Main Groups Of Compounds Research Articles

Therapeutic potential of nucleotides in the eye

AbstractAdenine mononucleotides present the ability to produce changes in the intraocular pressure in New Zealand rabbits. Two main groups of compounds were found in terms of their behaviour—on the one hand, those that increased intraocular pressure, and on the other hand, those that reduced it. The hypotensive compounds showed a concentration–response behaviour, and were blocked by the P2 receptor antagonist pyridoxalphosphate‐6‐azophenyl‐2′,4′‐disulfonic acid. Moreover, the hypotensive compounds were unaffected by the pretreatment with sympathetic antagonists but were completely abolished by the parasympathetic antagonists. This fact suggests the possibility of these P2 receptors to be present at the cholinergic terminal that control intraocular pressure. Adenine mononucleotides also were assayed in their ability to increase tear secretion rate. This study showed that tear secretion is stimulated via P2Y2 receptors. Drug Dev. Res. 52:190–195, 2001. © 2001 Wiley‐Liss, Inc.

Determination of polar compounds, polymerized and oxidized triacylglycerols, and diacylglycerols in oils and fats: results of collaborative studies and the standardized method (Technical report)

Abstract A description is given of the development by collaborative study of two standardized methods for the determination of polar compounds in oils and fats by adsorption chromatography using silica minicolumns, and for quantification of polymerized triacylglycerols, oxidized triacylglycerols, and diacylglycerols in polar compounds by high-performance size-exclusion chromatography. The first procedure is sensitive, allowing savings in time, solvents, and reagents as compared to the previous determination (Standard Method 2.507), while the second is very rapid, giving a detailed information on the main groups of compounds in fats and oils associated with hydrolysis, oxidation, and thermal polymerization. Both methods are useful for the analysis of used frying fats as well as for the analysis of virgin or refined oils.

Characterization of tyrosinase- and polyphenol esterase-catalyzed end products using selected phenolic substrates.

The oxidative end products that result from the biocatalysis of tyrosinase (PPO) and/or a polyphenol esterase (PPE) extract have been investigated simultaneously in model systems containing selected phenolic compounds as substrates. The spectrophotometric scanning of brown color, formed in the presence of both PPO and PPE, showed a decrease in the absorbance compared to that obtained with PPO only. Graphical analyses of the iterative spectra of oxidized phenolic end products by PPO confirmed the presence of, at least, three kinetically related absorbing species. HPLC analyses of the end products, obtained by the biocatalysis of PPE or PPO activity, indicated the presence of two main groups of compounds: colored ones of lambda(max) at 294-324 nm and colorless products of lambda(max) at 264-290 nm. PPE produced both compounds when selected substrates were used as substrates, whereas PPO produced only one type of oxidation product. However, when both enzymes were incubated together, the nature of the end products was similar to that obtained with PPE only.

Chemicals Generated During Oxygen-Organosolv Pulping of Wood

Abstract In this paper, we have characterized the black liquors from oxygen-organosolv pulping of Eucalyptus globulus wood in ethanol/water solutions (50:50, V/V) and acetic acid/water solutions (80:20, V/V). After pulp separation, the organic solvent has been distilled and recycled; the precipitated lignin has been recovered by filtration. The degradation products in solution have been easily separated by simple extraction techniques. Five main groups of compounds have been isolated: solid lignin (11–12% o.d.w.), sugars (10–17% o.d.w.), aliphatic acids (12,5%), aromatic acids (2% o.d.w.) and low molecular weight phenols (1% o.d.w.). Most of these compounds were identified by HPLC and GC. Solid lignins have been analyzed by FTIR and 13C NMR spectroscopy. It has been concluded that oxygen-organosolv pulping process can be a new and interesting way for pulp preparation with little pollution and possibility of total biomass recovery; alternatively, it can be used for the fractionation and valorization of the...

Systematic Implications of the Distribution of Iridoids and Other Chemical Compounds in the Loganiaceae and Other Families of the Asteridae

The distribution of the chemical compounds iridoids, anthraquinones, and verbascosides is demonstrated in Dahlgrenograms. An analysis of iridoid biosynthesis and structure allows distinction of two main groups of compounds. Thus, the biosynthetic route I gives rise to the seco-iridoids and their derivatives, and another (route II) to aucubin and similar decarboxylated iridoid glucosides. Seco-iridoids from route I are widely distributed in Cornanae, Loasanae, and Gentiananae but never in Lamianae. Aucubinlike compounds derived by route II are commonly found in Lamianae and in three small families in Cornanae, but are not found in Gentiananae (...)

Characterization of condensates from peat and bark drying

An analytical system for determining the composition of condensates from the steam drying of peat and bark was developed. Both hydrophilic and lipophilic compounds could be separated by gas-liquid and liquid chromatographic methods. The dominant compound groups in the peat and pine bark condensates were carboxylic acids, aldehydes and monosaccharides, whereas the main compound groups detected in the birch bark condensate included carboxylic acids and terpenoids.

Fouling of a heat exchange surface by whey, milk and model fluids. An analytical study

Summary Fouling caused by sweet whey, milk, artificial ultrafiltrate, phosphate and calcium solution and prote in solutions was studied in weil defined hydrodynamic (flow rate: 0.096 m.s -1) and thermal conditions (temperatures ranging from 25 to 88 C with a standard value of 72 C ; temperature difference with the heat carrier fluid : 0, 5 or 10 C) using a laboratory fouling deviee. Deposits were assessed quantitatively by weighing and qualitatively by Auger electron spectrocopy, X photoelectron spectroscopy and infrared spectroscopy. These spectra gave evidence for three main groups of compounds: proteins, phosphates and lipids as weil as the corresponding atoms (calcium, phosphorus, nitrogen and carbon). These findings suggest a fouling mecha- nism based on calcium phosphate building-up, with various structures ranging from simple weil crystallized phases «<phosphate + calcium» solution) to much more complex phases including carboxylate groups ; the latter are present in substances as different as citrate (artificial ultrafiltrate and whey) or proteins (soluble or caseins). In the case of milk and whey, proteins participate in the formation of the first fouling layers. Thus, the best way of preventing fouling seems to be the inhibition of calcium phosphate formation.

GC/MS Identification of Organic Pollutants in the Caroni River, Trinidad

Abstract Water samples from the Caroni River, Trinidad and other rivers which flow into the Caroni River were qualitatively analyzed for trace organic contaminants by procedures based on XAD extraction followed by GC/MS analysis. Pesticides, polyaromatic hydrocarbons, aliphatic hydrocarbons, phenols and phthalate esters were the main groups of compounds found. Many of the contaminants present in these water samples are known industrial pollutants, and several have been found in waste waters examined by other workers, which suggests that the factories of an industrial complex located upstream of the Caroni/Arena Water Treatment Plant may be the major source of the pollutants. Some compounds identified in the water samples have not been previously reported.

Isolation and analytical aspects of Valeriana compounds

Valepotriates are considered as one of the main groups of compounds responsible for the sedative activity of Valeriana preparations. An extraction method for valepotriates is given and the isolation of (iso) valtrate, didrovaltrate andIvhd-valtrate by means of column chromatography on silicagel was shown to be a fast method without giving much decomposition. Toluene-ethyl acetate-methyl ethyl ketone (80+15+5) as a mobile phase gives an excellent indication of the presence of the various valepotriates in Valeriana preparations. For the quantitative determination of valepotriates a direct spectrophotometric scanning onTlc plates was compared with aHplc