Synthesis, Antimycobacterial Evaluation and Docking Studies of Some 7-Methyl-5,6,7,8-tetrahydropyrido[4',3':4,5]thieno[2,3-d]pyrimidin-4(3H)-ones.

Two series of 3-substituted-7-methyl-5,6,7,8-tetrahydropyrido[4',3':4,5] thieno[2,3-d]pyrimidin-4(3H)-one (6a-k) and 3-substituted-7,2-dimethyl-5,6,7,8-tetrahydropyrido[4',3':4,5]thieno[2,3-d]pyrimidin-4(3H)-one (7a-k) derivatives were synthesized and characterized using spectral data i.e., IR, 1H-, 13C-NMR, Mass and CHN elemental analyses. The synthesized compounds were evaluated for antibacterial activity against each of two strains of Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria and antimycobacterial activity screened against two strains i.e., Mycobacterium tuberculosis (MTB) H37Rv and an isoniazid-resistant clinical sample. Further to validate potentiality of our design was analyzed using molecular docking studies by taking crystal structure of MTB pantothenate synthetase (MTB-PS) (PDB: 3IVX). In this study, some compounds 6k (Minimum Inhibitory Concentration (MIC): MIC-22 µM), 7d (MTB: MIC-22 µM) and 7k (MTB: MIC-11 µM) showed potential antibacterial and antimycobacterial activities.

Hydroxamates of para-aminobenzoic acid as selective inhibitors of HDAC8.

A series of hydroxamates (4a-4l) were prepared from p-aminobenzoic acid to inhibit HDAC8. The idea is to substitute rigid aromatic ring in place of less rigid piperazine ring of hydroxamates reported earlier by our group. It is expected to increase potency retaining the selectivity. Result obtained suggested that the modifications carried out retained the selectivity towards HDAC8 isoform and increasing the potency in very few cases. Increase in potency is also associated with variation in cap aryl region. Two compounds (4f &4l) were found to inhibit HDAC8 at concentrations (IC50) less than 20µM.

Methyl-2-arylidene hydrazinecarbodithioates: synthesis and biological activity.

Methyl-2-arylidene hydrazine-carbodithioate has not been of particular interest to researchers even though its metal complexes are extensively reported on due to their biological activity. This study examined the cytostatic and antiviral activity of twelve methyl-2-arylidene hydrazinecarbodithioates reported by many researchers as intermediates for the synthesis of thiosemicarbazides and the preparation of their metal complexes. Compounds IIc, IIi, and IIl with tridentate ligand features were found to have the lowest IC50 value (6.5 µM, ≈ 1 µM, and 0.8 µM, respectively) against HL60 human promyelocytic leukemia cells. They were also most inhibitory to human embryonic lung (HEL) fibroblast proliferation (5.3 µM, 17 µM, and 2.6 µM). Compound IIc and IIl show antiviral activity against wild-type herpes simplex virus (HSV), varicella zoster virus (VZV), and acyclovirresistant HSV; however, these activities were observed at concentrations at which the compounds also markedly inhibit HL60 and HEL cell proliferation.

Synthesis, antimicrobial and anticancer activity of new thiosemicarbazone derivatives.

Thiosemicarbazones of p-aminobenzoic acid (PABA) were synthesized and tested for their antimicrobial and anticancer activity. Hydroxamate derivatives 4a-4l were found to have better antimicrobial and anticancer activity than their acid counterpart. Compound 4d was found to have good antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis with IC(50) value of about 1 µM. Compound 4f showed potent antifungal activity against Candida albicans (IC(50) = 1.29 µM) and compound 4h showed potent anticancer activity (IC(50) = 0.07 µM).

Symphony of the DNA flexibility and sequence environment orchestrates p53 binding to its responsive elements.

