Potentiometric Surfactant Sensor with a Pt-Doped Acid-Activated Multi-Walled Carbon Nanotube-Based Ionophore Nanocomposite.

Two new surfactant sensors were developed by synthesizing Pt-doped acid-activated multi-walled carbon nanotubes (Pt@MWCNTs). Two different ionophores using Pt@MWCNTs, a new plasticizer, and (a) cationic surfactant 1,3-dihexadecyl-1H-benzo[d]imidazol-3-ium-DHBI (Pt@MWCNT-DHBI ionophore) and (b) anionic surfactant dodecylbenzenesulfonate-DBS (Pt@MWCNT-DBS ionophore) composites were successfully synthesized and characterized. Both surfactant sensors showed a response to anionic surfactants (dodecylsulfate (SDS) and DBS) and cationic surfactants (cetylpyridinium chloride (CPC) and hexadecyltrimethylammonium bromide (CTAB)). The Pt@MWCNT-DBS sensor showed lower sensitivity than expected with the sub-Nernstian response of ≈23 mV/decade of activity for CPC and CTAB and ≈33 mV/decade of activity for SDS and DBS. The Pt@MWCNT-DHBI surfactant sensor had superior response properties, including a Nernstian response to SDS (59.1 mV/decade) and a near-Nernstian response to DBS (57.5 mV/decade), with linear response regions for both anionic surfactants down to ≈2 × 10-6 M. The Pt@MWCNT-DHBI was also useful in critical micellar concentration (CMC) detection. Common anions showed very low interferences with the sensor. The sensor was successfully employed for the potentiometric titration of a technical grade cationic surfactant with good recoveries. The content of cationic surfactants was measured in six samples of complex commercial detergents. The Pt@MWCNT-DHBI surfactant sensor showed good agreement with the ISE surfactant sensor and classical two-phase titration and could be used as an analytical tool in quality control.

Anti-Neuroinflammatory Effects of a Novel Bile Acid Derivative.

In the search for novel potent immunomodulatory nuclear factor-erythroid 2 related factor 2 (Nrf2) activators, a derivative of cholic bile acid, SB140, was synthesized. The synthesis of SB140 aimed to increase the electrophilic functionality of the compound, enhancing its ability to activate Nrf2. Effects of SB140 on microglial cells, myeloid-derived cells (MDC), and T cells were explored in the context of (central nervous system) CNS autoimmunity. SB140 potently activated Nrf2 signaling in MDC and microglia. It was efficient in reducing the ability of microglial cells to produce inflammatory nitric oxide, interleukin (IL)-6, and tumor necrosis factor (TNF). Also, SB140 reduced the proliferation of encephalitogenic T cells and the production of their effector cytokines: IL-17 and interferon (IFN)-γ. On the contrary, the effects of SB140 on anti-inflammatory IL-10 production in microglial and encephalitogenic T cells were limited or absent. These results show that SB140 is a potent Nrf2 activator, as well as an immunomodulatory compound. Thus, further research on the application of SB140 in the treatment of neuroinflammatory diseases is warranted. Animal models of multiple sclerosis and other inflammatory neurological disorders will be a suitable choice for such studies.

Synthesis and anticancer potential of novel 5,6-oxygenated and/or halogenated steroidal d-homo lactones.

