A quantitative method for the detection and validation of catalase activity at physiological concentration in human serum, plasma and erythrocytes.

A novel method has been proposed to develop a simple, rapid, sensitive and affordable chromogenic attempt for the quantification of catalase (CAT) activity in blood samples. The method is based on the oxidation of pyrocatechol (PC) to give quinone form which by oxidative coupling with aminyl radical of 4-aminoantipyrine (4-AAP) resulting from HO/CAT to produce a pink colored quinone-imine product with λ = 530 nm in a 100 mmol/L of tris buffer of pH 9.8 at room temperature (30 °C).

Critical Review on the Analytical Mechanistic Steps in the Evaluation of Antioxidant Activity.

Electrophysiological systems are prone to release free radicals for functioning of biological system with proper balancing of antioxidant-prooxidant ratio for establishing a healthy living system. The biostress condition releases different reactive oxygen species, such as hydroxyl, alkoxyl, superoxide, hydrogen peroxide, hydroperoxyl, ozone, singlet oxygen, hypochlorus acid, thiyl radical, etc. This review tries to discuss the general aspects of the antioxidant assay methodologies that are currently used for the detection of antioxidant property.

Ninhydrin-sodium molybdate chromogenic analytical probe for the assay of amino acids and proteins.

A sensitive method has been proposed for the quantification of amino acids and proteins using ninhydrin and sodium molybdate as chromogenic substrates in citrate buffer of pH5.6. A weak molybdate-hydrindantin complex plays the role in the formation of Ruhemann's purple.

Quantification of antioxidants by using chlorpromazine hydrochloride: application of the method to food and medicinal plant samples.

Chlorpromazine hydrochloride (CPH) (3-(2-chloro-phenothiazine-10-yl)-propyl] dimethylamine hydrochloride) has been the subject of a large number of studies employing a broad spectrum of oxidants, and chosen to examine the course of electron transfer reactions. We report on a method to determine the antioxidant activity of some food and medicinal plants using the oxidation of CPH by chromium(VI) to form a stable CPH radical in the 1:1 orthophosphoric acid-ethyl alcohol (OPA-EtOH) medium. The pink color of the control solution was measured at λ(max) of 530 nm.

Quantification and evaluation of kinetic bio-catalytic pathway of horseradish peroxidase in an electron mediated reaction system and its applications in plant extracts.

The intermolecular coupling of 2,5-dimethoxyaniline (DMA) as mediated electron transfer reaction in presence of H(2)O(2) and peroxidase in acetate buffer of pH 4.2 resulting green colored product having maximum absorption at λ(max)=740 nm was investigated by spectrophotometer. Under optimum conditions, linearity range for the quantification of H(2)O(2) was 2.

Amaranth dye in the evaluation of bleaching of cerium (IV) by antioxidants: application in food and medicinal plants.

A simple, low-cost, sensitive, and diversely applicable spectrophotometric method for the determination of total antioxidant capacity of several medicinal plants and food has been developed. The method is based on the bleaching of cerium (IV) by antioxidants and dye in slightly acid medium at room temperature. The unbleached dye, imparting pink color to the solution, is measured at λ(max) 530 nm which is directly proportional to the antioxidant concentration.

Quantification of creatinine in biological samples based on the pseudoenzyme activity of copper-creatinine complex.

Glomerular filtration rate (GFR), the marker of chronic kidney disease can be analyzed by the concentration of cystatin C or creatinine and its clearance in human urine and serum samples. The determination of cystatin C alone as an indicator of GFR does not provide high accuracy, and is more expensive, thus measurement of creatinine has an important role in estimating GFR. We have made an attempt to quantify creatinine based on its pseudoenzyme activity of creatinine in the presence of copper.

Development of quantitative enzymatic method and its validation for the assay of glucose in human serum.

Objective: To develop a simple, rapid, sensitive and affordable assay method for the determination of glucose in blood samples using a novel approach.

Design And Methods: A spectrophotometric method for glucose quantification in human serum samples based on self-coupling of activated 2,5-dimethoxyaniline (DMA) in the presence of peroxidase (POD)/glucose oxidase (GOD) and H(2)O(2) is described. H(2)O(2) generated in situ by catalytic reaction between GOD and glucose, activates DMA in the presence of POD to form a green-colored product, which has a strong absorption at λ(max)=740 nm at room temperature (30°C) in a 100 mmol/L acetate/acetic acid buffer of pH 4.

Determination of catalase activity using chromogenic probe involving iso-nicotinicacidhydrazide and pyrocatechol.

A biocatalatic pathway involving chromogenic probe has been proposed for the determination of catalase activity by means of iso-nicotinicacidhydrazide (INH) and pyrocatechol (PC). The assay is based on the enzymatic consumption of hydrogen peroxide using INH-PC system. The response of the catalase activity was ascertained by the rate of the reaction involving 14.

Quantification of ultra-trace molybdenum using 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid monosodium salt as a chromogenic probe.

A simple, ultrasensitive, nonextractive spectrophotometric method has been developed for the assay of Mo(VI), which involves Mo-catalyzed oxidation of 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid monosodium salt (AHNDSA) by H(2)O(2) in acetic acid/sodium acetate buffer yielding an intense pink colored product with λ(max) of 540 nm. Beer's law is obeyed in the range of 10-240 ng/ml with molar absorptivity of 3.0137×10(5)L mol(-1)cm(-1).

