Pharmaceutical Sciences and Natural Products - Research Publications
Permanent URI for this collectionhttps://kr.cup.edu.in/handle/32116/56
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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 Chemical composition and biological effects of artemisia maritima and artemisia nilagirica essential oils from wild plants of Western Himalaya(Georg Thieme Verlag, 2014) Stappen, Iris; Wanner, J, rgen; Tabanca, Nurhayat; Wedge, David E.; Ali, Abbas; Khan, Ikhlas A.; Kaul, Vijay K.; Lal, Brij; Jaitak, Vikas; Gochev, Velizar; Girova, Tania; Stoyanova, Albena; Schmidt, Erich; Jirovetz, Leopold; Stappen, I.; Wanner, J.; Tabanca, N.; Wedge, D.E.; Ali, A.; Khan, I.A.; Kaul, V.K.; Lal, B.; Jaitak, V.; Gochev, V.; Girova, T.; Stoyanova, A.; Schmidt, E.; Jirovetz, L.Artemisia species possess pharmacological properties that are used for medical purposes worldwide. In this paper, the essential oils from the aerial parts of Artemisia nilagirica and Artemisia maritima from the western Indian Himalaya region are described. The main compounds analyzed by simultaneous GC/MS and GC/FID were camphor and 1,8-cineole from A. maritima, and camphor and artemisia ketone from A. nilagirica. Additionally, the oils were evaluated for their antibacterial, antifungal, mosquito biting deterrent, and larvicidal activities. A. nilagirica essential oil demonstrated nonselective antifungal activity against plant pathogens Colletotrichum acutatum, Colletotrichum fragariae, and Colletotrichum gloeosporioides, whereas A. maritima did not show antifungal activity. Both Artemisia spp. exhibited considerable mosquito biting deterrence, whereas only A. nilagirica showed larvicidal activity against Aedes aegypti. Antibacterial effects assessed by an agar dilution assay demonstrated greater activity of A. maritima essential oil against Staphylococcus aureus and Pseudomonas aeruginosa compared to A. nilagirica.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.Item Computer-aided design of negative allosteric modulators of metabotropic glutamate receptor 5 (mGluR5): Comparative molecular field analysis of aryl ether derivatives(Elsevier Ltd, 2016) Selvam, Chelliah; Thilagavathi, Ramasamy; Narasimhan, Balasubramanian; Kumar, Pradeep; Jordan, Brian C.; Ranganna, Kasturi; Selvam, C.; Thilagavathi, R.; Narasimhan, B.; Kumar, P.; Jordan, B.C.; Ranganna, K.The metabotropic glutamate receptors (mGlu receptors) have emerged as attractive targets for number of neurological and psychiatric disorders. Recently, mGluR5 negative allosteric modulators (NAMs) have gained considerable attention in pharmacological research. Comparative molecular field analysis (CoMFA) was performed on 73 analogs of aryl ether which were reported as mGluR5 NAMs. The study produced a statistically significant model with high correlation coefficient and good predictive abilities. ? 2016