most novel steroidal derivatives and 5α-reductase and 17α-hydroxylase-17,20-lyase enzymes.

Heterocycles in Breast Cancer Treatment: The Use of Pyrazole Derivatives

Among the aromatic heterocycle rings, pyrazole -a five-membered ring with two adjacent nitrogen atoms in its structure has been postulated as a potent candidate in the pharmacological context. This moiety is an interesting therapeutic target covering a broad spectrum of biological activities due to its presence in many natural substances. Hence, the potential of the pyrazole derivatives as antitumor agents has been explored in many investigations, showing promising results in some cases. In this sense, breast cancer, which is already the leading cause of cancer mortality in women in some countries, has been the topic selected for this review, which covers a range of different research from the earliest studies published in 2003 to the most recent ones in 2021.

Reaction of 7α-bromo-6-nitrocholest-5-enes with hydrazine: Formation of steroidal pyrazolines and molecular docking against SARS-CoV-2 omicron protease

The present work reports simple and effective protocol for preparing 6α-nitro-5α-cholestano[7α,5-cd] pyrazolines (4-7) by the reaction of 7α-bromo-6-nitrocholest-5-enes (1-3) with hydrazine hydrate under reflux [the substrate (2) gave products (5) and (6) and the later on acetylation with AC₂O/Py gave (7)]. In the case of reaction of 3β-hydroxy analogue (3) with hydrazine, however, 6α-nitro-5α-cholestano [3α,5-cd] pyrazoline (8) and 6α-nitro-3β, 5-oxido-5β-cholestane (9) were obtained. The probable mechanism of the formation of pyrazolines has also been outlined. In the current pandemic coronavirus disease 2019 scenario, the in-silico study was performed with reactants (1-3), their products (4-9) against SARS-CoV-2 omicron protease (PDB ID:7T9L) for knowing significant interactions between them. Docking results give information that both reactants and products have binding energies ranges from -5.7 to 7.7 kcal/mol and strong interactions with various hydrophilic and hydrophobic amino acids such as ASP, PRO, PHE, SER and LEU which are significant residues playing important role in SARS-CoV-2 Omicron main protease (Mpro).

Novel 4-Azapregnene Derivatives as Potential Anticancer Agents: Synthesis, Antiproliferative Activity and Molecular Docking Studies

A series of novel 21E-arylidene-4-azapregn-5-ene steroids has been successfully designed, synthesized and structurally characterized, and their antiproliferative activity was evaluated in four different cell lines. Within this group, the 21E-(pyridin-3-yl)methylidene derivative exhibited significant cytotoxic activity in hormone-dependent cells LNCaP (IC₅₀ = 10.20 µM) and T47-D cells (IC₅₀ = 1.33 µM). In PC-3 androgen-independent cells, the steroid 21E-p-nitrophenylidene-4-azapregn-5-ene was the most potent of this series (IC₅₀ = 3.29 µM). Considering these results, the 21E-(pyridin-3-yl)methylidene derivative was chosen for further biological studies on T47-D and LNCaP cells, and it was shown that this azasteroid seems to lead T47-D cells to apoptotic death. Finally, molecular docking studies were performed to explore the affinity of these 4-azapregnene derivatives to several steroid targets, namely 5α-reductase type 2, estrogen receptor α, androgen receptor and CYP17A1. In general, compounds presented higher affinity to 5α-reductase type 2 and estrogen receptor α.

Synthesis, molecular docking, molecular dynamics and evaluation of Drug-Likeness properties of the fused N-Formyl pyrazoline substituted new dehydroepiandrosterone derivatives

The hybrid molecules bearing heterocyclic structures in the A or D rings of steroids have significant biological activity. 16 (E)-Hetereoarylidene steroids were synthesized from the reaction of different heteroaromatic carbaldehydes and trans-Dehydroepiandrosterone (DHEA) in a basic medium. Then, synthesis of the N-formyl pyrazoline substituted new DHEA derivatives were carried out from the reaction of hydrazine hydrate and 16 (E)-hetereoarylidene steroids. The structures of the synthesized compounds were elucidated by elemental analysis, FT-IR, ¹H NMR, and ¹³C NMR spectroscopy. To investigate the activation pathway of synthesized N-formyl pyrazoline substituted steroid derivatives, a molecular docking study was performed on human cytochrome P450-(CYP17A1: PDB ID 5IRQ) with the help of the free AutoDock Vina. 100 ns molecular dynamic simulation process was performed to monitor the behavior of the complex structure formed by CYP17A1 and to calculate the stability over time of 2a and 2d (-9.8 kcal/mol), which gave the lowest value according to the results obtained in the molecular docking study with AutoDock Vina. Accordingly, RMSD, RMSF, Rg, and SASA analyzes of 2a and 2d were performed, and MMPBSA was calculated. Lastly, the ADMET (absorption, distribution, metabolism, excretion, and toxicity) analyses of the novel steroid derivatives were investigated.Communicated by Ramaswamy H. Sarma.