A series of 5,6-modified steroidal d-homo lactones, comprising of halogenated and/or oxygenated derivatives, was synthesized and evaluated for potential anticancer properties. Preparation of many of these compounds involved investigating alternative synthetic pathways. In silico ADME testing was performed for both novel and some previously synthesized compounds. Calculated physicochemical properties were in accordance with the Lipinski, Veber, Egan, Ghose and Muegge criteria, suggesting the potential of these molecules as orally active agents. Cytotoxicity of the synthesized steroid derivatives was tested on six tumor and one normal human cell line. None of the investigated derivatives was toxic to non-cancerous MRC-5 control cells. Most of the compounds showed significant cytotoxicity against the treated cancer cell lines. Most notably, the 3ß,5α,6ß-trihydroxy derivative exhibited strong cytotoxicity against multiple cell lines (MCF-7, MDA-MB-231 and HT-29), with the highest effect observed for lung adenocarcinoma (A549) cells, for which this steroid was more cytotoxic than all of the three commercial chemotherapeutic agents used as reference compounds. Molecular docking suggests the 3ß,5α,6ß-trihydroxy derivative could bind the EGFR tyrosine kinase domain with high affinity, providing a potential mechanism for its cytotoxicity via inhibition of EGFR signaling. The most active compounds were further studied for their potential to induce apoptosis by the double-staining fluorescence method; where the 5α,6ß-dibromide, 5α,6ß-dichloride and 3ß,5α,6ß-triol induced apoptotic changes in all three treated cell lines: MDA-MB-231, HT-29 and A549. To predict interactions with nuclear steroidal receptors, affinity for the ligand binding domains of ERα, ERß and AR was measured using a yeast-based fluorescence assay. The 5ß,6ß-epoxide, dibromide and 5α-hydroxy-3,6-dioxo derivatives showed affinity for ERα, while the 5α-fluoro-6ß-hydroxy and 3ß-acetoxy-5α,6ß-dihydroxy derivatives were identified as ERß ligands. None of the tested compounds showed affinity for AR. Structure-activity relationships of selected compounds were also examined.

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction.

A practical and high-yielding Schmidt reaction for the synthesis of fused tetrazoles from bile acid precursors was developed. Mild reaction conditions using TMSN3 instead of hydrazoic acid as an azide source produced good yields of the desired tetrazoles. These conditions could be applied to other steroidal precursors. Additionally, an improved methodology for the synthesis of different ketone and enone precursors from cholic acid, deoxycholic acid, and chenodeoxycholic acid was established. Newly obtained tetrazole derivatives were characterized by NMR and X-ray diffraction spectroscopy. In a number of cases, preliminary antiproliferative tests of new compounds showed strong and selective activity towards certain tumor cell lines.

Application of Spectrophotometric Fingerprint in Cluster Analysis for Starch Origin Determination.

The botanical origin of starch is of importance in industrial applications and food processing because it may influence the properties of the final product. Current microscopic methods are time-consuming. Starch consists of an origin-dependent amylose/amylopectin ratio. Triiodide ions bind characteristically to the amylose and amylopectin depending on the botanical origin of the starch. The absorbance of the starch-triiodide complex was measured for: wheat, potato, corn, rye, barley, rice, tapioca and unknown origin starch; and within the different cultivars. Each starch sample had specific parameters: starch-triiodide complex peak wavelength maximum (λ max/nm), maximum absorbance change at λ max (ΔA) and λ max shift towards the unknown origin starch sample values. The visible absorption spectra (500-800 nm) for each starch sample were used as a unique fingerprint, and then elaborated by cluster analysis. The cluster analysis managed to distinguish data of two clusters, a cereal type cluster and a potato/tapioca/rice starch cluster. The cereal subclusters extensively distinguished wheat/barley/rye starches from corn starches. Data for cultivars were mostly in good agreement within the same subclaster. The proposed method that combines cluster analysis and visible absorbance data for starch-triiodide complex was able to distinguish starch of different botanical origins and cultivars within the same species. This method is simpler and more convenient than standard time-consuming methods.

Micellization parameters (number average, aggregation number and critical micellar concentration) of bile salt 3 and 7 ethylidene derivatives: Role of the steroidal skeleton II.

BACKGROUND: Bile salts are steroidal biosurfactants. Micellar systems of bile salts are not only important for solubilization of cholesterol, but they also interact with certain drugs thus changing their bioavailability. METHODS: The number-average aggregation numbers (n¯) are determined using the Moroi-Matsuoka-Sugioka thermodynamic method. Critical micellar concentrations were determined by spectrofluorometric method using pyren and by surface tension measurements. RESULTS: Micelles of ethylidene derivatives possess the following values for n¯: 7-Eth-D (n¯=11 (50 mM)-n¯=14.8 (100 mM)); 12-Ox-7-Eth-L (n¯≈8.8, without concentration dependence) and 7,12-diOx-3-Eth-Ch (n¯≈2.9, without concentration dependence). In the planes n¯-ln k and ln CMC-ln k derivative 7-Eth-D is outlier in respect to hydrophobic linear congeneric groups. CONCLUSION: Gibbs energy of formation for 7-Eth-D anion micelles in addition to the Gibbs energy of hydrophobic interactions consists excess Gibbs energy (GE) from hydrogen bond formation between building blocks of micelles. Gibbs energy of formation for 7,12-diOx-3-Eth-Ch and 12-Ox-7-Eth-L anion micelle is determined by the Gibbs energy of hydrophobic interactions. Relative increase in hydrophobicity and aggregation number for ethylidene derivatives is larger when ethylidene group is introduced from the C7 lateral side of steroidal skeleton then it is when ethylidene group is on C3 carbon. GENERAL SIGNIFICANCE: Position of outlier towards hydrophobic congeneric groups from n¯-ln k and ln CMC-ln k planes indicates the existence of excess Gibbs energy (GE) which is not of hydrophobic nature (formation of hydrogen bonds). For the bile salt micelles to have GE (formation of secondary micelles) it is necessary that steroidal skeleton possesses C3-α-(e)-OH and C12-α-(a)-OH groups.

