• YAKHAK HOEJI
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• v.38 no.6
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• pp.637-645
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• 1994

The effect of various drugs on the stability of the liposomal membrane of phosphatidylcholine and cholesterol was studied, employing the fluorescence self-quenching method. Calcein was entrapped into the phospholipid small unilamellar vesicles and the leakage of the fluorescence probe was monitored on adding the drug to the system. The results of the experiments showed that phenothiazine derivatives, some potent local anesthetics and surface active agents were very effective in inducing the leakage of calcein from the liposome. The leakage-inducing activity of these drug substances has been ascribed to their surface activity and the perturbation of the liposomal membrane by these substances. On the other hand drug substance with low surface activity or without amphiphilic moieties did not show any effect or only small effect on the leakage of calcein from the liposomes. The effect of lipid concentration on the stability of the liposomes was also investigated to show that the higher concentrations of lipid more drug was required to induce the leakage. The effect of surface charges of vesicles was also studied, and the results showed that the charge on the liposomes enhanced the stability of the liposomes against the leakage-inducing activity of these drug substances.

• YAKHAK HOEJI
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• v.38 no.2
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• pp.131-139
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• 1994

Calcein-encapsulated small unilamellar vesicles of various lipid composition were prepared using the sonication technique, and their stabilities at $20^{\circ}C$ were examined by measuring calcein leakage from the liposomes. The fluidity of these liposomal bilayers was also investigated by measuring the fluorescence polarization of DPH labelled into the liposomes. The results showed that liposomes made of PC mixtures with different acyl chain length were very stable, which may be due to the formation of interdigitated bilayer structure. The addition of cholesterol further stabilized these PC liposomes. However, addition of cholesterol reduced the encapsulation efficiences of liposomes. The fluidity of the liposomes was significantly decreased by cholesterol in the liquid crystalline state, but not changed in the gel state. These results suggest that the enhanced stability of PC mixture liposomes may be ascribed to the formation of stable interdigitated bilayer structure. In membrane-mimetic and drug-delivery studies, vesicles made of mixtures of various phospholipids are recommended instead of addition of cholesterol to the phospholipid.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.726-734
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• 1989

To analyze the components of dense coat fractions associated with fat globule membrane, The membrane was treated with various concentrations of Triton X-100, a non-ionic detergent, and the composition of lipids associated to the detergent insoluble material was analyzed. The amount of protein, phospholipid, cholesterol and ganglioside in milk fat globule membrane was reduced consistently with increasing concentrations of Triton X-100. Butyrophilin (band 12), xanthine oxidase (band 3) and band 16 as constituents of insoluble coat materials was revealed after electrophorisis on SDS-polyacrylamide gels. Phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl serine, phosphatidyl inositol and sphingomyelin were identified as the major phospholipids of the coat materials without selective concentration relative to the original membranes. Percentages of total phospholipid were not changed by any of the treatments. Fatty acids of total lipid were myristate, palmitate, stearate (major saturated acids), oleate and linoleate (major unsaturated acids). Cholesterol contents on a protein basis were slightly reduced with increasing concentrations of Triton X-100. Cholesterol adhered to protein more tightly than other constituents The contents of gangliosides was proportionally refuted with increasing concentration of Triton X-100.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.144-151
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• 1991

Composition and unsaturation ratio of fatty acids composing phospholipid which is the main constituent of biological membranes are known to be related to the response of plant to cold stress. In order to investigate a relationship between fatty acid unsaturation ratio of phospholipid and the range of cold tolerance of rice cultivars obtained in the field experiment, the lipid from the leaves of 32 rice cultivars were isolated and the fatty acid composition of phospholipid was determined by gas chromatography. In this experiment, composition and unsaturation ratio of fatty acids composing phopholipid on rice plants grown under natural condition and treated with chilling temperature were compared with the cold tolerance in the field for rice cultivars. The results obtained were summarized as follows ; 1. The phospholipids isolated from the leaves of 32 rice cultivars both grown under natural condition and chilling treatment contained palmitic, linoleic and linolenic acid as major components and palmitoleic, stearic and oleic acid as minor components. 2. The content of palmitic acid, a saturated fatty acid, was reduced in rice seedlings subjected to chilling treatment for 3 days at $15^{\circ}C$, and contents of linoleic and linolenic acid, unsaturated fatty acids, were increased. 3. The unsaturation ratio of fatty acid was increased by chilling treatment, and was high in cold-tolerant cultivars but low in cold-susceptible cultivars and the results were correlated with the range of cold tolerance investigated in the field. 4. The content of palmitic acids among fatty acids composing phospholipid was reduced and that of linolenic acid was increased by hardening treatment. 5. The unsaturation ratio of fatty acid was increased 18~24% by hardening treatment compared to control.

