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Uttam Das

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Trianthema portulacastrum L.: Traditional medicine in healthcare and biology

Indian Journal of Biochemistry and Biophysics

Medicinal plants are the major folk and traditional medicine for the prevention of diseases world... more Medicinal plants are the major folk and traditional medicine for the prevention of diseases worldwide. Trianthema portulacastrum L. (family: Aizoaceae), a small perennial weed, found in the America, Africa, India, and other regions of the world, and are extensively used not only as medicine but also as vegetable for its various health benefits. Phytochemical analysis of T. portulacastrum reveals the presence of alkaloids, phytosterols, terpenoids, saponins, flavonoids and phenolic compounds. In vitro and in vivo studies have demonstrated its pharmacological and biological activities. Different parts of T. portulacastrum L. are conventionally being used as analgesic, anti-pyretic, lipid lowering and microbicide agent; and protect liver and kidney from carcinogen, inflammation and oxidant chemicals.

Synthesis, characterization and structure of pentadentate azoimine ligand and its dinuclear copper complex

Department of Chemistry, University of Kalyani, Kalyani-741 235, West Bengal, India Department of... more Department of Chemistry, University of Kalyani, Kalyani-741 235, West Bengal, India Department of Chemistry, Kalyani Govt. Engineering College, Kalyani-741 235, West Bengal, India E-mail : [email protected] The new protonated form of pentadentate ligand [H<sub>2</sub>L]ClO<sub>4</sub> , 1, was synthesized by metal assisted template pathway. Reaction of 2,6-diformyl-4-methyl phenol and 2-(<em>p</em>-chloro phenyl) azo aniline in presence of zinc perchlorate afforded 1. New dinuclear [(L)<sub>2</sub>Cu<sub>2</sub> ](ClO<sub>4</sub> )<sub>2</sub> , 2, complex was prepared by the reaction of [H<sub>2</sub>L]ClO<sub>4</sub> , 1 with Cu(ClO<sub>4</sub> )<sub>2</sub> · 6H<sub>2</sub>O. Also the [(L)<sub>2</sub>Cu<sub>2</sub> ](ClO<sub>4</sub> )<sub>2</sub> , 2, complex was isolated upon reaction of...

Antioxidant Properties of Trianthema Portulacastrum and Protection Against Ionizing Radiation-Induced Liver Damage Ex vivo

Indian Journal of Clinical Biochemistry

Antioxidants in fruits and vegetables protect cells against radiation induced damage. Trianthema ... more Antioxidants in fruits and vegetables protect cells against radiation induced damage. Trianthema portulacastrum is used as vegetables from ancient time. The effects of T. Portulacastrum ethanolic extracts against γ-radiation induced liver tissue damage ex vivo were evaluated in this study. Antioxidant phytochemicals present in T. Portulacastrum includes flavonoids [3.3 ± 0.15 to 10 ± 0.16 mg catethin equivalent (CE)/g fresh weight (fw)], ascorbic acid (0.15 ± 0.03 to 0.21 ± 0.03 mg/g fw), glutathione s-transferase (GST) (1.57 ± 0.06 to 3.59 ± 0.05 nmole/mg fw/min), superoxide dismutase (SOD) (1.6 ± 0.03 to 1.79 ± 0.04 U/min), peroxidase (3.26 ± 0.18 to 6.38 ± 0.03 U/g fw) and catalase (0.51 ± 0.03 to 2.84 ± 0.15 mg H 2 O 2 decomposed/g fw/min). Total phenolic content varied from 122.9 ± 8.7 to 302.8 ± 15.7 mg gallic acid equivalent/g extract, and flavonoid content varied from 316.7 ± 33.3 to 800.7 ± 28.9 CE mg/g extract. The IC 50 value of Nitric oxide (NO • ) scavenging activity of extracts varies from 208.7 to 387.4 µg/ ml. Pre-treatment with the T. portulacastrum extracts mitigated the 4-Gy gamma(γ) radiation-induced oxidative stress related parameters in hepatic tissue such as TBARS, catalase, nitrite, Glutathione reductase (GR), SOD and GST in dose dependent manner. The ethanolic extract of the stem from T. Portulacastrum demonstrated highest protection in comparison to leaf and whole plant extracts. This study demonstrated the hepatoprotective efficacy of T. portulacastrum extracts against γ-radiation in ex-vivo condition was possibly due to its potential antioxidant properties of phenolic and flavonoids present in extracts.

