• Macromolecular Research
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• v.13 no.3
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• pp.253-256
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• 2005

We prepared amino acid-derived diacetylene monomers using solid-phase organic synthesis. The solid-phase synthetic method allowed for the rapid and efficient preparation of functional diacetylenes. Amino acids having hydrophobic sidechains such as alanine, leucine, and phenylalanine, as well as hydrophilic sidechains such as aspartic acid and lysine, were successfully coupled to the diacetylene lipid. The diacetylene monomers prepared in this way were subjected to routine procedures for the generation of polydiacetylene vesicles. Depending on the nature of the side-chains, pink to blue colored polydiacetylenes were generated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.491-494
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• 2000

Conductive Langmuir-Blodgett(LB) films have recently attracted much interest from the viewpoint of ultrathin film conductors at the molecular level. The result shows that the Maxwell-displacement-current(MDC) measuring technique is useful in the detection of phase-transition over the entire range of molecule areas. At the liquid-solid phase transition, a striking feature in the present current measurement was observed; the I-A isotherm for a DPPC monolayer has sharp bend. Dynamic behavior of monolayers in the presence of an external field was also investigated using the current-measuring technique. Dynamic behavier of DPPC monolayer was measured by displacement current when the molecules are stimulated by pressure velocity. As result, it is known that current is generated of higher current pe마 as compression velocity become faster. Also, in order to clarify the reorganization of the lipid monolayers, it is instructive to plot the relationship between I and 1/$A^2$.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.478-485
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• 2014

This study is to form the self assembly of cubic crystalline phase to penetrate into the skin epidermis. The various performance synthesized diglyceryl phytylacetate (DGPA) having hydroxyl group (-OH) and 4 methyl chains with phytyl group was carried out as an amphoteric lipid such as emulsifying power, self assembly. Emulsifying activity of DGPA was very stabilized on only 1% of small content, it could make a W/O emulsion containing high internal phase incorporated with water. Cubic liquid crystal structure with DGPA on three-phase diagram was formed, when mixed DGPA, dimethicone (2CS), and water. Through three-phase diagram forming the cubic liquid crystal area, hexagonal structure zone, and mixing water phase and hexagonal structure area, reversed micelle area were respectively certified. Its structure was proved by the SAXS (small angled x-ray scattering) analysis. As an application, formation of cubosome containing 10% of magnesium ascorbylphosphate and 5% of pyridoxine tris-hexyldecanoate was encapsulated. Occlusive effect of cubosome had above 1.7 times better than reversed micelle. From using poloxamer of dispersing agent, phase structure recovered from W/O emulsion to cubic liquid crystal phase when storage in $33^{\circ}C$ incubator. Therefore, our this study is expected to be as epidermal-dermal skin absorbers in skin care cosmetics and pharmaceuticals industries as raw materials to form a cubic crystal phase through a more in-depth research to DGPA having amphoteric lipid property.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4655-4660
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• 2012

Opuntia humifusa, member of the Cactaceae family, was previously demonstrated to have radical scavenging, anti-inflammatory and anti-proliferative effects in in vitro models. It was suggested that O. humifusa could function in the prevention of carcinogenesis. To investigate the in vivo chemopreventive effect of O. humifusa, mice were fed a diet containing either 1% or 3% following 7, 12-dimethylbenz[a] anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA) induction of skin carcinogenesis. Significant decrease in the numbers of papilloma and epidermal hyperplasia were observed in mice fed with O. humifusa, compared to the control group. O. humifusa also upregulated high total antioxidant capacity and level of phase II detoxifying enzyme such as superoxide dismutase and glutathione S-transferase activity in the skin. Lipid peroxidation activity level was measured in skin cytosol and significantly inhibited in 3% OH fed group compared to the control group. These results suggest that O. humifusa exerts chemopreventive effects on chemical carcinogenesis in mouse skin and that prevention effects are associated with reduction of oxidative stress via the modulation of cutaneous lipid peroxidation, enhancing of total antioxidant capacity especially in phase II detoxifying enzyme system and partial apoptotic influence.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5273-5279
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• 2012

