Standard Colorimetric Procedure Research Articles

Evaluation of Antioxidant, Anti-Inflammatory and Antityrosinase Potential of Extracts from Different Aerial Parts of Rhanterium suaveolens from Tunisia.

The genus Rhanterium (Asteraceae) is a widely distributed medicinal plant throughout western North Africa and some Rhanterium species are used in folk medicine. The aim of research was to investigate methanolic extracts from different parts (flowers, leaves, and stems) of Tunisian Rhanterium suaveolens as potential sources of bioactive products useful for healthy purposes. In particular, were analyzed the phenolic composition of these extracts and their antioxidant, anti-inflammatory, and anti-tyrosinase properties. The phytochemical analyses were performed using standard colorimetric procedures, HPLC-DAD and HPLC-DAD-ESI-MS. Then, several in vitro cell-free assays have been used to estimate the antioxidant/free radical scavenging capability of the extracts. Moreover, in vitro, and in vivo anti-melanogenesis activities of these extracts were tested, respectively, with the tyrosinase inhibition assay and the Zebrafish embryo model. Finally, the anti-inflammatory potential of these extracts in an in vitro model of acute intestinal inflammation in differentiated Caco-2 cells was evaluated. The R. suaveolens extracts under study appeared particularly rich in flavonols and hydroxycinnamic acids and all extracts appeared endowed with good antioxidant/free radical scavenging properties, being the flower extracts slightly more active than the others. Moreover, R. suaveolens flowers extract was able to inhibit in vitro tyrosinase activity and exhibited bleaching effects on the pigmentation of zebrafish embryos. Furthermore, all extracts showed good anti-inflammatory activity in intestinal epithelial cells as demonstrated by the inhibition of TNF-α-induced gene expression of IL-6 and IL-8. R. suaveolens aerial parts may be considered as a potential source of whitening agents, as well as of agents for the treatment of disorders related to oxidative stress and inflammation.

Phytochemical and Biological Characterization of Methanolic Extracts from Rumex algeriensis and Rumex tunetanus.

The present study is aimed at the evaluation of the phytochemical profile and the biochemical properties of methanolic extracts obtained from different parts of Rumex algeriensis and Rumex tunetanus, two relict species limited to the North Africa. Phytochemical analyses of these extracts were performed using standard colorimetric procedures, HPLC-DAD, and HPLC-DAD-ESI/MS, and their antioxidant/free radical scavenging capability was estimated through several in vitro cell-free assays. Moreover, the anti-inflammatory potential of these extracts was demonstrated in an in vitro model of acute intestinal inflammation using differentiated Caco-2 cells. The results showed that all the extracts appeared endowed with excellent antioxidant/free radical scavenging properties. In particular, the extracts from both R. algeriensis and R. tunetanus flowers, and that from R. algeriensis stems were characterized by a remarkable SOD-like and NO-scavenging activity, as well as by the capability to protect albumin against HClO-induced degradation. Furthermore, the extracts from flowers of both Rumex species, as well as R. algeriensis stems, showed an anti-inflammatory effect in intestinal epithelial cells, as demonstrated by the inhibition of TNF-α-induced gene expression of IL-6 and IL-8. In conclusion, R. algeriensis and R. tunetanus have shown to be potential sources of bioactive products to be used in the prevention and treatment of pathologies related to oxidative stress and inflammation.

Evaluation of Anticancer, Antioxidant and Possible Anti-microbial Properties of extracts of Momordica diocia roots

Since many years, plants were known to possess anticancer activities against different cancer cell lines. In this paper, we report a study based on anticancer,anti-bacterial and antioxidant properties plants Momordicadioica . The roots of plant material were collected, shade dried and extracted with methanol using soxhlet extraction procedure. Anticancer activities were assayed with standard XTT colorimetric procedure against MCF-7 and Hep-G2 cell lines. From the analysis, it was found that Momordicadioica showed good cytotoxic activity on MCF-7 cell line at tested dose. Further work is in progress to evaluate the chemical constituents present in these plants

Preparation and certification of a reference material for the determination of nutrients in seawater.