The p53 tumor suppressor protein maintains the genome fidelity and integrity by modulating several cellular activities. It regulates these events by interacting with a heterogeneous set of response elements (REs) of regulatory genes in the background of chromatin configuration. At the p53-RE interface, both the base readout and torsional-flexibility of DNA account for high-affinity binding. However, DNA structure is an entanglement of a multitude of physicochemical features, both local and global structure should be considered for dealing with DNA-protein interactions. The goal of current research work is to conceptualize and abstract basic principles of p53-RE binding affinity as a function of structural alterations in DNA such as bending, twisting, and stretching flexibility and shape. For this purpose, we have exploited high throughput in-vitro relative affinity information of responsive elements and genome binding events of p53 from HT-Selex and ChIP-Seq experiments respectively. Our results confirm the role of torsional flexibility in p53 binding, and further, we reveal that DNA axial bending, stretching stiffness, propeller twist, and wedge angles are intimately linked to p53 binding affinity when compared to homeodomain, bZIP, and bHLH proteins. Besides, a similar DNA structural environment is observed in the distal sequences encompassing the actual binding sites of p53 cistrome genes. Additionally, we revealed that p53 cistrome target genes have unique promoter architecture, and the DNA flexibility of genomic sequences around REs in cancer and normal cell types display major differences. Altogether, our work provides a keynote on DNA structural features of REs that shape up the in-vitro and in-vivo high-affinity binding of the p53 transcription factor.

AQbD Driven Development of an RP-HPLC Method for the Quantitation of Abiraterone Acetate for its Pharmaceutical Formulations in the Presence of Degradants.

OBJECTIVES: Abiraterone acetate is a well-known anticancer drug and a steroidal derivative of progesterone for treatment of patients with hormone-refractory prostate cancer. Chemometrics-assisted reverse phase high performance liquid chromatography (RP-HPLC) development of the drug abiraterone acetate has been employed in this study using an analytical quality by design (AQbD) approach. MATERIALS AND METHODS: Drug separation was performed using a Princeton Merck-Hibar Purospher STAR (C18, 250 mm × 4.6 mm) i.d., 5 µm particle size) with ultraviolet detection at 235 nm. A Box-Behnken statistical experimental design with response surface methodology was executed for method optimization and desired chromatographic separation from its formulation with a few numbers of experimental trials. The impact of three independent variables, namely, composition of the mobile phase, pH, and flow rate, on response retention time and peak area was studied by constructing an arithmetic model from these variables. RESULTS: Optimized experimental conditions for the proposed work include the mobile phase acetonitrile and phosphate buffer (10 mM KH2PO4) (20:80 %v/v). At the concentration range of 2-100 µg/mL, a linear calibration curve was found. Recovery was performed at three concentrations and was foun to be between 98% and 102%. The 3D response surface curves revealed that mobile phase composition and flow rate were the most substantial critical factors affecting desired responses. CONCLUSION: An attempt has been made to develop and validate an economical, precise, robust, stability-indicating AQbD-based RP-HPLC method that can be employed successfully for the routine analysis of abiraterone acetate in quality control labs.

A Selective and Sensitive Method Development and Validation of 1,1-Dimethyl-3-Hydroxy-Pyrrolidinium Bromide Impurity in Glycopyrrolate Oral Solution by Liquid Chromatography-Tandem Mass Spectroscopy.

OBJECTIVE: A selective and sensitive liquid chromatography-tandem mass spectrometer (LC-MS/MS) method has been developed for the quantification of 1,1-dimethyl-3-hydroxy-pyrrolidinium bromide impurity in glycopyrrolate oral solution. MATERIALS AND METHOD: The LC-MS/MS analysis was done on X Bridge HILIC (100 × 4.6 mm, 5 µm) analytical column, and the mobile phase used was10 mM ammonium formate with 0.2% formic acid as mobile phase-A and acetonitrile as mobile phase-B with a gradient programme of 5.0 min. The flow rate used was 1.2 mL/min. Triple quadrupole mass detector coupled to positive electrospray ionization operated in multiple reactions monitoring mode was used for the quantification at m/z 116.10 ± 0.5. RESULTS: Retention time of impurity was found ~3.2 min. The method was validated in terms of specificity, linearity, accuracy, precision, range, limit of detection, limit of quantitation (LOQ) and robustness. Relative standard deviation (RSD) for system suitability was found 1.3%. Calibration plot was linear over the range of 0.050-2.000 µg/mL. Limit of detection and limit of quantification were found 0.017 and 0.051 µg/mL, respectively. The intra- and inter-day precision RSD was 2.3% and the obtained recovery at LOQ to 200% was in between 86.7 and 107.4%. CONCLUSION: The low RSD values and high recoveries of the method confirm the suitability of the method.

