Department Of Pharmaceutical Sciences and Natural Products
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Item Recent trends in anticancer drug development: Challenges and opportunities(Bentham Science Publishers B.V., 2017) Skvortsova, Ira-Ida; Kumar, Vinod[No abstract available]Item In silico study of flavonoids as DPP-4 and α-glucosidase inhibitors(Bentham Science Publishers B.V., 2018) Kaur, J.; Singla, Ramit; Jaitak, VikasBackground: Diabetes being among the most prevalent disease is being studied widely to achieve most potent drug with lesser side-effects. Numerous targets have been explored and several drugs have been developed to combat type-2 diabetes. Worldwide scenario depicts an increase in the number of diabetics at an alarming rate. Due to this critical need in the current scenario, the focus has been shifted to natural products. Amongst which flavonoids have been extensively studied for their anti-diabetic potential. Among various targets inhibition of DPP-4, ?-glucosidase arose as an advantageous methodology for the management of type-2 diabetes. DPP-4 inhibitor helps to maintain the insulin levels in the body and ?-glucosidase inhibitor aids in the control of the postprandial glycemia. Methods: In the present study, the molecular modeling of 155 flavonoids has been performed using GLIDE against Dipeptidyl Peptidase-4 (DPP-4) (PDB ID:2ONC) and ?-glucosidase (PDB ID: 2QMJ) so as to achieve lead compounds that can be further used to develop a new drug. Results: Rutin and Theaflavin-3,3'-di-O-gallate were observed to possess the best docking score for ?-glucosidase and DPP-4 respectively. Conclusions: The top scoring flavonoids show promising results, but further studies are required to be carried out including the pharmacophore mapping, SAR and QSAR studies. The results illustrated that the hydrogen bonding plays a crucial role in the binding and positioning of the molecules into the active site. Further, the rescoring of the docking values mentioned as MMGB/SA also reconfirmed that these compounds show favorable results. ? 2018 Bentham Science Publishers.Item Genome-wide association study of 25(OH) Vitamin D concentrations in Punjabi Sikhs: Results of the Asian Indian diabetic heart study(Elsevier Ltd, 2016) Sapkota, B.R.; Hopkins, R.; Bjonnes, A.; Ralhan, S.; Wander, G.S.; Mehra, N.K.; Singh, J.R.; Blackett, P.R.; Saxena, R.; Sanghera, D.K.Vitamin D deficiency is implicated in multiple disease conditions and accumulating evidence supports that the variation in serum vitamin D (25(OH)D) levels, including deficiency, is under strong genetic control. However, the underlying genetic mechanism associated with vitamin 25(OH)D concentrations is poorly understood. We earlier reported a very high prevalence of vitamin D deficiency associated with an increased risk for type 2 diabetes and obesity in a Punjabi Sikh diabetic cohort as part of the Asian Indian diabetic heart study (AIDHS). Here we have performed the first genome-wide association study (GWAS) of serum 25(OH)D on 3538 individuals from this Punjabi Sikh population. Our discovery GWAS comprised of 1387 subjects followed by validation of 24 putative SNPs (P < 10-4) using an independent replication sample (n = 2151) from the same population by direct genotyping. A novel locus at chromosome 20p11.21 represented by rs2207173 with minor allele frequency (MAF) 0.29, [? = -0.13, p = 4.47 ? 10-9] between FOXA2 and SSTR4 was identified to be associated with 25(OH)D levels. Another suggestive association signal at rs11586313 (MAF 0.54) [? = 0.90; p = 1.36 ? 10-6] was found within the regulatory region of the IVL gene on chromosome 1q21.3. Additionally, our study replicated 3 of 5 known GWAS genes associated with 25(OH)D concentrations including GC (p = 0.007) and CYP2R1 (p = 0.019) reported in Europeans and the DAB1 (p = 0.003), reported in Hispanics. Identification of novel association signals in biologically plausible regions with 25(OH)D metabolism will provide new molecular insights on genetic drivers of vitamin D status and its implications in health disparities. ? 