Cotelomer type zwitterionic surfactants having multi-hexyl chains and multi-carboxylate and muti-pyridinium functions (R6S-zR6VPQ-wVP-yAA, w and y means the number of 4-vinylpyridine and sodium acrylate, respectively; z means number of hexyl chains by quaternization) were prepared by quaternization and hydrolyses of cotelomers, which were prepared by cotelomerization of 4-vinylpyridine and methyl acrylate in presence of hexanethiol, and examined for their surface activities. Critical micelle concentration (cmc) of zwitterionic cotelomers shifted to lower concentration with increasing number of hexyl chains. The cmcs of R6S-zR6VPQ-wVP-yAA with z of 2.1-3.8 were from one 110th to one 4th of those of the corresponding cationic cotelomers. Zwitterionic cotelomers gave surface tension of 40-44 mN m-1 at the cmc. The increase of number of hexyl chains in R6S-zR6VPQ-wVP-2.3AA series reduced the surface activities. Vigorous shaking of the mixtures of water and chloroform solution of zwitterionic cotelomers formed oil-in-water type emulsion. Highly stable emulsion was formed by using R6S-zR6VPQ-wVP-2.3AA with z of 1.4-2.1 and the degrees of emulsification were kept at the level of 60-70% after 360 min of standing. Zwitterionic cotelomers gave interfacial tension of 2-4 mN m-1 at the water-chloroform interfaces and oriented themselves easier than equimolar mixtures of cationic cotelomer and anionic cotelomer.
Properties of the three-phase emulsion of hexadecane have been investigated at 40°C as a function of mole fraction of hexadecane (X) in tha mixture of hexadecane and dimyristoylphosphatidylglycerol sodium salt (NaDMPG). NaDMPG used as an emulsifier was the aqueous dispersion of the IM or the Gel-2 state. Here the IM state was a nematic-like metasable state that appeared above the critical temperature T* (31.7°C), while the Gel-2 state was a stable gel state that was established after approximately 15 day aging of the IM state. DSC data showed that hexadecane was solubilized into the NaDMPG bilayers up to approximately X=0.5, and that at X>0.5 stable hexadecane emulsions were formed regardless of the states of the NaDMPG dispersions. XRD data showed that hexadecane emulsions were stabilized with the NaDMPG multibilayers solubilizing hexadecane in their palisade layers. In the region of X<0.5, hexadecane solubilized into the IM phase promoted formation of a gel structure of the IM phase, while hexadecane solubilized into the Gel-2 phase promoted hydrolytic cleavage of the ester bonds between glycerol and myristic acid in NaDMPG molecules. The emulsion prepared with the NaDMPG dispersions in the Gel-2 state were more stable than these prepared with the dispersions in the IM state, reflecting the different physical states of the NaDMPG dispersions.
The methanol extract from Alpinia oxyphylla showed a suppressive effect on umu gene expression of SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract from A. oxyphylla was successively re-extracted with CH2Cl2, EtOAc, BuOH, and water. A dichloromethane fraction showed a suppressive effect. The suppressive compound in the dichloromethane fraction was isolated by SiO2 column chromatography and identified as yakuchinone A(1) by GC, GC/MS, 1H and 13C NMR spectroscopy. Compound 1 suppressed the SOS-inducing activity of furylfuramide in the umu test. Compound 1 suppressed 51.7% of the SOS-inducing activity at a concentration of 0.32μM/mL. The ID50 value (50% inhibition dose) of compound 1 was 0.30μM/mL. This compound was assayed with an other mutagen, 3-amino-14-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which requires a liver metabolizing enzyme, activated Trp-P-1.
The oxidative stability of conjugated linoleic acid (CLA) and its ethyl ester (ethyl CLA) was compared with that of linoleic acid (LA) and ethyl LA in the bulk phase at 50°C. Progress of oxidation was determined by the measurement of oxygen absorption. The oxidative stability of CLA was almost the same as that of LA, but ethyl CLA was oxidatively more stable than ethyl LA. In the present study oxidative stabilities of soybean-triacylglycerol (TG) and TG containing CLA (CLA-TG) ware also compared. Although the content of CLA (59.4%) in CLA-TG was slightly higher than that of LA (55.3%) in soybean-TG, CLA-TG was much more stable to oxidation than soybean-TG. On the other hand, the oxidative stability of α-linolenic acid (LN) and docosahexaenoic acid (DHA) decreased by the isomerization of double bonds in both fatty acids. The same result was obtained in the case of their ethyl esters. The isomerized LN and DHA contained conjugated trienes other than conjugated dienes. The lower oxidative stability of isomerized LN and DHA would be due to conjugated trienes in these PUFAs, whereas conjugated deines had little effect on their oxidative stabilities.
