Benzylidine pregnenolones and their oximes as potential anticancer agents: synthesis and biological evaluation

Synthesis, photophysical properties, anticancer evaluation, and molecular docking studies of new pyrimidine linked 4-arylidene-thiazolidin-4-ones as potent anticancer agents

The reaction of 4-(chloroacetamido)pyrimidine (1) with ammonium thiocyanate gave 2-(pyrimidin-4-ylimino)thiazolidin-4-one (2), which, when condensed with four substituted benzaldehyde analogues, gave the consequent 5-arylidine-2-(pyrimidin-4-ylimino)thiazolidin-4-ones 3a-d. In addition, the absorbance and fluorescence behaviours of pyrimidinylimino-thiazolidin-4-one hybrids 3a-d in various organic solvents were investigated. The emphasis was on studying UV absorption capacities and the effect of various structural components on photophysical qualities such as the 5-arylidene-2-(pyrimidin-4-ylimino)thiazolidin-4-ones and N,N-dimethylamino tail. The cytotoxic effect of four pyrimidinylimino-thiazolidin-4-one hybrids 3a-d on tumour cell lines (HepG2, HCT-116, PC3, MCF-7) and a normal cell line (WI38) is investigated in this work. The cytotoxicity was measured by comparing the half-maximal inhibitory concentration (IC50 ) to the reference medication, 5-fluorouracil. The findings indicate that these hybrid compounds had varying cytotoxic effects on the cell lines examined; hybrids 3b and 3c demonstrated significant anticancer activity against MCF-7 with IC50 values of 7.53 ± 0.43 and 9.17 ± 0.31 μM, respectively. The inhibitory efficacy of various synthesized hybrids on the epidermal growth factor receptor (EGFR) kinase was investigated. EGFR is a crucial target in cancer treatment because inhibiting it may reduce tumour development and proliferation. The IC50 value was used to calculate the inhibitory activity, which is the concentration of inhibitor necessary to induce half-maximal inhibition of EGFR kinase activity. In addition, the predicted ADME results show that pyrimidinylimino-thiazolidin-4-one hybrids have good pharmacokinetic properties; hybrid 3d is more lipophilic than the other compounds. It has a medium molecular weight, a small number of hydrogen bond acceptors and donors, and a large number of aromatic heavy atoms. Moreover, molecular docking simulations revealed precise information on the interactions of pyrimidinylimino-thiazolidin-4-one hybrids 3a-d and 5-Fu with their respective protein targets. These interactions point to possible pathways for their biological activities and call for more testing to establish their effectiveness as bioactive molecules or therapeutic candidates.

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.

Cytotoxicity against A549 Human Lung Cancer Cell Line via the Mitochondrial Membrane Potential and Nuclear Condensation Effects of Nepeta paulsenii Briq., a Perennial Herb

The genus Nepeta belongs to the largest Lamiaceae family, with 300 species, which are distributed throughout the various regions of Africa, Asia, India, and America. Along with other plant families distinguished by their medicinal and therapeutic values, the Nepeta genus of Lameaceae remains relatively valuable. Hence, the phytochemicals of N. paulsenii Briq. were extracted using different plant parts, i.e., leaves, stem, roots, flowers, and the whole plant by using various solvents (ethanol, water, and ethyl acetate), obtaining 15 fractions. Each extract of dried plant material was analyzed by FT-IR and GC-MS to identify the chemical constituents. The cytotoxicity of each fraction was analyzed by MTT assay and mitochondrial membrane potential and nuclear condensation assays against lung cancer cells. Among the ethyl acetate and ethanolic extracts, the flowers showed the best results, with IC₅₀ values of 51.57 μg/mL and 50.58 μg/mL, respectively. In contrast, among the water extracts of the various plant segments, the stem showed the best results, with an IC₅₀ value of 123.80 μg/mL. 5-flourouracil was used as the standard drug, providing an IC₅₀ value of 83.62 μg/mL. The Hoechst 33342 stain results indicated apoptotic features, i.e., chromatin dissolution and broken down, fragmented, and crescent-shaped nuclei. The ethanolic extracts of the flowers showed more pronounced apoptotic effects on the cells. The mitochondrial membrane potential indicated that rhodamine 123 fluorescence signals suppressed mitochondrial potential due to the treatment with the extracts. Again, the apoptotic index of the ethanolic extract of the flowers remained the highest. Hence it can be concluded that the flower part of N. paulsenii Briq. was found to be the most active against the A459 human lung cancer cell line.

