Antitubercular activity assessment of fluorinated chalcones, 2-aminopyridine-3-carbonitrile and 2-amino-4H-pyran-3-carbonitrile derivatives: In vitro, molecular docking and in-silico drug likeliness studies

A series of newer previously synthesized fluorinated chalcones and their 2-amino-pyridine-3-carbonitrile and 2-amino-4H-pyran-3-carbonitrile derivatives were screened for their in vitro antitubercular activity and in silico methods. Compound 40 (MIC~ 8 μM) was the most potent among all 60 compounds, whose potency is comparable with broad spectrum antibiotics like ciprofloxacin and streptomycin and three times more potent than pyrazinamide. Additionally, compound 40 was also less selective and hence non-toxic towards the human live cell lines-LO2 in its MTT assay. Compounds 30, 27, 50, 41, 51, and 60 have exhibited streptomycin like activity (MIC~16–18 μM). Fluorinated chalcones, pyridine and pyran derivatives were found to occupy prime position in thymidylate kinase enzymatic pockets in molecular docking studies. The molecule 40 being most potent had shown a binding energy of -9.67 Kcal/mol, while docking against thymidylate kinase, which was compared with its in vitro MIC value (~8 μM). These findings suggest that 2-aminopyridine-3-carbonitrile and 2-amino-4H-pyran-3-carbonitrile derivatives are prospective lead molecules for the development of novel antitubercular drugs.

Design, Synthesis, and Antibacterial and Antifungal Activities of Novel Trifluoromethyl and Trifluoromethoxy Substituted Chalcone Derivatives

Despite the availability of many drugs to treat infectious diseases, the problems like narrow antimicrobial spectrum, drug resistance, hypersensitivities and systemic toxicities are hampering their clinical utility. Based on the above facts, in the present study, we designed, synthesized and evaluated the antibacterial and antifungal activity of novel fluorinated compounds comprising of chalcones bearing trifluoromethyl (A1-A10) and trifluoromethoxy (B1-B10) substituents. The compounds were characterized by spectroscopic techniques and evaluated for their antimicrobial activity against four pathogenic Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Bacillus subtilis) bacterial and fungal (Candida albicans and Aspergillus niger) strains. In this study, the compounds with trifluoromethoxy group were more effective than those with trifluoromethyl group. Among the 20 fluorinated chalcones, compound A3/B3 bearing an indole ring attached to the olefinic carbon have been proved to possess the most antimicrobial activity compared to the standard drugs without showing cytotoxicity on human normal liver cell line (L02). Further, the minimum inhibitory concentration (MIC) for A3/B3 was determined by serial tube dilution method and showed potential activity. These results would provide promising access to future study about the development of novel agents against bacterial and fungal infections.

Sekikaic acid modulates pancreatic β-cells in streptozotocin-induced type 2 diabetic rats by inhibiting digestive enzymes

The antioxidant and antidiabetic effects of sekikaic acid (SA) were investigated using in vitro and in vivo study models. SA possessed good antioxidant activity as assessed through hydroxyl radicals (IC₅₀ value = 41.5 µg/mL) and ferric ions assay (IC₅₀ value = 42.0 µg/mL). SA exhibited stronger α-glucosidase and α-amylase inhibition than that of aldose-reductase and protein tyrosine phosphatase 1B. The hypoglycemic activity of SA caused significant reduction of plasma glucose levels in normal and glucose loaded rats. The anti-hyperglycemic activity of SA (2 mg/Kg body weight) was indicated by the reduction of blood glucose by 44.17 ± 3.78% in the third week in streptozotocin-induced diabetic rats. The hypolipidaemic action of SA was evident by the significant decrease in the levels of low-density lipoprotein, total cholesterol, and total glycerides. Histologically, the pancreas of the treated groups showed significant regeneration of the pancreatic β-cells compared to diabetic control, possibly due to the inhibition of digestive enzymes.

Development and Validation of a Stability Indicating RP-HPLC Method for Simultaneous Estimation of Teneligliptin and Metformin

Objectives

The main objective of the present work is to develop a simple, precise, specific and stability method indicating reverse phase high performance liquid chromatography method for simultaneous estimation of teneligliptin and metformin in bulk and tablet dosage form.

Materials and Methods

The analysis was performed with a Kromasil C18 column (250×4.6 mm, 5 μm) at 30°C using buffer: acetonitrile: methanol (65:25:10, v/v/v) as mobile phase. The detection was carried out with a flow rate of 1.0 mL/min at 254 nm.

Results

The retention time of teneligliptin and metformin was 2.842 min and 2.017 min, respectively. The linearity range was 5-30 μg/mL for teneligliptin and 125-750 μg/mL for metformin. The forced degradation studies were performed as per the guidelines of the The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use under acidic, alkaline, oxidative, thermal, photostability, and neutral conditions.

Conclusion

This method was successfully validated for all the parameters and could detect the the correct amounts of active drug substance in formulations that are available in the market. This developed method in the present study could be successfully employed for the simultaneous estimation of teneligliptin and metformin in bulk and tablet dosage form.