Synthesis and anti-inflammatory activity of novel steroidal chalcones with 3β-pregnenolone ester derivatives in RAW 264.7 cells in vitro

To identify new potential anti-inflammatory agents, we herein report the synthesis of novel steroidal chalcones with 3β-pregnenolone esters of cinnamic acid derivatives using pregnenolone as the starting material. The structures of the newly synthesised compounds were confirmed by 1H NMR, 13C NMR, HRMS and infrared imaging. All the derivatives were examined to determine their in vitro anti-inflammatory profiles against LPS-induced inflammation in RAW 264.7 cells; the derivates were evaluated by the quantification of the pro-inflammatory mediator nitric oxide (NO) in the cell culture supernatant based on the Griess reaction, which measures nitrite levels, followed by an in vitro cytotoxicity study. Among these novel derivatives, compound 11e [3β-3-phenyl acrylate-pregn-5-en-17β-yl-3' -(p-fluoro)-phenylprop-2'-en-1'-one] was identified as the most potent anti-inflammatory agent, which showed significant anti-inflammatory activity by inhibiting the LPS-induced pro-inflammatory mediator NO in a dose-dependent manner without any cytotoxicity. Moreover, compound 11e markedly inhibited the expression of pro-inflammatory cytokines, 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. Further studies confirmed that compound 11e significantly suppressed the transcriptional activity of NF-κB in activated RAW 264.7 cells. Molecular docking study revealed the strong binding affinity of compound 11e to the active site of the pro-inflammatory proteins, which confirmed that compound 11e acted as an anti-inflammatory mediator. These results indicated that steroidal chalcones with 3β-pregnenolone esters of cinnamic acid derivatives might be considered for further research in the design of anti-inflammatory drugs, and compound 11e might be a promising therapeutic anti-inflammatory drug candidate.

Antiproliferative and antimetastatic characterization of an exo-heterocyclic androstane derivative against human breast cancer cell lines

Cancer in general, and specifically gynaecological neoplasms, represents a major public health issue worldwide. Based on the effect of sex hormones on breast tumorigenesis and prognosis, as well as on the development of breast cancer metastases, modification of the steroid skeleton is a hotspot of research for novel anticancer agents. Numerous recent studies support that minor modifications of the androstane skeleton yield potent antiproliferative and antimetastatic drug candidates. The aim of the present study was to assess the antitumor and antimetastatic properties, as well as the mechanism of action of a D-ring-modified exo-heterocyclic androstadiene derivative named 17APAD. The test compound was found to be highly selective towards human breast cancer-derived cell lines (MCF-7, T47D, MDA-MB-361, MDA-MB-231) compared to non-cancerous fibroblast cells (NIH/3T3), and exerted superior effect compared to the clinically applied reference drug cisplatin. Changes in MCF-7- and MDA-MB-231 cell morphology and membrane integrity induced by the test substance were assessed by fluorescent double staining. Cell cycle disturbances were analyzed by flow cytometry, and concentration-dependent alterations were detected on breast cancer cell lines. Mitochondrial apoptosis induced by the test compound was demonstrated by JC-1 staining. Inhibitory effects on metastasis formation, including the inhibition of migration, invasion and intravasation were investigated in 2D and 3D models. Significant anti-migratory and anti-invasive effects on MCF-7 and MDA-MB-231 cells were detected after 24 h exposure in 2D wound healing and Boyden-chamber assays. The anti-intravasative properties of 17APAD were evident after 4 h of incubation in a co-culture 3D circular chemorepellent-induced defects (CCID) assay, and the level of inhibition at concentrations ≥2 µM was comparable to that exerted by the focal adhesion kinase inhibitor defactinib. Single cell mass cytometry revealed that chemosensitive subpopulations of MDA-MB-231 cells engaged to apoptosis were less positive for EGFR, CD274, and CD326, while the percentage of cells positive for GLUT1, MCT4, Pan-Keratin, CD66(a,c,e), Galectin-3 and TMEM45A increased in response to 17APAD treatment. Finally, the novel androstane analogue 17APAD had an outstanding inhibitory effect on tumour growth in the 4T1 orthotopic murine breast cancer model in vivo after 2 weeks of intraperitoneal administration. These findings support that substitution of the androsta-5,16-diene framework with a N-containing heterocyclic moiety at C17 position yields a molecular entity rational to be considered for design and synthesis of novel, effective antitumor agents, and 17APAD is worth further investigation as a promising anticancer drug candidate.