The aim of the present study was to investigate the chemopreventive effect of coumarin against 7, 12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis by monitoring tumor incidence and histopathological changes as well as by analyzing the status of biochemical markers (lipid peroxidation, enzymatic and non-enzymatic antioxidants, phase I and phase II detoxification enzymes). Oral squamous cell carcinomas were induced in the buccal pouch of Syrian golden hamsters by painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. We noted 100% tumor formation with marked abnormalities in the biomarkers status in hamsters treated with DMBA alone. Oral administration of coumarin at a dose of 100 mg/kg body weight (bw) to DMBA treated hamsters completely prevented the tumor formation as well as restored the staus of biochemical variables. The results of the present study thus suggest that the chemopreventive effect of coumarin is probably due to its anti-lipid peroxidative potential and modulating effect on carcinogen detoxification agents in favor of the excretion of ultimate carcinogenic metabolites of DMBA during DMBA-induced hamster buccal pouch carcinogenesis.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.21 no.1
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• pp.38-52
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• 1995

The liposomes have been developed in many drugs and cosmetics fields. In this context, it should be mentioned that MLV liposomes can be prepared standing with the main compounds of the intercellular lipids, cholesterol, palmitic acid, cholesteryl ester and lecithin, by swelling reaction. We report properties of the formation of MLV liposomes with use of the lipid base and Microfluidizer. MLV liposomes formed as multilamellar vesicles(MLV). The effect of the gelation of MLV liposomes have been on swelling reaction which have been mixed lipid with polyol and water phase at high temperature(90$\pm$5$^{\circ}C$). MLV liposomes have been prepared in incorporating alpha hydroxy acid ligrediens. Optimum condition of MLV liposomes were passed three times in the microfluidizer, particle size of the vesicles should be within 150-350nm and those confirmed by freeze-fracture electron microscopy.

• Archives of Pharmacal Research
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• v.9 no.2
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• pp.75-79
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• 1986

The effect of phenothiazine derivatives on the thermotropic transition of liposomal lipid bilayer made of dipalmitoyl phosphatidylchline and dipalmitoyl phosphatidic acid was investigated with differential scanning calorimetry. The thermograms of the liposomal bilayer incorporated with levomepromazine, chlopromazine, prochloperazine, perphenazine and fluphenazine were obtained and the size of cooperative unit of the transition were calculated from the ratio of the van't Hoff enthalpy change to the calculated enthalpy change of the transition. The results showed that incorporation of phenothiazine derivatives into the liposomal bilayer reduced the transition temperature at which the transition from solid state to liquid-crystalline state occurs, and broadened the thermogram peaks. Phenothiazine derivatives also significantly reduced the size of cooperative unit of the transition. The effect of the drugs was proportional to the concentration of the drug in the bilayer. This means that phenothiazine derivatives might have significant fluidizing effects on the biomembrane. The sizes of cooperative unit were successfully corrlated with phar-macological activities of the drugs and the surface pressure increases of lipid monolayer by these drugs. These correlations might be ascribed to a possible hydrophobic nature of interaction between the biomembrane and the drugs involved in their pharmacology.