There is an urgent need for natural water reference materials certified for nutrients. In 1996, NRC collected seawater for a proposed CRM at a depth of 200 m in the North Atlantic; this was immediately filtered through 0.05-microm cartridge filters into 50-L carboys. The water was later homogenized in the NRC laboratories in Ottawa and stabilized via gamma irradiation. Over six years of stability testing no significant deterioration was detected. In addition to the usual customary standard colorimetric procedures, alternative analytical methods were developed to enable the certification process. The production of a CRM called MOOS-1 will be discussed. Certified values, with uncertainty components addressing the homogeneity, stability, and characterization of the material, were calculated to be: orthophosphate=1.56+/-0.07 micro mol L(-1), silicate=26.0+/-1.0 micro mol L(-1), nitrite=3.06+/-0.15 micro mol L(-1), and nitrite and nitrate=23.7+/-0.9 micro mol L(-1).

On-line determination of dissolved phosphate in sea-water by ion-exclusion chromatography inductively coupled plasma mass spectrometry

Direct determination of dissolved phosphate in sea-water by ion-exclusion chromatography in combination with inductively coupled plasma mass spectrometry is described. This method was developed as an independent, complementary approach to the standard colorimetric procedure used for the determination of dissolved phosphate in a proposed sea-water reference material. The developed on-line method is rapid, simple and accurate, requiring no sample pre-treatment. One determination can be completed in 6 min. The detection limit (3s), estimated at 0.06 µM (2.0 ng ml−1 as P) with injection of only 100 µl of sea-water, is superior to the 0.15 µM achieved using colorimetry. The dissolved phosphate concentration in sea-water of 1.69 ± 0.04 µM measured by a standard additions technique using the proposed method is in good agreement with the 1.71 ± 0.04 µM determined using a classic colorimetric approach.

Determination of total phenols in waters and wastewaters using flow injection with electrochemical detection; an alternative to the standard colorimetric procedure

A new flow injection (FI) method using a dual electrochemical detector is described for the analysis of total phenols in water and wastewater samples. The method relies upon in-line oxidative electrochemical removal or elimination of interferences at an upstream large surface area (coulometric) electrode combined with oxidative detection of all phenols at an amperometric electrode. Using the ESA dual electrode high sensitivity cell and a phosphate buffer carrier stream (pH 6.8), the ideal potentials were found to be +0.35 V for the coulometric electrode and +0.78 V for the sensing amperometric electrode. The method is fast, with sampling frequencies around 60 h −1 and precision is typically 0.1–4%. Several synthetic aqueous samples were analysed by the FI and colorimetric methods and compared with results obtained using reversed-phase liquid chromatography (LC). More reliable data were obtained for samples containing para-substituted phenols and nitrophenols with plots of FI vs. LC data resulting in correlation coefficients of r 2 = 0.71 and r 2 = 0.79, respectively, whereas the standard colorimetric method vs. LC data gave correlation coefficients of r 2 = 0.29 and r 2 = 0.04, respectively. The method was applied to the analysis of five industrial wastewaters.

Galacturonate in Pectic Substances from Fruits and Vegetables: Comparison of Anion Exchange HPLC with Pulsed Amperometric Detection to Standard Colorimetric Procedure

ABSTRACTA HPLC method was developed to identify and quantify galacturonate; results were compared with those from a standard colorimetric procedure. HPLC was also used to determine neutral monosaccharide profile of isolated pectic substances (PS). The PS, isolated with ammonium oxalate from the total dietary fiber of apple, cucumber, celery, grapefruit and radish, were analyzed. Mean PS on original dry matter basis ranged from 6.0 ± 0.51% for apple to 18.5 ± 0.1% for celery. Galacturonate of isolated PS determined using anion exchange chromatography coupled with pulsed amperometric detection was not significantly different (P > .2) from that determined colorimetrically. Major monosaccharides in PS of all substrates were arabinose and galactose. Rhamnose, xylose and glucose also were detected in certain sources in much lower amounts. This HPLC method allows precise quantification of galacturonate and will be a useful tool for study of chemical composition of pectin.

Spectrophotometric determination of iron(II) by extraction of its ion associated complex with 3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine and tetraphenylborate into molten naphthalene

A new spectrophotometric method for the determination of iron (II) after extraction of its 3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine complex with tetraphenylborate anion into molten naphthalene has been developed. The optimum pH range for the extraction is 6.0–7.0. The solid naphthalene containing the iron(II) associated complex is separated by filtration and dissolved in DMF. Beer's law is obeyed in the concentration range 1.0–16µg of iron(II) in 10 ml of DMF solution. The molar absorptivity and sensitivity are 2.85×104 1 mol−1 cm−1 and 0.00194μg cm−2, respectively. The interference of various ions has been studied. Conditions have been satisfactorily applied for the determination of iron in standard reference materials and practical samples and results compared with other standard colorimetric procedures.