Discovery of Anticancer Agents from 2-Pyrazoline-Based Compounds

As nitrogen-containing five-membered heterocyclic structural units, the substituted pyrazole derivatives have a broad spectrum of pharmacological activities, especially 4,5-dihydro-1H-pyrazoles that also commonly known as 2-pyrazolines. Since 2010, considerable studies have been found that the 2-pyrazoline derivatives possess potent anticancer activities. In the present review, it covers the pyrazoline derivatives reported by literature from 2010 till date (2010-2019). This review aims to establish the relationship between the anticancer activities variation and different substituents introduced into a 2-pyrazoline core, which could provide important pharmacophore clues for the discovery of new anticancer agents containing 2-pyrazoline scaffold.

Highlights on Steroidal Arylidene Derivatives as a Source of Pharmacologically Active Compounds: A Review

Steroids constitute a unique class of chemical compounds, playing an important role in physiopathological processes, and have high pharmacological interest. Additionally, steroids have been associated with a relatively low toxicity and high bioavailability. Nowadays, multiple steroidal derivatives are clinically available for the treatment of numerous diseases. Moreover, different structural modifications on their skeleton have been explored, aiming to develop compounds with new and improved pharmacological properties. Thus, steroidal arylidene derivatives emerged as a relevant example of these modifications. This family of compounds has been mainly described as 17β-hydroxysteroid dehydrogenase type 1 and aromatase inhibitors, as well as neuroprotective and anticancer agents. Besides, due to their straightforward preparation and intrinsic chemical reactivity, steroidal arylidene derivatives are important synthetic intermediates for the preparation of other compounds, particularly bearing heterocyclic systems. In fact, starting from arylidenesteroids, it was possible to develop bioactive steroidal pyrazolines, pyrazoles, pyrimidines, pyridines, spiro-pyrrolidines, amongst others. Most of these products have also been studied as anti-inflammatory and anticancer agents, as well as 5α-reductase and aromatase inhibitors. This work aims to provide a comprehensive overview of steroidal arylidene derivatives described in the literature, highlighting their bioactivities and importance as synthetic intermediates for other pharmacologically active compounds.

Recent Progress on Anticancer Agents Incorporating Pyrazole Scaffold

The search of new anticancer agents is considered as a dynamic field of medicinal chemistry. In recent years, the synthesis of compounds with anticancer potential has increased and a large number of structurally varied compounds displaying potent anticancer activities have been published. Pyrazole is an important biologically active scaffold that possessed nearly all types of biological activities. The aim of this review is to collate literature work reported by researchers to provide an overview on in vivo and in vitro anticancer activities of pyrazole based derivatives among the diverse biological activities displayed by them and also presents recent efforts made on this heterocyclic moiety regarding anticancer activities. This review has been driven from the increasing number of publications, on this issue, which have been reported in the literature since the ending of the 20th century (from 1995-to date).

Discovery of novel steroidal-chalcone hybrids with potent and selective activity against triple-negative breast cancer

A series of novel steroidal-chalcone derivates were designed and synthesized based on the molecular hybridization strategy and further evaluated for their growth inhibitory activity against three human cancer cell lines. The MTT results indicated that most compounds were apparently more sensitive to human breast cancer cells MDA-MB-231. Compounds 8 and 18 exerted the best cytotoxic activity against triple-negative MDA-MB-231 cells with the IC₅₀ values of 0.42 μM and 0.52 μM respectively, which were 23-fold increase or more compared with 5-Fu. Further mechanism studies demonstrated that compound 8 could induce cells apoptosis through regulating Bcl-2/Bax proteins and activating caspase-3 signaling pathway. Moreover, compound 8 could upregulate the cellular ROS levels which accelerated the apoptosis of MDA-MB-231 cells. In addition, interestingly, cell cycle assay showed that compound 8 could arrest MDA-MB-231 cells at S phase but not commonly anticipated G2/M phase. These evidences fully confirmed that compound 8 could be a potential candidate that deserves further development as an antitumor agent against triple-negative breast cancer.