The antioxidizig action of 20-hydroxyecdysone was investigated in several systems in vitro. Changes in the parameters of chemiluminescence in the presence of 20-hydroxyecdysone were found in rat liver mitochondrial fractions. The effect of 20-hydroxyecdysone on methyl linoleate micelles free radical oxidation was studied. The rate of oxygen uptake in methyl linoleate micelles was found to be smaller when 20-hydroxyecdysone was present than at its absence. The action of 20-hydroxyecdysone in the liposomal membranes oxidation was investigated be means of α-tocopherol consumption. A lower rate of α-tocopherol consumption in the oxidation of liposomal membranes was found when 20-hydroxyecdysone was present. The effect of cholesterol on free radical formation in liposomal membranes was investigated. The rate of free-radical formation was smaller when cholesterol was present in the membrane than in membranes free of cholesterol. The α-tocopherol antioxidant effect in the membrane was also lower when cholesterol was present. We show here for the first time that 20-hydroxyecdysone has an antioxidant action in combination with α-tocopherol in membranes with cholesterol overload. Kinetic measurements were revealed the 20-hydroxyecdysone antioxidant effect on free radical reactions in membranes.
Hydrogen peroxide has been used in detergent products as a bleaching agent for many years owing to its oxidizing capacity. In bleaching, decoloration occurs through oxidative decomposition of colored stain with hydrogen peroxide. The mechanism for this process has been extensively studied but detailed aspects remain unclarified. This study was conducted to provide further clairfication of this mechanism using the anthraquinone dye, Alizarin Red S (ARS), as a model of colored stain. ESR was carried out for analysis of decomposition reactions of ARS. Four radical intermediates were noted to be formed through three elementary reactions. The first intermediate was to be a semiquione radical of ARS, suggesting oxidative decomposition initiated by one-electron transfer from the dye to hydrogen peroxide. This intermediate induced the second decomposition by attacking hydrogen peroxide anions to afford two second intermediates, is followed by formation of phthalic acid as the final product. Kinetic study indicated the formation of the first intermediate, i.e., electron transfer from hydrogen peroxide to the dye, to be the rate-determining step of oxidative decomposition.
Four strains that produce docosahexaenoic acid (DHA), two Schizochytriums (SR21/N1-27) and two Thraustochytriums (F3-1/W20), were cultured using oleic acid (OA), linoleic acid (LA), and α-linolenic acid (ALA) as carbon sources. These fatty acids in the medium were emulsified with Tween 80 using a ultrasonicator. Though SR21 grew faster than the other strains did, the fatty acid profile of SR21 did not changed throughout the culture period and the DHA content was not affected by the three fatty acids. The fatty acid profiles of the other three strains were affected by the fatty acids, i.e., ALA resulted in a higher DHA content and LA in a lower DHA content. Schizochytrium limacinum SR21 seems to have a different fatty acid syhthetic pathway from the other strains and none of OA, LA and ALA seem to become precursors of DHA in the strain.
Photooxidation of dibenzothiophene in the presence of molecular oxygen and a photosensitizer like anthraquinone (AQ) proceeded in MeCN, AcOH, acetone and MeOH but not in benzene or n-octane, indicating the requirement of polar solvents. The addition of MeCN to nonpolar solvent initiated the AQ-sensitized photooxidation even when the solvent was biphasic as in an n-octane/MeCN mixture. The major oxidation product of dibenzothiophene was the corresponding sulfoxide. 4,6-Dimethyldibenzothiophene is a very unreactive sulfur compound during hydrodesulfurization but its photooxidation proceeds about 4 times faster than that of dibenzothiophene during the co-photooxidation. Sulfur content in light gas oil was reduced to below 10 ppm in the AQ-sensitized photooxidation in biphasic system consisting of light gas oil and MeCN
New 1,4,5,8-naphthalenetetracarboxydiimide (NDIM) derivatives were prepared in order to evaluate their solubities and binding properties to form dimers via hydrogen bonds. Di-tert-butylphenyl groups of NDIMs effectively disturbed their intermoleculater interaction even in high concentration and in low-polar solvent. The 1H NMR titration studies in CDCl3 indicated that all diimide derivatives did not exhibit the π-π stacking of naphthalene rings even in high concentration, and N-(2,5-di-tert-butylphenyl)-N′-hydrogen-1,4,5,8-naphthalenetetracarboxydiimide (2,5-BDIM), N-(3,5-di-tert-butylphenyl)-N′-hydrogen-1,4,5,8-naphthalenetetracarboxydiimide (3,5-BDIM), and N-(3,3-diphenylpropyl)-N′-hydrogen-1,4,5,8-naphthalenetetracarboxydiimide (3,3-PDIM) showed self-assembly properties through intermolecular hydrogen bondings.
5-Chloromethyl-2-furfural, generated in situ by surface active agent-catalysed dehydration of D(-)-fructose, was conducted to obtain 5-methyl-2-furfural,2,5-dimethyl furan,2,5-hexanedione and 2,5-dimethyl-1-thioureidopyrrole.