The present review concerning the thermal properties of phospholipid bilayers, solubilization of hydrocarbon in the bilayers, and emulsification of hexadecane with the bilayers, has been described by combing our recent publications and some of our fresh data in regard to the bilayer properties. Phospholipid bilayers of dimyristoylphosphatidylcholine, dimyristoylphosphatidylglycerol sodium salt, and dimyristoylphosphatidylglycerol ammonium salt were investigated. In the thermal properties of phospholipid bilayers, two new transition temperatures of T* and TI, which were found by us, were introduced other than the main transition of Tm. Dispersion of phospholipids took a long period of time to establish the favorable hydration of bilayer-assemblies, and to transform from Lα phase into a new gel phase, transition temperature of which was expressed by TI. From the solubilization studies of octane and hexadecane, we showed that the locus of solubilization for hydrocarbon in the phospholipid bilayers turned out to occur in the palisade layers, being dissimilar in that of the usual surfactant bilayers. Finally, we showed that emulsion of hexadecane prepared with these lipid dispersions at 25°C thermodynamically took the three-phase structure composed of oil phase, emulsifier phase of bilayers, and water phase, and confirmed that it was more stable than the thermal stability of emulsion whose surface was adsorbed by monolayer.
The treatment method for wastewater containing surfactant is discussed. The biodegradability of nonionic surfactants such as nonylphenol ethoxylates is low. In addition, it is difficult to treat them by a coagulation process. The adsorption method using activated carbons is quite effective in treating them. Activated carbons effectively adsorb all kinds of surfactants and are especially effective with nonionic surfactant, which have the highest adsorbability. The order of adsorbability of surfactants is as follows: nonionic>cationic>anionic. It has been recently shown that nonylphenol (NP), a biodegradation product of nonylphenol ethoxylates, has endocrine disrupting effects on aquatic life. It is a pressing issue to establish a method to remove NP. The author has examined the adsorbability of 67 endocrine disruptors including NP. The results showed that almost all endocrine disruptors are effectively adsorbed onto activated carbons at quite low concentration. It has been found that alkylphenols with different lengths of alkyl chains have high adsorbability onto activated carbons. Microporous carbons made from various kinds of organic waste, such as used textile products, could be utilized to adsorb endocrine disruptors.
α,ω-Bischlorosilanes, Cl3SiCH2CH2(CF2)nCH2CH2SiCl3(n=4 (I), 6 (II), or 8 (III)), were synthesized using hydrosilylation reaction with trichlorosilane of the corresponding α,ω-divinylpolyfluoroalkanes, CH2=CH(CF2)nCH=CH2(n=4, 6, or 8), in the presence of hexachloroplatinate(IV) as catalyst at 100°C. Two other α,ω-bissilanes, (CH3O)3 SiCH2CH2(CF2)nCH2CH2Si(OCH3)3(n=4 (IV), 6 (V), or 8 (VI)), and (OCN)3SiCH2CH2(CF2)nCH2CH2Si(NCO)3(n=4 (VII), 6 (VIII), or 8 (IX)), were prepared via reactions of α,ω-bischlorosilanes synthesized with sodium methoxide and silver cyanate, respectively. The structures of silicon wafer surfaces modified with the α,ω-bismethoxysilanes were investigated by polarized FT-IR spectroscopy. The bismethoxysilanes reacted with silicon wafer surface through only one of the reactive groups, -Si(OCH3)3, thereby forming no loop structure on the surface.
Anionic derivatives of β-glycyrrhetinic acid (GA) containing a carboxylate- and a sulfate-terminated substituent at the C-3 position were prepared and assessed for their relative sweetness. A molecular mechanism for sweet taste expression of these derivatives was discussed assuming CPK molecular models of the N-terminal α-helix fragment of the T1R3 protein, which was a likely candidate for the binding site of GA derivatives and helped well explain their sweetness.
This study was designed to determine whether yogurt supplemented with insoluble dietary fibers would lower the levels of serum lipids in 89 normal and hyper-cholesterolemic adults. Yogurt supplemented with brewer’s yeast cell wall (BYC) was administered to 89 volunteers, and its effects on serum cholesterol levels were examined. The yoturt used contained 6g of BYC per 200ml, and an other batch without BYC served as control diet. The volunteers ingested 200ml of BYC-yogurt (BYC-Y) or control yogurt (CT-Y) everyday for four weeks in a crossover experiment. Blood samples were drawn from the subjects for analysis on five occasions two weeks before the start of the experimental period, and immediately before and after each dietary period. It was observed that the levels of the serum total cholesterol (TC), high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) cholesterol significantly decreased following ingestion of BYC-Y compared with those before BYC-Y ingestion. Furthermore, the TC levels of the subjects (serum TC≥200mg/dl) taking the BYC-Y diet were found to be significantly lower than those taking the CT-Y diet. However, the HDL- and LDL-chloesterol levels of those taking the BYC-Y diet were not found to be significantly different from those taking the CT-Y diet. No abnormalities in serum biochemical parameters were observed during the experimental period in all the subjects. These results indicate that taking BYC-Y is effective in lowering the serum cholesterol levels in subjects with the tendency for hypercholesterolemia. The results suggest that BYC-Y may be utilized as a food for controlling hypercholesterolemia.