Pyrazoline Hybrids as Promising Anticancer Agents: An Up-to-Date Overview

Pyrazolines are five-membered heterocycles possessing two adjacent nitrogens. They have attracted significant attention from organic and medicinal chemists due to their potent biological activities and the numerous possibilities for structural diversification. In the last decade, they have been intensively studied as targets for potential anticancer therapeutics, producing a steady yearly rise in the number of published research articles. Many pyrazoline derivatives have shown remarkable cytotoxic activities in the form of heterocyclic or non-heterocyclic based hybrids, such as with coumarins, triazoles, and steroids. The enormous amount of related literature in the last 5 years prompted us to collect all these published data from screening against cancer cell lines, or protein targets like EGFR and structure activity relationship studies. Therefore, in the present review, a comprehensive account of the compounds containing the pyrazoline nucleus will be provided. The chemical groups and the structural modifications responsible for the activity will be highlighted. Moreover, emphasis will be given on recent examples from the literature and on the work of research groups that have played a key role in the development of this field.

Steroidal pyrazolines as a promising scaffold in drug discovery

Steroidal pyrazolines constitute an interesting and promising scaffold for drug discovery as they display diverse chemical reactivity and a wide range of biological activities. Literature reports indicate potent anticancer potential of steroidal pyrazolines along with broad-spectrum antimicrobial activities. Strong neuroprotective effects with steroids possessing pyrazoline moiety have also been observed. Among all the therapeutically active steroidal pyrazolines, D-ring-substituted derivatives are highly potent and the least toxic. The current and futuristic research approaches in this area are focused towards the exploration of this promising scaffold to develop molecules with widespread pharmacological activities. This review article mainly covers the synthetic and pharmacological aspects of steroidal pyrazolines, which will assist the medicinal chemists working in this area in their scientific endeavors.

Design, Synthesis, and Biological Evaluation of Two Series of Novel A-Ring Fused Steroidal Pyrazines as Potential Anticancer Agents

BACKGROUND

Increasingly, different heterocyclic systems have been introduced into the steroid nucleus to significantly enhance the antitumor activities of steroid molecules. However, in this study, few literature precedents describing the pyrazine heterocyclic-condensed modification to an A-ring of steroid monomers were found, although the pyrazine group is thought to be essential for the potent anticancer activity of clinically relevant drugs and natural steroid dimers.

METHODS AND RESULTS

Two series of novel A-ring fused steroidal pyrazines were designed and efficiently synthesized from commercially available progesterone via key α-ketoenol intermediates. Through a cell counting kit-8 cytotoxic assay of 36 derivatives for three tumor cells, 14 compounds displayed significant antiproliferative activity compared to 5-fluorouracil, especially for human prostatic tumor cells (PC-3) in vitro. Further mechanistic studies indicated that the most active compound, 12n (IC₅₀, 0.93 μM; SI, 28.71), could induce the cell apoptosis of PC-3 cells in a dose-dependent manner and cause cell cycle arrest in the G2/M phase. The molecular docking study suggested that compound 12n fitted the active sites of cytochrome P450 17A1 (6CIZ) well.

CONCLUSIONS

12n might serve as a promising lead compound for the development of novel anticancer drugs. This facile ring-closing strategy may provide a novel and promising avenue for the cycloaddition reaction of the steroidal skeleton through α-ketoenol intermediates.

Synthesis of novel hybrid hetero-steroids: Molecular docking study augmented anti-proliferative properties against cancerous cells

Hetero-steroids, hybrid anticancer agents, have received much interest in view of their numerous and promising biological activities. In this study, a novel class of hetero-steroids were synthesized, analytical and spectral data proved the validity of the novel synthesized steroid derivatives. The cytotoxicity of the synthesized compounds 2, 5, 6, 7, 10, 11, 12, 14, 15, 17 were evaluated using human hepatocellular carcinoma cell lines (HepG2 and Huh-7) and non-small cell lung cancer (A549) cell lines. The synthesized compounds reported a remarkable gradual decrease in the cell viability of the three tested cancer cell lines. It was observed that compounds 2 and 12 had the lowest IC_50s and the highest cytotoxic effects against all tested cell lines. As attempt to explain the cytotoxic activity achieved by the tested compounds in the in vitro study, molecular simulation was done to reveal the activity of the tested compounds against four different proteins (CDK2, CYP19, JAK2, and BCL2) which are highly implicated in cancer regulation and progression. We found that compound 2, and 12 were the best docked compounds against all tested receptors, which was indicated by lowest binding energy compared to reference ligand. Interestingly enough, our molecular study was in agreement with the cytotoxic activity. As future prospective, we are recommending further study on compounds 2, and 12 against the four different proteins to prove their mode of action.

