POTENTIAL IN VITRO ANTIOXIDANT AND PROTECTIVE EFFECT OF CASSIA FISTULA LINN. FRUIT EXTRACTS AGAINST INDUCED OXIDATIVE DAMAGE IN HUMAN ERYTHROCYTES

Objective: To evaluate the antioxidant potential and protective effect of Cassia fistula Linn. on hydrogen peroxide induced oxidative damage in erythrocytes.Methods: The in vitro antioxidant potency was screened by various established chemical, biochemical and electrochemical techniques. The Chemical assays allowed an evaluation of their total phenolic and flavonoid contents, total antioxidant capacity, reducing power, radical scavenging activities and metal chelating activity. Both, CFE (C. fistula ethanolic extract) and CFA (C. fistula aqueous extract) were analyzed for phenolic acids and flavonoids by HPLC. The biochemical assays were employed to evaluate the lipid peroxidation and protective effect on induced oxidative damage in erythrocytes. Electrochemical measurement of CFE and CFA was determined by cyclic voltammetry.Results: CFE showed strong antioxidant activity as well as >90% protection of erythrocytes. This might be due to the presence of high 464.3 ± 0.02 µg EGA mgˉ1total phenolics and 272.5 ± 0.5 µg EQ mgˉ1 total flavanoids while, CFA showed 75% antioxidant and protective activity possibly due to 250.84 ± 0.25 µg EGA mgˉ1 total phenolics and 195 ± 0.5 µg EQ mgˉ1 total flavonoid content. Moreover, HPLC of CFE and CFA exhibited widely known various good antioxidant molecules such as gallic acid, coumaric acid, ellagic acid, rutin, quercetin, myricetin and kaempferol. The cyclic voltammetric behavior shows the broad peak towards anodic potential represents the antioxidant property of CFE and CFA.Conclusion: The present study clearly indicates that, C. fistula Linn. Fruit is an excellent source of natural antioxidant.Â

Botany, chemistry, and pharmaceutical significance of Sida cordifolia: a traditional medicinal plant

Sida cordifolia Linn. belonging to the family, Malvaceae has been widely employed in traditional medications in many parts of the world including India, Brazil, and other Asian and African countries. The plant is extensively used in the Ayurvedic medicine preparation. There are more than 200 plant species within the genus Sida, which are distributed predominantly in the tropical regions. The correct taxonomic identification is a major concern due to the fact that S. cordifolia looks morphologically similar with its related species. It possesses activity against various human ailments, including cancer, asthma, cough, diarrhea, malaria, gonorrhea, tuberculosis, obesity, ulcer, Parkinson’s disease, urinary infections, and many others. The medical importance of this plant is mainly correlated to the occurrence of diverse biologically active phytochemical compounds such as alkaloids, flavonoids, and steroids. The major compounds include β-phenylamines, 2-carboxylated tryptamines, quinazoline, quinoline, indole, ephedrine, vasicinone, 5-3-isoprenyl flavone, 5,7-dihydroxy-3-isoprenyl flavone, and 6-(isoprenyl)- 3-methoxy- 8-C-β-D-glucosyl-kaempferol 3-O-β-D-glucosyl[1–4]-α-D-glucoside. The literature survey reveals that most of the pharmacological investigations on S. cordifolia are limited to crude plant extracts and few isolated pure compounds. Therefore, there is a need to evaluate many other unexplored bioactive phytoconstituents with evidences so as to justify the traditional usages of S. cordifolia. Furthermore, detailed studies on the action of mechanisms of these isolated compounds supported by clinical research are necessary for validating their application in contemporary medicines. The aim of the present chapter is to provide a detailed information on the ethnobotanical, phytochemical, and pharmacological aspects of S. cordifolia

Biosynthesis of Silver Nanoparticles Using Leaves of Acacia Melanoxylon and their Application as Dopamine and Hydrogen Peroxide Sensors