The Structural Diversity and Biological Activity of Steroid Oximes

Steroids and their derivatives have been the subject of extensive research among investigators due to their wide range of pharmacological properties, in which steroidal oximes are included. Oximes are a chemical group with the general formula R1R2C=N-OH and they exist as colorless crystals and are poorly soluble in water. Oximes can be easily obtained through the condensation of aldehydes or ketones with various amine derivatives, making them a very interesting chemical group in medicinal chemistry for the design of drugs as potential treatments for several diseases. In this review, we will focus on the different biological activities displayed by steroidal oximes such as anticancer, anti-inflammatory, antibacterial, antifungal and antiviral, among others, as well as their respective mechanisms of action. An overview of the chemistry of oximes will also be reported, and several steroidal oximes that are in clinical trials or already used as drugs are described. An extensive literature search was performed on three main databases-PubMed, Web of Science, and Google Scholar.

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.

Preparation and cytotoxic evaluation of new steroidal oximes and aza-homosteroids from diosgenin and cholesterol

Using cholesterol and diosgenin as starting materials, we have designed a straightforward methodology to prepare in a reduced number of steps a novel series of steroidal oximes and their aza-homolactam analogs with four types of side chains: cholestane, spirostane, 22-oxocholestane and 22,26-epoxycholestene. The products were evaluated for their cytotoxic activity against the MCF-7 breast cancer cell line. Moreover, the selectivity of the most active compounds was determined against peripheral blood lymphocytes. Compounds 5, 8 and 13 were found to be the most active derivatives, exhibiting IC₅₀ values in the low micromolar range (7.9-9.5 µM) and excellent selectivities (IC₅₀ > 100 µM) against the non-tumor cell line.

Searching for drug leads targeted to the hydrophobic cleft of dengue virus capsid protein

We synthesised and screened 18 aromatic derivatives of guanylhydrazones and oximes aromatic for their capacity to bind to dengue virus capsid protein (DENVC). The intended therapeutic target was the hydrophobic cleft of DENVC, which is a region responsible for its anchoring in lipid droplets in the infected cells. The inhibition of this process completely suppresses virus infectivity. Using NMR, we describe five compounds able to bind to the α1-α2 interface in the hydrophobic cleft. Saturation transfer difference experiments showed that the aromatic protons of the ligands are important for the interaction with DENVC. Fluorescence binding isotherms indicated that the selected compounds bind at micromolar affinities, possibly leading to binding-induced conformational changes. NMR-derived docking calculations of ligands showed that they position similarly in the hydrophobic cleft. Cytotoxicity experiments and calculations of in silico drug properties suggest that these compounds may be promising candidates in the search for antivirals targeting DENVC.

Visible-light mediated stereospecific C(sp2)-H difluoroalkylation of (Z)-aldoximes

A visible light mediated stereospecific C(sp²)-H difluoroalkylation of (Z)-aldoximes to (E)-difluoroalkylated ketoximes has been described. In this reaction, (hetero)-aromatic and aliphatic difluoroalkylated ketoximes could be obtained with the retention of the configuration of the starting aldoximes. A preliminary mechanism study showed that a difluoromethyl radical via an SET pathway was involved.

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.

Synthesis, pharmacological evaluation and Molecular modelling studies of pregnenolone derivatives as inhibitors of human dihydrofolate reductase

In current study, we synthesized chalcone derivatives (13a-c) via base-catalyzed Claisen-Schmidt condensation reaction. We further treated diamino compounds with synthesized chalcones to produce 3,4-dihydropyrimidin-2(1H)-one (18a-c), 3,4-dihydropyrimidin-2(1H)-thione (19a-c) and 2-aminopyrimidine (20a-c) derivatives of pregnenolone by cyclization reaction. Cell viability test of synthesized steroidal chalcones and their pyrimidine and thiopyrimidine derivatives against human breast (MCF-7), human lung (A549) and human prostate (PC-3) cancer cell lines was performed using (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), assay. Compounds were further evaluated for their inhibition potential against recombinant human DHFR (rhDHFR). All compounds showed activity from low micromolar to submicromolar range. Compound 20b with IC50 value of 180 nM emerged as most potent compound against rhDHFR. Interaction of the newly synthesized pregnenolone derivatives with hDHFR and estrogen receptor alpha (ERα) were also explored via docking simulations. The overall results of hDHFR inhibition have shown that these analogues can be further optimized and developed as potent anticancer agents.

