Bile acids and their oxo derivatives: Potential inhibitors of carbonic anhydrase I and II, androgen receptor antagonists and CYP3A4 substrates.

Some biological properties of bile acids and their oxo derivatives have not been sufficiently investigated, although the interest in bile acids as signaling molecules is rising. The aim of this work was to evaluate physico-chemical parametar b (slope) that represents the lipophilicity of the examined molecules and to investigate interactions of bile acids with carbonic anhydrase I, II, androgen receptor and CYP450s. Thirteen candidates were investigated using normal-phase thin-layer chromatography in two solvent systems. Retention parameters were used in further quantitative structure-activity relationship analysis and docking studies to predict interactions and binding affinities of examined molecules with enzymes and receptors. Prediction of activity on androgen receptor showed that compounds 3α-hydroxy-12-oxo-5ß-cholanoic and 3α-hydroxy-7-oxo-5ß-cholanoic acid have stronger antiandrogen activity than natural bile acids. The inhibitory potential for carbonic anhydrase I and II was tested and it was concluded that molecules 3α-hydroxy-12-oxo-5ß-cholanoic, 3α-hydroxy-7-oxo-5ß-cholanoic, 3,7,12-trioxo-5ß-cholanoic acid and hyodeoxycholic acid show the best results. Substrate behavior for CYP3A4 was confirmed for all investigated compounds. Oxo derivatives of bile acids show stronger interactions with enzymes and receptors as classical bile acids and lower membranolytic activity compared with them. These significant observations could be valuable in consideration of oxo derivatives as building blocks in medicinal chemistry.

Bile acids and their oxo derivatives: environmentally safe materials for drug design and delivery.

PURPOSE: Animal tests have been often used in toxicology to determine parameters describing toxicity of a particular substance. However, in vivo tests must fulfill ethical requirements, and are both time and money consuming. Therefore, computational methods are considered to be very useful in toxicity prediction. METHODS: Retention parameters were acquired by normal-phase TLC. Lipophilicity was used as a key parameter for predicting toxic potential. The correlation coefficients between calculated log P values obtained by five different software and experimentally determined hydrophobicity parameters ([Formula: see text](tol/et), [Formula: see text](tol/but), b(tol/et) and b(tol/but)) were calculated. RESULTS: Correlation analysis provided reliable information (r2 > 0,8) for aquatic species - minnow, medaka, daphnia, and algae. In addition valuable data regarding rodents and AMES test were obtained. CONCLUSIONS: Tested bile acids show relatively good toxicological properties. Less toxic effects are noticed in compounds with higher polarity. Compounds 5, 6, 7, 12, and 13 would be the best candidates for further testing. These compounds show good biological potential which is coupled with low toxicity.

Structural and functional implications of the interaction between macrolide antibiotics and bile acids.

Macrolide antibiotics, such as azithromycin and erythromycin, are in widespread use for the treatment of bacterial infections. Macrolides are taken up and excreted mainly by bile. Additionally, they have been implicated in biliary system diseases and to modify the excretion of other drugs through bile. Despite mounting evidence for the interplay between macrolide antibiotics and bile acids, the molecular details of this interaction remain unknown. Herein, we show by NMR measurements that macrolides directly bind to bile acid micelles. The topology of this interaction has been determined by solvent paramagnetic relaxation enhancements (solvent PREs). The macrolides were found to be bound close to the surface of the micelle. Increasing hydrophobicity of both the macrolide and the bile acid strengthen this interaction. Both bile acid and macrolide molecules show similar solvent PREs across their whole structures, indicating that there are no preferred orientations of them in the bile micelle aggregates. The binding to bile aggregates does not impede macrolide antibiotics from targeting bacteria. In fact, the toxicity of azithromycin towards enterotoxic E. coli (ETEC) is even slightly increased in the presence of bile, as was shown by effective concentration (EC50 ) values.

Influence of temperature on retention parameter of bile acids in normal phase thin-layer chromatography: the role of steroid skeleton.

