Major Water-soluble Components Research Articles

Comparison of catechins and aromas among different green teas using HPLC/SPME-GC

Green tea polyphenols (GTP) from Camellia sinensis (L.) O. Kuntze are the major water soluble components in tea liquor. The GTP extraction yield was determined using different extraction times from 10 to 60 min at 70°C, and also at different temperatures from 50°C to 100°C, keeping the extraction time constant. The composition of the GTP (catechins) from samples of different origins was determined by RP–HPLC, measuring the absorbance at 280 nm. The calibration curves of the catechins were linear between 5 ng and 2 μg, and their C.V. values for the quantitation were less than 4.0% for four replicates using four different sets of each type. The total epicatechin derivatives (EPD) and epigallocatechin-3-gallate (EGCG) from Azorean green tea, accounted for 74.5 and 47.9% (w/w) of the total GTP, respectively, and were compared with that from tea samples of different origins. The EGCG:caffeine ratio in Azorean green tea was fourfold higher as compared with others, which suggested a good source of a chemopreventive agent. The aroma composition of different green tea samples was compared using the SPME/GC headspace methodology.

Chemical composition of the atmospheric aerosol in the troposphere over the Hudson Bay lowlands and Quebec‐Labrador regions of Canada

Atmospheric aerosols were collected in the boundary layer and free troposphere over continental and coastal subarctic regions of Canada during the July–August 1990 joint U.S.‐Canadian Arctic Boundary Layer Expedition (ABLE) SB/Northern Wetlands Study (NOWES). The samples were analyzed for the following water soluble species: sulfate, nitrate, ammonium, potassium, sodium, chloride, oxalate, methylsulfonate, and total amine nitrogen. Ammonium and sulfate were the major water soluble components of these aerosols. The nearly neutral (overall) chemical composition of summertime aerosol particles contrasts their strongly acidic wintertime composition. Aerosol samples were separated into several air mass categories and characterized in terms of chemical composition, associated mixing ratios of gaseous compounds, and meteorological parameters. The fundamental category represented particles associated with“background”air masses. The summertime atmospheric aerosols in background air over the North American subarctic and Arctic regions were characterized by relatively small and spatially uniform mixing ratios of the measured species. These aerosol particles were aged to the extent that they had lost their primary source signature. The chemical profile of the background air aerosols was frequently modified by additions from biomass fire plumes, aged tropical marine air, and intrusions of upper tropospheric/lower stratospheric air. Aerosols in boundary layer background air over the boreal forested region of Quebec‐Labrador had significantly larger mixing ratios of ammonium and sulfate relative to the Hudson Bay region. This may reflect infiltration of anthropogenic pollution or be due to natural emissions from this region.

Effect of toluene on fathead minnow (Pimephales promelas Rafinesque) development.

The environmental levels of aromatic hydrocarbons present in freshwater systems have been poorly characterized. This study examines the effect of toluene, a major water-soluble component of petroleum fuels on teleost development under controlled conditions. The fathead minnowPimephales promelas Rafinesque, was chosen as a model teleost for this study. Live embryos as well as serial sections of paraffin-embedded embryos were examined to determine effects of the toxicant. The toluene concentrations utilized ranged from 30 to 45 mg/L. Abnormalities noted under these conditions included distorted embryonic axis, abnormal heart and circulatory system development, hydration and swelling of the pericardial coelom, hemorrhaging, an overall stunted appearance, microphthalmia, and a unique migration of the ventrally located yolk syncytial layer and its associated nuclei.

TDP-1, a toxic component causing tibial dyschondroplasia in broiler chickens, and trichothecenes from Fusarium roseum 'Graminearum'.

Fusarium roseum 'Graminearum' was isolated from overwintered oats in Alaska and was tested for its ability to cause tibial dyschondroplasia (TDP) in broiler chickens. The water-soluble fraction was tested and found to cause TDP. In addition, diacetoxyscirpenol and 7-hydroxydiacetoxyscirpenol were identified in the acetonitrile fraction of the extracts and caused mild mouth lesions in chickens. Six major water-soluble components were purified by thin-layer chromatography and tested for toxicity to chick embryos. One of the six components, called TDP-1, was found to be lethal to chick embryos. There was a 100% incidence of TDP in chickens fed a diet containing 75 ppm (wt/wt) of pure TDP-1, thus establishing the cause and effect relationship between TDP and TDP-1. Analyses by thin-layer chromatography and mass spectrometry revealed that TDP-1 is polar and ninhydrin positive, exhibits fluorescence with UV irradiation, and is a nitrogen-containing component with an empirical formula of C15H20N2O4.

Reaction of Xylose and Glycine: Identification of the Major Water Soluble Component

Abstract The reaction of equimolar amounts of D-xylose and glycine in D2O at 68°C resulted in the formation of a twelve carbon compound, as a major product. No intermediate was detected in the formation of this dimer. The eneaminol, formed on reaction of 0.1 molar D-xylose and glycine in H2O, after six weeks was isolated and purified. Based on 1H and 13C NMR, spin echo Fourier transform experiments, and other spectroscopic techniques including FAB-MS and CI-MS of TMS derivative, the structure: N, N[1-deoxy-D-threo-pent-2-enitol, 1′-deoxy-β-D-threo-pentose (2′,5′)] glycine, was assigned to the product.

Isolation and partial characterization of an elastase-associated acidic endopeptidase and its interaction with elastase at low ionic strength

An acidic endopeptidase has been isolated from dried preparations of swine pancrease by column chromatography on DEAE cellulose. The yield of acidic endopeptidase from 100 g of pancreas powder was 210 mg. The product was found to be electrophoretically homogeneous and produced a single peak in the analytical ultracentrifuge. The sedimentation coefficient (s 0 20,w) , diffusion coefficient (D 20,w) , apparent molecular weight, electrophoretic mobility, E 1 cm 1% at 280 mμ and pH optimum were respectively, 3.13, 8.7 · 10 −7 cm 2 · sec −1 , 35 300, −5.9 · 10 −5 cm 2 · V −1 · sec −1 , 14.6 and 10.7. The enzyme was inhibited by diisopropyl phosphorofluoridate, by swine serum and to a lesser extent by human serum. It was not “activated” by 1 · 10 −3 M FeCl 2 , MnCl 2, MgCl 2, CaCl 2 or CoCl 2 or by 1 · 10 −3 M ZnSO 4 ; however, the activity of the enzyme was increased by 1 · 10 −3 M cysteine. The similarity of the acidic endopeptidase to proteolytic enzymes described by other investigators is discussed. Gradient elution ion-exchange chromatography of water insoluble elastase euglobulin produces two major water soluble components, elastase and the acidic endopeptidase. When distilled water solutions of the purified enzymes were mixed complex formation occurred (precipitation) between the basic protein elastase and the acidic endopeptidase. The formation of the euglobulin when acid extracts of swine pancreas are dialyzed against distilled water is thus explained. Complex formation was maximal at low ionic strength when the enzymes were oppositely charged and was minimal below the isoelectric point of the acidic endopeptidase (∼ pH 4.1) or above the isoelectric point of elastase (pH 9.5). The reaction was essentially abolished at I 0.011. The equivalence point for the reaction was 2.8 mg of elastase  1 mg of acidic endopeptidase. One mole of acidic endopeptidase is capable of binding approximately four moles of elastase. Although trypsin, another basic protein, was precipitated by the acidic endopeptidase the data suggest a preferential reaction of the latter enzyme with elastase.