scholarly journals SYNTHESIS AND ANTIOXIDANT EVALUATION OF 3-BROMO-FLAVONE

Author(s):  
AYU MASYITA ◽  
RISFAH YULIANTY ◽  
YUSNITA RIFAI

Objective: The objective of the study was to obtain a flavone derivative compound through N-bromosuccinimide (NBS) reducing the reaction. Theantioxidant activity of the synthetic compound was then assayed by the 2,2-diphenyl-1-picrylhydrazyl method.Methods: Chalcone (3 mmol) as intermediate precursor was suspended with dimethyl sulfoxide and reacted with NBS (3 mmol), stirred at roomtemperature for 25 min and diluted in cold water. The synthesis of flavone derivatives resulted in yellow crystalline powder, freely soluble in methanoland ethanol, renamed 60% with a melting point of 87.7°C. Detection by thin-layer chromatography using hexane:chloroform (2:1) showed single spotwith Rf = 0.38 which is different from the Rf value of the starting compound (chalcone, 0.66 and 0.78).Results: The results of the characterization of the synthesized compound using ultraviolet-visible and Fourier transform-infared showed the groupcharacteristic containing C=C (1604.77 and 1639.49 cm-1), C=O (1681.93 cm-1), C-O-C (1242.16 cm-1), Ar-H (3032.1 and 3062.96 cm-1), and C-Br(663.51 cm-1) at maximum absorption of wavelength 253 nm.Conclusion: The synthesis of flavone using NBS resulted in 3-bromo-flavone with a weak antioxidant activity.

Author(s):  
Rand A Zeez ◽  
Ibrahim S Abaas ◽  
Enas J Kadhim

Objective: The aim of our study was to investigate chemical constituents of leaves and seeds of Elaeagnus angustifolia since no phytochemical investigation had been done previously in Iraq.Methods: Phytochemical screening of the extracts obtained from the leaves of E. angustifolia indicated the presence of flavonoids (type of flavonols), saponins, alkaloids, steroids, and terpenoids. Thin-layer chromatography fingerprinting and the spraying reagent (concentrated H2SO4 and vanillin in ethanol) were used to identify the hexane extract containing phytosterols.Results: The different chromatographic and spectroscopic results revealed the presence of β‐sitosterol isolated from E. angustifolia. Conclusion: The isolation and purification afforded white crystalline powder which was subjected to chemical and spectral identification by infrared and 1H-nuclear magnetic resonance. The compound was identified as β‐sitosterol.


2003 ◽  
Vol 58 (5) ◽  
pp. 410-414 ◽  
Author(s):  
Stefan Rannabauer ◽  
Wolfgang Schnick

By the reaction of (Me3SiNH)2SiClNMe2 with TiCl4 the by-product [Me2NH2]2[TiCl6] was obtained in form of crystals suitable for single-crystal XRD (Pnnm, Z = 2, a = 722.01(3), b = 1428.36(5), c = 703.31(3) pm, T = 200 K, 901 independent reflections, 57 variables, R1 = 0.0636). The product was also synthesized in higher yield by the stoichiometric reaction of two equivalents of [Me2NH2]Cl with TiCl4 in CHCl3 at room temperature as a yellow crystalline powder. Bis(dimethylammonium) hexachlorotitanate is built up from [TiCl6]2- anions forming elongated octahedra and [Me2NH2]+ ions. The [TiCl6]2- ions are connected by the [Me2NH2]+ ions through N-H···Cl hydrogen bridges forming an arrangement which resembles that of an expanded rutile structure type. The elongation of the [TiCl6]2- octahedra was also verified by IR and Raman spectroscopy, confirming a local symmetry reduction from Oh to D4h. The solubility of [Me2NH2]2[TiCl6] in MeNO2 and MeCN was determined by means of 14N-NMR to be about 0.1 mol% and 0.3 mol%, respectively.


2020 ◽  
Vol 3 (1) ◽  
pp. 30-33
Author(s):  
Muthulakshmi M ◽  
Madhumitha G

Nanotechnology is a field of applied science focused on design, synthesis and characterization of nanomaterials. The nickel and magnesium have improved their applications in transparent electrodes and nano electronics. In addition, magnesium oxide has moisture resistance and high melting point properties. In the present work has been carried out in the development of green crystalline powder of nickel doped magnesium oxide nanoparticles by Co-precipitation method, from the mixture of nickel chloride and magnesium chloride with KOH as solvent. From the XRD results, crystalline size of the particle can be observed. Spherical structure of Ni doped MgO nanoparticles were indicated by SEM results and powdered composition of samples were obtained from FTIR. EDAX represents the peak composition of the nanoparticle. The above analytical techniques have confirmed that the Ni doped MgO nanoparticles obtained from the mixture of NiCl2 and MgCl2.


2020 ◽  
Vol 6 (4) ◽  
pp. 380-387
Author(s):  
Jaswinder Kaur Virk ◽  
Vikas Gupta ◽  
Mukesh Maithani ◽  
Ravindra K. Rawal ◽  
Sanjiv Kumar ◽  
...  