In this paper, bile acids' retention parameter, R(M), obtained in normal phase thin-layer chromatography is determined as a function of the temperature (293-323 K). Analyzed bile acids belong to congeneric group with two oxygen atoms (OH or oxo groups) on the steroid core and congeneric group with three oxygen atoms. For molecules of both congeneric groups it is found that there is a linear relationship between R(M) and temperature, therefore R(M) decreases with the increase of temperature. In certain congeneric groups, parameters of linear function (R(M) - T) can be linked to the structural characteristics of bile acids, firstly with their spatial orientation (steric position in relation to the steroid mean plane) of the steroid oxygen atom (OH or oxo groups). Absolute values of slope (see text for symbol) of linear function (R(M) - T) increase if steroid oxygen atoms are not in the polar plane, since then the possibility of forming hydrogen bonds with stationary phase decreases. Besides that, absolute value of the parameter (see text for symbol) describes degree of hydrogen bond forming between bile acids and polar stationary phase in each congeneric group as well as hydrophobicity of the steroid skeleton.

Chitosan nanobeads loaded with Biginelli hybrids as cell-selective toxicity systems with a homogeneous distribution of the cell cycle in cancer treatment.

Tetrahydropyrimidines are a class of azaheterocycles, also called Biginelli hybrids (obtained from the Biginelli reaction), that have attracted an enormous interest in the medicinal chemistry community in recent years, due to a broad biological activity, such as anticancer, antiviral, anti-inflammatory, antidiabetic, antituberculosis activities, etc. According to SciFinder®, more than 70 000 different Biginelli-like compounds have been covered in publications. However, although the Biginelli reaction can yield a large number of compounds with a broad range of activities, none of them have been captured in a carrier. In this study, chitosan-based (Ch) nanoparticles (NPs) containing three different molecules (Biginelli hybrids) were developed and tested for the first time as simple and promising vehicles for anticancer Biginelli-based drugs. The key features of NPs, such as size, surface morphology, drug encapsulation efficiency, and in vitro release were systematically investigated. Rather weak cell selectivity of pure Biginelli hybrids (A-C) to selected cancer cell lines has improved and this has been accompanied with two-to-four times stronger cytotoxic effect of A-C loaded Ch NPs, with a triple reduction in toxicity to healthy cells (MRC-5). It has been observed that the examined NPs induce apoptosis. The cell cycle analysis has confirmed the influence of A-loaded Ch (A-Ch), B-loaded Ch (B-Ch), and C-loaded Ch (C-Ch) on the cell cycle distribution, which was homogenously affected. This is the difference with regard to the effect of A, B, and C on the cell cycle. It has been established that the increased selectivity and antitumor activity of NPs are related to the presence of the carrier.

Assessment of the pharmacokinetic profile of novel s-triazine derivatives and their potential use in treatment of Alzheimer's disease.

AIMS: The current treatment of Alzheimer's disease is purely symptomatic. Scientists are looking for new treatment options which could alter the course of the disease and improve the quality of life in patients with Alzheimer's disease. In this paper 14 novel s-triazine molecules have been evaluated for their lipophilicity. In addition docking study was carried out to evaluate acetylcholinesterase activity of these compounds. MAIN METHODS: Lipophilicity was evaluated by RP HPTLC using 5 different mobile phases and obtained results were used in calculations of pharmacokinetic parameters - logBB, Ka and Pej. Multiple linear regression analysis was refined, taking account of molecular polarity (total polar surface area, TPSA) and molecular weight (Mw) descriptors. Appropriate QSAR models were developed. Docking studies were carried out using the Vina docking. KEY FINDINGS: Five out of fourteen compounds evaluated [5-10] are selected as the most promising compounds with satisfactory pharmacokinetic properties and good docking scores. SIGNIFICANCE: Compound 10 possesses the best combination of favourable pharmacokinetic characteristics (brain penetration, intestinal absorption) and capacity for acetylcholinesterase inhibition. Consequently this molecule should be further evaluated for potential therapeutic use in Alzheimer's disease.