In work, we described a cost-effective and environmentally friendly technique for green synthesis of colloidal silver nanoparticles from an aqueous extract of fresh leaves of Acacia melanoxylon and their application as a dopamine and hydrogen peroxide sensor. The prepared silver nanoparticles were characterized using UV-Vis absorption spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta-potential analysis, thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), etc. This method was found to be cost-effective, eco-friendly when compared to that of chemical and physical methods of nanoparticle synthesis. Silver nanoparticles modified carbon paste electrode (CPE) was fabricated for the detection of dopamine and hydrogen peroxide. The fabricated electrode showed an excellent sensitivity towards the oxidation of both dopamine (DA) and hydrogen peroxide (H2O2) in 0.1 M phosphate buffer (PBS) solution at pH 7. The effects of scan rate, and concentration of the modifier and analyte were studied by the cyclic voltammetric technique. The result exhibits good electrocatalytic activity, diffusion-controlled process and linear increase in peak current with different concentrations of dopamine and hydrogen peroxide

Effect of Y2O3 Nanoparticles on Corrosion Study of Spark Plasma Sintered Duplex and Ferritic Stainless Steel Samples by Linear Sweep Voltammetric Method

The microstructure and corrosion properties of spark plasma sintered yttria dispersed and yttria free duplex and ferritic stainless samples were studied. Spark plasma sintering (SPS) was carried out at 1000°C by applying 50 MPa pressure with holding time of 5 minutes. Linear sweep voltammetry (LSV) tests were employed to evaluate pitting corrosion resistance of the samples. Corrosion studies were carried out in 0.5, 1 and 2 M concentration of NaCl and H2SO4solutions at different quiet time of 2, 4, 6, 8 and 10 seconds. Yttria dispersed stainless steel samples show more resistance to corrosion than yttria free stainless steel samples. Pitting potential decreases with increase in reaction time from 2 to 10 seconds. Similarly, as concentration of NaCl and H2SO4 increases from 0.5 M to 2 M the corrosion resistance decrements due to the availability of more Cl¯ and SO42¯ ions at higher concentration

Voltammetric Detection of Dopamine in Presence of Ascorbic Acid and Uric Acid at Poly (Xylenol Orange) Film-Coated Graphite Pencil Electrode

Poly (xylenol orange) film-coated graphite pencil electrode was fabricated for the detection of dopamine in the presence of ascorbic acid and uric acid in phosphate buffer solution of pH 7. The redox peaks obtained at modified electrode shows a good enhancement. The scan rate effect was found to be a diffusion-controlled electrode process. The electrochemical oxidation of dopamine was depended on pH, and the limit of detection was found to be 9.1 × 10−8 M. The simultaneous study gave and excellent result with great potential difference between dopamine and other bioactive organic molecules by using both cyclic voltammetric and differential pulse voltammetric techniques. The present modified graphite electrode was applied to the detection of dopamine in the injection samples, and the recovery obtained was satisfactory

Evaluation of performance characteristics of nano TiO2 and TiO2-ZnO composite for DSSC applications and electrochemical determination of potassium ferrocyanide using cyclic voltammetry

Nanoparticles of TiO _2 and TiO _2 -ZnO composite (2:1 molar ratio) were synthesized utilizing the sol-gel and solution combustion approaches, respectively. Scanning electron microscopic, energy dispersive x-ray, x-ray diffraction, UV-visible spectroscopy, and Brunauer–Emmett–Teller analysis were employed to characterize the synthesized nanoporous TiO _2 and the composite of TiO _2 -ZnO nanoparticles. Fabrication of dye-sensitized solar cells (DSSCs) was carried out by incorporating the synthesized nanoporous materials coating on the photoanodes using the doctor blade technique. Nano TiO _2 and the composite of TiO _2 -ZnO were also analyzed using cyclic voltammetry test, and their performance was compared for the electrochemical detection of potassium ferrocyanide. The composite of TiO _2 -ZnO exhibited better electrocatalytic activity in comparison with the pure TiO _2 nanoparticles. The fabricated DSSCs by employing nano TiO _2 particles and TiO _2 -ZnO composite as the semiconductor photoanode materials were compared for photovoltaic performance. The DSSC fabricated with TiO _2 nanoparticles exhibited better photovoltaic performance with an efficiency of 2.22% and a current density of 4.152 mA cm ^−2 than that fabricated with TiO _2 -ZnO composite with an efficiency of 0.0022% and a short circuit current density of 0.014 mA cm ^−2