Functional properties and applications of several biosurfactants such as bile acids (BA), lung surfactants (LS) and so on have been so far studied particularly in the boundary fields between colloids and surface chemistry and medical science. The main themes are as follows;
(1) Studies on colloidal and surface properties of various bile salts.
Changes of the shapes and structures of mixed micelles prepared by mixing a bile salt with various mole fractions in aqueous solutions of the nonionic surfactant with homogeneous ethylene oxide chain length (C₁₀E₈) were estimated for various mixed ratios of bile salts. These are itemized as follows;
(a) CMCs, structures, aggregation numbers and hydrophobicities of micelles for single bile salt systems and for aqueous binary mixed systems between one of bile salts and C₁₀E₈.
(b) Absorption of vitamine E (VE) solubilized in micellar solutions of various bile salts by a rat small intestine.
(2) Studies on the functions and developements of LS. The mechanism of a synthetic lung surfactant including surfactant proteins named “TA” developed by Fujiwara et al., being more effective for respiratory distress syndrome (RDS), was evaluated by surface rheology as follows;
(a) Surface rheological properties of proteolipids, surfactant protein (SP-B, SP-C, SP-BC) and their mixtures containing lecithin, palmitic acid (PA) and egg phosphatidyl glycerol (EggPG) and the efficiency as LS.
(3) Studies on the fundamental properties of liposomes.
(a) Evaluation of phase transition temperature (Tc) of lipid liposomes by using a tautomerism of α-benzoylacetoanilide (BAA) and effects of addition of cholesterol.
(b) Influences of addition of ionic and nonionic surfactants on the membrane of lipid liposomes.
(4) Solubilities of insoluble drugs into water.
(a) Dissolution of calcium bilirubinate disk as a model of a gallstone by some solvents.
(b) Dissolution of dicrofenac sodium by the complexes formed among hydrotropic substances in water.

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The paper is primarily based on the article that qualified for the 2000 Japan Oil Chemists' Society Award. Novel synthetic routes of functional materials and intermediates involving reactions of epoxides were established. Reactions of epoxides with halogen compounds gave insertion products of epoxide into carbon-halogen bonds. Reactions of epoxides with carbonyl compounds gave 1, 3-dioxolane compounds. Special surfactants containing chemically cleavable surfactants, α, ω-type surfactants and others were developed. The major chemically cleavable surfactants each possessed a 1, 3-dioxolane ring as connecting group of hydrophobic moiety with the hydrophilic moiety. Chemically cleavable surfactants were useful as ecofriendly surfactants owing to lose surface activity subsequent to acid, base or ozone addition after usage and the resulting oily residue could be recovered. The surfactants were useful for producing of high purity polymer by emulsion polymerization. Properties of surfactant mixed system were studied. Sodium dodecylsufate (SDS) - alkyl glucoside (AG) and SDS - alkyl ethoxylate (AE) mixed systems showed greater dissociation of sodium ions of SDS than SDS alone. The SDS - AG mixed system showed no molecular interaction in mixed micelles, while the SDS - AE mixed system did so. Percent leakage of a liposome probe was found strongly dependent on composition of mixed surfactants.

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This review is based on the article that qualified for the 2000 Japan Oil Chemists' Society Award. Peroxidative stress on lipid molecules not only invites diminution of the nutritive value of foods, but also takes part in several biochemical consequences, aging and the pathophysiology of diseases. It is important to measure lipid hydroperoxide as a primary oxidation product in order to determine the degree of lipid oxidized in foods and in the biomembranes of the body, and also to maintain health and the wholesomeness of foods. In 1987, we established a new methodology called chemiluminescence detection - high performance liquid chromatography (CL-HPLC), which is sensitive and selective enough to determine the hydroperoxide lipid class level in foods and human blood plasma. The unique post-column chemiluminescence reagent consists of cytochrome C and luminol in an alkaline borate buffered solution. Using CL-HPLC, we confirmed bis-hydroperoxides formation other than mono-hydroperoxides in the initial stage of triacylglycerol oxidation in food oils. Long-term fish oil consumption in animals invites a high risk of membrane lipid peroxidation together with an increased need for α-tocopherol. The principal cause of cellular lipid peroxidation is aging (senescence) of the body. Membrane lipid peroxidation is essential to the pathogenesis of atherosclerosis, diabetes, Alzheimer's disease, and other diseases.

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Solubilization techniques by surfactants are very useful to dissolve perfumes into many industrial products having the medium of water. Since the molecular structures of perfumes are intricate, it is difficult to predict solubilization of perfumes. In the present review, the solubility of perfumes into micellar phase and their solubilization mechanism were described. The characteristics of solubilization of perfumes in a variety of systems : solubilization of binary mixed perfume system, solubilization by mixed surfactant system, and solubilization by concentrated surfactant solution system, were also shown in this review. Moreover, mechanism of volatility of perfumes from aqueous surfactant solutions and controlled release of perfumes using phase transition of aqueous surfactant solutions were explained.