A robust photoluminescence screening assay identifies uracil-DNA glycosylase inhibitors against prostate cancer

Many cancers have developed resistance to 5-FU, due to removal by the enzyme uracil-DNA glycosylase (UDG), a type of base excision repair enzyme (BER) that can excise uracil and 5-fluorouracil (5-FU) from DNA. However, the development of UDG inhibitor screening methods, especially for the rapid and efficient screening of natural product/natural product-like compounds, is still limited so far. We developed herein a robust time-resolved photoluminescence method for screening UDG inhibitors, which could significantly improve sensitivity over the screening method based on the conventional steady-state spectroscopy, reducing the substantial fluorescence background interference. As a proof-of-concept, two potential UDG inhibitors were identified from a database of natural products and approved drugs. Co-treatment of these two compounds with 5-FU showed synergistic cytotoxicity, providing the basis for treating drug-resistant cancers. Overall, this method provides an avenue for the rapid screening of small molecule regulators of other BER enzyme activities that can avoid false negatives arising from the background fluorescence.

The discovery of UDG inhibitors against prostate cancer by using a robust photoluminescence screening assay that can avoid false negatives arising from the background fluorescence.

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.

Interaction of C20-substituted derivative of pregnenolone acetate with copper (II) leads to ROS generation, DNA cleavage and apoptosis in cervical cancer cells: Therapeutic potential of copper chelation for cancer treatment

Cervical cancer is a leading cause of cancer-related deaths among women in developing countries. Therefore, development of new chemotherapeutic agents is required. Unlike normal cells, cancer cells contain elevated copper levels which play an integral role in angiogenesis. Thus, targeting copper via copper-specific chelators in cancer cells can serve as effective anticancer strategy. In this work, a copper chelator pregnenolone acetate nucleus-based tetrazole derivative (ligand-L) was synthesized and characterized by elemental analysis, ESI-MS, ¹H NMR and ¹³C NMR. DNA binding ability of ligand-L was studied using UV-Vis and fluorescence spectroscopy. Fluorescence spectroscopy studies reveal that quenching constant of ligand-l-DNA and ligand-L-Cu(II) were found to be 7.4 × 10³ M^-1 and 8.8 × 10³ M^-1, respectively. In vitro toxicity of ligand-L was studied on human cervical cancer C33A cancer cells. Results showed that ligand-L exhibit significant cytotoxic activity against cervical cancer C33A cells with IC₅₀ value 5.0 ± 1.8 µM. Further, it was found that ligand-L cytotoxicity is due to redox cycling of copper to generate ROS which leads to DNA damage and apoptosis. In conclusion, this is the report where we synthesized pregnenolone acetate-based tetrazole derivative against C33A cells that targets cellular copper to induce pro-oxidant death in cancer cells. These findings will provide significant insights into the development of new chemical molecules with better copper chelating and pro-oxidant properties against cancer cells.

Thieno[2,3-d]pyrimidine as a promising scaffold in medicinal chemistry: Recent advances

Thienopyrimidine scaffold is a fused heterocyclic ring system that structurally can be considered as adenine, the purine base that is found in both DNA and RNA-bioisosteres. Thienopyrimidines exist in three distinct isomeric forms. The current review discusses thieno[2,3-d]pyrimidine as a one of the opulent heterocycles in drug discovery. Its broad range of medical applications such as anticancer, anti-inflammatory, anti-microbial, and CNS protective agents has inspired us to study its structure-activity relationship (SAR), along with its relevant synthetic strategies. The present review briefly summarizes synthetic approaches for the preparation of thieno[2,3-d]pyrimidine derivatives. In addition, the promising biological activities of this scaffold are also illustrated with explanatory diagrams for their SAR studies.