2015 Elsevier Ltd. All rights reserved.Item Cellular uptake, intracellular trafficking and cytotoxicity of silver nanoparticles(2012) Singh, R.P.; Ramarao, P.Silver nanoparticles (Ag NPs) are used in consumer products and wound dressings due to their antimicrobial properties. However, in addition to toxic effects on microbes, Ag NPs can also induce stress responses as well as cytotoxicity in mammalian cells. We observed that Ag NPs are efficiently internalized via scavenger receptor-mediated phagocytosis in murine macrophages. Confocal and electron microscopy analysis revealed that internalized Ag NPs localize in the cytoplasm. Ag NPs cause mitochondrial damage, induce apoptosis and cell death. These effects were abrogated in presence of Ag ion-reactive, thiol-containing compounds suggesting the central of Ag ions in Ag NP toxicity. Quantitative image analysis revealed that intracellular dissolution of Ag NPs occurs about 50 times faster than in water. In conclusion, we demonstrate for the first time that Ag NPs are internalized by scavenger receptors, trafficked to cytoplasm and induce toxicity by releasing Ag ions. ? 2012 Elsevier Ireland Ltd.Item Intracellular delivery of redox cycler-doxorubicin to the mitochondria of cancer cell by folate receptor targeted mitocancerotropic liposomes(2012) Malhi, Sarandeep Singh; Budhiraja, Abhishek; Arora, Sumit; Chaudhari, Kiran R.; Nepali, Kunal; Kumar, Raj; Sohi, Harmik; Murthy, Rayasa S.R.Cancer cells reflect higher level of ROS in comparison to the normal cell, so they become more vulnerable to further oxidative stress induced by exogenous ROS-generating agents. Through this a novel therapeutic strategy has evolved, which involves the delivery of redox cycler-doxorubicin (DOX) to the mitochondria of cancer cell where it acts as a source of exogenous ROS production. The purpose of this study is to develop a liposomal preparation which exhibits a propensity to selectively target cancer cell along with the potential of delivering drug to mitochondria of cell. We have rendered liposomes mitocancerotropic (FA-MTLs) by their surface modification with dual ligands, folic acid (FA) for cancer cell targeting and triphenylphosphonium (TPP) cations for mitochondria targeting. The cytotoxicity, ROS production and cell uptake of doxorubicin loaded liposomes were evaluated in FR (+) KB cells and found to be increased considerably with FA-MTLs in comparison to folic acid appended, mitochondria targeted and non-targeted liposomes. As confirmed by confocal microscopy, the STPP appended liposomes delivered DOX to mitochondria of cancer cell and also showed higher ROS production and cytotoxicity in comparison to folic acid appended and non-targeted liposomes. Most importantly, mitocancerotropic liposomes showed superior activity over mitochondria targeted liposomes which confirm the synergistic effect imparted by the presence of dual ligands - folic acid and TPP on the enhancement of cellular and mitochondrial delivery of doxorubicin in KB cells. ? 2012 Elsevier B.V. All rights reserved.Item Pyrazoloquinazolines: Synthetic strategies and bioactivities(2015) Garg, Mansi; Chauhan, Monika; Singh, Pankaj Kumar; Singh, Pankaj Kumar; Alex, Jimi Marin; Kumar, RajNumerous N-heterocycles are indisputably evidenced to exhibit myriad biological activities. In the recent past, attempts made to condense the various heterocycles have resulted in derivatives possessing better bioactivities. Among many such condensed heterocycles, pyrazoloquinazolines have managed to hold the attention of many researchers, owing to the broad spectrum of activities they portray. This review is the first of its kind to congregate the various pyrazoloquinazolines reported until now and categorizes these structurally isomeric classes into eleven different groups based on the fusion pattern of the ring such as [1,5-c], [5,1-b], [4,3-h], etc. Furthermore, this review is a concerted effort to highlight design, synthetic strategies as well as biological activities of each class of this condensed heterocycle. Structure-activity relationship studies and in silico approaches wherever reported have also been discussed. In addition, manuscript also offers scope for design, synthesis and generation of libraries of unreported classes of pyrazoloquinazolines for the biological evaluation. Copyright ? 2014 Elsevier Masson SAS. All rights reserved.Item Synthesis of rebaudioside A from stevioside and their interaction model with hTAS2R4 bitter taste receptor(Elsevier Ltd, 2016) Singla, Ramit; Jaitak, VikasSteviol glycosides (SG's) from Stevia rebaudiana (Bertoni) have been used as a natural low-calorie sweeteners. Its aftertaste bitterness restricts its use for human consumption and limits its application in food and pharmaceutical products. In present study, we have performed computational analysis in order to investigate the interaction of two major constituents of SG's against homology model of the hTAS2R4 receptor. Molecular simulation study was performed using stevioside and rebaudioside A revealed that, sugar moiety at the C-3?? position in rebaudioside A causes restriction of its entry into the receptor site thereby unable to trigger the bitter reception signaling cascade. Encouraged by the current finding, we have also developed a greener route using ?