Trianthema portulacastrum L. extract protects against gamma radiation induced human red blood cell membrane damage in vitro

Radiation-induced oxidation of membrane lipids and proteins appear to be responsible for damaging... more Radiation-induced oxidation of membrane lipids and proteins appear to be responsible for damaging the red cell membranes. The membrane integrity of circulating red blood cells (RBCs) is compromised by the deleterious action of γ-radiation in humans. Trianthema portulacastrum L. is an inexpensive, non-toxic herb commonly used in ayurvedic medicine due to its significant pharmacological activities. Methanolic extract of different parts of T. portulacastrum L. contain carbohydrates, polyphenols, flavonoids, alkaloids and terpenoids; whereas saponin is present only in root extract, while cardiac glycosides are absent in root extract. Here, we explored the radio-protective role of leaf, stem, root and whole plant extracts of T. portulacastrum L. against the γ-radiation induced membrane damage of human red blood cells (RBCs). The RBCs on γ-irradiation (4 Gy) exposure showed elevated TBARS level while inhibited ATPase activities in the membrane ghosts. Treatment of RBCs-with different extr...

Crystal Structure and Solid-State Properties of Metal Complexes of the Schiff Base Ligands Derived from Diacetylmonoxime: A Brief Review

Stability of Coordination Compounds [Working Title], 2020

The fabulous advancement of a large section of modern coordination chemistry depends upon differe... more The fabulous advancement of a large section of modern coordination chemistry depends upon different kinds of strategically designed and functionally tuned ligand systems; Schiff base ligands play a pivotal role among them. Such Schiff bases become more motivating when they are designed to be synthesized using very simple organic molecules. This paper reviews our work on a family of three functionally different types of Schiff base ligands, derived from diacetylmonoxime, which have been employed to synthesize mononuclear metal complexes with various binding modes of ligands and topologies around the metal centers. Such Schiff base ligands have been synthesized by reacting diacetylmonoxime with diethylenetriamine, 1,3-diaminopropane-2-ol, and morpholine N-thiohydrazide. The synthesized Schiff bases and the metal complexes of such "privileged ligands" show many interesting supramolecular coordination architectures involving different weak forces, e.g., H-bonding, C-HÁÁÁπ interactions, etc.

Global dynamics of a tritrophic food chain model subject to the Allee effects in the prey population with sexually reproductive generalized‐type top predator

Computational and Mathematical Methods, 2019

In this article, we have considered a continuous tritrophic food chain model subject to the Allee... more In this article, we have considered a continuous tritrophic food chain model subject to the Allee effect on the prey growth function with prey-dependent Holling type II functional response between the prey and intermediate predator; Crowley-Martin senses functional response between intermediate predator and top predator, and the top predator is of sexually reproductive type. We have established the positivity and boundedness of the system and the condition of existence of different equilibrium points. The local and global stability of the solutions about the various equilibrium points has been investigated. The center manifold theorem has been used to find the nature of the solution in the neighborhood of the nonhyperbolic equilibrium points and the direction of Hopf bifurcations. Numerical simulation has been carried out to establish the theoretical findings and finally some concluding remarks are given.

Synthesis of New Oxido-Vanadium Complexes: Catalytic Properties and Cytotoxicity

Journal of Chemical Research, 2018

Reaction of 2,3-dihydroxy benzaldehyde with 2-({2-amino phenyl}diazenyl)phenol afforded the ligan... more Reaction of 2,3-dihydroxy benzaldehyde with 2-({2-amino phenyl}diazenyl)phenol afforded the ligand 3-(2-(2-hydroxyphenyl)diazenyl)-4-alkylphenyliminomethyl)benzene-1,2-diol. Reaction of H2L with VOSO4. 5H2O gave the oxido-vanadium(IV) complexes [(L)VO], which exhibited a quasi-reversible oxidative cyclic voltammetric response in a V(IV)/V(V) oxidative process. The complexes act as catalysts in the oxidation of organic thioethers and bromination of phenol. Their cytotoxic properties were examined for three cancer cell lines.

