The synergistic antioxidant effects of L-proline (Pro), L-methionine (Met), L-lysine (Lys), L-histidine (His) or L-tryptophan (Trp) with a mixed tocopherol concentrate (m-Toc) in cookies were studied by a storage test at 40°C for 12 months after baking. Cookie stability toward oxidative deterioration was evaluated based on changes in peroxide value (POV) of the lipid fraction and the residue amount of added amino acid and tocopherol (Toc). 1) The time course of POV for the control sample without amino acid and/or m-Toc indicated a clear induction period (IP) and IP was prolonged by the addition of any amino acid. 2) Pro most effectively enhanced the antioxidant effect of m-Toc in cookies, followed by Met>Trp>Lys>His. 3) During storage for 12 months, protective effects of amino acid on Toc were noted. When Pro and m-Toc were added together, the residue amount of Toc was higher than with other amino acids, and the residue amount of Pro was highest for any amino acid.
Sterically stabilized liposomes were produced by incorporation a poly (oxyethylene) poly (oxypropylene) block copolymer (Pluronic F-68) into the lipid bilayer using a high-pressure homogenizer. Mean vesicle size of liposomes incorporating Pluronic F-68 greatly decreased from 480 nm to 110 nm with minor change in marker entrapment after passing three times through the high-pressure homogenizer. Liposomes stabilized with Pluronic F-68 were characterized with respect to entrapment efficiency, vesicle size and surface charge. Entrapment efficiency of a marker increased with Pluronic F-68 content, and was maximum at 0.13 (% wt/vol) -Pluronic F-68. In particle size and surface charge, no change was noted with increase in Pluronic F-68 content. Surface charge decreased slightly for liposomes incorporating Pluronic F-68, compared to those coated with Pluronic F-68. Pluronic F-68 is thus distributed between the bilayer and/ or inner phase of liposomes as well as the liposome surface. Liposomes stabilized with Pluronic F-68 were significantly stable in calcium and fetal bovine serum (FBS) solution at 37°C compared with Pluronic F-68-free liposomes. The incorporation of Pluronic F-68 into the bilayer caused significant increase in 31P-NMR line width. Pluronic F-68 is thus shown to stabilize liposomes by restricting phospholipid motion in the bilayer.
For the effective utilization of compounds obtained from nature, we synthesized derivatives considered to possibly have physiological activity, using 6- [(8 Z, 11 Z) -8, 11, 14-pentadecatrienyl] salicylic acid (1) from cashew nut shell oil as the starting material. Eight derivatives were obtained via acetylation, methylation and/or oxidation of (1). They were examined for capacity to inhibit tyrosinase and found to inhibit its activity more than (1).
Lipids extracted from three pine seeds, Pinus koraiensis, Pinus armandi and Pinus cembra, were studied for general properties, fatty acid, sterol, phospholipids, and tocopherol content and autoxidation by the AOM test. All the lipids contained 14.718.6 % of Δ cis-5, cis-9, cis-12-octadecatrienoic acid (Δ 5, 9, 12-18 : 3 and designated here tentatively as pinolenic acid). The content of this acid in polar lipids was considerably less than in neutral lipids. The content of pinolenic acid in 2-monoacylglycerol was very low (1.22.6 %) and was thus considered distributed mainly at the 1, 3-position. Sterol composition consisted of three sterols, sitosterol, Δ 5-avenasterol and campesterol. Total sterol content of lipid extracted from P. armandi seeds was higher than that in the other two species. Phosphatidylcholine (PC), phosphatidyl ethanolamine (PE) and phosphatidylinositol (PI) were present as the major phospholipids. Total tocopherol content in pine seed lipids was less than in vegetable oils having high iodine value such as soybean oil and safflower oil. Oxidative stability by the AOM test was essentially the same as that of the above vegetable oils.
3-Methyl-2- (2-propeny1) -2-cyclopentenone (Allylrethrone, 1) is an important component of an insecticidal pyrethroid and an intermediate for the synthesis of pyrethrins. The procedure for the synthesis of (1) from methyl 3-formyl propionate (2) is shown in Scheme-1. Keto ester (4), prepared from (2) and 2-methyl-2-vinyl-1, 3-dioxolane (3) by radical addition reaction in 76 % yield, was treated with ethylene glycol to give diacetal (5) in 72 % yield. Reduction of (5) with sodium bis (2-methoxyethoxy) aluminium hydride in benzene gave diacetal alcohol (6) in 95 % yield, which was oxidized to diacetal aldehyde (7) with pyridinium chlorochromate in 66 % yield. Diacetal aldehyde (7) was reacted with the ylid prepared form methyltriphenylphosphonium iodide to give (8) in 91 % yield, which was hydrolyzed with hydrochloric acid to afford diketone (9) in 95 % yield. The base-catalized cyclization of (9) gave (1) in 92 % yield.