Two-dimensional Thermodynamic Properties of Sterols.

Iwahashi, Makio; Minami, Hiroyuki; Yamaguchi, Yukari; Iimura, Ken–ichi; Kato, Takeshi

doi:10.5650/jos.50.787

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…[46][47][48] Π c ∼ 41 mN m -1 was reported for epicoprostanol 33 on pure water at a compression rate of 20 Å 2 molecule -1 min -1 . A Π-A isotherm for epicoprostanol that begins rising just above 45 Å 2 molecule -1 and with a collapse pressure near 28 mN m -1 at 298 K was reported 49 and is similar to that shown in Figure 2. The structures observed by BAM during the interaction of the sterols with tomatine appear well below the collapse pressures.…”

Section: Discussionsupporting

confidence: 74%

Interaction of the Glycoalkaloid Tomatine with DMPC and Sterol Monolayers Studied by Surface Pressure Measurements and Brewster Angle Microscopy

et al. 2006

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The interaction of the glycoalkaloid tomatine with monolayers of dimyristoylphosphatidylcholine (DMPC) and cholesterol, as well as other selected sterols, has been investigated using surface pressure measurements at constant area and Brewster angle microscopy (BAM). The interaction of tomatine with sterol monolayers is found to vary with the structure of the sterol. The interaction of tomatine with cholesterol-containing monolayers results in a surface pressure increase accompanied by the appearance of a mottled texture. Morphological changes are observed that suggest the formation of tomatine-cholesterol complexes that aggregate at the water-air interface. No morphology change observable by BAM is observed for monolayers containing epicholesterol, suggesting that the stereochemistry of hydrogen bonding between the sterol and the sugar units on tomatine is of particular significance. Strong interactions are observed with cholestanol- and coprostanol-containing monolayers, and BAM reveals formation of spiked aggregates upon interaction with 7:3 mole ratio DMPC/coprostanol mixed monolayers. More modest surface pressure changes are observed for cholestenone- and epicoprostanol-containing monolayers. A much smaller surface pressure increase is observed when tomatine is injected beneath a pure DMPC monolayer.

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Section: Discussionsupporting

confidence: 74%

Interaction of the Glycoalkaloid Tomatine with DMPC and Sterol Monolayers Studied by Surface Pressure Measurements and Brewster Angle Microscopy

et al. 2006

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“…15 Physicochemical properties and crystal structures of cholesterol also have been investigated. [18][19][20] Furthermore, liquid crystals and gallstones of cholesterol were also precisely studied. 21 However, the direct interaction between oleic acid and cholesterol molecules especially in the liquid state has scarcely been studied.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cholesterol and Other Additives on Viscosity, Self-Diffusion Coefficient, and Intramolecular Movements of Oleic Acid

et al. 2007

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It has been empirically known that cholesterol largely increases the viscosity of oleic acid. To clarify the mechanism of the effect of cholesterol on the intermolecular and the intramolecular (segmental) movements of oleic acid in the liquid state, we measured density, viscosity, IR, 1H NMR chemical shift, self-diffusion coefficient, and 13C NMR spin-lattice relaxation time for the liquid samples of oleic acid containing a small amount of cholesterol. Furthermore, the above measurements were also carried out for the samples of oleic acid containing a small amount of cholestanol, cholestane, cholesteryl oleate, ethanol, or benzene. Cholesterol, possessing one OH group and one double bond in its molecular structure, largely increased the viscosity and reduced the self-diffusion and the intramolecular movement of oleic acid. Cholestanol, possessing one OH group but not a double bond, and cholesteryl oleate, not possessing an OH group, also reduced the self-diffusion and the intramolecular movement; cholestane, not possessing an OH group, slightly reduced the self-diffusion and the intramolecular movements. In contrast with these sterols, ethanol and benzene reduced the viscosity and increased the self-diffusion and the intramolecular movements. In addition, cholesterol and ethanol, both having one OH group, promoted the upfield shift of the 1H NMR signal of the carboxyl group of oleic acid; IR difference spectra for the cholesterol/oleic acid system quite resemble those for the ethanol/oleic acid system. These results suggest that oleic acid makes a complex with cholesterol as well as with ethanol. On the basis of the formation of the complex, we have revealed the role and the functional mechanism of cholesterol to the intermolecular and the intramolecular movements of oleic acid in the liquid state.

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Two-dimensional Thermodynamic Properties of Sterols.

Cited by 2 publications

References 14 publications

Interaction of the Glycoalkaloid Tomatine with DMPC and Sterol Monolayers Studied by Surface Pressure Measurements and Brewster Angle Microscopy

Interaction of the Glycoalkaloid Tomatine with DMPC and Sterol Monolayers Studied by Surface Pressure Measurements and Brewster Angle Microscopy

Effect of Cholesterol and Other Additives on Viscosity, Self-Diffusion Coefficient, and Intramolecular Movements of Oleic Acid

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