IR and turbidity studies of vitamin E-cholesterol-phospholipid membrane interactions

Severcan, Feride; Kazancı, Nadide; Baykal, Ulku; Süzer, Şefik

doi:10.1007/bf01540456

Cited by 28 publications

(25 citation statements)

References 20 publications

(21 reference statements)

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“…Observing no effect for 6 mol% CLX in the liquid crystalline phase may have resulted from the effect of cholesterol on the membrane system. It has been widely accepted and also observed in our studies (data not shown) that cholesterol exerts opposite effects on the acyl chain conformation below and over the T m of phospholipids; disordering the membrane in the gel phase and ordering it in the liquid crystalline phase [1,24,31,33]. When the ternary system of DSPC:Chol:CLX is considered, the ordering effect of cholesterol in the liquid crystalline phase most probably have surpassed the similar effect of 6 mol% CLX resulting in no significant difference.…”

Section: Resultssupporting

confidence: 70%

Effects of the non-steroidal anti-inflammatory drug celecoxib on cholesterol containing distearoyl phosphatidylcholine membranes

2011

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Abstract.The effects of different concentrations of celecoxib on the acyl chain order, dynamics and the hydration status of the head group and interfacial region of model membranes containing DSPC and cholesterol were investigated in detail using Fourier transform infrared spectroscopy. Our results reveal that regardless of the presence of cholesterol, celecoxib is able to alter the physical properties of membranes. It exerts opposing effects on membrane order at high and low concentrations and decreases membrane fluidity in the presence of cholesterol. An evidence of phase separation has also been observed. The decrease in membrane fluidity supports the hypothesis that celecoxib may induce changes in the activity of membrane bound enzymes through modulating physical properties of the membrane thereby contributing to its anticancer activity. A possible change in the location of celecoxib in DSPC membranes when cholesterol is present has also been proposed. These results clarify, to a certain extent, the molecular interactions of celecoxib with membrane systems and may additionally contribute to a better understanding of COX-2 independent mechanisms of celecoxib action.

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Section: Resultssupporting

confidence: 70%

Effects of the non-steroidal anti-inflammatory drug celecoxib on cholesterol containing distearoyl phosphatidylcholine membranes

2011

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“…The bandwidth jumps near the main phase transition. These modifications are analyzed in the literature [7,[11][12][13][14][15][16] for various types of phospholipids. We give a physical explanation of these modifications by analyzing the bandwidth values at different temperatures and different GS concentrations relevant for the dynamics of the chemical bonds implied in the IR bands' appearance.…”

Section: Resultsmentioning

confidence: 99%

“…Multilamellar DPPG liposomes were obtained [11,14,15] by vortexing DPPG thin films in excess Na 2 HPO 4 buffer for 20 min at 66 C. The liposomes were incubated in a shaking water bath for 1 h at a temperature around 45 C. The DPPG=GS systems were obtained from a stock solution of GS in ethanol. Multilamellar GS-containing vesicles were obtained using the same procedure followed for the DPPG vesicle preparation proposed in Refs.…”

Section: Methodsmentioning

confidence: 99%

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Effect of Gramicidin S on the Dipalmitoylphosphatidyl-glycerol Thermotropic Phase Transition in DPPG/GS Systems: A Mathematical Approach

Stan

Cristescu

Severcan

et al. 2006

Molecular Crystals and Liquid Crystals

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We present a mathematical approach to the experimental data recorded via Fourier transform-infrared spectroscopy regarding the influence of the concentration of the antimicrobial peptide gramicidin S (GS) on the thermotropic phase transition of the dipalmitoylphosphatidyl-glycerol (DPPG) lipid bilayer membrane in DPPG=GS systems. The model is based on the influence of the GS concentration on the parameters of a nonlinear damped oscillator, which models the CH 2 symmetric stretching band.

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Concentration Dependent Different Action of Tamoxifen on Membrane Fluidity

Kazancı

Severcan

2007

Bioscience Reports

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Tamoxifen (TAM) is a non-steroidal antiestrogen drug, which is widely used to prevent and treat breast, liver, pancreas and brain cancers. The present work investigates, in detail, the concentration dependent behavior of TAM (varying from 1 mol% to 45 mol%) on membrane fluidity. The differential scanning calorimetry (DSC) studies showed that tamoxifen eliminates the pre-transition and decreases the main phase transition to lower temperatures. Using visible spectroscopy at 440 nm and Fourier transform infrared (FTIR) spectroscopy it was found that membrane dynamics decreases for 1 and 3 mol% tamoxifen in both the gel and liquid crystalline phases. Above these concentrations up to 18-24 mol%, it increases and reaches its maximum values. As tamoxifen concentration was further increased, the membrane dynamics is found to be gradually decreased, although TAM still has fluidifying effect in comparison to pure phospholipid membrane. These findings are important for the effective use of tamoxifen in the cancer therapy to eliminate its dose dependent side effects reported in the literature.

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IR and turbidity studies of vitamin E-cholesterol-phospholipid membrane interactions

Cited by 28 publications

References 20 publications

Effects of the non-steroidal anti-inflammatory drug celecoxib on cholesterol containing distearoyl phosphatidylcholine membranes

Effects of the non-steroidal anti-inflammatory drug celecoxib on cholesterol containing distearoyl phosphatidylcholine membranes

Effect of Gramicidin S on the Dipalmitoylphosphatidyl-glycerol Thermotropic Phase Transition in DPPG/GS Systems: A Mathematical Approach

Concentration Dependent Different Action of Tamoxifen on Membrane Fluidity

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