The chemistry and vertical flux of particles in the northeastern Gulf of Alaska

The physical and chemical compositions of settling particles and underlying sediments collected from a pristine coastal environment south of Icy Bay in the northeastern Gulf of Alaska were compared to investigate the processes affecting the compositions, flux, and early diagenesis of the materials. Settling particles were collected with three self-closing sediment traps moored vertically approximately 30 km offshore. Sediments collected by gravity coring at the site were dated by 210Pb geochronology. Total particulate Al, Si, Cr, Mn, Fe, Ni, Cu, Zn, and Pb were determined on all samples by flameless atomic absorption and standard colorimetric procedures. Total C and N were determined by dry combustion gas chromatography. A dilute hydrogen peroxide oxidation dissolution treatment was used to study element associations with labile particulate organic matter. A selective biogenic SiO 2 dissolution treatment also was employed to determine the biogenic SiO 2 fraction. Results suggest that the sediment traps efficiently collected settling particles. The elemental accumulation rates, remineralization of particulate organic matter, and remobilization of trace elements, notably Cu, were quantified by comparing the composition of the trapped materials with the underlying sediments. The majority of the remineralization appears to occur within the sediments below the zone influenced by resuspension, presumably as a result of biological activity.

Spectrophotometric Determination of Iron(III) After Separation by Adsorption of its 2-Thenoyltrifluoroacetone Complex on Microcrystalline Naphthalene

A new spectrophotometric method for the determination of iron (III) after adsorption of its red TTA complex onto microcrystalline naphthalene has been developed. Iron(III) reacts with 2-thenoyltri-fluoroacetone in pH range 2.4–5.2 to form a water-insoluble 1∶3 red complex which is easily adsorbed onto microcrystalline naphthalene from its acetone solution. The naphthalene mixture is separated, dried and dissolved in 10 ml dioxane. The red organic phase has a plateau around 480–500 nm while the reagent has no absorbance beyond 420 nm. The system obeys Beer's law over 20–120μg iron(III) in 10 ml of dioxane solution or 0.4–2.4 ppm aqueous. The molar absorptivity of the complex species is 3.9×103·l·mol−1·cm−1, while the sensitivity for Fe(III) extends to 1.43×10−2μg cm−2 for 0.001 absorbance. Samples containing 80μg of iron gave a relative standard deviation of 1.23%. The effects of experimental variables such as pH, amount of reagents, shaking and digestion time, aqueous volume and diverse ions have been examined. The method has been applied to the determination of iron(III) in standard reference and environmental samples and results compared with other standard colorimetric procedures.

Fluorometric determination of cyanide in biological fluids with p-benzoquinone

A sensitive, specific fluorometric method has been combined with microdiffusion to measure cyanide in biological fluids. Cyanide reacts with p-benzoquinone to form fluorescent product(s) which are determined in dimethyl sulfoxide. Approximately 0.001 μmol/ml cyanide can be analyzed by this procedure. Sodium thiosulfate interferes with the determination of cyanide by the standard colorimetric procedure, but not with this fluorometric method. Blood cyanide concentrations in mice pretreated with sodium thiosulfate were compared by the fluorometric and colorimetric methods. These results demonstrate that thiosulfate interferes with the detection of cyanide colorimetrically, but not fluorometrically.

The determination of serum cholinesterase activity by kinetic direct injection enthalpimetry

A method is described for the enthalpimetric determination of serum cholinesterase activity. Physiological amounts of cholinesterase (2–5 IU cm -3) in aqueous solutions and reconstituted sera are determined with a precision of 2.5% and 1.4% (r.s.d.), respectively. Typical errors of 1.0% are observed when the enthalpimetric results are compared with a standard colorimetric procedure.

Determination of tocopherols in vegetable oils

AbstractA rapid (ten minute) and selective method for measuring individual tocopherols found in vegetable oils has been developed using High Performance Liquid Chromatography (HPLC) with ultraviolet absorbance detection. The samples are analyzed directly following dissolution in the mobile phase. α ‐and γ‐tocopherols are quantitated based upon their peak areas relative to standard calibration curves. The measurement of β ‐ and δ‐tocopherols in the samples is also based upon the calibration data for the α ‐ and δ‐tocopherol standards since the individual β‐ and δ‐ standards were unavailable. The data obtained are compared with the total tocopherol content as found by a standard colorimetric procedure. The results indicate the HPLC method to be more reliable in the measurement of samples with high α ‐tocopherol levels. Soybean, safflower, sunflower, cottonseed, corn, peanut and olive oils have been examined using this method.

