Novel four 2,3-dihydro-1H-imidazo[1,2-a]pyridine-4-ylium derivatives were formed by reaction of PE and hexose or oligosaccharides including of hexose moiety in soybean lecithin with increase of UV absorption at 350 nm and browning of the solution. Therefore, several pentoses, a heptose and 2-deoxysugars besides hexoses were examined. When any pentose was reacted with PE in DSSL fr. in octane, two 2,3-dihydro-1H-imidazo[1,2-a]pyridine-4-ylium derivatives without a substitute at 6 position on the aromatic ring were formed with increase of UV absorption at 345nm and browning of the solution. On the other hand, two 2,3-dihydro-1H-imidazo[1,2-a]pyridine-4-ylium derivatives with 1,2-dihydroxyethyl group at 6 position on the ring were formed when a heptose was reacted with PE in DSSL fr. in octane. Contrary to these results, when 2-deoxysugars, regardless hexose or pentose, were reacted with PE in DSSL fr. in octane, the derivatives were not formed at all and change of UV absorption and browning in the solution could not also be observed. From these results, it is concluded that existence of an oxygen atom on 2 position of sugars is essential to brown, change the UV absorption, and form the pyridinium derivatives by heating and that rearrangement of carbon(s) in the sugar might involve the reaction of PE and sugars to form the pyridinium derivatives.
This paper deals with a novel preparation method of nanocapsules with alginate/polylysine complex wall. The preparation method consisted of the following steps: dispersion of an aqueous sodium alginate solution into cyclohexane to give a W/O emulsion, preparation of calcium alginate gel beads by adding the emulsion into a calcium aerosol OT solution in cyclohexane, and alginate/polylysine complex wall formation on the surface of calcium alginate beads by adding the beads into an aqueous poly-L-lysine solution. The size of alginate/polylysine complex capsules thus prepared was found to be 100-500 nm. Moreover, an attempt was made to prepare much smaller capsules using a laboratory-made apparatus for electrocapillary emulsification and the capsule size could be reduced to about 40 nm.
The results of our previous study indicated the presence of cerebroside in Saccharomyces kluyveri and related species. The present study was performed to determine to distribution and content of ceramide, cerebroside and acidic sphingolipids in S. kluyveri. Ceramide, cerebroside, inositolphosphorylceramide (IPC), mannosylinositolphosphorylceramide (MIPC) and mannosyl-diinositolphosphoryl ceramide [M(IP)2C] as acidic sphingolipids were all clearly shown to be present in S. kluyveri. Sphingoid bases were recovered at a rate of 74% from the acidic sphingolipid fraction, while recoveries of ceramide and cerebroside, were only 10 and 16%, respectively. The major fatty acid and sphingoid bases in ceramide and acidic sphingolipid of S. kluyveri were C26 2-hydroxy fatty acid (>70%) and trihydroxy sphingoid bases (4-hydroxysphinganine and 4-hydroxyicosasphinganine, >90%), respectively. These results indicated that S. kluyveri has acidic sphingolipids as most sphingolipid classes and major constituents were essentially the same with that of S. cerevisiae.
Lipase-catalyzed transesterification of racemic N-benzyl-4-hydroxyalkanamides with vinyl acetate proceeded enantioselectively to afford the reacted (S)-N-benzyl-4-acetoxyalkanamides and the unreacted (R)-N-benzyl-4-hydroxyalkanamides, which were separated easily by recrystallization in n-hexane. Both enantiomers were converted easily to optically active 4-substituted γ-lactones.
1H-NMR measurements show that the modes of hydrogen-bonding interaction of C-tetraundecenylresorcarene with the guest molecules are classified into four groups, depending on whether the guest molecule is a hydrogen-bond donor, a hydrogen-bond acceptor or works as both donor and acceptor.
Determination was made of the microscopic structures of binary mixtures of water and amphiphile (propyleneglycol-monomethylether (MPG) or propyleneglycol-monopropylether (PPG)) based on the NMR relaxation time (T1) of water and mass spectra of clusters isolated from solutions. The ratio of hydrating to non-hydrating water was derived from T1 and indicated water in MPG-water mixtures to be present more easily in the amphiphile hydration layer than in PPG-water mixtures. Hydrogen-bonded self-association clusters of MPG and PPG could be found in the aqueous solutions by mass spectrometry, the data from which showed MPG self-association clusters to undergo hydrogen bonding with water more readily than PPG self-association clusters. The results of NMR and mass spectrometry were found to be closely correlated. Microscopic structures and intermolecular interactions in aqueous solutions were accurately clarified.
We chemically synthesized astaxanthin n-octanoic acid monoester and diester from free astaxanthin and n-octanoic acid by a dehydration reagent in 32 and 22% yield, respectively. The oral absorbability of the n-octanoic acid monoester and diester was evaluated by examining the plasma and liver concentrations of astaxanthin after oral administration of the compounds. The monoester significantly increased the plasma and liver concentration of astaxanthin compared with the long-chain fatty acid ester mixture derived from Haematococcus algae. The diester is inclined to increase it although it is not significant. It is possible that medium-chain fatty acid esters give better oral-absorbability of astaxanthin than long-chain fatty acid esters.