Molecular docking based screening of G6PS with 1, 5 Benzothiazepine derivates for a potential inhibitor

Glucosamine-6-phosphate synthase (G6PS) (EC 2.6.1.16) is a known target for anti-bacterial and anti-fungal infections. Therefore, it is of interest to design potential inhibitors using 1, 5 benzo-thiazepine skeleton with appropriate modifications. We report the binding data for 20 derivatives of the skeleton molecule to G6PS having binding energy from -7.35 to -9.99 Kcal/mol with predicted IC50 value range of 4.11 to 47.68 nano-molar. It should be noted that this data should be further evaluated using in vitro and in vivo studies for safety, activity, efficacy and toxicity.

Molecular docking based screening of novel designed chalcone series of compounds for their anti-cancer activity targeting EGFR kinase domain

Epidermal growth factor receptors (EGFR) are critical for the growth of many tumors and expressed at high levels in about one third of epithelial cancers. Hence, blockade of the binding sites for EGFR has been hypothesized as an effective anti-cancer therapy. Chalcone derivative compounds have been shown to be highly effective anti-cancer agents, however there are still so many novel derivatives possible, one of which might get us the best targeted EGFR inhibitor. In this effort directed towards the discovery of novel, potent anti-tumor agents for the treatment of cancer, in the present study a library of novel chalcone series of compounds has been designed and evaluated for their anti-cancer activity targeting EGFR kinase domain using various computational approaches. Among the twenty five novel designed chalcone series of compounds, all of them have found to be successfully docking inside the active binding domain of EGFR receptor target with a binding energy in a range of -6.10 to -9.25 Kcal/mol with predicted IC50 value range of 33.50 micor molar to 164.66 nano molar respectively. On the other hand, calculated 2DQSAR molecular descriptor properties of the compounds showed promising ADME parameters and found to be well in compliance with Lipinski׳s rule of five. Among all the twenty five compounds tested, compound 21 ((2E)-3-(anthracen-9-yl)-1-phenylprop-2-2n-1- one) was found to be the best lead like molecule with a binding energy of -9.25 kcal/mol with predicted IC50 value of 164.66 nano molar. Conclusively, novel designed compound 21 of the present study have shown promising anti-cancer potential worth considering for further evaluations.

A rapid and sensitive LC-MS/MS assay for the determination of saxagliptin and its active metabolite 5-hydroxy saxagliptin in human plasma and its application to a pharmacokinetic study

The authors proposed a simple, rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method for the simultaneous determination of saxagliptin and its active metabolite 5-hydroxy saxagliptin in human plasma. The developed method was fully validated as per the US FDA guidelines. The method utilized stable labeled isotopes saxagliptin-15 N d2 (IS1) and 5-hydroxy saxagliptin-15 N-d2 (IS2) as internal standards for the quantification of saxagliptin and 5-hydroxy saxagliptin, respectively. Analytes and the internal standards were extracted from human plasma by a single step solid-phase extraction technique without drying, evaporation and reconstitution steps. The optimized mobile phase was composed of 0.1% acetic acid in 5 mM ammonium acetate and acetonitrile (30:70, v/v) and delivered at a flow rate of 0.85 mL/min. The method exhibits the linear calibration range of 0.05-100 ng/mL for both the analytes. The precision and accuracy results for both the analytes were well within the acceptance limits. The different stability experiments conducted in aqueous samples and in matrix samples are meeting the acceptance criteria. The chromatographic run time was set at 1.8 min; hence more than 400 samples can be analyzed in a single day.

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry method for the determination of dienogest in human plasma and its pharmacokinetic applications under fasting

A simple, rapid and sensitive analytical method using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) detection with positive ion electrospray ionization was developed for the determination of dienogest in human K2 EDTA plasma using levonorgestrel d6 as an internal standard (IS). Dienogest and IS were extracted from human plasma using simple liquid-liquid extraction. Chromatographic separation was achieved on a Zorbax XDB-Phenyl column (4.6 × 75 mm, 3.5 µm) under isocratic conditions using acetonitrile-5 mm ammonium acetate (70:30, v/v) at a flow rate of 0.60 mL/min. The protonated precursor to product ion transitions monitored for dienogest and IS were at m/z 312.30 → 135.30 and 319.00 → 251.30, respectively. The method was validated with a linearity range of 1.003-200.896 ng/mL having a total analysis time for each chromatograph of 3.0 min. The method has shown tremendous reproducibility with intra- and inter-day precision (coefficient of variation) <3.97 and 6.10%, respectively, and accuracy within ±4.0% of nominal values. The validated method was applied to a pharmacokinetic study in human plasma samples generated after administration of a single oral dose of 2.0 mg dienogest tablets to healthy female volunteers and was proved to be highly reliable for the analysis of clinical samples.

