Peroxynitrite and hypochlorite are oxidants relevant in many pathological situations. We propose a simple spectrophotometric assay to determine antioxidant capacity against hypochlorite and peroxynitrite based on protection against Pyrogallol Red decolorization. The assay can be performed on a microplate and requires minute amounts of material. Standard antioxidants show different reactivities ...

A method for solubilizing HMG-CoA reductase is described that reproducibly yielded approximately 190% of the activity assayed in rat liver microsomes. Optimal solubilization occurred when microsomal membranes were frozen at a fixed concentration, thawed, homogenized in a buffer containing 50% glycerol, and incubated at 37 degrees C for 60 minutes. A rapid spectrophotometric assay of the reducta...

In this paper we describe the microcomputer-aided determination of cell proliferation kinetics and doubling times utilizing a crystal violet assay and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay in microtitration plates. The analysis of spectrophotometric data provides the doubling times at any time of incubation. Plots of doubling time versus time of incubation giv...

A diverse collection of actinomycete strains were screened for production of extracellular peroxidase activity by adapting a chemiluminescence analysis system developed for horseradish peroxidase-based enzyme-linked immunosorbent assay. Extracellular peroxidase activity was found to be common but quantitatively variable, and this rapid and sensitive screening system permitted identification of ...

A rapid and precise microfluorometric method for the determination of free fatty acid concentrations in 2-5 microliters of plasma is described. The assay is performed directly on plasma, eliminating the need for extraction with organic solvents, and is based on the quantitation of AMP generated from the formation of acyl coenzyme A in the presence of ATP and acyl CoA synthetase. Because of the ...

A spectrophotometric assay for the determination of branched-chain L-amino acid aminotransferase activity is described. It is based on the transamination of L-leucine in the presence of 2-oxoglutarate yielding 4-methyl-2-oxopentanoate. The rate of formation of the branched-chain 2-oxo acid is specifically monitored in a coupled enzymatic reaction using NAD(+)-dependent D-2-hydroxyisocaproate de...

Numerous studies have provided evidence that diets rich in anthocyanins show a broad spectrum of health benefits. Anthocyanins nature are usually found the form glycosides. Their aglycone forms called anthocyanidins. The chemical structure is based on flavylium cation, but they differ position and number substituents. However, bioactives foods contain them frequently treated as uniform group co...

Instrumental techniques are preferred over bioassay methods for antibiotic quantification mainly due to speed and ability quantify metabolites in biological samples; however, the potency activity of these drugs cannot be assessed. Two - agar well diffusion (bio-assay) spectrophotometric were used evaluate amikacin sulfate injection. Agar plates inoculated with S. aureus inoculum; zones inhibiti...

Pyridine-4-carboxylic acid hydrazide, commercially known as isoniazid (INH), is an antitubercular drug and is now widely used together with rifampicin and streptomycin for the chemotherapy of tuberculosis. Ritodrine hydrochloride (RTH), chemically, 1-(4-hydroxyphenyl)-2-[2-(4-hydroxyphenyl)ethylamino]propanol is a potent tocolytic drug and is a selective β2-adrenoceptor agonist and is used to c...

Two titrimetric and two spectrophotometric methods are described for the assay of famotidine (FMT) in tablets using N-bromosuccinimide (NBS). The first titrimetric method is direct in which FMT is titrated directly with NBS in HCl medium using methyl orange as indicator (method A). The remaining three methods are indirect in which the unreacted NBS is determined after the complete reaction betw...