Sunil Sharma

Bio: Sunil Sharma is an academic researcher from Guru Jambheshwar University of Science and Technology. The author has contributed to research in topics: Glycogen & Diabetes mellitus. The author has an hindex of 18, co-authored 57 publications receiving 1099 citations.

A Review on Biological Activities and Chemical Synthesis of Hydrazide Derivatives

Abstract: There has been considerable interest in the development of novel compounds with anticonvulsant, antioxidant, hormone antagonist, analgesic, anti-inflammatory, antiplatelet, antimalarial, antimicrobial, antimycobacterial, antitumoral, vasodilator, antiviral and anti-trypanosomal activities. Hydrazones possessing an azometine -NHN=CH- proton constitute an important class of compounds for new drug development. Therefore, many researchers have synthesized these compounds as target structures and evaluated their biological activities. These observations have been guiding for the development of new hydrazide derivatives that possess varied biological activities.

Oxidative Stress: Major Threat in Traumatic Brain Injury.

Abstract: Background & objective Traumatic Brain Injury (TBI) is one of the major causes of mortality and morbidity worldwide. It represents mild, moderate and severe effects of physical assault to brain which may cause sequential, primary or secondary ramifications. Primary injury can be due to the first physical hit, blow or jolt to one of the brain compartments. The primary injury is then followed by secondary injury which leads to biochemical, cellular, and physiological changes like blood brain barrier disruption, inflammation, excitotoxicity, necrosis, apoptosis, mitochondrial dysfunction and generation of oxidative stress. Apart from this, there is also an immediate increase in glutamate at the synapses following severe TBI. Excessive glutamate at synapses in turn activates corresponding NMDA and AMPA receptors that facilitate excessive calcium influx into the neuronal cells. This leads to the generation of oxidative stress which further leads to mitochondrial dysfunction, lipid peroxidation and oxidation of proteins and DNA. As a consequence, neuronal cell death takes place and ultimately people start facing some serious disabilies. Conclusion In the present review we provide extensive overview of the role of reactive oxygen species (ROS)-induced oxidative stress and its fatal effects on brain after TBI.

Oculohypotensive effect of angiotensin-converting enzyme inhibitors in acute and chronic models of glaucoma.

Abstract: We have studied the effects of various angiotensin-converting enzyme (ACE) inhibitors on intraocular pressure (IOP) of rabbits with experimentally induced ocular hypertension and their mechanism of action. Acute ocular hypertension was induced by infusion of 5% glucose (15 ml/kg) through marginal ear vein, whereas chronic glaucoma was induced by injection of alpha-chymotrypsin into the posterior chamber of the eye. IOP was measured by tonometer. All ACE inhibitors were instilled topically in the eye in a sterile solution. The effect of ACE inhibitors also was studied on serum cholinesterase (true and pseudo) and the enzyme ACE in vitro. Enalaprilat, ramiprilat, and fosinopril produced a time-dependent decrease of IOP in both acute and chronic models of ocular hypertension in rabbits. The decrease in IOP was observed for >4 h, and the extent of decrease was comparable to that with both pilocarpine and betaxolol. Prodrugs enalapril and ramipril failed to produced any change in IOP. Losartan also produced a significant decrease in IOP in the chronic model of ocular hypertension in rabbits. All the three ACE inhibitors were found to inhibit ACE activity in aqueous humor. The enzyme cholinesterase was found to be inhibited by enalaprilat, ramiprilat, and fosinopril. However, atropine did not alter the IOP-lowering effect of enalaprilat in rabbits. Indomethacin pretreatment produced slight but significant inhibition of the IOP-lowering effect of enalaprilat in rabbits. Our data suggest that ACE inhibitors enalaprilat, ramiprilat, and fosinopril produce a significant ocular hypotensive effect in acute and chronic models of ocular hypertension in rabbits. Inhibition of ACE in aqueous humor, and in ocular tissues, resulting in reduced angiotensin II formation, could be one of the major mechanisms responsible for the IOP reduction by ACE inhibitors in rabbits.