Synthesis and anticancer cell potential of steroidal 16,17-seco-16,17a-dinitriles: identification of a selective inhibitor of hormone-independent breast cancer cells.

We report the synthesis of steroidal 16,17-seco-16,17a-dinitriles and investigate their antitumor cell properties. Compounds were evaluated for anticancer potential by in vitro antiproliferation studies, molecular docking and virtual screening. Several compounds inhibit the growth of breast and prostate cancer cell lines (MCF-7, MDA-MB-231 and PC3), and/or cervical cancer cells (HeLa). Supporting this, molecular docking predicts that steroidal 16,17-seco-16,17a-dinitriles could bind with high affinity to multiple molecular targets of breast and prostate cancer treatment (aromatase, estrogen receptor α, androgen receptor and 17α-hydroxylase) facilitated by D-seco flexibility and nitrile-mediated contacts. Thus, 16,17-seco-16,17a-dinitriles may be useful for the design of inhibitors of multiple steroidogenesis pathways. Strikingly, 10, a 1,4-dien-3-on derivative, displayed selective submicromolar antiproliferative activity against hormone-dependent (MCF-7) and -independent (MDA-MB-231) breast cancer cells (IC50 0.52, 0.11µM, respectively). Ligand-based 3D similarity searches suggest AKR1C, 17ß-HSD and/or 3ß-HSD subfamilies as responsible for this antiproliferative activity, while fast molecular docking identified AKR1C and ERß as potential binders-both targets in the treatment of hormone-independent breast cancers.

Synthesis, structural analysis and antitumor activity of novel 17α-picolyl and 17(E)-picolinylidene A-modified androstane derivatives.

The heterocyclic ring at C-17 position of the androstane compounds plays an important role in biological activity. The aim of the present study was to synthesize and evaluate potential antitumor activity of different A-modified 17α-picolyl and 17(E)-picolinylidene androstane derivatives. In several synthetic steps, novel derivatives bearing the hydroximino, nitrile or lactame functions in A-ring were synthesized and characterized according to the spectral data, by mass analysis as well as XRD analysis (compounds 6, 13 and 15). The structurally most promising compounds 6, 11-17 were investigated as antitumor agents. The in vitro antiproliferative activity was evaluated against six human cancer cell lines: estrogen receptor negative (ER-) breast adenocarcinoma (MDA-MB-231); estrogen receptor positive (ER+) breast adenocarcinoma (MCF-7); prostate cancer (PC-3); human cervical carcinoma (HeLa); lung adenocarcinoma (A549) and colon adenocarcinoma (HT-29) using MTT assay. The results of the 48h incubation time in vitro tests showed that compound 15 was the most effective against PC-3 (IC50 6.6µM), compound 17 against MCF-7 (IC50 7.9µM) cells, while compound 16 exhibited strong antiproliferative effect against both, MCF-7 (IC50 1.7µM) and PC-3 (IC50 8.7µM) cancer cells. It was also found that compounds 16 and 17 induced apoptosis in MCF-7 cells (dicyano derivative 17 stronger then dioxime 16 and reference formestane), with no distinct changes in the cell cycle of MCF-7 cells.

Androstane derivatives induce apoptotic death in MDA-MB-231 breast cancer cells.

