Department Of Pharmaceutical Sciences and Natural Products
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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.