Synthesis, characterization and in vitro biological evaluation of some novel 1,3,5-triazine-Schiff base conjugates as potential antimycobacterial agents

A series of some novel 1,3,5-triazine-Schiff base conjugates (1-32) have been synthesized and evaluated for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using Alamar Blue assay and the activity expressed as the minimum inhibitory concentration (MIC) in μg/mL. Compounds 4 (4-Methoxy-6-methyl-N-(3,4,5-trimethoxybenzylidene)-1,3,5-triazin-2-amine), 11 (4-Methoxy-6-methyl-N-(2-hydroxy-3-bromo-5-chloro-benzylidene)-1,3,5-triazin-2-amine) and 24 (4-Methoxy-6-methyl-N-(1-(2,5-dihydroxyphenyl)ethylidene)-1,3,5-triazin-2-amine) exhibited a significant activity at 3.125, 6.25 and 6.25μg/mL, respectively, when compared with the antitubercular drugs such as ethambutol (3.125μg/mL), pyrazinamide (6.25μg/mL) and streptomycin (6.25μg/mL) and it could be a potential starting point to develop new lead compounds in the fight against Mycobacterium tuberculosis H37Rv.

Synthesis, characterization and biological evaluation of some novel 2,4-thiazolidinediones as potential cytotoxic, antimicrobial and antihyperglycemic agents

A series of some novel 2,4-thiazolidinediones (TZDs) (2a-x) have been synthesized and characterized by FTIR, (1)H NMR, (13)C NMR and LC mass spectral analysis. All the synthesized compounds were evaluated for their cytotoxicity, antimicrobial and in vivo antihyperglycemic activities. Among the tested compounds for cytotoxicity using Brine Shrimp Lethality assay, compound 2t ((Z)-5-(4-((E)-3-oxo-3-(thiophen-2-yl)prop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) exhibited significant inhibitory activity at ED(50) value 4.00±0.25 μg/mL and this level of activity was comparable to that of the reference drug podophyllotoxin with ED(50) value 3.61±0.17 μg/mL. Antimicrobial activity was screened using agar well diffusion assay method against selected Gram-positive, Gram-negative and fungal strains and the activity expressed as the minimum inhibitory concentration (MIC) in μg/mL. From the results of antimicrobial activity compound 2s ((Z)-5-(4-((E)-3-(3,5-bis(benzyloxy)phenyl)-3-oxoprop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) was found to be the most active against all the tested strains of microorganisms with MIC value 16 μg/mL. In vivo antihyperglycemic effect of twenty four TZDs (2a-x) at different doses 10, 30 and 50mg/kg b.w (oral) were assessed using percentage reduction of plasma glucose (PG) levels in streptozotocin-induced type II diabetic rat models. From the results, the novel compound 2x ((Z)-5-(4-((E)-3-(9H-fluoren-2-yl)-3-oxoprop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) exhibited considerably potent blood glucose lowering activity than that of the standard drug rosiglitazone and it could be a remarkable starting point to evaluate structure-activity relationships and to develop new lead molecules with potential cytotoxicity, antimicrobial and antihyperglycemic activities. In addition molecular docking studies were carried out against PPARγ molecular target using Molegro Virtual Docker v 4.0 to accomplish preliminary confirmation of the observed in vivo antihyperglycemic activity.

Dissolution studies and quantification of meloxicam in tablet dosage form by spectrophotometry

Two simple and inexpensive UV spectrophotometric methods were developed for the quantification and dissolution studies of meloxicam in tablet dosage forms. Meloxicam was estimated at 365nm and 360nm in Method I and Method II, respectively. The calibration curve was linear over a concentration range from 2.0 to 12.0μg/ml for both methods. The limit of detection and limit of quantitation were found to be 0.12μg/ml and 0.38μg/ml, 0.09μg/ml and 0.27μg/ml for Method I and Method II, respectively. The percentage recoveries of meloxicam were found to be 99.68 to 100.61% and 99.11 to 100.96% for Method I and Method II, respectively. It was concluded that the developed methods are precise, accurate and were successfully applied for the estimation of meloxicam in pharmaceutical formulations and in vitro dissolution studies.

Synthesis, characterization and in vitro biological evaluation of some novel diarylsulfonylureas as potential cytotoxic and antimicrobial agents

A series of novel diarylsulfonylureas (1-28) have been synthesized and characterized by FTIR, (1)H NMR, (13)C NMR and LC mass spectral analysis. All the synthesized compounds were evaluated for their in vitro cytotoxicity and antimicrobial activities. Among the tested compounds for cytotoxicity using Brine Shrimp Lethality assay, compounds 18 and 22 exhibited significant cytotoxicity at ED(50) values 3.96±0.21 and 4.02±0.19μg/mL, respectively. This level of activity was found comparable to that of the reference drug podophyllotoxin with ED(50) value 3.61±0.17μg/mL and it could be a remarkable starting point to develop new lead molecules with major cytotoxicity. Antimicrobial activity was screened using agar well diffusion assay method against selected Gram-positive, Gram-negative and fungal strains. Most of the compounds showed promising antibacterial and antifungal activity and the activity expressed as the minimum inhibitory concentration (MIC) in μg/mL.