Biological investigation was conducted to study in vitro antiproliferative and pro-apoptotic potential of selected 17α-picolyl and 17(E)-picolinylidene androstane derivatives. The antiproliferative impact was examined on six human tumor cell lines, including two types of breast (MCF-7 and MDA-MB-231), prostate (PC3), cervical (HeLa), colon (HT 29) and lung cancer (A549), as well as one normal fetal lung fibroblasts cell line (MRC-5). All derivatives selectively decreased proliferation of estrogen receptor negative MDA-MB-231 breast cancer cells after 48 h and 72 h treatment and compounds showed time-dependent activity. We used this cell line to investigate cell cycle modulation and apoptotic cell death induction by flow cytometry, expression of apoptotic proteins by Western blot and apoptotic morphology by visual observation. Tested androstane derivatives affected the cell cycle distribution and induced apoptosis and necrosis. Compounds had different and specific mode of action, depending on derivative type and exposure time. Some compounds induced significant apoptosis measured by Annexin V test compared to reference compound formestane. Higher expression of pro-apoptotic BAX, downregulation of anti-apoptotic Bcl-2 and cleavage of PARP protein were confirmed in almost all treated samples, but the lack of caspase-3 activation suggested the induction of apoptosis in caspase-independent manner. More cells with apoptotic morphology were observed in samples after prolonged treatment. Structure-activity relationship analysis was performed to find correlations between the structure variations of investigated derivatives and observed biological effects. Results of this study showed that some of the investigated androstane derivatives have good biomedical potential and could be candidates for anticancer drug development.

Determination of 17α-hydroxylase-C17,20-lyase (P45017α) enzyme activities and their inhibition by selected steroidal picolyl and picolinylidene compounds.

17α-hydroxylase-C17,20-lyase (P45017α) is a key regulator enzyme of the steroid hormone biosynthesis in both the adrenals and the testes. Inhibition of this enzyme can block androgen synthesis in an early step, and may thereby be useful in the treatment of several androgen-dependent diseases. We developed radio-substrate in vitro incubation methods for the determination of the distinct 17α-hydroxylase and C17,20-lyase activities of the enzyme using rat testicular homogenate as enzyme source. With this method we have studied the inhibiting activity of selected steroidal picolyl and picolinylidene compounds. Tests revealed a substantial inhibitory action of the 17-picolinyliden-androst-4-en-3-one compound.

Synthesis and biological evaluation of novel D-ring fused steroidal N(2)-substituted-1,2,3-triazoles.

In this study, a series of 13 new D-ring fused steroidal N(2)-substituted-1,2,3-triazoles were synthesized, characterized and evaluated for their biological activities. The relative binding affinities of the synthesized compounds for the ligand-binding domains of estrogen receptors α and ß, androgen receptor and glucocorticoid receptor demonstrated that androstane derivatives 3a and 3h and estratriene derivative 4e showed highly specific and strong binding affinity for estrogen receptor ß, while 3b, 3e, 4a and 4b displayed high binding affinity for the glucocorticoid receptor. The synthesized compounds were tested for their ability to inhibit aldo-keto reductases 1C3 and 1C4 in vitro by monitoring NADPH consumption using fluorescence spectroscopy. The most potent aldo-keto reductase 1C3 inhibitors were compounds 3h (71.17%) and 3f (69.9%). Moreover, a molecular docking study was carried out for compounds 3f and 3h against aldo-keto reductase 1C3 and results showed that compounds 3h and 3f could bind in the same site and orientation as EM1404. However, polar atoms in the triazole group enable additional hydrogen bonding deeper in SP1 with Tyr319, Tyr216 and the NADP+ cofactor, which are not visible in the AKR1C3-EM1404 crystal structure. The synthesized compounds were screened for their anticancer activity against four cancer cell lines. Compound 3f demonstrated moderate toxic effects across various cancer types, while displaying lower toxicity towards the healthy cell line. In summary, our findings indicate that N(2)-substituted-1,2,3-triazoles are high-affinity ligands for estrogen receptor ß and glucocorticoid receptor, inhibitors of aldo-keto reductase 1C3 enzyme, and exhibit antiproliferative effects against cancer cells, suggesting that they could serve as scaffolds for anticancer drug development.

Synthesis, in vitro and in silico anticancer evaluation of novel pyridin-2-yl estra-1,3,5(10)-triene derivatives.