Use of N, N-diethyl-p-phenylenediamine sulphate for the spectrophotometric determination of some phenolic and amine drugs.

Spectrophotometric methods are proposed for the determination of drugs containing a phenol group [salbutamol sulphate (SLB), ritodrine hydrochloride (RTD), isoxsuprine hydrochloride (IXP)] and drugs containing an aromatic amine group [dapsone hydrochloride (DAP), sulfamethoxazole (SFM), and sulfadiazine (SFD)] in pharmaceutical dosage forms. The methods are based on coupling of N, N-diethyl-p-phenylenediamine sulphate with the drugs in the presence of KIO4 to give a green colored product (λmax at 670 nm) and a red colored product (λmax at 550 nm), respectively. Linear relationships with good correlation coefficients (0.

Simple and sensitive method for the quantification of total bilirubin in human serum using 3-methyl-2-benzothiazolinone hydrazone hydrochloride as a chromogenic probe.

We here describe a new spectrophotometric method for measuring total bilirubin in serum. The method is based on the cleavage of bilirubin giving formaldehyde which further reacts with diazotized 3-methyl-2-benzothiazolinone hydrazone hydrochloride giving blue colored solution with maximum absorbance at 630 nm. Sensitivity of the developed method was compared with Jendrassik-Grof assay procedure and its applicability has been tested with human serum samples.

A simple and sensitive spectrophotometric method for the determination of trace amounts of nitrite in environmental and biological samples using 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt.

A very simple, sensitive, fairly selective and rapid spectrophotometric method for the determination of trace amounts of nitrite has been described. This method is based on the diazotized intramolecular coupling of electrophilic diazonium cation with the phenolic group of 4-amino-5-hydroxynaphthalene-2,7-disulphonic acid monosodium salt (AHNDMS) in a phosphate buffer solution of pH 7.5.

Development and evaluation of kinetic spectrophotometric assays for horseradish peroxidase by catalytic coupling of paraphenylenediamine and mequinol.

This paper presents a novel spectrophotometric method to measure peroxidase activity using paraphenylenediamine dihydrochloride (PPDD) and Mequinol (MQ). The PPDD traps the free radical, and gets oxidized to electrophilic 1,4-diimine; this couples with MQ to an give intense violet-colored chromogenic species with the maximum absorbance at 560 nm. This assay was adopted for the quantification of hydrogen peroxide between 10 x 10(-6) to 80 x 10(-6) M.

Quantification of hydrogen peroxide and glucose using 3-methyl-2-benzothiazolinonehydrazone hydrochloride with 10,11-dihydro-5H-benz(b,f)azepine as chromogenic probe.

A sensitive, selective, and rapid enzymatic method is proposed for the quantification of hydrogen peroxide (H(2)O(2)) using 3-methyl-2-benzothiazolinonehydrazone hydrochloride (MBTH) and 10,11-dihydro-5H-benz(b,f)azepine (DBZ) as chromogenic cosubstrates catalyzed by horseradish peroxidase (HRP) enzyme. MBTH traps free radical released during oxidation of H(2)O(2) by HRP and gets oxidized to electrophilic cation, which couples with DBZ to give an intense blue-colored product with maximum absorbance at 620 nm. The linear response for H(2)O(2) is found between 5x10(-6) and 45x10(-6) mol L(-1) at pH 4.

Peroxidase-catalyzed oxidative coupling of paraphenylenediamine with 3-dimethylaminobenzoic acid: application in crude plant extracts.

This paper presents a novel spectrophotometric method to measure peroxidase activity using paraphenylenediamine dihydrochloride (PPDD) and 3-dimethylaminobenzoic acid (DMAB). The PPDD traps free radicals and becomes oxidized to electrophillic 1,4-diimine, which couples with DMAB to give an intense green-colored chromogenic species with maximum absorbance at 710 nm. This assay was adopted for the quantification of hydrogen peroxide between 5 and 45 microM.

Spectrophotometric method for the determination of chromium (VI) in water samples.

A simple and sensitive spectrophotometric method for the determination of chromium has been developed. The method is based on the diazotization of Dapsone in hydroxylamine hydrochloride medium and coupling with N-(1-Napthyl) Ethylene Diamine Dihydrochloride by electrophilic substitution to produce an intense pink azo-dye, which has absorption maximum at 540 nm. The Beer's law is obeyed from 0.

Sensitive spectrophotometric methods for the assessment of nitrite in water sample.

Two spectrophotometric methods have been developed for the determination of nitrite using dapsone (DAP) with alpha-naphthol and 4-amino-5-hydroxynapthalene-2,7-disulphonic acid monosodium salt (AHNDMS) as chromogenic reagents with maximum absorbance wavelength at 540 and 520 nm respectively. For the method that utilizes dapsone with alpha-naphthol (DAP-alpha-naphthol), the beer's law range is obeyed between 0.05-0.

A sensitive spectrophotometric method for the determination of sulfonamides in pharmaceutical preparations.

A new, simple and sensitive spectrophotometric method for the determination of some sulfonamide drugs has been developed. The method is based on the diazotization of sulfacetamide, sulfadiazine, sulfaguanidine, sulfamerazine, sulfamethazine, sulfamethoxazole, and their coupling with 8-hydroxyquinoline in alkaline media to yield red coloured products with absorption maxima at 500 nm. Beer's law is obeyed from 0.