Search results for "Satu"
showing 10 items of 1367 documents
Photoelectrocatalytic selective oxidation of 4-methoxybenzyl alcohol in water by TiO2 supported on titanium anodes
2013
The photoelectrocatalytic partial oxidation of 4-methoxybenzyl alcohol in aqueous solution irradiated by near-UV light was carried out in a three-electrode batch reactor. TiO2 films were either deposited by dip-coating of a TiO2 sol onto a Ti foil and subsequent calcination or generated on Ti plates by thermal oxidation in air at 400-700 degrees C. The effects of the anode preparation method and bias potential values on conversion and selectivity to the corresponding aldehyde were investigated. The photoelectrocatalytic results were compared with the photocatalytic and electrocatalytic ones. The results indicated that no reaction occurred during the electrocatalytic experiments, whereas the…
EFFECTS OF DIETARY 18:3 N-3 TRANS ISOMERS ON THE ?6 DESATURATION OF ?-LINOLENIC ACID
1995
Trans isomers of polyunsaturated fatty acids (PUFA) are formed during heat treatment of oils. In the present work, the effect of dietary geometrical isomers of α-linolenic acid (18:3 n-3) on the Δ6 desaturation of all cis 18:3 n-3 was investigated, using rat liver microsomes. The desaturation rates were higher in microsomes from animals fed a cis n-3 deficient diet, as compared to those from the control group or those from rats fed 18:3 n-3 and its trans isomers. These data and the incorporation of long chain trans PUFA in microsomal lipids suggest that geometrical isomers of 18:3 n-3 are probably slowly desaturated and elongated into long chain trans polyunsaturated fatty acids compared to…
New Acylated Presenegenin Saponins from Two Species ofMuraltia
2004
Six new acylated bisdesmosidic triterpene glycosides 1–6 were isolated from the roots of Muraltia heisteria (L.) DC., as three inseparable mixtures 1/2, 3/4, and 5/6 of the (E)- and (Z)-3,4,5-trimethoxycinnamoyl derivatives. The compound pair 1/2 along with four known saponins were also isolated from the roots of Muraltia satureioides DC. Their structures were elucidated mainly by spectroscopic experiments including 2D-NMR techniques as 3-O-(β-D-glucopyranosyl)presenegenin 28-{O-β-D-apiofuranosyl-(13)-O-[β-D-xylopyranosyl-(14)]-O-α-L-rhamnopyranosyl-(12)-O-[6-O-acetyl-β-D-galactopyranosyl-(13)]-4-O-[(E)-3,4,5-trimethoxycinnamoyl]-β-D-fucopyranosyl} ester (1) and its (Z)-isomer 2, 3-O-(β-D-g…
Regulatory activity of polyunsaturated fatty acids in T-cell signaling.