Development of selective and reversible pyrazoline based MAO-A inhibitors: Synthesis, biological evaluation and docking studies.

3,5-Diaryl pyrazolines analogs were synthesized and evaluated for their monoamine oxidase (MAO) inhibitory activity. The compounds were found reversible and selective towards MAO-A with selectivity index in the magnitude of 10(3)-10(5). The docking studies were carried out to gain further structural insights of the binding mode and possible interactions with the active site of MAO-A. Interestingly, the theoretical (K(i)) values obtained by molecular docking studies were in congruence with their experimental (K(i)) values.

Synthesis, antimicrobial evaluation, and docking studies of novel 4-substituted quinazoline derivatives as DNA-gyrase inhibitors.

Quinazoline derivatives are reported to have anti-inflammatory, analgesic, antibacterial, and anticancer activities. The incorporation of "OCH2CONH2" (oxymethylcarbamide) at 4th position of the quinazoline ring was found to influence the biological activities of the molecules. With this rationale, some new oxadiazolyl methyloxy quinazolines, pyrazolyl acetoxy methyl quinazolines, triazolylmethyloxy quinazolines were synthesized from anthranilic acid through quinazolyl oxyacetylhydrazide intermediates. All the compounds were characterized by IR, ¹H-NMR, EI-MS, and C, H, N analyses and evaluated for their antimicrobial activity. Docking studies on the DNA-gyrase enzyme (1KZN) show their role in the antimicrobial activity of the molecules and explain the higher potency of compounds 6a, 6b, 8a, 8b based on ReRanking scores and binding poses of the molecules.

Non-Invasive Delivery of Nano-Emulsified Sesame Oil-Extract of Turmeric Attenuates Lung Inflammation.

Turmeric, the golden Indian spice, and the edible oil of sesame seeds are the essential ingredients of Indian food created by ancestors and established the belief of the curative effect of food for many generations. Considering the anti-inflammatory effects of turmeric, we formulated a nano-emulsion of turmeric infused in edible sesame oil, with a globule size of 200-250 nm using high-energy microfluidization. The product with a zeta potential of -11.5 mV showed spherical globules when imaged for scanning and transmission electron microscopy. We explored the anti-inflammatory potential of this edible nano-emulsion in lung inflammation. The lungs are the internal organ most vulnerable to infection, injury, and rapid inflammation from the external environment because of their constant exposure to pollutants, pathogenic microorganisms, and viruses. We evaluated the nano-emulsion for efficacy in ovalbumin-induced lung injury in mice with an oral treatment for two weeks. The therapeutic effect of nano-emulsion of the sesame oil-extract of turmeric was evident from biochemical analysis of bronchoalveolar lavage fluid, lung histopathology, and flow cytometric analysis. The developed nano-emulsion significantly reduced the inflammation and damage to the alveolar network in ovalbumin-injured mice. Significant reduction in the levels of neutrophils and inflammatory cytokines like IL-4, IL-6, and IL-13 in bronchoalveolar lavage fluid was observed in the nano-emulsion-treated group. Leukotriene B4 and IgE were also significantly altered in the treated group, thus suggesting the suitability of the formulation for the treatment of allergy and other inflammatory conditions. The nano-emulsification process potentiated the immunoregulatory effect of turmeric, as observed from the elevated levels of the natural anti-inflammatory cytokine, IL-10. The dietary constituents-based nano-emulsion of spice turmeric helped in scavenging the free radicals in the injured lungs, thus modulating the inflammation pathway. This easily scalable formulation technology approach can therefore serve as a potential noninvasive and safe treatment modality for reducing lung inflammation in lung injury cases.