Background: Vriddhi is one of the Rasayana herbs in Ayurveda broadly used in vitality, strengthening Ayurvedic formulations. To fulfill steeply increased demand and declined supply, tubers have been collected in destructive manner resulting in reduced plant population and pushing the plant in Red list of IUCN endangered species. However, manufacturers are using substitutes and other substandard drugs leading to adulteration which puts the importance of therapeutically rich herbal plants at stake. Lack of chemical markers is the main inability of regulatory authorities for not taking any action against this adulteration. Objective: Isolation of chemical marker of plant that can be used as a reference compound for identification of unauthorized substitution. Methods: Preliminary phytochemical screening of methanolic and toluene extract of H. intermedia D. Don was done using standard methods followed by column chromatography for the isolation of phytoconstituents. A total of 3004 fractions were collected with Thin Layer Chromatography (TLC) profiling and different fractions were pooled. A single compound was isolated and confirmed by chemical test, melting point, spectral analysis and compared with the literature. Results: Phytochemical screening of extracts shows the presence of alkaloids, carbohydrates, steroids, terpenoids, flavonoids, tannins and phenolics. A pure white crystalline powder was isolated by column chromatography which was characterized as 3,5-dimethoxy-4- hydroxycinnamic acid (Sinapic acid) with the help of IR and Mass spectroscopy. Conclusion: This is the first report of Sinapic acid as a novel compound from Vriddhi, Habenaria genus and Orchidaceae family. It can be used as a marker for the identification of unauthorized substitution and adulteration claiming the use of Vriddhi.


1998 ◽  
Vol 548 ◽  
Author(s):  
S. Sarciaux ◽  
A. Le Gal La Salle ◽  
A. Verbaere ◽  
Y Piffard ◽  
D. Guyomard

ABSTRACTA large variety of EMD and HTMD samples with various oxygen and water contents and various structural parameters Pr and Mt has been prepared. We show that the physico-chemical and structural parameters of the λ-MnO2 compounds are related to the synthesis conditions. New compounds were obtained with unusual amounts of intergrowth and twinning defects.The Li insertion study focuses on a comprehensive investigation of the relationships between the material characteristics of the samples and their Li insertion behavior, and on the structural characterization of selected compounds after cycling. The oxygen content drastically affects the shape of the discharge curve after the first cycle and the total reversible capacity. The amount of structural water has an influence on the transformation kinetics of the starting phase. For optimized oxygen content (y= 2 in MnOY), the intrinsic reversible Li insertion capacity is maximum when the amount of microtwinning defects is minimum and when the structure is either mostly Ramsdellite or faulted Pyrolusite. Results show that, upon cycling, the λ-MnO2 structure seems to evoluate towards less Pyrolusite defects together with the apparition of new kinds of defects.This work shows that λ-MnO2, compounds could be good candidates for the cathode application of Li-metal rechargeable batteries, provided that the physico-chemical and structural parameters of the starting compound are well chosen.


2002 ◽  
Vol 68 (12) ◽  
pp. 6237-6245 ◽  
Author(s):  
Tara D. Sutherland ◽  
Irene Horne ◽  
Robyn J. Russell ◽  
John G. Oakeshott

ABSTRACT The gram-positive bacterium Mycobacterium sp. strain ESD is able to use the cyclodiene insecticide endosulfan as a source of sulfur for growth. This activity is dependent on the absence of sulfite or sulfate in the growth medium. A cosmid library of strain ESD DNA was constructed in a Mycobacterium-Escherichia coli shuttle vector and screened for endosulfan-degrading activity in Mycobacterium smegmatis, a species that does not degrade endosulfan. Using this method, we identified a single cosmid that conferred sulfur-dependent endosulfan-degrading activity on the host strain. An open reading frame (esd) was identified within this cosmid that, when expressed behind a constitutive promoter in a mycobacterial expression vector, conferred sulfite- and sulfate-independent β-endosulfan degradation activity on the recombinant strain. The translation product of this gene (Esd) had up to 50% sequence identity with an unusual family of monooxygenase enzymes that use reduced flavins, provided by a separate flavin reductase enzyme, as cosubstrates. An additional partial open reading frame was located upstream of the Esd gene that had sequence homology to the same monooxygenase family. A flavin reductase gene, identified in the M. smegmatis genome, was cloned, expressed, and used to provide reduced flavin mononucleotide for Esd in enzyme assays. Thin-layer chromatography and gas chromatography analyses of the enzyme assay mixtures revealed the disappearance of β-endosulfan and the appearance of the endosulfan metabolites, endosulfan monoaldehyde and endosulfan hydroxyether. This suggests that Esd catalyzes the oxygenation of β-endosulfan to endosulfan monoaldehyde and endosulfan hydroxyether. Esd did not degrade either α-endosulfan or the metabolite of endosulfan, endosulfan sulfate.


2000 ◽  
Vol 88 (2) ◽  
Author(s):  
D. Rößler ◽  
K. Franke ◽  
R. Süß ◽  
E. Becker ◽  
H. Kupsch

A natural moor soil humic acid (HA) was labeled with Tc-99m via reduction of pertechnetate with stannous chloride. The humic acid species obtained were characterized by thin layer chromatography (TLC), gel permeation chromatography (GPC), sequential chromatographic analysis (SCA), paper electrophoresis and micropore filtration. Labeling was found to take place in all ranges of molecular weight. Due to the complex humic acid composition and the formation of hydroxo species the labeling yields strongly depend on the separation conditions, ranging from 42% to 80%. The pH-dependent distribution of mobile and immobile species was determined by SCA for HTcO


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