Aim: The aim of this study was the synthesis of steroid compounds with heterocyclic rings and good anticancer properties. Materials & methods: The synthesis, in silico and in vitro anticancer testing of novel pyridin-2-yl estra-1,3,5(10)-triene derivatives was performed. Results: All synthesized compounds have shown promising results for, antiproliferative activity, relative binding affinities for the ligand binding domains of estrogen receptors α, ß and androgen receptor, aromatase binding potential, and inhibition of AKR1C3 enzyme. Conclusion: 3-Benzyloxy (17E)-pycolinilidene derivative 9 showed the best antitumor potential against MDA-MB-231 cell line, an activity that can be explained by its moderate inhibition of AKR1C3. Molecular docking simulation indicates that it binds to AKR1C3 in a very similar orientation and geometry as steroidal inhibitor EM1404.

The series of pyridine-containing estra-1,3,5(10)-triene derivatives was synthesized. One novel derivative stood out by its excellent activity against the MDA-MB-231 cell line. This activity can be explained by its moderate inhibition of the AKR1C3 enzyme.

17(E)-picolinylidene androstane derivatives as potential inhibitors of prostate cancer cell growth: antiproliferative activity and molecular docking studies.

We report a rapid and efficient synthesis of A-ring modified 17α-picolyl and 17(E)-picolinylidene androstane derivatives from dehydroepiandrosterone. Compounds were validated spectroscopically and structurally characterized by X-ray crystallography. Virtual screening by molecular docking against clinical targets of steroidal anticancer drugs (ERα, AR, Aromatase and CYP17A1) suggests that 17(E)-picolinylidene, but not 17α-picolyl androstanes could specifically interact with CYP17A1 (17α-hydroxylase) with similar geometry and affinity as Abiraterone, a 17-pyridinyl androstane drug clinically used in the treatment of prostate cancer. In addition, several 17(E)-picolinylidene androstanes demonstrated selective antiproliferative activity against PC3 prostate cancer cells, which correlates with Abiraterone antiproliferative activity and predicted CYP17A1 binding affinities. Based on these preliminary results, 17(E)-picolinylidene androstane derivatives could be a promising starting point for the development of new compounds for the treatment of prostate cancer.

How do different bile acid derivatives affect rat macrophage function - Friends or foes?

Due to an increased need for new immunomodulatory agents, many previously known molecules have been structurally modified in order to obtain new drugs, preserving at the same time some of the benevolent characteristics of the parent molecule. This study aimed to evaluate the immunomodulatory potential of a selected library of bile acid derivatives (BAD) using a broad spectrum of assays, evaluating rat peritoneal macrophages viability, cell membrane damage, lysosomal and adhesion function, and nitric oxide and cytokine production as a response to lipopolysaccharide stimulation. Also, in silico studies on two bile acid-activated receptors were conducted and the results were related to the observed in vitro effects. All tested BAD exerted significant toxicity in concentrations higher than 10 µM, which was determined based on mitochondria and cell membrane damage in a panel of assays. On the other hand, at lower concentrations, the tested BAD proved to be immunomodulatory since they affected lysosomal function, cell adhesion capacities and the ability to produce inflammatory cytokines in response to a stimulus. One of the compounds proved to exhibit significant toxicity toward macrophages, but also caused a concentration-dependent decrease in nitric oxide levels and was identified as a potential farnesoid X receptor agonist.

Structural diversity of bioactive steroid compounds isolated from soft corals in the period 2015-2020.

Marine soft corals are known as a good source of biologically active compounds, among which a large number of steroid compounds are identified. Structures and activities of these compounds have been used in drug discovery and development. From 2015 to 2020, 179 new steroid compounds were isolated from soft corals and structurally characterized. In this review, we report the structural classification and bioactivities of these compounds. The largest group of steroids from soft corals are hydroxysteroids, while the most common biological activity is anticancer. Besides, anticancer hydroxysteroids from soft corals exhibit anti-inflammatory and antibacterial activity. Unlike anticancer and antibacterial activity that can be observed in a number of steroid classes, antioxidant activity and antileishmanial effect were observed only in 19-oxygenated steroids, antiviral activity in pregnane-type steroids and spirosteroids, immunosuppressive activity in epoxy- and epidioxysteroids, and antibacterial activity in two steroid classes, hydroxysteroids and ketosteroids. This systematically analyzed link between the structure and activity of natural marine steroids is a good starting point for future drug design.