Acute and chronic animal models for the evaluation of anti-diabetic agents

Abstract: Diabetes mellitus is a potentially morbid condition with high prevalence worldwide thus being a major medical concern. Experimental induction of diabetes mellitus in animal models is essential for the advancement of our knowledge and understanding of the various aspects of its pathogenesis and ultimately finding new therapies and cure. Experimental diabetes mellitus is generally induced in laboratory animals by several methods that include: chemical, surgical and genetic (immunological) manipulations. Most of the experiments in diabetes are carried out in rodents, although some studies are still performed in larger animals. The present review highlights the various methods of inducing diabetes in experimental animals in order to test the newer drugs for their anti-diabetic potential.

Cinnamon: A Multifaceted Medicinal Plant

Abstract: Cinnamon (Cinnamomum zeylanicum, and Cinnamon cassia), the eternal tree of tropical medicine, belongs to the Lauraceae family. Cinnamon is one of the most important spices used daily by people all over the world. Cinnamon primarily contains vital oils and other derivatives, such as cinnamaldehyde, cinnamic acid, and cinnamate. In addition to being an antioxidant, anti-inflammatory, antidiabetic, antimicrobial, anticancer, lipid-lowering, and cardiovascular-disease-lowering compound, cinnamon has also been reported to have activities against neurological disorders, such as Parkinson's and Alzheimer's diseases. This review illustrates the pharmacological prospective of cinnamon and its use in daily life.

Oximes and Hydrazones in Bioconjugation: Mechanism and Catalysis

Abstract: The formation of oximes and hydrazones is employed in numerous scientific fields as a simple and versatile conjugation strategy. This imine-forming reaction is applied in fields as diverse as polymer chemistry, biomaterials and hydrogels, dynamic combinatorial chemistry, organic synthesis, and chemical biology. Here we outline chemical developments in this field, with special focus on the past ∼10 years of developments. Recent strategies for installing reactive carbonyl groups and α-nucleophiles into biomolecules are described. The basic chemical properties of reactants and products in this reaction are then reviewed, with an eye to understanding the reaction’s mechanism and how reactant structure controls rates and equilibria in the process. Recent work that has uncovered structural features and new mechanisms for speeding the reaction, sometimes by orders of magnitude, is discussed. We describe recent studies that have identified especially fast reacting aldehyde/ketone substrates and structural effects...

Iconography : Advanced glycation end products, their receptors and diabetic angiopathy

Abstract: The role of chronic hyperglycemia in the development of diabetic microvascular complications and in neuropathy has been clearly established by intervention studies. However, the biochemical or cellular links between elevated blood glucose levels, and the vascular lesions remain incompletely understood. This review focuses on the consequences of hyperglycemia on the formation of advanced glycation end-products (AGEs), and on the role of AGEs and of their specific receptors (RAGE) in the functional and anatomical alterations of the vascular wall. AGEs are formed during the Maillard reaction by the binding of aldoses on free NH(2) groups of proteins, which, after a cascade of molecular rearrangements, result in molecules of brown color and specific fluorescence. Experimental studies have indicated that the binding of AGEs to RAGE activates cells, particularly monocytes and endothelial cells. Activated endothelial cells produce cytokines, and express adhesion molecules and tissue factor. The role of AGEs in increased oxidative stress, and in the functional alterations in vascular tone control observed in diabetes, in part related to a reduction in nitric oxide, is also discussed. The microvascular retinal, glomerular and nerve lesions induced by experimental diabetes in animals are prevented by an inhibitor of AGEs formation, aminoguanidine. The administration in diabetic animals of recombinant RAGE, which hinders AGEs-RAGE interaction, prevents hyperpermeability and vascular lesions. These data suggest a central role of AGEs and RAGE in the development of chronic complications of diabetes.