Direct Conversion of Alcohols into Alkenes by Dehydrogenative Coupling with Hydrazine/Hydrazone Catalyzed by Manganese

Angewandte Chemie (International ed. in English), Jan 6, 2018

We have developed unprecedented methods for the direct transformation of primary alcohols to alke... more We have developed unprecedented methods for the direct transformation of primary alcohols to alkenes in the presence of hydrazine, and for the synthesis of mixed alkenes by the reaction of alcohols with hydrazones. The reactions are catalyzed by a manganese pincer complex and proceed in absence of added base or hydrogen acceptors, liberating dihydrogen, dinitrogen, and water as the only byproducts. The proposed mechanism, based on preparation of proposed intermediates and control experiments, suggests that the transformation occurs through metal-ligand cooperative N-H activation of a hydrazone intermediate.

N-Substituted Hydrazones by Manganese-Catalyzed Coupling of Alcohols with Hydrazine: Borrowing Hydrogen and Acceptorless Dehydrogenation in One System

Angewandte Chemie (International ed. in English), Jan 19, 2018

An unprecedented one-step synthesis of N-substituted hydrazones by coupling of alcohols with hydr... more An unprecedented one-step synthesis of N-substituted hydrazones by coupling of alcohols with hydrazine is reported. This partial hydrogen-borrowing reaction is catalyzed by a new manganese pincer complex under mild reaction conditions, thus liberating water and dihydrogen as the only byproducts. Mechanistic insight, based on the observation of intermediates, is provided.

Manganese Catalyzed α-Olefination of Nitriles by Primary Alcohols

Journal of the American Chemical Society, Aug 30, 2017

Catalytic α-olefination of nitriles using primary alcohols, via dehydrogenative coupling of alcoh... more Catalytic α-olefination of nitriles using primary alcohols, via dehydrogenative coupling of alcohols with nitriles, is presented. The reaction is catalyzed by a pincer complex of an earth-abundant metal (manganese), in the absence of any additives, base, or hydrogen acceptor, liberating dihydrogen and water as the only byproducts.

Design, synthesis and properties of orthopalladated complexes: Proheterogeneous catalyst

Polyhedron, 2016

Abstract The reaction of multidentate ligand, 3-((E)-(2-((E)-4-aryldiazenyl)phenylimino)methyl)be... more Abstract The reaction of multidentate ligand, 3-((E)-(2-((E)-4-aryldiazenyl)phenylimino)methyl)benzene-1,2-diol, H2L (H2L1, 1a; H2L2, 1b and H2L3, 1c) and (E)-2-((2-(aryldiazenyl)phenylamino)methyl)phenol, HA (HA1, 3a; HA2, 3b and HA3, 3c) [where H represents the dissociable protons upon complexation, and aryl groups of H2L and HA are phenyl for H2L1 and HA1, p-methylphenyl for H2L2 and HA2, and p-chlorophenyl for H2L3 and HA3], with Na2PdCl4 separately afforded orthometallated complexes [(L)Pd], (2a, 2b and 2c) and [(A)PdCl] (4a, 4b and 4c) respectively. In the case of [(L)Pd], the deprotonated L2− ligands bind palladium (II) in a tetradentate (C,N,N,O) fashion whereas in the case of [(A)PdCl], the deprotonated A− ligands bind Pd(II) in tridentate (C,N,N) manner. X-ray structures of [(L1)Pd], (2a) and [(A1)PdCl] (4a) were determined to confirm the molecular structures. Both the complexes 4a and 5a exhibited catalytic activity toward Suzuki and Heck reactions. Conversion of [(A)PdCl] to its oxidized form upon ligand oxidation is reported.

Global Dynamics of an Exploited Prey-Predator Model with Constant Prey Refuge

ISRN Biomathematics, 2013

This paper describes a prey-predator model with Holling type II functional response incorporating... more This paper describes a prey-predator model with Holling type II functional response incorporating constant prey refuge and harvesting to both prey and predator species. We have analyzed the boundedness of the system and existence of all possible feasible equilibria and discussed local as well as global stabilities at interior equilibrium of the system. The occurrence of Hopf bifurcation of the system is examined, and it was observed that the bifurcation is either supercritical or subcritical. Influences of prey refuge and harvesting efforts are also discussed. Some numerical simulations are carried out for the validity of theoretical results.