• Biomolecules & Therapeutics
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• v.30 no.1
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• pp.55-63
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• 2022

Oleanolic acid (OA), a natural pentacyclic triterpenoid, has been reported to exert protective effects against several neurological diseases through its anti-oxidative and anti-inflammatory activities. The goal of the present study was to evaluate the therapeutic potential of OA against acute and chronic brain injuries after ischemic stroke using a mouse model of transient middle cerebral artery occlusion (tMCAO, MCAO/reperfusion). OA administration immediately after reperfusion significantly attenuated acute brain injuries including brain infarction, functional neurological deficits, and neuronal apoptosis. Moreover, delayed administration of OA (at 3 h after reperfusion) attenuated brain infarction and improved functional neurological deficits during the acute phase. Such neuroprotective effects were associated with attenuation of microglial activation and lipid peroxidation in the injured brain after the tMCAO challenge. OA also attenuated NLRP3 inflammasome activation in activated microglia during the acute phase. In addition, daily administration of OA for 7 days starting from either immediately after reperfusion or 1 day after reperfusion significantly improved functional neurological deficits and attenuated brain tissue loss up to 21 days after the tMCAO challenge; these findings supported therapeutic effects of OA against ischemic stroke-induced chronic brain injury. Together, these findings showed that OA exerted neuroprotective effects against both acute and chronic brain injuries after tMCAO challenge, suggesting that OA is a potential therapeutic agent to treat ischemic stroke.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.10-16
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• 2001

To evaluate an effect of circadian variation on the xylene metabolizing enzyme activities, 50% m-xylene in olive oil(0.25 $m\ell$/100g body weight) was intraperitoneally administered to the rats every other day for 6 days both in the night; 24:00 and the day; 12:00. Then animals were sacrigiced at 8hr after last injection of m-xylene. Hepatic microsomal cytochrome p450 contents were more increased both in control and xylene treated rats of night phase than those of day phase. But the activity of hepatic alcohol dehydrogenase(ADH) in control of night phase showed the similar value with that in those of day phase and xylene treated rats of day phase showed an increasing tendency of hepatic ADH activity as those of night phase showing similar activity. Furthermore, control rats of night phase than those of day phase. And by xylene treatment, enzyme activities of rats of day phase were higher tendency in rats of control but those of night phase were somewhat inhibited. Besides, xylene-treated animals of night phase showed increasing tendency of urinary methylhippuric acid concentration compared with those of day phase. On the other hand, liver weight per body weight(%), hepatic lipid peroxide content and serum xanthine oxidase activity were higher in night phase. And the activities of hepatic oxygen free radical metabolizing enzymes such as xanthine oxidase, gluthathione S-transferase, and xylene-treated rats of night phase than those of day phase. In conclusion, it can be hypothesized on the basis of the results that the accumulation rate of m-xylene intermediate metabolite, i.e. m-methylbenzaldehyde in liver tissus may be higher in night phase than in day phase and it may be responsible for higher liver toxicity in bight phase than in day phase.

• Mass Spectrometry Letters
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• v.8 no.4
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• pp.109-113
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• 2017

Single analytical procedure including extraction, liquid chromatography, and mass spectrometric analysis was evaluated for the simultaneous measurement of lysophospholipids (LPLs). LPLs, particularly, lysophosphatidic acids (LPA) and sphingosine 1-phosphate (S1P) are lipid messengers ubiquitously found in various biological matrix. The molecular species mediate important physiological roles in association with many diseases (e.g. cancer, inflammation, and neurodegenerative disease), which emphasize the significance of the simple and reliable analytical method for biomarker discovery and molecular mechanistic understanding. Thus, we developed analytical method mainly focusing on, but not limited by those lipid species S1P and LPA using reverse phase liquid chromatography-tandem mass spectrometry (RPLC-ESI-MS-MS). Extraction method was modified based on Folch method with optimally minimal level of ionization additive (ammonium formate 10 mM and formic acid). Reverse-phase liquid-chromatography was applied for chromatographical separation in combination with negative ionization mode electrospray-coupled Orbitrap mass spectrometry. The method validation was performed on human blood plasma in a non-targeted lipid profiling manner with full-scan MS mode and data-dependent MS/MS. The proposed method presented good inter-assay precision for primary targets, S1P and LPA. Subsequent analysis of other types of LPLs identified a broad range of lysophosphatidylcholines (LPCs) and lysophosphatidyl-ethanolamines (LPEs).