interaction of the non steroidal anti-inflammatory drug celecoxib with pure and cholesterol-containing model membranes

Sade, Aslı
The interactions of the non steroidal anti-inflammatory drug celecoxib with pure and cholesterol containing distearoyl phosphatidylcholine multilamellar vesicles were studied using Fourier transform infrared spectroscopy, differential scanning calorimetry and turbidity technique at 440 nm. The results reveal that celecoxib exerts opposing effects on membrane order in a concentration dependent manner while cholesterol disorders and orders the membrane in the gel and liquid crystalline phase, respectively. Ternary mixtures of DSPC/Cholesterol/celecoxib behave similar to cholesterol with a small effect of celecoxib. While celecoxib decreases fluidity of the DSPC membranes, cholesterol shows an opposite effect, and in ternary mixtures, a dominant effect of cholesterol is observed. Celecoxib induces opposite effects on the hydration status of the carbonyl groups in the binary system whereas; cholesterol induces hydrogen bonding around this group. An evidence of phase separation has also been observed for all three systems (DSPC/celecoxib, DSPC/Chol, and DSPC/Chol/celecoxib). In addition, a possible location of celecoxib in the interfacial region of the membrane has been proposed. Finally, penetration of celecoxib into the hydrophobic core of the ternary system at high cholesterol concentrations and formation of a new phase has also been suggested. Thus, depending on the concentration used, celecoxib induces significant changes in the biophysical properties of membranes that may aid in understanding its mechanism of action. Furthermore, highly complex interactions take place in ternary membrane systems and further investigations are needed to explore them in detail.


Biophysical investigation of the effects of antioxidants on normal and diabetic rat bone tissues at molecular level
Boyar, Handan; Severcan, Feride; Department of Biology (2004)
In the first part of this study, the effect of diabetes mellitus on the long bones (femur and tibia) of the streptozocin induced diabetic rats and the effect of selenium (Se) treatment on these bones are investigated at molecular level by Fourier transform infrared (FTIR) spectroscopy, light and electron microscopy. In the second part of this study, the effect of selenium and vitamin E deficiency or selenium toxicity on rat bones have been studied by FTIR spectroscopy. The results of the first part of the p...
The effect of diabetes on rat skeletal muscle tissues at molecular level
Bozkurt, Özlem; Severcan, Feride; Department of Biology (2006)
In the present study Fourier Transform Infrared Spectroscopy was used to examine the effects of streptozotocin-induced diabetes mellitus on the structural components of slow- and fast-twitch rat skeletal muscles, at molecular level. Diabetes mellitus is a chronic disorder of carbohydrate, fat and protein metabolism, which is characterized by hyperglycemia caused by a defective or deficient insulin secretory response. The effect of diabetes is seen on a variety of tissues leading to important secondary compl...
Interactions of cholesterol reducing agent simvastatin with charged phospholipid model membranes
Sarıışık, Ediz; Severcan, Feride; Department of Biology (2010)
Interactions of cholesterol reducing agent simvastatin with charged model membranes were investigated. Effects of cholestrol reducing agent simvastatin on the phase transition behaviour and physical properties of the anionic dipalmitoyl phosphatidylglycerol (DPPG) multilamellar liposome were studied as a function of temperature and simvastatin concentration. Moreover the effect of acyl chain length on the simvastatin model membrane interactions was monitored using dipalmitoyl phosphatidylglycerol (DPPG) and...
Investigating the anticarcinogenic role of salix aegyptiaca l. in colorectal carcinoma
Enayat, Shabnam; Banerjee, Sreeparna; Department of Biology (2009)
In this study, extracts from bark, leaves and catkins of Salix aegyptiaca L. were investigated for their antioxidant content by 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) free radical quenching assay, total phenolic and total flavonoid assays. The highest antioxidant activity (19 ug/ml IC50 for inhibition of DPPH radical activity), total phenolic content (212 mg gallic acid equivalents/g of dried extract) and total flavonoid (479 mg catechin equivalents/g of dried extract) was observed in the ethanolic ex...
Tip enhanced Raman scattering with adiabatic plasmon focusing tips.
Bek, Alpan; DAS, G; Di, Fabrizio; LAZZARINO, M (Elsevier BV, 2011-06-01)
Tip-Enhanced Raman spectroscopy (TERS) is a promising microscopy technique which combines, in principle, outstanding spatial resolution with a detailed chemical analysis of the sample. However, as yet, it is not routinely used although an increasing number of research groups are becoming more actively involved in the field. Among the several reasons which can explain the relatively low usage of TERS, the lack of reproducibility of tips as field enhancers is probably the most critical. Here we propose and de...
Citation Formats
A. Sade, “interaction of the non steroidal anti-inflammatory drug celecoxib with pure and cholesterol-containing model membranes,” M.S. - Master of Science, Middle East Technical University, 2009.