Dynamical behaviour of a delayed stage-structured predator–prey model with nonmonotonic functional response

International Journal of Dynamics and Control, 2014

In this paper we have considered a prey-predator type fishery model with stage-structure for pred... more In this paper we have considered a prey-predator type fishery model with stage-structure for predator and harvesting of both the prey and predator species. Our study shows that, using the harvesting effort as control, it is possible to break the cycle behaviour of the system and drive it to required steady state. It is also shown that the time delay can cause a stable equilibrium to become unstable and even a switching of stabilities. We also investigate the stability of the bifurcating limit cycles and direction of Hopf bifurcation by applying the normal form method and the center manifold theorem. Lastly some numerical simulations are carried out to validate our analytical results.

format_quoteBifurcations can jeopardize species in food chains, potentially leading to extinction in changing ecosystems.format_quote

Bifurcation Analysis of a Delayed Predator-Prey Model with Holling Type III Functional Response and Predator Harvesting

Journal of Nonlinear Dynamics, 2014

This paper tries to highlight a delayed prey-predator model with Holling type III functional resp... more This paper tries to highlight a delayed prey-predator model with Holling type III functional response and harvesting to predator species. In this context, we have discussed local stability of the equilibria, and the occurrence of Hopf bifurcation of the system is examined by considering the harvesting effort as bifurcation parameter along with the influences of harvesting effort of the system when time delay is zero. Direction of Hopf bifurcation and the stability of bifurcating periodic solutions are also studied by applying the normal form theory and the center manifold theorem. Lastly some numerical simulations are carried out to draw for the validity of the theoretical results.

Effect of harvesting and infection on predator in a prey–predator system

Nonlinear Dynamics, 2015

In this article, we propose and analyze a mathematical model of a prey-predator system where infe... more In this article, we propose and analyze a mathematical model of a prey-predator system where infection spreads among the predators and predator is subject to harvesting. Dynamical behavior of the system is studied, and the consequences of harvesting on the long-run equilibrium fish biomass are evaluated. Optimal control theory has been used to determine the optimal harvesting policy for fish stocks to maximize the discounted utility of harvesting over time, employing a constant time discount rate. Some simulation works are given to verify our analytic results.

Aggregation enhanced emission (AEE) in organic salt: A structure-property correlation based on single crystal studies

Journal of Chemical Sciences, 2014

Salt formation has been shown as a simple strategy to induce aggregated induced emission or aggre... more Salt formation has been shown as a simple strategy to induce aggregated induced emission or aggregated enhanced emission in primary ammonium salts derived from 9-anthracene carboxylic acid, 1-pyrene carboxylic acid, 3-coumarin carboxylic acid and histamine. All the salts displayed enhanced fluorescence in their solid state compared to that in their solution state. Single crystal structure of the salt of 9-anthracene carboxylic acid i.e., His-anthracene revealed that restricted intramolecular rotation of the fluorphoric moiety (anthracene) was responsible for such radiative pathway leading to enhanced emission.

A dynamic reaction model of a prey-predator system with stage-structure for predator

Modern Applied Science, 2010

In this paper, we have considered a prey-predator model with stage-structure for predator and sel... more In this paper, we have considered a prey-predator model with stage-structure for predator and selective harvesting of prey species. A regulatory agency controls exploitation by imposing a tax per unit biomass of the prey species. The existence of steady states and their stability are studied. The problem of optimal harvesting policy is solved by using Pontryagin's maximal principle. It is also shown that time delay may cause a stable equilibrium to become unstable. Finally, some numerical simulations are carried out.

Synthesis and structure of copper(II) complexes of two new poly(2-pyridylalkyl)diamine ligands