Novel pregnenolone derivatives modulate apoptosis via Bcl-2 family genes in hepatocellular carcinoma in vitro

A series of pregnenolone derivatives were synthesized and assessed for anti-cancer activity against hepatocellular carcinoma cell line (HepG2). The synthesized hetero-steroids (compounds 3, 4, 5, 6, 7, 8a and 8b) were evaluated for their cytotoxic activities using MTT (3-(4,5-Dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide) assay. Apoptotic activity was assessed using dual acridine orange/ethidium bromide staining method and DNA fragmentation assay. Pro-apoptotic genes (Bax and Bak) and anti-apoptotic genes (Bcl-2 and Bcl-xL) were analyzed using quantitative real time PCR. The results revealed that compounds 4 and 6 displayed cytotoxic activity (IC_50s, 36.97 ± 2.18 and 18.46 ± 0.64 μM, respectively), while compounds 5 and 7 exhibited weak cytotoxic activity (IC_50s, 93.87 ± 8.30 μM and 93.48 ± 4.14 μM, respectively). All synthesized heterocyclic pregnenolone derivatives induced apoptosis through DNA fragmentation. Compounds 4 and 6 increased early and late apoptotic cell percentages while compounds 3, 5, 7 and 8b increased either early or late apoptotic cell percentage. Moreover, compounds 3, 6 and 8b up-regulated the expression level of Bak gene. On the other hand, compounds 4, 5, 7 and 8a down-regulated the Bcl-2 expression level, besides, compounds 5, 7 and 8a down-regulated the Bcl-xL expression level. Compounds 5, 7, 8a and 8b increased the Bak/Bcl-xL ratio, besides, compound 8a raised the Bax/Bcl-xL ratio whereas compound 5 elevated Bax/Bcl-2 and Bak/Bcl-2 ratios. The present work introduced novel pro-apoptotic pregnenolone derivatives that acted against HepG2 cells through DNA fragmentation, apoptotic morphological changes and were able to increase the pro-apoptotic/anti-apoptotic ratios of Bcl-2 family genes. This study particularly revealed that the cytotoxic compound 4 is the most promising pro-apoptotic compound among other synthesized derivatives where it induced apoptosis (late and early) through the down-regulation of Bcl-2 gene expression level.

Synthesis and evaluation of the antiproliferative activity of benzylidenes of 16-dehydroprogesterone series

Novel benzylidenes (chalcones) of the 16-dehydroprogesterone series have been characterized and their antitumor activity against two breast cancer cell lines was evaluated. Benzylidenes exhibit significant antiproliferative effect on cells and inhibit cell growth in hormone-dependent MCF-7 and hormone-independent MDA-MB-231 breast cancer cell lines. Compound 3d exhibits the highest activity against two breast cancer cell lines, with the IC₅₀ value of about 2 µM. Compounds 3e,m,n display considerable selectivity for hormone-dependent breast cancer cells, with the IC₅₀ value lower than 6 µM. Moreover, these steroidal benzylidenes regulate ERα signaling and reveal p53-independent mechanism of pro-apoptotic action in MCF-7 cells. The new class of antitumor compounds holds promise as the basis for the design of agents for cancer therapy.

Catalytic cyclometallation in steroid chemistry VI: Targeted synthesis of hybrid molecules based on steroids and tetradeca-5Z,9Z-diene-1,14-dicarboxylic acid and study of their antitumor activity

Hybrid molecules based on a number of steroids (cholesterol, pregnenolone, androsterone) and 1,14-tetradeca-5Z,9Z-dienedicarboxylic acid linked via mono- and diethylene glycol spacers were synthesized for the first time and studied for antitumor activity in vitro. The acid was prepared using catalytic cyclomagnesiation of oxygenated 1,2-dienes with Grignard reagent in the presence of Cp₂TiCl₂ as the key synthetic step. Using flow cytometry, the new molecules were shown for the first time to be efficient apoptosis inducers in the HeLa, Hek293, U937, Jurkat, and K562 cell cultures and to have dose-dependent effect on the S and G2 phases of the cell cycle.

Recent advances in the application of carbohydrates as renewable feedstocks for the synthesis of nitrogen-containing compounds

Carbohydrates, in the form of chitin, chitosan and cellulose, are one of the most available, renewable, and sustainable chemical feedstocks. Their conversion to biofuels, fine chemicals, and industrially-relevant monomers is becoming increasingly viable and promising as innovation decreases the price of this technology, and climate change and the price of fossil fuels increases the social and economic costs of using traditional feedstocks. In recent years, carbohydrates have been increasingly used as sources for nitrogen-containing fine chemicals. This chapter, with 86 references, provides a brief overview of the conversion of carbohydrate biomass to the standard hydrocarbon and oxygen-containing derivatives, and then provides a survey of recent progress in converting the biopolymers, and the derived mono and di-saccharides, into nitrogen-containing molecules with a special focus on N-heterocycle synthesis for medicinal applications.