Structural insights into anticancer activity of D-ring modified estrone derivatives using their lipophilicity in estimation of SAR and molecular docking studies.

Many forms of breast carcinoma are hormone-dependent and therefore development of novel aromatase inhibitors is of particular interest. Since brain metastases are frequent in patients with advanced breast carcinoma, one of the goals of modern drug development is the discovery of drugs with specific pharmacokinetic profile. High performance thin layer chromatography (HPTLC) is often used to determine lipophilicity of the molecules based on their retention constant. As a predictive analysis, multiple linear regression method was performed to connect pharmacokinetic-dependent parameters with independent physicochemical properties such are: RM0 , TPSA and Mw of fourteen D-ring modified oestrone derivatives. Additionally, docking studies were performed. Conducted correlation analysis indicates excellent dependence between experimental RM parameter values and calculated values of pharmacokinetic parameters. Results show sufficient intestinal absorption of all the investigated molecules as well as moderate volumes of distribution and strong affinity for binding to plasma proteins. Crossing blood-brain barrier is predicted to be successful for 11 compounds. The created quantitative structure activity relationship model represents an excellent predictive tool and enables determination of pharmacokinetic properties of examined compounds. Docking analysis defined molecules I3 and II3 to be the best candidates; however, compound II3 violates the Lipinski rule. It has been concluded that molecules with hydroxyl group at C-3 more effectively pass through blood-brain barrier while structures with benzyloxy groups have stronger interactions with CYP1A19. Molecules II2 , II4 , II6 , and II7 are regarded as most suitable candidates for further investigation considering their good pharmacokinetic and docking characteristics. Copyright © 2017 John Wiley & Sons, Ltd.

Retention data of bile acids and their oxo derivatives in characterization of pharmacokinetic properties and in silico ADME modeling.

PURPOSE: Information on ADME properties of examined bile acids and their oxo derivatives are scarce, although the interest for bile acids and their use in nanochemistry and macromolecular chemistry is increasing. The purpose of this research was to evaluate the lipophilicity, a crucial physicochemical parameter for describing ADME properties of selected bile acids and their oxo derivatives, and to compare two approaches: experimentally determined hydrophobicity parameters and calculated logP values. METHODS: Commercially available bile acids - deoxycholic, chenodeoxycholic, hyodeoxycholic and ursodeoxycholic acid were used to synthesize oxo derivatives. Lipophilicity was evaluated in two solvent systems: toluene/ethanol and toluene/butanol. Retention parameters were acquired by normal-phase TLC. The correlations between calculated logP values obtained using five different software and experimentally determined hydrophobicity parameters (RM(0)(tol/eth), RM(0)(tol/but), b(tol/eth) and b(tol/but)) were examined. RESULTS: Correlation analysis confirmed significant dependence between experimental RM(0) values and software calculated parameters. Results suggest satisfactory intestinal absorption after oral administration for all of the examined compounds as well as low volumes of distribution, and high affinity for binding with plasma proteins. Penetration through blood-brain barrier and skin is not satisfactory. All of the examined compounds show high affinity for binding with G-protein coupled receptors and consequently inhibition of ionic channels. Results also suggest possible binding with nuclear receptors. CONCLUSIONS: Established lipophilicity testing model of studied compounds showed excellent predictive ability and might represent significant tool in development of relations between chromatographic behavior and ADME properties. Compounds 3α-hydroxy-7,12-dioxo-5ß-cholanoic and 12α-hydroxy-3,7-dioxo-5ß-cholanoic acid might be the most suitable candidates for further development studies (satisfactory pharmacokinetic properties and lowest haemolytic potential) followed by 3α-hydroxy-12-oxo-5ß-cholanoic acid and 3α-hydroxy-7-oxo-5ß-cholanoic acid (slightly higher haemolytic potential, but better ligand properties).