• The Korean Journal of Pharmacology
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• v.28 no.1
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• pp.103-114
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• 1992

Selective quenching of 1,6-diphenyl-1,3,5-hexatriene (DPH) by trinitrophenyl groups was utilized to examine the transbilayer fluidity domains of the model membranes of total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from synaptosomal plasma membrane vesicles. At $37^{\circ}C$, all anisotropy (r), limiting anisotropy $(r_{\infty})$, and order parameter (S) values of DPH in the SPMVTL were larger than those in SPMVPL. The anisotropy, limiting anisotropy, and order parameter of DPH in the inner monolayer were 0.025, 0.033, and 0.070, respectively, greater than calculated for the outer monolayer of SPMVTL. In SPMVPL, the anisotropy, limiting anisotropy, and order parameter of DPH in the inner monolayer were 0.014, 0.018, and 0.047, respectively, greater than calculated for the outer monolayer. Selective quenching of DPH by trinitrophenyl groups was also utilized to examine the effects of barbiturates on the transbilayer fluidity domains of SPMVTL and SPMVPL. Barbiturates did not affect the anisotropy of DPH in the transbilayer domains of SPMVTL. In contrast, barbiturates increased the fluorescence anisotropy, limiting anisotropy, and order parameter of DPH in the SPMVPL in a dose-dependent manner. Barbiturates showed a greater ordering effect on the outer monolayer as compared to the inner monolayer of SPMVPL. Hence, it has been demonstrated for the first time that the Sheetz-Singer hypothesis (1974) may be valid for phospholipid model membranes.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.1-6
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• 1997

We determined the microviscosity of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine cerebral cortex and liposomes of total lipids (SPMTL) and phospholipids (SPMPL) extracted from SPMV. Changes in the microviscosity induced by the range and rate of lateral diffusion were measured by the intramolecular excimerization of 1, 3-di(1-pyrenyl)propane (Py-3-Py). The microviscosity values of the direct probe environment in SPMV, SPMTL and SPMPL were 38.17, 31.11 and 27.64 cP, respectively, at$37^{\circ}C$and the activation energies $(E_a)$ of the excimer formation of Py-3-Py in SPMV, SPMTL and SPMPL were 8.236, 7.448 amd 7.025 kcal/mol, respectively. Probe location was measured by polarity and polarizability parameters of the probe Py-3-Py and probe analogues, pyrene, 1-pyrenenonanol and 1-pyrenemethyl-3${\beta}$-hydroxy-22, 23-bisnor-5-cholenate (PMC), incorporated into membranes or solubilized in reference solvents. There existed a good linear relationship between the first absorption peak of the $^1_a$ band and the polarizability parameter $(n^{2}-1)/(2n^{2}+1)$.The calculated refractive index values for SPMV, SPMTL and SPMPL were close to 1.50, which is higher than that of liquid paraffin (n=l.475). The probe location was also determined by using a polarity parameter $(f-1/2f^{I})$. Here f=$({\varepsilon}-1)/(2{\varepsilon}+1)$ is the dielectric constant function and $f^I=(n^2-1)/(2n^2+1)$ is the refractive index function. A correlation existed between the monomer fluorescence intensity ratio and the solvent polarity parameter. The probes incorporated in SPMV, SPMTL, and SPMPL report a polarity value close to that of 1-hexanol $({\varepsilon}=13.29)$. In conclusion, Py-3-Py is located completely inside the membrane, not in the very hydrophobic core, but displaced toward the polar head groups of phospholipid molecules, e.g., central methylene region of aliphatic chains of phospholipid molecules.

• Journal of Ginseng Research
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• v.19 no.1
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• pp.39-44
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• 1995

Total saponin from Korean red ginseng changed thermodynamic parameters of membranes from dipalmitoylphosphatidylcholine (DPPC) and ghost erythrocytes of human. In liposomes from DPPC, temperature of the main transition (Lb'-La) in liquid-crystalline phase increases by 0.2$^{\circ}C$ in average, but enthalpy does not change. Total saponin at a concentration of smaller than $10^5$% "stabilizes" the timid bilayers. At larger than 0.07 of saponin/DPPC ratio, saponin leads to an exclusion of the bound lipid molecules from the main phase transition into lamella liquid crystalline La-phase. Total saponin influences specifically all erythrocyte membrane transitions in a concentration-dependent manner, i.e. on the structures of all the main membrane skeleton proteins. A high structural specificity of saponin with membrane proteins, could be a base of specificity of physiological response of not only erythrocytes, but also other cells.her cells.