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Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), n-3 polyunsaturated fatty acid (n-3PUFA), have been shown to have beneficial effects on what? The beneficial effects of n-3PUFA, especially EPA on bone metabolism in vitro and in vivo were examined in this study.
Osteoblasts are bone forming cells, that produce prostaglandin E₂, an endogenous potent bone resorbing factor. To clarify the effects of EPA on bone metabolism, the effects of EPA on MC3T3-E1 cells, osteoblast-like cells were studied. The addition of MC3T3-E1 cells to EPA, but not DHA, caused increased calcium accumulation and Von-Kossa staining. In vivo experiments, the effect of EPA on strength of the femur in ovariectomized and low calcium/vitamin D₃ fed rats were studied. EPA abolished the effects of ovariectomy with consequent recovery of the bone strength.
Preliminary epidemiology studies indicate EPA ingestion possibly useful for preventing loss of bone weight and strength with aging. These findings and epidemiological studies, demonstrate EPA and marine oil to possibly have beneficial effects for preventing and improving age-related osteoporosis

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The amounts and compositions of wax esters (WE) of salted roe and salted and dried roe ('Karasumi') of the mullet, Mugil cephalus, caught in Australia were examined. Both salted and salted and dried roes contained large amounts of lipids (TL : 30.631.6% of dry weight) comprised almost entirely of WE (82.884.3%) consisting mainly of C₃₂ and C₃₄ components (53.161.1%) Fatty alcohols originating from WE were essentially saturated (83.586.4%) with the predominant component of 16 : 0 alcohol (59.363.4%). Each of monoenoic fatty alcohols (11.915.0%) comprised their isomers and the most abundant component was 16 : 1n-7 alcohol (5.89.2%). Appreciable amounts of odd chain fatty alcohols with 15 : 0 alcohol (3.1-12.0%) were also present. Component fatty acids in WE were more monoenoic (56.160.6%) with 16 : 1n-7 acid (34.038.8%) and polyenoic (26.631.1%) with 20 : 5n-3, 22 : 5n-3 and 22 : 6n-3 acids. Among triacylglycerols, 16 : 0 (32.934.6%), 16 : 1n-7 (16.622.5%) and 18 : 1n-7 (7.88.7%) acids were characteristic. No oxidation of polyenoic fatty acids in different lipid classes of salted and dried roe of mullet could be detected.

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Anionic derivatives of β-glycyrrhetinic acid (GA) were prepared and assessed for sweetness. It was found that the presence of both a carboxyl group (COOH, free form) at C20 position and a carboxylate moiety (COO^-) at C3 position in the GA molecule is essential for sweet taste. A plausible mechanism for sweet taste is proposed.

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Amphiphiles of symmetrical bis-quaternary ammonium salts possessing ammonium groups, with methyl as head group, dodecyl and aralkyl as hydrophobic groups, and connected by an alkanediyl were synthesized. Aralkyls are p-heptylbenzyl and 8-phenyloctyl (corresponding ammonium salts are designated “phenylene type” and “phenyl type”, respectively). The effect of a benzene ring in the hydrophobic chain on the hydrolytic and substrate recognizing activity of amino acid esters were examined. The phenyl type showed higher hydrolytic rate, particularly so in the case of phenylalanine and methionine esters, than the corresponding ammonium salts having no benzene ring (“alkyl type”). The phenylene type was less active compared to an alkyl type and hydrolyzed only phenylalanine ester. The position of benzene ring is thus a significant determinant of hydrolytic rate and substrate recognition. The orientation or formation of a molecular assembly as well as the uptaken site of a substrate are also affected by this position.

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Molecular orbital study was conducted so as to clarify the reactivity of nucleophilic substitution between phenoxide anions of tocopherols (Vitamin E) and catechins and the three-membered oxirane ring (binding site to biomolecules) of some mutagens. All stationary points including transition state structures (TSs) were optimized with no geometrical constraint at the PM3 level and energies of all species including TSs were evaluated at the Becke3LYP/3-21G level based on PM3 geometry. The reactions of model compounds of three tocopherols (β-, γ-, and δ-tocopherol) and catechins with ethylene oxide were examined. The tocopherols and catechins were found to possess nucleophilic reactive sites to which electrophilic mutagens each having oxirane ring could bind.
Activation energy (ΔE^≠) for the rate-determining C-C bond forming step for electrophilic substitution of phenoxide anions of three tocopherol models with ethylene oxide was found to range in 43-53kJ/mol. Predicted reactivity followed the order βγ<δ-tocopherol. The most stable TS was that for the reaction of δ-tocopherol model and had the lowest ΔE^≠ (+43.3kJ/mol), at which electrophilic reaction occurs at the C-7 position. In catechin models, TS whose O-5 phenoxide anion reacts with ethylene oxide at the C-8 position had the lowest ΔE^≠ (+40.5kJ/mol). These considerably small ΔE^≠ suggest tocopherols and catechins to be capable of directly capturing electrophilic mutagens having the reactive oxirane ring and eliminating their activities so as to bind to biomolecules.

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Detergency effects of poly (sodium α-hydroxyacrylate); PHA on artificially soiled cotton fabrics without surfactant were investigated at various values of water hardness and molecular weight of the polymer and compared those of sodium dodecyl sulfate; SDS and other similar-structured polymers, such as poly (sodium acrylate); PA and poly (vinyl alcohol); PVA.
The detergency of PHA was found not to depend on water hardness and was much higher than that of SDS for any value of high hardness. Detergency increased with molecular weight and remained constant above 10500. PHA showed higher detergency than PA or PVA.

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A ¹³C-labeled docosahexaenoic acid (DHA) highly enriched with ¹³C atoms was prepared using the DHA-producing Thraustochytrid, Schizochytrium sp. strain N1-27. Following 115h-cultivation with sodium acetate-1, 2-¹³C₂ as the sole labeled carbon source, 2.53g/L total lipids were obtained from the cells. The ¹³C-labeled DHA ethyl ester was prepared from total lipids and fractionated to almost 100% purity with 53% recovery on HPLC. The ¹³C atom ratio was estimated at more than 97% from GC-MS. The productivity of labeled DHA was 0.29g/L. Other ¹³C-labeled fatty acids such as docosapentaenoic acid (DPA), eicosapentaenoic acid, and palmitic acid, were obtained as by-products. The present Thraustochytrid is thus shown useful for producing labeled DHA and DPA.

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