Antiproliferative Properties of Newly Synthesized 19-Nortestosterone Analogs Without Substantial Androgenic Activity

19-Nortestosterone C-17 epimers with prominent antiproliferative properties have been previously described. In our present study, five novel 17α-19-nortestosterones (3-7) were synthesized to increase their beneficial biological activities with no associated undesired hormonal effects. The compounds were screened by a viability assay against a panel of human adherent gynecological cancer cell lines. Three of the tested derivatives (3-5) exhibited a remarkable inhibitory effect on the proliferation of HeLa cells with IC₅₀ values lower than that of our reference agent cisplatin (CIS). These three active agents also displayed considerable cancer selectivity as evidenced by their weaker growth inhibitory effect on non-cancerous fibroblast cells compared to CIS. The most potent newly synthesized 17α-chloro derivative (3) was selected for additional experiments in order to characterize its mechanism of action. Since nandrolone (19-nortestosterone, 1) is a structural analog with selective antiproliferative action on cervical carcinoma cells, it was utilized as a positive control in these studies. A lactate dehydrogenase (LDH) assay demonstrated a moderate cytotoxic effect of the test compounds. Cell cycle disturbance and the elevation of the hypodiploid population elicited by the test agents were detected by flow cytometry following propidium staining. The proapoptotic effects of the tested steroids were confirmed by fluorescent microscopy and a caspase-3 activity assay. Treatment-related caspase-9 activation without a substantial change in caspase-8 activity indicates the induction of the intrinsic apoptotic pathway. The selected agents directly influence the rate of tubulin assembly as evidenced by a polymerization assay. Yeast-based reporter gene assay revealed that the androgenic activity of the novel 19-nortestosterone derivative 3 is by multiple orders of magnitude weaker than that of the reference agent 1. Based on the behavior of the examined compounds it can be concluded that a halogen substitution of the 19-nortestosterone scaffold at the 17α position may produce compounds with unique biological activities. The results of the present study support that structurally modified steroids with negligible hormonal activity are a promising basis for the research and development of novel anticancer agents.

Facile one-pot multicomponent synthesis and molecular docking studies of steroidal oxazole/thiazole derivatives with effective antimicrobial, antibiofilm and hemolytic properties

A series of steroidal oxazole and thiazole derivatives have been synthesized employing thiosemicarbazide/semicarbazide hydrochloride and ethyl 2-chloroacetoacetate with a simple and facile one-pot multicomponent reaction pathway. The antimicrobial activity of newly synthesized compounds were evaluated against four bacterial strains namely Gram-negative (Escherichia coliand Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) in addition to pathogenic fungi (Candida albicans and Cryptococcus neoformans). Bioactivity assay manifested that most of the compounds exhibited good antimicrobial activity. To provide additional insight into antimicrobial activity, the compounds were also tested for their antibiofilm activity against S. aureus biofilm. Moreover, molecular docking study shows binding of compounds with amino acid residues of DNA gyrase and glucosamine-6-phosphate synthase (promising antimicrobial target) through hydrogen bonding interactions. Hemolytic activity have been also investigated to ascertain the effect of compounds over RBC lysis and results indicate good prospects for biocompatibility. The expedient synthesis of steroidal heterocycles, effective antibacterial and antifungal behavior against various clinically relevant human pathogens, promising biocompatibility offer opportunities for further modification and potential applications as therapeutic agents.

Synthesis and cytotoxic effect of pregnenolone derivatives with one or two α,β-unsaturated carbonyls and an ester moiety at C-21 or C-3

Four series of pregnenolone derivatives having one or two α,β-unsaturated carbonyls and an ester moiety at C-21 or C-3 were synthetized to compare their cytotoxicity effect. The final compounds were evaluated on three human cancer cell lines: PC-3 (prostate cancer), MCF-7 (breast cancer), SKLU-1 (lung cancer) and a noncancerous cell line HGF (human gingival fibroblast). Two steroids with a 4-fluorinated benzoic acid ester at C-21 were the most active against lung cancer cell line with IC₅₀ of 13.1 ± 1.2 and 12.8 ± 0.5 μM and showed a low percentage of cytotoxicity for noncancerous cells (27.63 ± 2.3 and 18.39 ± 1.2% in the screening at 50 μM).