-1,3-glucanase from Irpex lacteus for the synthesis of de-bittered rebaudioside A from stevioside. The rebaudioside A obtained was of high quality with percent conversion of 62.5%. The results here reported could be used for the synthesis of rebaudioside A which have large application in food and pharmaceutical industry. ? 2016 Elsevier Ltd. All rights reserved.Item Interaction model of steviol glycosides from Stevia rebaudiana (Bertoni) with sweet taste receptors: A computational approach(Elsevier Ltd, 2015) Mayank; Jaitak, Vikas; Mayank, Jaitak, V.Docking studies were performed on natural sweeteners from Stevia rebaudiana by constructing homology models of T1R2 and T1R3 subunits of human sweet taste receptors. Ramachandran plot, PROCHECK results and ERRAT overall quality factor were used to validate the quality of models. Furthermore, docking results of steviol glycosides (SG's) were correlated significantly with data available in the literature which enabled to predict the exact sweetness rank order of SG's. The binding pattern indicated that Asn 44, Ans 52, Ala 345, Pro 343, Ile 352, Gly 346, Gly 47, Ala 354, Ser 336, Thr 326 and Ser 329 are the main interacting amino acid residues in case of T1R2 and Arg 56, Glu 105, Asp 215, Asp 216, Glu 148, Asp 258, Lys 255, Ser 104, Glu 217, Leu 51, Arg 52 for T1R3, respectively. Amino acids interact with SG's mainly by forming hydrogen bonds with the hydroxyl group of glucose moieties. Significant variation in docked poses of all the SG's were found. In this study, we have proposed the mechanism of the sweetness of the SG's in the form of multiple point stimulation model by considering the diverse binding patterns of various SG's, as well as their structural features. It will give further insight in understanding the differences in the quality of taste and will be used to improve the taste of SG's using semi-synthetic approaches. ? 2015 Elsevier Ltd. All rights reserved.Item Anticancer activity of essential oils: A review(2013) Bhalla, Yashika; Gupta, Vinay Kumar; Jaitak, VikasNatural essential oil constituents play an important role in cancer prevention and treatment. Essential oil constituents from aromatic herbs and dietary plants include monoterpenes, sesquiterpenes, oxygenated monoterpenes, oxygenated sesquiterpenes and phenolics among others. Various mechanisms such antioxidant, antimutagenic and antiproliferative, enhancement of immune function and surveillance, enzyme induction and enhancing detoxification, modulation of multidrug resistance and synergistic mechanism of volatile constituents are responsible for their chemopreventive properties. This review covers the most recent literature to summarize structural categories and molecular anticancer mechanisms of constituents from aromatic herbs and dietary plants. ? 2013 Society of Chemical Industry.Item A Perspective on Monoamine Oxidase Enzyme as Drug Target: Challenges and Opportunities(2017) Kumar, Bhupinder; Gupta, Vivek Prakash; Kumar, VinodThe monoamine oxidase (MAO) enzyme is responsible for the deamination of monoamine neurotransmitters and regulates their concentration in the central and peripheral nervous systems. Imbalance in the concentration of neurotransmitters in the brain and central nervous system is linked with the biochemical pathology of various neurogenic disorders. Irreversible MAO inhibitors were the first line drugs developed for the management of severe depression but most of these were withdrawn from the clinical practice due to their fatal side effects including food-drug interactions. New generations of MAO inhibitors were developed which were reversible and selective for one of the enzyme isoform and showed improved pharmacological profile. The discovery of crystal structure of MAO-A & MAO-B isoforms helped in understanding the drug-receptor interactions at the molecular level and designing of ligands with selectivity for either of the isoforms. The current article provides an overview on the MAO enzyme as potential drug target for different disease states. The article describes catalytic mechanism of MAO enzyme, crystal structures of the two MAO isoforms, traditional MAO inhibitors and various problems associated with their use, new developments in the MAO inhibitors and their potential as therapeutic agents especially in neurological disorders.