2009
n-3 Polyunsaturated fatty acids (PUFA) are considered to be authentic immunosuppressors and appear to exert beneficial effects with respect to certain immune-mediated diseases. In addition to promoting T-helper 1 (Th1) cell to T-helper 2 (Th2) cell effector T-cell differentiation, n-3 PUFA may also exert anti-inflammatory actions by inducing apoptosis in Th1 cells. With respect to mechanisms of action, effects range from the modulation of membrane receptors to gene transcription via perturbation of a number of second messenger cascades. In this review, the putative targets of anti-inflammatory n-3 PUFA, activated during early and late events of T-cell activation will be discussed. Studies h…
Digestion and absorption of polyunsaturated fatty acids
1991
Polyunsaturated fatty acids play an important part in the structure and function of cellular membranes and are precursors of lipid mediators which play a key role in cardiovascular and inflammatory diseases. Dietary sources of essential fatty acids are vegetable oils for either linoleic or alpha-linolenic acids, and sea fish oils for eicosapentaenoic and docosahexaenoic acids. Because of the specificity of the pancreatic lipid hydrolases, triglyceride fatty acid distribution is an essential parameter in the digestibility of fats. The efficiency of the intestinal uptake depends on the hydrolysis and especially on their micellarization. n-3 polyunsaturated fatty acid ethyl ester digestion is …
Unsaturated fatty acid bioavailability in growing rats fed low or adequate protein diets with sunflower or soybean oils
1993
Abstract The relationship of serum very low density lipoproteins (VLDL) to hepatic lipid composition was studied after 28 days of protein depletion to determine the interactions between dietary protein levels and the essential fatty acid (EFA) availability. This was examined in rats using a dietary combination of 20% or 2% casein with 5% vegetable oils, variable in their n-6:n-3 fatty acid ratios. Rats were divided into four groups, SFC (20% casein + 5% sunflower oil ); SFd (2% casein + 5% sunflower oil ); SC (20% casein + 5% soybean oil ); Sd (2% casein + 5% soybean oil ). Dietary protein depletion decreased phospholipid and protein concentrations in liver and VLDL, whereas triacylglycerol…
On the problematic nature of vitamin E requirements: net vitamin E
1991
The requirement for vitamin E is closely related to the dietary intake of polyunsaturated fatty acids (PUFA). By the protective mechanism to prevent PUFA from being peroxidized, vitamin E is metabolically consumed. In addition, PUFA impair the intestinal absorption of vitamin E. Therefore PUFA generate an additional vitamin E requirement on the order of 0.6, 0.9, 1.2, 1.5, and 1.8 mg vitamin E (RRR-alpha-tocopherol-equivalents), respectively, for 1 g of dienoic, trienoic, tetraenoic, pentaenoic, and hexaenoic acid. For this reason, the gross vitamin E content of food containing PUFA does not allow an evaluation of this food as a source of vitamin E. A suitable measure is the net vitamin E c…
Vaccinium Genus Berry Waxes and Oils
2019
Vaccinium is a common and widespread genus of about 450 species of shrubs or dwarf shrubs in the heath family (Ericaceae). Most of Vaccinium species produce edible berries and many berries are widely cultivated at an industrial scale, for example, bilberries (Vaccinium myrtillus L.), highbush blueberries (Vaccinium corymbosum L.), lingonberries (Vaccinium vitis-idaea L.), and cranberries (Vaccinium oxycoccos L.). These berries are important articles in the markets of berries in Northern countries both raw, and processed. Vaccinium berries are at first valued considering high vitamin concentrations as well as high concentrations of phenolics. However, also oils and waxes (lipids) of Vacciniu…
Revisiting delta-6 desaturase regulation by C18 unsaturated fatty acids, depending on the nutritional status.
2009
Dietary polyunsaturated fatty acids (PUFA) play a key role in regulating delta-6 desaturase (D6D), the key enzyme for long-chain PUFA biosynthesis. Nevertheless, the extent of their effects on this enzyme remains controversial and difficult to assess. It has been generally admitted that C18 unsaturated fatty acids (UFAs) regulate negatively delta-6 desaturase (D6D). This inhibition has been evidenced in regard to a high glucose/fat free (HG/FF) diet used in reference. However, several nutritional investigations did not evidence any inhibition of desaturases when feeding fatty acids. Because the choice of the basal diet appeared to be of primary importance in such experiments, our goal was t…
Unsaturated fatty acid bioconversion by apple pomace enzyme system. Factors influencing the production of aroma compounds
1996
Productions of volatile compounds (hexanal and 2,4-decadienal) obtained from polyunsaturated fatty acids by action of specific apple pomace enzyme system were quantitatively improved by increasing substrate and enzyme concentrations in the reaction medium. The importance of an exogenous supply of oxygen during bioconversion was also shown. Some physico-chemical factors involved in the pomace enzyme system expression were screened. A temperature of 25°C was favourable to the bioconversion. The control of alkaline or acidic conditions in the reaction medium may orientate the reaction preferentially to the production of one or other aldehyde.