• Archives of Pharmacal Research
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• v.15 no.2
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• pp.152-161
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• 1992

Selective quenching of 1, 6-diphenyl-1, 3, 5-hexatriene (DPH) by trinitrophenyl groups was utilized to examine the transbilayer fluidity asymmetry of model membranes of phospholipids (SPMVPL) extracted from synaptosomal plasma membrane vesicles (SPMV). The polarization (P), anisotropy (r), limiting anisotropy $(r_\infty$), and order parameter (S) of DPH in the inner monolayer were 0.019, 0.014, 0.018, and 0.047, respectively, greater than calculated for the outer monolayer of SPMVPL. Selective quenching of DPH by trinitrophenyl groups was also utilized to examine the effects of n-alkanols on the individual monolayer structure of SPMVPL. n-Alkanols fluidized the hydrocarbon region of bulk SPMVPL and the potencies of n-alkanols up to 1-nonanon increased with carbon chain length. It appears that the potencies in bilayer fluidization increase by 1 order of magnitude as the carbon chain length increases by two carbon atoms. The cut-off phenomenon was reached at 1-decanol, where further increase in hydrocarbon length resulted in a decrease in pharmacological activity. The n-alkanols had greater fluidizing effects on the outer monolayer as compared to the inner monolayer of SPMVPL, even though these selective effects tended to become weaker as the carbon chain length increased. Thus, it has been proven that n-alkanols exhibit selective rather than nonselective fludizing effects within transbilayer domains of SPMVPL.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.181-188
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• 1992

To study the effect of alginic acid on modulation of the aging process, Sprague-Dawley(SD) male rats were fed the diets containing 0, 3, 6 and $9\%$ alginic acid isolated from brown algae(Undaria pinnatifida) for 16 weeks. The effects of alginic acid on body weight, malondialdehyde(MDA) content, peroxidizability index, cholesterol and phospholipid levels, cholesterol/phospholipid(Ch/Ph) molar ratio, and fatty acid compositions in liver membranes were investigated. Increasing alginic acid level in diets did not alter food intakes but effectively decreased body weights gain(p<0.01-0.005). Malondialdehyde(MDA) contents of diets containing 6 and $9\%$ alginic acid were effectively decreased in ranges of $54.1-43.0\%$ in mitochondria, and $65.5-87.7\%$ in microsome compared with $100\%$ of control group. Cholesterol levels of all diets containing alginic acid were significantly decreased in ranges of $87.0-72.3\%$ in mitochondria, and $87.4-68.1\%$ in microsome compared with $100\%$ of control group. Phopholipid levels in microsome were significantly decreased by diets containing 3 and $ 6\%$ alginic acid but Ch/Ph molar ratios in both membranes were decreased by diets containing 3 and $6\%$ alginic acid. Increasing alginic acid level in diets significantly decreased total fatty acid but effectively increased linoleic acid in microsome except for diet containing $9\%$ alginic acid. These data on liver membranes suggest that alginic acid added to diets can modulate the physiological changes if the aging process.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.3
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• pp.125-130
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• 2003

The aim of this study was to provide a basis for studying the molecular mechanism of pharmacological action of chlorhexidine digluconate. Fluorescence polarization of n-(9-anthroyloxy)stearic acid was used to examine the effect of chlorhexidine digluconate on differential rotational mobility of different positions of the number of membrane bilayer phospholipid carbon atoms. The six membrane components differed with respect to 2, 3, 6, 9, 12, and 16-(9-anthroyloxy)stearic acid (2-AS, 3-AS, 6-AS, 9-AS, 12-AS and 16-AP) probes, indicating different membrane fluidity. Chlorhexidine digluconate increased the rate of rotational mobility of hydrocarbon interior of the cultured Porphyromonas gingivalis outer membranes (OPG) in a dose-dependent manner, but decreased the mobility of surface region (membrane interface) of the OPG. Disordering or ordering effects of chlorhexidine digluconate on membrane lipids may be responsible for some, but not all of its bacteriostatic and bactericidal actions.