Arsenic(III) mixed derivatives having oximes and morpholinedithiocarbamate along with their cytotoxic, antimicrobial, and antioxidant studies

Consecutive substitution reactions of arsenic(III)chloride with sodium salts of various oximes and morpholinedithiocarbamate (morphdtc) were carried out in 1:2:1 stoichiometry to obtain six new arsenic(III) mixed derivatives of the type: [(R)(R¹ )C = NO]₂ Sb[S₂ CN(CH₂ CH₂ )₂ O] [where R is -C₆ H₅ , R¹  = -CH₃ (1); R = -C₆ H₄ CH₃ , R¹  = -CH₃ (2); R = -C₆ H₄ Cl, R¹  = -CH₃ (3); R = -C₆ H₄ Br, R¹  = -CH₃ (4); R = -C₆ H₄ OH, R¹  = -H (5); R(R¹ )C =  (6)]. These derivatives are characterized by elemental and physicochemical analyses and the tentative distorted trigonalbipyramidal geometry around arsenic assigned using spectral data of infrared (¹ H, ¹³ C) nuclear magnetic resonance and liquid chromatography-mass. Powder X-ray diffraction study revealed their nanoranged particle size to be approximately 40 nm and crystalline nature. These derivatives examined against microbes and results revealed that these derivatives expressed more antifungal potential than antibacterial. The antioxidant activity was carried out by ferric reducing ability of plasma assay, and the cytotoxic study was performed in 3T₃ fibroblast cell lines by tetrazolium-based colorimetric assay.

Unsubstituted Oximes as Potential Therapeutic Agents

Oximes, which are highly bioactive molecules, have versatile uses in the medical sector and have been indicated to possess biological activity. Certain oximes exist in nature in plants and animals, but they are also obtained by chemical synthesis. Oximes are known for their anti-inflammatory, antimicrobial, antioxidant and anticancer activities. Moreover, they are therapeutic agents against organophosphate (OP) poisoning. Two oximes are already commonly used in therapy. Due to these abilities, new oxime compounds have been synthesized, and their biological activity has been verified. Often, modification of carbonyl compounds into oximes leads to increased activity. Nevertheless, in some cases, oxime activity is connected to the activity of the substrate. Recent works have revealed that new oxime compounds can demonstrate such functions and thus are considered to be potential drugs for pathogenic diseases, as adjuvant therapy in various types of cancer and inflammation and as potential next-generation drugs against OP poisoning.

Theoretical and experimental study of the coordination ability of 4,6-dimethylpyrimidinylhydrazone diacetylmonooxime towards Ni(ii), Mn(ii), Fe(iii) and Co(iii) ions

The complexing ability of diacethylmonooxime 4,6-dimethylpyrimidylhydrazone ligand with Ni(ii), Mn(ii), Fe(iii) and Co(iii) salts have been studied.

New cinnamic acid-pregenolone hybrids as potential antiproliferative agents: Design, synthesis and biological evaluation

A series of new cinnamic acid-pregenolone hybrids (5a-5o) was designed, synthesized and evaluated for their in vitro antiproliferative activity. Some of them showed potential antiproliferative activity and selectivity towards a panel of cancer cell lines, including A549, H157, HepG2, MCF-7, and HL-60. Among these analogs, compound 5f showed the most promising activity with IC₅₀ values ranging from 3.2 to 6.8 μM, and it was taken as a model compound in the following antiproliferative mechanism study. In Hoechst 33258 staining assay, 5f-treated A549 cells displayed significant apoptosis characteristics. Flow cytometry analysis revealed that 5f showed the antiproliferative activity against A549 via G1 cell cycle arrest and inducing apoptosis. Western blotting analysis demonstrated that 5f enhanced apoptosis of A549 cells by down-regulating Bcl-2 and up-regulating Bax protein expression. The present study highlighted this series of cinnamic acid-pregenolone hybrids as a new antiproliferative lead prototype.

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.

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).

Synthesis and biological evaluation of 3β-androsta-5,8(14),15-trien-17-one derivatives as potential anticancer agents

A novel and operationally simple method for highly efficient synthesis of promising anti-cancer 3β-hydroxy-16-arylandrosta-5,8(14),15-trien-17-ones was reported. Compounds were tested for their cytotoxic activities against A549, SKOV3, MKN-45 and MDA-MB-435 cancer cell lines. The preliminary results showed that compounds 5e, g were the most active especially against cancer cell lines tested.

