A recently recognized group of glycerolipids called betaine lipids, which are composed of diacylglycerol and N-permethylated hydroxyamino acids, are widely distributed in lower plants and algae as well as in some non-photosynthetic microorganisms. The present state of knowledge of the phylogenetic distribution, the fatty acid composition, the thermal properties, and the biosynthesis of the betaine lipids is reviewed in the perspective of a future sought for their biological roles and activities.
A method for determining cis-trans isomers in dimethyl di (9-octadecenyl) ammonium chloride was devised based on NMR spectrometry. Chemical shift of the vinyl carbon of cis-9-octadecenoic acid was noted at around 130 ppm, this being essentially the same as that of trans-9-octadecenoic acid. However, chemical shifts of methylene carbons adjacent to the double bond differed between the two isomers. The ratio of signal intensities of isomers in standard mixtures agreed well with isomer content. The cis-trans ratio of dimethyl di (9-octadecenyl) ammonium chloride was determined by the same procedure. The ratio and degree of unsaturation were determined in the starting oleic acid, the intermediate octadecennitrile, dioctadecenylamine, methyl dioctadecenylamine, and finally obtained quaternary salts. Considerable increase in the trans isomer and decrease in unsaturation were observed during the conversion of the nitrile into dioctadecenylamine. Reductive reaction is thus not completely selective to the nitrile group; that is the double bound of the alkenyl group is partially hydrogenated.
Five groups of weanling male rats were each fed palm oil, palm olein, their randomly interesterified oils, and soybean oil, as control, for 28 d. Comparative studies were made on cholesterol and its metabolites in several tissues and feces from these rats and on chemical and physical properties between the palm and interesterified oils. 1) By interesterification of the palm oil, palmitic and oleic acids, rich in oil, became essentially uniformly distributed at each position of triglyceride, causing an increase in saturated triglycerides of high melting point, and improved plasticity. 2) The serum cholesterol concentrations of the interesterified palm oil and palm olein groups did not differ significantly from those of the soybean oil group, and did not change with interesterification of palm oil. The same was noted for the serum triglyceride and bile acid concentrations. As also palm oil, palmitic acid was present as a minor constituent in the serum and liver lipids of rats fed interesterified palm oil, and preferentially excreted in the feces, despite modifying the triglyceride structures. 3) Cholesterol content in both liver and adipose tissue was essentially the same in all the five groups, and cholesterol and its metabolites in feces from the interesterified palm oil and palm olein groups were present in amounts almost equal to those of the original oil groups, but significantly lower than those of the soybean oil group. However, the ratio of metabolites to cholesterol in the feces was basically the same in all groups. Thus, the effect of interesterified palm oil on cholesterol metabolism may be equivalent to that of either its original oil or soybean oil.
The distribution of cis-monoenoic fatty acids with n-5 unsaturation within jujube (Zizyphus jujuba var. inermis) fruit was examined by GC and GC-MS. Analytical data indicated a series of n-5 monoenoic acid isomers with C14, C16, and C18 chain length to be present as the major acyl moieties in the pulp lipids (34.0%) and peel lipids (14.1%). No n-5 acid isomers could be detected in the seed lipids. Following separation of the pulp lipids into nonpolar lipid, glycolipid and phospholipid fractions, the n-5 homologues were found widely distributed among these fractions without distinct localization. Thus in jujube pulp n-5 monoenoic acids appear to be important component fatty acids of membrane lipids, glycolipids and phospholipids.
Removal of myristic acid by aqueous SDS solution was investigated, directing attention to solubilization as a removal mechanism. Removal after 5h by SDS solution at various concentrations and 30°C was clearly correlated to the limit of solubilization, A (sat) linearly related to the concentration of SDS. Thus, removed myristic acid soil is solubilized in SDS micelles. The value of β, determined from a plot of removal against log t (t=washing time), increased with the concentration of SDS. Linearity in a reciprocal plot of β against 1/A (sat) indicated that, during a short time, myristic acid was removed by solubilization. The effects of temperature on solubilization and the removal of myristic acid were also studied. At equilibrium, a clear isotropic solution was obtained at 20-35°C, while opaque white dispersions were noted above 40°C. The latter system appeared assignable to dispersions of ternary liquid crystalline (myristic acid-SDS-water), LC, since the temperature (Tp) at which SDS-water penetrated solid myristic acid was 38.5°C for the 0.5% SDS system. The removal of myristic acid improved with increase in washing temperature, and that after 5 h at 20-35°C was quite similar to that expected from the limit of solubilization. However, above the penetration temperature, removal rapidly increased more than that expected from solubilization. The dispersion of LC was considered a possible cause for this.
The reasons why emulsification of vegetable oils by physico-chemical technics is difficult were studied using phase diagrams of nonionic surfactant/oil/water systems. The phase diagrams indicated the solubility of oil in a surfactant continuous phase to be higher for a hydrocarbon system than a that of a triglyceride system and solubility of surfactant in the oil phase to be higher for a triglyceride system. All the oil to be emulsified must be dissolved in the surfactant continuous phase to produce fine O/W emulsions in conventional phase inversion emulsification. To stabilize O/W emulsions, no surfactants should be present in the oil phase at a concentration exceeding cmc (critical micellization concentration). Thus, hydrophilic surfactants must be used to stabilize O/W emulsions for emulsion systems of triglyceride. D phase emulsification can produce fine O/W emulsions only by hydrophilic surfactants. This method is thus useful for the emulsification of vegetable oils. Several types of vegetable oils were emulsified in submicron droplets by this method.
In a previous work, the rate equation for the washing process was proposed for fatty soil removal. Here, removal rates of soild particulate soils (Fe2O3 and Carbonblack) and redeposition rates of the removed solid particulate soils were measured by a spectrophotometric system. Kinetic analysis of the results indicated the removal of solid particulate soils to occur by elementary processes, 1 and 2, as also noted in the case of fatty soil. The rate equation for washing process proposed in the previous paper is thus applicable to the removal process of solid particulate soils. The temperature and mechanical force dependence of the rate constants of this process (k1) as obtained experimentally were examined in detail. The results of redeposition experiments of the removed soil indicated the rate constant of redeposition (k-2) to be first order kinetics. Process 2 in the rate equation is reversible, involving the redeposition of removed soil and removal of redeposited soil. The rate constant for redeposited soil removal (k2) can thus be obtained as the difference between the rate constant (slope of linear plots) of process 2 and k_2. The good agreement between k1 and k2 indicates soil removal in processes 1 and 2 to be essentially same for solid particle and fatty soil.
The ene-type chlorination of terpene alcohols (1) such as linalool and geraniol with hypochlorous acid gave allylic chlorides (2) in good yields. Allylic chlorides (2) reacted with Grignard reagents such as isopentylmagnesium bromide and 3, 7-dimethyloctylmagnesium bromide in the presence of CuCl to give γ-cross coupling products (5) and (6) such as 6, 7-dehydroisophytol (5 b, 6 b) and 6, 7-dehydrophytol (5 d, 6 d) with high regioselectivities.
A method was devised for preparation of N-succinimidyl carboxylates (N-succinimidyl esters of fatty, benzoic and arylacetyl acids) using N, N'-disuccinimidyl oxalate (DSO). Reaction of acids with DSO in the presence of pyridine in acetonitrile gave the corresponding esters in good yields. N-Hydroxysuccinimide which was formed during the reactions and pyridine in the reaction mixtures could be easily removed by treatment with water. This method was compared with those previously reported using N, N'-dicyclohexylcarbodiimide (DCC) and N, N'-disuccinimidyl carbonate (DSC).