α-Tocopherol, ascorbic acid, catechins ((+)-catechin, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate), furanones (2,5 dimethyl-4-hydroxy-3(2H)-furanone and 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone), pyrogallol, hydroxyhydroquinone and resveratrol donated hydrogen atoms to stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) in a biphasic solvent system. When ascorbic acid, (-)-epicatechin gallate or (-)-epigallocatechin gallate was combined with α-tocopherol, the mixtures donated hydrogen atoms more than those calculated. Most of these water-soluble antioxidants inhibited the formation of thiobarbituric acid-reactive substances in the radical initiator-induced oxidation of methyl linoleate in a homogeneous system. However, the water-soluble antioxidants except for ascorbic acid showed no significant synergistic antioxidant activities when they were combined with α-tocopherol. In this system, ascorbic acid strongly inhibited α-tocopherol decomposition, whereas other water-soluble antioxidants slightly. Interestingly, α-tocopherol slightly inhibited decomposition of most of these water-soluble antioxidants. It is unlikely that water-soluble antioxidants except for ascorbic acid regenerate α-tocopherol and acts as synergists in combination with α-tocopherol.
Mouse liver microsomal lipid peroxidation and antioxidant effect of α-tocopherol at the low oxygen concentration close to that in the cells (20-50 μM) was examined. The endogenous α-tocopherol level in liver microsomes of mice fed a vitamin E-deficient diet was 50 ng/mg protein. The level of thiobarbituric acid-reactive substances (TBARS) of the microsomal suspension on treatment with ADP/Fe(II) ion in Tris-HCl buffer (pH 7.5) at 37°C and at 270 μM O2 gradually increased to reach a plateau at 14 nmol/mg protein after 60 min. The maximum level of TBARS was decreased to 6 nmol/mg protein at 34 μM O2, indicating that lipid peroxidation was suppressed to about 1/2 at the limited O2 concentration. The 50% inhibition concentration of the exogenously added α-tocopherol against the TBARS formation was almost linearly decreased as the O2 concentration decreased, 2.8 μM α-tocopherol at 270 μM O2 and 0.2 μM α-tocopherol at 34 μM O2. Above results indicate that the degree of lipid peroxidation is lower and the antioxidant effect of α-tocopherol is much higher at the limited O2 concentration than those at the atmospheric O2 concentration.
To elicit the effect of dietary fat structure on mammary tumorigenesis, young female rats were given dimethylbenz(a)anthracene (DMBA) followed by diets containing triacylglycerol (TAG) or diacylglycerol (DAG). Two types of DAG prepared from fatty acids from rapeseed and palm oils in addition to these vegetable oils (TAG as respective control oils) were fed at the dietary level of 7%. DAG, irrespective of the source, showed similar effects on the indices of mammary tumorigenesis including the incidence and cumulative number of tumors, tumor multiplicity, and tumor burden to those for the corresponding TAG during 90 days of the feeding period, although the cumulative number of tumor tended to be lower in both TAG and DAG from palm oil than those from rapeseed oil. DAG in relation to TAG gave same results with respect to food intake and weight gain, but there was a decreasing trend of white adipose tissue weights, in particular the periovarian tissue. The weight of brown adipose tissue remained unchanged. Serum TAG level in rats fed DAG was lower than in those fed TAG. These observations indicate that DAG is at least no more tumorigenic than TAG in DMBA-induced mammary tumor model, but reduces body fat mass.
Nutritional labeling legislation relies on several methods estimating the fat content in foods by measuring the amount of acyl lipids and giving the results as the sum of all fatty acids expressed as triacylglycerides (TAG). Many of these methods have not been evaluated using soft oilseeds such as flaxseed, which is of increasing interest for use in foods. Four oilseeds (solin, flax, mustard and canola) were analyzed for oil content using exhaustive extraction with petroleum ether (FOSFA method, AOCS Am 2-93), extraction with chloroform:methanol (Bligh and Dyer, Folch, AOAC 983.23), two combinations of acid hydrolysis, Soxhlet extraction with petroleum ether (AOAC 996.06 and modified AOAC 996.06), and saponification. Determination of the acyl lipid content by gas chromatography (GC) was performed on the extracts obtained by FOSFA, saponification, and the two acid hydrolysis-extraction combinations. The Folch modification of the Bligh and Dyer method resulted in the removal of only about 80% of the oil recovered by the FOSFA method for flax and canola. This underestimation was likely due to a non-exhaustive extraction, repeating the extraction would probably have resulted in an increase in the amount of oil recovered. A modification of the acid hydrolysis method (AOAC 996.06), called extraction-hydrolysis-extraction, gave gravimetric results that were statistically similar to those of the FOSFA method. The acyl lipid contents obtained by the saponification/GC method were less than 5% lower than the results obtained by the FOSFA method, however there was more than 10% error between triplicates. Results obtained using the hydrolysis-extraction procedure followed by determination of oil content by GC could not be used due to the enormous variation observed between triplicates. This variation was due to a poor recovery of the internal standard and losses that occurred during the hydrolysis and/or extraction steps.
Determination of fatty acid composition at sn-2 acyl position in triacylglycerol was carried out by capillary gas chromatography,with a microbial lipase from Rhizopus delemar. Triacylglycerol was partially hydrolyzed at 40°C, pH 7 for 3 minutes with the lipase. The sn-2 monoacylglycerol fraction of the lipase product was separated by thin-layer chromatography with a developing solvent which was composed of petroleum ether, diethyl ether and acetic acid (50: 50 : 1v /v /v). The sn-2 monoacylglycerol fraction was methylated with sodium methoxide and analyzed by capillary gas chromatography. Three collaborative studies with 7 laboratories on capillary gas chromatography with a reference standard, beef tallow fatty acid analysis by means of methyl esterification with sodium methoxide, and the determination of fatty acid composition at the sn-2 acyl position in beef tallow were carried out. The reproducibility coefficients of variation of major fatty acids in the samples in the above collaborative studies were less than 1.60%, 3.28% and 5.05%, respectively.
Cotton garments were coated with small particles. Liquid paraffin, Triolein and Oleic Acid organic soils served as the sources of produced with human wear. The clothing with titanium dioxide was immersed in aceton solutions of these compounds, withdrawn and irradiated with UV from a low pressure Hg lamp. Spectral reflectance was then measured with a spectrograph and found to increase at more than 400 nm. Detergency and reflectance decrease at less than 400 nm were assessed following irradiation at both these wavelengths, and was found, respectively to be positive and negative. Without titanium dioxide, negative detergency was observed. From these results it may be recognized that changes in model soil materials were occurred by photo catalytic action of titanium dioxide.
Brine shrimp Artemia nauplii, an important live food used in aquaculture, were enriched with five marine oil triacylglycerols (TAG) in order to enhance n-3 highly unsaturated fatty acids (HUFA) essential for fish larvae. Positional distribution of fatty acids in TAG was determined for both of the enriched Artemia nauplii and dietary marine oils. In all of the enriched Artemia nauplii, docosahexaenoic acid was preferentially located in the sn-1,3 position followed by the sn-2 position. Icosapentaenoic acid was preferentially located in the sn-2 position. Distribution patterns of these fatty acids were not similar to those in dietary TAG of fish oil origin. Positional distribution of HUFA characteristic of marine fish TAG does not appear to hold for Artemia TAG during the HUFA enrichment.