Anna Lombard

A modified solvent system and multiple detection technique for the separation and identification of mono- and oligosaccharides on cellulose thin layers.

Abstract A method of separating oligosaccharides (DP 2- io ) by means of chromatography on cellulose thin layers has been developed. The solvent system formic acid-methyl ethyl ketone- tert. -butanol-water (15:25:35:25) gives the best resolution for the saccharides tested, still allowing the separation of sucrose, glucose and fructose. A multiple detection technique is also described, based upon the successive application of different spray reagents to the same plate. The utilization of the technique in the location of sugars and their identification is discussed.

Quantitative Analysis of Carbohydrates and Organic Acids in Honeydew, Honey and Royal Jelly by Enzymic Methods

SummaryGlucose, fructose, sucrose, malic and citric acid were quantitatively determined in samples of honeydew, honey and royal jelly by means of enzymic UV tests. Preliminary qualitative analysis of carbohydrates present in the analysed samples was performed by silica gel thin-layer chromatography. The enzymic method employed shows appreciable advantages in specificity and ease of working.

Rat brain metabolism enzyme activity variations following He−Ne laser irradiation

In order to gain insight into the metabolic modifications induced in rat brain tissues by helium-neon (He-Ne) laser irradiation, in the research described here, we investigated the variations in the activity of the enzymes aspartate transferase (AST, EC 2.6.1.4), both cytosolic and mitochondrial, glutamate dehydrogenase (GIDH, EC 1.4.1.3), and total superoxide dismutase (SOD, EC 1.15.1.1), in the brain of rats treated with a very small dose (1.08 J) of He-Ne laser radiation. The rats were sacrificed 4 h after the treatment. The enzymes were evaluated spectrophotometrically in brain extracts of irradiated animals and also in untreated rats (controls) and rats that underwent simulated treatment (stressed). The data obtained from 5-10 animals assayed individually showed that, in the in toto brain tissues of the irradiated rats compared to the stressed rats, there was a marked increase of total SOD, together with an appreciable decrease of cytosolic AST, and insignificant variations in mitochondrial AST and GIDH. Stress alone caused a considerable decrease of total SOD and small but statistically significant increases of s-AST, m-AST, and GIDH.

Some aspects of the carbohydrate composition of callaphidid honeydew

SummaryThe carbohydrate composition of the honeydews produced by Myzocallis castanicola, Tuberculatus (Tubercu-loides) borealis, Betulaphis helvetica and B. quadrituberculata was examined by means of thin-layer chromatography (TLC), gas-liquid chromatography (GLC) and acid and enzymic hydrolysis. Fructose, glucose, sucrose, maltose, turanose, trehalose, melibiose, raffinose, melezitose and oligosaccharides with DP ⩾ 4 were detected. Melezitose is the main component of the trisaccharide fraction of M. castanicola and B. quadrituberculata honeydews.

Effect of in vivo HeNe laser irradiation on biogenic amine levels in rat brain

In order to elucidate the metabolic modifications induced in rat brain by low power He-Ne laser irradiation in vivo, the variations in the biogenic amine levels in cortex, striatum and hippocampus were studied. Noradrenaline (NA), dopamine (DA) and serotonin (5-HT) were evaluated by HPLC-EC on irradiated rats, untreated rats (controls) and rats which had undergone restraint stress (stressed). The results obtained on groups of four to eight rats assayed individually showed that irradiation caused a strong increase in 5-HT in striatum and hippocampus, a small but significant decrease in NA in cortex, and DA levels were not significantly affected. Restraint stress per se led to a considerable decrease in 5-HT and DA in striatum and hippocampus, but did not significantly alter the NA levels.

Analysis of the oligosaccharides from the roots of Arnica montana L., Artemisia absinthium L., and Artemisia dracuncula L.

Abstract The oligosaccharides extracted from the roots of Arnica montana L., Artemisia absinthium L. and Artemisia dracunculus L. have been analysed by thin-layer and gel-permeation chromatography to assess their applicability as ‘guide’ substances for pharmacological activity. Differences observed in the oligosaccharide component composition of such extracts might be more related to the vegetative stage of the plants at time of harvest than to the species themselves. In addition to a series of non-reducing oligofructosides, a series of reducing inulin-type oligosaccharides was found at the initial stages of growth, whereas in later stages of growth only non-reducing oligofructosides were present. These differences have been related to different stages of biosynthetic activity within the plants.

Studies on the in vitro inversion of flurbiprofen

This paper reports in vitro studies on the metabolic inversion of flurbiprofen (FL), an arylpropionic acid antiinflammatory agent (2-APA). The inversion was studied with both rac-FL and R-FL, by incubation with rat hepatic microsomes, in the presence of either CoASH and ATP or NADPH. The two isomers of the drug were separated as their (+)-(R)-1-phenylethylamides by direct phase high-performance liquid chromatography on a silica gel column with an achiral mobile phase. The inversion was more pronounced in the presence of CoASH and ATP for both the racemate and the R-isomer, which supports the key role of CoA thioesters in the metabolic inversion of profens. The inversion observed in the presence of NADPH suggests that, when the incubation is run with hepatic microsomes, a CYP450-mediated pathway is also active. In order to get more insight into the CYP450-mediated inversion pathway, we studied the effect of irradiating microsomes with a low dose of He-Ne laser radiation (0.2 J). Such irradiation caused a significant increase in inversion at all times studied and normalized the anomalous value of inversion observed at 15 min in this pathway.