Studies on 16,17-Pyrazoline Substituted Heterosteroids as Anti-Alzheimer and Anti-Parkinsonian Agents Using LPS Induced Neuroinflammation Models of Mice and Rats

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common forms of neurodegenerative disorders. Dehydroepiandrosterone (DHEA) has been reported as a neuroprotective steroid useful in the therapeutic management of neurodegenerative disorders such as AD and PD. Herein we report the synthesis and evaluation of a new series of 16,17-pyrazolinyl DHEA analogues 2-4a-d as neuroprotective agents using LPS-induced neuroinflammation animal models. Treatment with the pyrazoline substituted steroids considerably improved the LPS-induced learning, memory and movement deficits in animal models. Suppression of biochemical parameters of oxidative and nitrosative stress, acetylcholinesterase activity, and TNF-α levels was also observed. 16,17-Pyrazolinyl steroids 2c-4c substituted with a 4-pyridyl moiety at the 5-position of the heterocyclic ring were found to be the most potent agents and produced neuroprotective effects better than standard drugs celecoxib and dexamethasone. Of these pyrazoline substituted steroids, the N-acetyl analogue 3c displayed neuroprotective effects better than N-phenyl (4c), which in turn showed potency more than N-unsubstituted analogue 2c.

Synthesis and cytotoxic activity of novel steroidal derivatives containing a [1,2,4]triazolo[1,5-a]pyrimidine ring

The synthesis of steroidal derivatives containing [1,2,4]triazolo[1,5- a]pyrimidine derived from progesterone is described. The Claisen condensations of Δ1,4-pregnadien-3,20-dione and 4-chloro-Δ1,4-pregnadien-3,20-dione with dimethyl oxalate afforded 21-methoxalylpregn-1,4-diene-3,20-dione and 4-chloro-21-methoxalylpregn-1,4-diene-3,20-dione, respectively. Furthermore, the reactions of these compounds with 3-amino-1,2,4-triazole yielded the corresponding [1,2,4]triazolo[1,5- a]pyrimidine derivatives. The newly synthesised compounds were evaluated in vitro by means of sulforhodamine B assays for antiproliferative activity against HeLa and MCF-7 cells.

One-pot asymmetric synthesis of a spiro[dihydrofurocoumarin/pyrazolone] scaffold by a Michael addition/I2-mediated cyclization sequence

An asymmetric formal one-pot reaction of 4-hydroxycoumarins with unsaturated pyrazolones has been developed by merging a chiral bifunctional organocatalyst with molecular iodine, which furnished a series of optically active spiro[dihydrofurocoumarin/pyrazolone] heterocycles with spiro quaternary stereogenic centers in moderate to excellent yields (up to 99%) with excellent diastereoselectivities (up to >99 : 1 dr) and good to excellent enantioselectivities (up to 99% ee). The application in the gram-scale synthesis of chiral spiro[dihydrofurocoumarin/pyrazolone] compounds was also successfully realized.

Ultrasound promoted facile one pot synthesis of triazole derivatives catalyzed by functionalized graphene oxide Cu(I) complex under mild conditions

A facile one pot three component reaction of alkyl halides, sodium azide with terminal alkynes can be catalyzed by functionalized graphene oxide copper (I) complex under ultrasonic irradiation at room temperature. In this protocol, the 1,4-disubstituted 1,2,3-triazoles were afforded as target pure products in excellent yields and short reaction times. The prepared catalyst has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), Energy Dispersive X-ray (EDX) and field emission scanning electron microscopy (FE-SEM) techniques. Also, the catalyst is chemoselective and stable and can be reused several times without any appreciable loss of its catalytic activity.

Synthesis of monomeric and dimeric steroids containing [1,2,4]triazolo[1,5-a]pyrimidines

The synthesis of several monomeric and dimeric steroidal [1,2,4]triazolo[1,5-a]pyrimidines (TPs) derived from steroids are described. These derivatives were prepared from α,β-unsaturated carbonyl compounds through a Claisen Schmidt condensation and rearrangement of the spiro moiety followed by a cycloaddition with 3-amino-1,2,4-triazole. The antiproliferative activity of compounds 7, 13-15 was tested against human cancer cells; several IG₅₀ values were below 10μM.