Antitumor potential of novel 5α,6ß-dibromo steroidal D-homo lactone.

New steroidal D-homo androstane derivative, 5α,6ß-dibromo-3ß-hydroxy-17-oxa-17a-homoandrostan-16-one was synthesized and its structure was confirmed by NMR spectroscopy. In silico ADME properties of this compound were assessed using the SwissADME online prediction tool. Six human cancer cell lines (MDA-MB-231, MCF-7, PC3, HT-29, HeLa, and A549) and one human noncancerous cell line (MRC-5) were used for in vitro cytotoxicity testing. Novel steroidal dibromide was also tested for relative binding affinity for the ligand binding domain of estrogen receptor α and ß or the androgen receptor using a published assay in yeast cells. Ligand binding domains of each steroid receptor were expressed in-frame with yellow fluorescent protein in yeast and the fluorescence intensity changes upon addition of test compound was measured. The new compound showed selective cytotoxic activity against HT-29 (colon adenocarcinoma) and A549 (lung adenocarcinoma) cell lines, as well as the potential to induce apoptosis in HT-29 cells, while results obtained from ligand binding assay in yeast suggested a lack of significant estrogenic or androgenic properties.

Novel alkylaminoethyl derivatives of androstane 3-oximes as anticancer candidates: synthesis and evaluation of cytotoxic effects.

Steroid anticancer drugs are the focus of numerous scientific research efforts. Due to their high cytotoxic effects against tumor cells, some natural or synthetic steroid compounds seem to be promising for the treatment of different classes of cancer. In the present study, fourteen novel O-alkylated oxyimino androst-4-ene derivatives were synthesized from isomerically pure 3E-oximes, using different alkylaminoethyl chlorides. Their in vitro cytotoxic activity was evaluated against eight human cancer cell lines, as well as against normal fetal lung (MRC-5) and human foreskin (BJ) fibroblasts, to test the efficiency and selectivity of the compounds. Most derivatives displayed strong activity against malignant melanoma (G-361), lung adenocarcinoma (A549) and colon adenocarcinoma (HT-29) cell lines. Angiogenesis was assessed in vitro using migration scratch and tube formation assays on HUVEC cells, where partial inhibition of endothelial cell migration was observed for the 17α-(pyridin-2-yl)methyl 2-(morpholin-4-yl)ethyl derivative. Among the compounds that most impaired the growth of lung cancer A549 cells, the (17E)-(pyridin-2-yl)methylidene derivative bearing a 2-(pyrrolidin-1-yl)ethyl substituent induced significant apoptosis in these cells. In combination with low cytotoxicity toward normal MRC-5 cells, this molecule stands out as a good candidate for further anticancer studies. In addition, in vitro investigations against cytochrome P450 enzymes revealed that certain compounds can bind selectively in the active sites of human steroid hydroxylases CYP7, CYP17A1, CYP19A1 or CYP21A2, which could be important for the development of novel activity modulators of these enzymes and identification of possible side effects.

Synthesis of some epoxy and/or N-oxy 17-picolyl and 17-picolinylidene-androst-5-ene derivatives and evaluation of their biological activity.