A study of the Bratton and Marshall hydrolysis procedure utilizing high performance liquid chromatography

Most analytical methods for conjugated aromatic amines require hydrolysis to free the amine group. The rate of conversion of N-acetyl- p-aminohippuric acid to its deacetylated and deglycinated derivatives is directly related to the hydrolysis reaction time and the concentration of hydrochloric acid used in the reaction. Variations in methodology involving either of these hydrolysis parameters produced artifacts which were not detectable by the standard colorimetric procedures. High performance liquid chromatography offers an improved tool for detecting and quantitating the changes produced during hydrolysis.

β-HEXOSAMINIDASES IN THE NERVOUS SYSTEM: THE QUANTITATIVE HISTOCHEMISTRY OF β-GLUCOSAMINIDASE AND β-GALACTOSAMINIDASE IN THE CEREBELLAR CORTEX AND SUBJACENT WHITE MATTER

A modification of an existing fluorimetric method for the assay of β-glucosaminidase and β-galactosaminidase, based upon the hydrolysis of the corresponding 4-methylumbelliferyl glycosaminides, is described. The method is simple and convenient; its sensitivity is 3 x 10–8 M for the assay of β-glucosaminidase and 1 x 10–8 M for β-galactosaminidase. The results obtained on brain homogenates and dissected sections of cerebellar cortex and subjacent white matter of rat, rabbit and monkey were found to be similar to those obtained with the standard colorimetric procedures using p-nitrophenyl substrates. In each species, in each layer of cerebellar cortex and subjacent white matter, there were only minimal differences in the ratios of β-glucosaminidase to β-galactosaminidase activity, suggesting that a single enzyme possesses both activities. β-Glucosaminidase and β-galactosaminidase in the cerebellum were most active in the cellular granular layer, suggesting an association of β-hexosaminidase activity with neuronal cell bodies as has been found with other lysomal enzymes.

INDUCTION AND REPRESSION OF L-ARABINOSE ISOMERASE IN PEDIOCOCCUS PENTOSACEUS.

Dobrogosz, Walter J. (University of Illinois, Urbana) and Ralph D. DeMoss. Induction and repression of l-arabinose isomerase in Pediococcus pentosaceus. J. Bacteriol. 85:1350-1355. 1963.-The inducible l-arabinose isomerase of Pediococcus pentosaceus can be rapidly and conveniently measured in whole-cell preparations by use of a standard colorimetric procedure originally developed for studies with cell-free enzyme preparations. The enzyme is measured by its ability to catalyze the isomerization of l-arabinose to l-ribulose. Whole cells suspended in a suitable buffer and pretreated with toluene were shown to exhibit this isomerase activity at a level comparable with that observed in cell-free enzyme preparations. Conditions for optimal induction of l-arabinose isomerase are described. In addition, it was determined that the formation of this enzyme is subject to repression by glucose, i.e., via catabolite repression.

Metabolism of plasmalogen: II. The determination of alkenyl ethers in the presence of free aldehydes

SUMMARY A rapid and sensitive method for the analysis of alkenyl ethers (plasmalogens) in the presence of free aldehyde is proposed. The method is applicable over the range 0.02-0.2 pmoles of plasmalogen and is particularly useful for following the course of enzymatic or chemical reactions in mixtures containing both free aldehydes and plasmalogens in aqueous media. Plasmalogens, naturally occurring alkenyl ethers, react with a variety of acidic carbonyl reagents in a manner similar to free aldehydes. This reactivity may be due to rapid hydrolysis of the acid-labile alkenyl ether group, thus producing the free aldehyde. As a result, many of the standard colorimetric procedures are unsuitable for the specific determination of aldehydes in the presence of alkenyl ethers, and, similarly, there are few convenient procedures for determining alkenyl ethers in the presence of free aldehydes. The iodometric method of Norton (1) for the determination of alkenyl ethers is of considerable value, but this method is less sensitive than the reaction for aldehydes with fuchsin-sulfurous acid and is subject to interference from other iodine-reactive compounds (e.g. , reducing agents such as sulfhydryl derivatives), if present. More sensitive iodometric methods have been reported recently by Gottfried and Rapport (2) and Williams et al. (3), but these are still not directly applicable to systems that contain mercaptans. The latter are present in many enzymatic reaction mixtures. Although most interfering substances may be removed by washing a lipid extract with water, this process will considerably lengthen the time needed for analysis.