Delving into Eukaryotic Origins of Replication Using DNA Structural Features.

DNA replication in eukaryotes is an intricate process, which is precisely synchronized by a set of regulatory proteins, and the replication fork emanates from discrete sites on chromatin called origins of replication (Oris). These spots are considered as the gateway to chromosomal replication and are stereotyped by sequence motifs. The cognate sequences are noticeable in a small group of entire origin regions or totally absent across different metazoans. Alternatively, the use of DNA secondary structural features can provide additional information compared to the primary sequence. In this article, we report the trends in DNA sequence-based structural properties of origin sequences in nine eukaryotic systems representing different families of life. Biologically relevant DNA secondary structural properties, namely, stability, propeller twist, flexibility, and minor groove shape were studied in the sequences flanking replication start sites. Results indicate that Oris in yeasts show lower stability, more rigidity, and narrow minor groove preferences compared to genomic sequences surrounding them. Yeast Oris also show preference for A-tracts and the promoter element TATA box in the vicinity of replication start sites. On the contrary, Drosophila melanogaster, humans, and Arabidopsis thaliana do not have such features in their Oris, and instead, they show high preponderance of G-rich sequence motifs such as putative G-quadruplexes or i-motifs and CpG islands. Our extensive study applies the DNA structural feature computation to delve into origins of replication across organisms ranging from yeasts to mammals and including a plant. Insights from this study would be significant in understanding origin architecture and help in designing new algorithms for predicting DNA trans-acting factor recognition events.

Stability indicating Rp-UPLC method development and validation for the simultaneous estimation of fosnetupitant and palonosetron in bulk and injection dosage form

Abstract A stability indicating UPLC method has been developed and validated for the simultaneous determination of fosnetupitant and palonosetron in bulk and in injection dosage form. This combination is used for the prevention of acute and delayed nausea and vomiting associated with initial and repeated courses of highly emetogenic chemotherapy for cancer. The chromatographic analysis was performed on an HSS, RP C18 column (2.1 x 100 mm, 1.8 µm) with an isocratic mobile phase composed of 0.25 M potassium dihydrogen orthophosphate buffer (pH 6.5), pH adjusted with dilute sodium hydroxide:acetonitrile (55:45 v/v), at a flow rate of 0.5 mL/min, and the eluents were monitored at an isosbestic point of 286 nm. The developed method was validated according to the ICH guidelines pertaining to specificity, precision, accuracy, linearity and robustness, and the stability indicating nature of the method was established by forced degradation studies. The retention times of fosnetupitant and palonosetron were observed at 1.390 and 2.404 min, respectively. The developed method proved to be accurate and precise. Linearity was established between 4.70 and 14.10 µg/mL for fosnetupitant and between 0.05 and 0.15 µg/mL for palonosetron. The LOD and LOQ were 0.115 and 0.385 µg/mL, respectively, for fosnetupitant, and 0.005 and 0.016 µg/mL, respectively, for palonosetron. Therefore, the proposed UPLC method was reliable, reproducible, precise and sensitive for the quantification of fosnetupitant and palonosetron.

In silico evaluation of TERT inhibition by anticancer drugs.

The activation of telomerase represents an early step in carcinogenesis. Increased telomerase expression in malignant tumors suggests that telomerase inactivation may represent a potential chemotherapeutic target. In this work, existing anticancer drugs were docked against telomerase reverse transcriptase (TERT) using a Lamarckian genetic algorithm (LGA). Autodock's scoring function was applied to each of the molecules in order to identify the inhibitor with the strongest pharmacological action. The structural insights provided by this study regarding binding poses and possible interactions, free energies of binding, and drug scores aided in the identification of potential inhibitory compounds. The ranks of the various ligands investigated were based on the final docked energy values. Among nine selected compounds, vindesine, temsirolimus, and cyclosporine were found to be more potent TERT inhibitors than the standard inhibitor, curcumin.