Inorganica Chimica Acta, 2004

The new complexes of compositions [(L a) 2 Cu] and [(L b) 2 Cu] were prepared by treating with 2-... more The new complexes of compositions [(L a) 2 Cu] and [(L b) 2 Cu] were prepared by treating with 2-hydroxy-5-methyl-3-(2-aryldiazenyl)phenylimino) methyl) benzaldehyde (HL a) and ethyl-2-cyano-3-(2hydroxy-5-methyl-3-(-(2-aryldiazenyl) phenylimino) methyl) phenyl) acrylate (HL b) ligands [where aryl is phenyl for HL 1 a and HL 1 b ; p-methyl phenyl for HL 2 a and HL 2 b ; and p-chloro phenyl for HL 3 a and HL 3 b ] with Cu(OAc) 2 .H 2 O, respectively. Both the bis copper(II) complexes consist of tridentate (N,N,O) anionic ligands, L − a or L − b. X-ray structures of the representative complexes [(L 1 a) 2 Cu] and [(L 2 b) 2 Cu] were determined to confirm the molecular species unequivocally. The molecular structure of copper complexes exhibited tetragonally distorted (Jahn-Teller) geometry consistent with the d 9 configuration of Cu(II) metal ion. Oxidation of benzyl alcohols using the newly synthesized complexes as catalyst has been studied. Photoluminescence properties of [(L 2 a) 2 Cu] and [(L 2 b) 2 Cu] were exploited for selective cyanide recognition. The [(L b) 2 Cu], complexes displayed antibacterial activity toward gram positive and gram negative bacteria.

format_quoteCu(II) complexes effectively catalyzed selective oxidation of benzyl alcohol to carbonyl compounds, highlighting their utility in organic synthesis.format_quote

Attenuation of Hyperglycemia and Hyperlipidemia in Streptozotocin-Induced Diabetic Rats by Aqueous Extract of Seed of Tamarindus indica

Biological and Pharmaceutical Bulletin, 2005

Streptozotocin (STZ)-induced diabetic rats were divided into mild diabetic (MD) and severe diabet... more Streptozotocin (STZ)-induced diabetic rats were divided into mild diabetic (MD) and severe diabetic (SD) on the basis of fasting blood glucose (FBG) levels. Diabetes was confirmed here by intravenous glucose tolerance test (GTT), biochemical assay of glycogen content in liver and skeletal muscle, glucose-6-phosphatase activity in liver, and serum insulin levels. Hyperlipidemia developed in these experimental diabetic rats was assessed by quantification of total cholesterol (TC), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc) and triglyceride (TG) in serum. Aqueous extract of seed of Tamarindus indica was given to MD and SD rats at the dose of 80 mg and 120 mg/0.5 ml distilled water/100 g body weight/d respectively for 14 d. Significant attenuation of hyperglycemia was indicated by measuring FBG, glycogen level and glucose-6-phosphatase activity along with monitoring of intravenous GTT and serum insulin level. Similarly, correction of hyperlipidemia in diabetic rats after this extract supplementation was confirmed by significant reduction in the levels of above-mentioned hyperlipidemic indicators. Intravenous GTT was performed that highlights the antidiabetic action of this extract is not due to its effect on the intestinal rate of glucose absorption but may be due to modulation of intracellular glucose utilization in target organs. This study focus the efficacy of this extract for the management of experimental diabetes in rat model which may shed some light on the scientific basis of ancient herbal therapy in this line using this seed.

format_quoteAqueous extract of T. indica significantly reduced fasting blood glucose levels in mild and severe diabetic rats after 14 days.format_quote

Antioxidant and Antiinflammatory Activities of Different Solvent Extracts and Isolated Compounds of Ipomoea pes-caprae (L) Sweet of Sunderban Mangrove Eco-complex

Asian Journal of Chemistry, 2013

Ipomoea pes-caprae (L) sweet belonging to the family Convolvulaceae are widely distributed in tro... more Ipomoea pes-caprae (L) sweet belonging to the family Convolvulaceae are widely distributed in tropical and subtropical countries. Some of the species belonging to the genus Ipomoea are frequently used in folk medicine for the treatment of several diseases 1,2. It had been employed as a herbal remedy in countries like Brazil, Mexico, Thailand, India to cure inflammations, colonic, diuretic disorders, gonorrhoea, dolorous processes 3,4. I. pes-caprae is known as Rinonina in Mexico which is used as infusions for kidney ailments and as decoctions to treat functional digestive disorders, colic, dysentery, internal-external pain and inflammatory conditions 5. Pre-clinical and clinical investigations have confirmed some pharmacological properties 6-9 of this plant, but no systematic pharmacological and chemical work was done on this species, particularly grown up in the struggling marine environment of the Sunderban mangrove eco-complex where it is used for the prevention of rheumatoid arthritis 10. This prompted the present investigator to study the antioxidant and antiinflammatory activities of the plant to establish the scientific basis of such application and to identify the chemical entities responsible for such activities.

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