Steroidal epoxy and/or N-oxy 17-picolyl and 17-picolinylidene-androst-5-ene derivatives have been prepared using 3beta,17beta-dihydroxy-17alpha-picolyl-androst-5-ene (1), 3beta-acetoxy-17-picolinylidene-androst-5-ene (2), and 3beta-hydroxy-17-picolinylidene-androst-5-ene (3) as synthetic precursors. The compounds 2 and/or 3 were reacted with m-chloroperoxybenzoic acid (MCPBA). The compounds synthesized from 2 were 17-picolinylidene-N-oxide 4, 5alpha,6alpha-epoxy and 5beta,6beta-epoxy-17-picolinylidene-N-oxide 5 and 6, and 5alpha,6alpha:17alpha,20alpha- and 5beta,6beta:17alpha,20alpha-diepoxy-N-oxide 7 and 8. Starting from compound 3, a mixture of 5alpha,6alpha-epoxy and 5beta,6beta-epoxy-17-picolinylidene 9 and 10, 5alpha,6alpha-epoxy and 5beta,6beta-epoxy-17-picolinylidene-N-oxide 11 and 12, and 5alpha,6alpha:17alpha,20alpha- and 5beta,6beta:17alpha,20alpha-diepoxy-N-oxide 13 and 14 were obtained. From compounds 15 and 18, obtained from 1 and 3 by the Oppenauer oxidation, the 4alpha,5alpha-epoxy and 4beta,5beta-epoxy derivatives 16, 17 and 20, 21 were prepared by oxidation with 30% H(2)O(2). Oxidation of 18 with MCPBA yielded only the N-oxide 19. The structures of compounds 15 and 18 were proved by the X-ray analysis. Compounds 1-6, 9, 15, 17, 18, and 21 were tested on activity against the enzyme aromatase. Antitumor activity against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER-, MDA-MB-231, and prostate cancer PC3) was evaluated. Three tested compounds (1, 4, and 19) showed strong activity against PC3, the IC(50) values being in the range 0.55-10microM, whereas compound 17 showed strong activity against MDA-MB-231 (IC(50) 10.4microM).

Synthesis and biological evaluation of some new A,B-ring modified steroidal D-lactones.

Starting from the D-homo lactones of androst-4-en-3-one 3 and 4, prepared from 1 and 2, the new 17a homolactones 5-12, 14 and 15, were synthesized. The 4-hydroxy compounds 9 and 10 were obtained through the reaction of 4alpha,5alpha- (5 and 7) and 4beta,5beta- (6 and 8) epoxides with formic acid. The epoxides 5 and 6 were prepared from compound 3, and epoxides 7 and 8 from compound 4 by oxidation with H(2)O(2) under basic conditions. Compound 1 served as a starting substance for obtaining lactones 11-13. Oxidation of compound 1 with m-chloroperbenzoic acid yielded 11 and 12, but compound 13 gave 14. Compound 15 was obtained from 13 by oxidation with H(2)O(2) under basic conditions. The structures of epoxides 6 and 14 were confirmed by X-ray structural analysis. Cytotoxic activity against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER-, MDA-MB-231, and prostate cancer PC3) was evaluated. Compounds 6 and 14 showed strong activity against PC3, the IC(50) being 10.6 and 2.2 microM, respectively, whereas compounds 3 and 8 showed strong activity against MDA-MB-231 (IC(50) is 9.3 and 3.6 microM, respectively). Aromatase inhibition assay showed that the tested compounds 9, 10, and 14 possess lower activity compared to formestane.

Synthesis and biological evaluation of a series of A,B-ring modified 16,17-secoandrostane derivatives.

The starting compound for the synthesis of 16,17-secoandrostane derivatives with the 4-en-3-on, 1,4-dien-3-on, 4,6-dien-3-on, and 1,4,6-trien-3-on systems was 3beta-hydroxy-17-methyl-16,17-secoandrost-5-en-16-nitrile-17-one (1), the Oppenauer oxidation of which yielded the corresponding 4-en-3-one derivative 2. Dehydrogenation of compound 2 with the aid of 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) gave the three products: 17-methyl-16,17-secoandrosta-1,4-dien-3,17-dione-16-nitrile (3), 17-methyl-16,17-secoandrosta-4,6-dien-3,17-dione-16-nitrile (4), and 17-methyl-16,17-secoandrosta-1,4,6-trien-3,17-dione-16-nitrile (5). On the other hand, epoxidation of compound 2 resulted in a mixture of alpha and beta isomers of 4,5-epoxy-17-methyl-16,17-secoandrosta-3,17-dione-16-nitrile (6 and 7). Opening of the oxirane rings of the mixture of 6 and 7 by the action of formic acid yielded the 4-hydroxy-4-en derivative 8. Antiaromatase activity and in vitro cytotoxicity against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER-, MDA-MB-231, and prostate cancer PC3) of selected compounds were evaluated. Compound 2 exhibited a relatively strong inhibition of aromatase and extremely potent cytotoxicity against PC3 cells. Compound 8 showed satisfactory cytotoxicity against MCF-7 cells.