Design, synthesis and cytotoxic activity of a novel series of steroidal phenylpyrazoles

Thirty novel steroidal pyrazole derivatives were designed and synthesized via a highly efficient route from pregnenolone (1) as starting material. The key intermediates 3a-c were obtained under Vilsmeier conditions, and the subsequent hydrolysis, acetylation or Borch reduction afforded thirty target compounds. These compounds were mainly characterized by (1)H NMR, (13)C NMR, DEPT135°. The structure of compound 3a was also confirmed by X-ray single crystal diffraction. The cytotoxicity of these compounds was evaluated by the SRB method against four cancer cell lines, including A549, Hela, MCF-7 and HepG2, and the results indicated that compounds 5a, 6a, 7a and 8a exhibited significant cytotoxicity with IC50 values ranging from 0.91 to 5.44 μM. Most importantly, compound 5a exhibited excellent cytotoxicity against A549 with an IC50 value of 0.91 μM. On the basis of our research the structure-activity relationships (SAR) of these compounds were discussed. This work provides some important hints for further structural modification of steroids towards developing novel and highly effective anticancer drugs.

Chalcone Scaffold in Anticancer Armamentarium: A Molecular Insight

Cancer is an inevitable matter of concern in the medicinal chemistry era. Chalcone is the well exploited scaffold in the anticancer domain. The molecular mechanism of chalcone at cellular level was explored in past decades. This mini review provides the most recent updates on anticancer potential of chalcones.

Solvent-free mechanochemical synthesis of arylcyanomethylenequinone oximes from phenylacetonitriles and 4-unsubstituted nitroaromatic compounds using KF/nano-γ-Al2O3 as catalyst

Solvent-free condensation of phenylacetonitriles with 4-unsubstituted nitroaromatic compounds to produce arylcyanomethylenequinone oximes catalyzed by KF/nano-γ-Al₂O₃ under HSVM conditions in moderate to excellent yields at short reaction times.

Synthesis and Anticancer Activity of 4-azasteroidal-20-oxime Derivatives

A new series of 4-azasteroidal-20-oxime derivatives have been synthesised from progesterone. All the new compounds have been characterised by analysis and spectroscopic data and subsequently evaluated for their anticancer activity in vitro against T24 cell. The studies show that the methyl and ethyl oxime-ethers exhibited higher activity than the aryl substituted oxime-esters.

Synthesis, characterization and fungicidal activity of binary and ternary metal(II) complexes derived from 4,4'-((4-nitro-1,2-phenylene) bis(azanylylidene))bis(3-(hydroxyimino)pentan-2-one)

Ternary copper(II) and binary copper(II), nickel(II) and cobalt(II) complexes derived from 4,4'-((4-nitro-1,2-phenylene)bis(azanylylidene))bis(3-(hydroxyimino)pentan-2-one) (H2L) were synthesized and characterized by elemental and thermal analyses, IR, UV-Vis. and (1)H NMR spectroscopy, conductivity and magnetic moments measurements. The analytical and spectral data showed that, the ligand acts as dibasic tetradentate or dibasic hexadentate bonding to the metal ion via the two-imine nitrogen, two nitrogen and/or oximato oxygen atoms of deprotonated oxime groups forming five and/or six rings including the metal ions. The complexes adopt either tetragonal distorted octahedral or square planar geometry around metal ions. The ESR spectra of the solid copper(II) complexes are characteristic to d(9) configuration and having an axial symmetry type of a d(x2-y2) ground state. The g values confirmed the geometry is elongated tetragonal octahedral geometry with considerably ionic or covalent environment. The antifungal biological activity of the prepared compounds was studied using well diffusion method. The obtained results showed that, the ligand is biologically inactive while its metal complexes were more potent fungicides than the ligand and standard antifungal drug (Amphotericin B).

Steroidal pyrazolines and pyrazoles as potential 5α-reductase inhibitors: synthesis and biological evaluation

Taking pregnenolone as the starting material, two series of pyrazolinyl and pyrazolyl pregnenolones were synthesized through different routes. The synthesis of the analogs of both series is multistep and proceeds in good overall yields. While the key step in the synthesis of pyrazolinyl pregnenolones is the heterocyclization of benzylidine derivatives (3) in presence of hydrazine hydrate, it is the condensation of 3β-hydroxy-21-hydroxymethylidenepregn-5-en-3β-ol-20-one (5) with phenylhydrazine in the synthesis of pyrazolyl derivatives. Compounds of both the series were tested for their 5α-reductase inhibitory activities. Amongst all the compounds screened for their 5α-reductase inhibitory activities, compound 4b, 4c and 6b were found to be the most active.