To reveal the mechanism(s) of the cholesterol-lowering effect of brewer’s yeast cell wall (BYC), we examined the effect of BYC on fecal steroid excretion in rats fed a high-cholesterol and -fat (HCF) diet or a cholesterol-free standard (STD) diet. Male Sprague-Dawley rats were fed an HCF diet or an HCF diet supplemented with 5% or 10% BYC for 14 days. The addition of BYC to the HCF diet dose-dependently reduced the increment of serum total cholesterol concentration and increased the fecal bile acid and neutral steroid(cholesterol and coprostanol) excretion levels. In this experiment, a negative correlation between serum total cholesterol concentration and fecal bile acid excretion level was observed; however, a correlation between serum total cholesterol concentration and fecal neutral steroid excretion level was not observed. Next, male Sprague-Dawley rats were fed an STD diet or an STD diet supplemented with 5% or 10% BYC for 14 days, to investigate whether BYC could lower serum total cholesterol concentration in the rats with normal serum cholesterol concentrations. The addition of BYC to the STD diet also slightly increased the fecal bile acid excretion level; however, it did not affect the serum cholesterol concentration. Furthermore, we examined whether BYC can reduce the serum total cholesterol concentration in Sprague-Dawley rats fed an HCF diet prior to the administration of BYC, to increase the serum total cholesterol concentration. In this experimental model, BYC reduced serum total cholesterol concentration and increased fecal total steroid excretion level, and a negative correlation between serum total cholesterol concentration and fecal bile acid excretion level was observed. These results suggest that BYC reduces serum total cholesterol concentration by increasing fecal bile acid excretion level.
Normal-phase high performance liquid chromatography was developed with evaporative light scattering detection (HPLC-ELSD) for determining cerebroside (monoglycosylceramide) present in commercially available “Plant ceramide”. Authentic cerebroside, isolated from wheat flour by preparative HPLC, served as the standard. A standard curve was obtained for what at 1 to 40 μg of cerebroside, the equation for which was y=axb (x: cerebroside weight; y: peak area). The regression correlation coefficients was above 0.997. Prior to making determination, food samples were saponified so as to remove glycerolipids, and thus improve the precision of cerebroside. Determination on three foodstuffs each containing cerebroside, the present method was conducted and evaluated has on the resulted. Statistically significant intra- and inter-laboratory variation in the data were analyzed. The present HPLC-ELSD was shown quite effective for accurately determining cerebroside content in “Plant ceramide” food samples.
The tyrosinase inhibitory activity of N-acetyldopamine dimers purified from the exuviae of cicada (Cryptotympana tustulata FABR.) was found in the present study. Isomers, trans-1, trans-2, and a mixture of cis isomers, expressed strong activity comparable to that of arbutin, a typical whitening agent. Trans-1 had the strongest activity, exceeding that of arbutin at 100 μM and was found to function quite well as a cosmetic whitening agent. The inhibition mechanism is discussed.
Claisen rearrangement of 1-substituted 2-cinnamyloxybenzenes was carried out in decalin. For methyl-, acetyl- and methoxycarbonyl derivatives, the para-rearranged product was predominant. Reactions of nitro- and carboxyl derivatives were relatively fast and produced ortho-rearranged products. For other derivatives, intramolecular hydrogen bonds formed so that keto-enol tautomerism between the ortho-dienone intermediate and ortho-rearranged product proceeded smoothly.
(−)-Hydroxycitric acid (HCA), a competitive inhibitor of ATP-citrate lyase, is frequently used in dietary supplements for weight loss in humans, and is the principal acid in the rinds of Garcinia cambogia, a fruit native to Asia. NOAEL (no-observed-adverse-effect level) of G. cambogia extract was determined in the present study and examination was made of adverse effects of high-dose administration to 44 healthy volunteers who had received 4000 mg HCA. No adverse effect was noted in any subjects. NOAEL of G. cambogia extract was estimated as more than 4000 mg HCA. Sequential-high-doses administration study was condusted in subjects who had been given 3000 mg HCA daily for 10 days. Blood samples were used to obtain clinical data before and after treatment. The clinical data were essentially the same for either time. G. cambogia extract at more than 3000 mg HCA may be considered safe for healthy persons.