Effect of conjugated linoleic acid on asolecitin liposomes dynamics

Abstract

Conjugated linoleic acid (CLA) consists of octadecadienoic acid isomers (18:2) with conjugated double bond systems. CLA has demonstrated important suppression effect on tumor cell growth. This effect can be improved by the CLA incorporation into liposomes, which can be used as nanocarriers for drug delivery.Therefore, it is important to understand molecular interactions between CLA and liposomes. In this study, the effect of (9Z,11E)-CLA (Figure 1a) on the physico-chemical properties of soybean asolectin (ASO) liposomes was monitored by using Fourier Transform Infrared Spectroscopy (FTIR). ASO liposomes, containing 25% phosphatidylcholine (Figure 1a), were prepared without and with CLA (5% m/m) by the method of vesicle hydration. Horizontal Attenuated Total Reflectance (HATR)-FTIR interferograms were averaged for 50 scans in a resolution of 2 cm-1, in the wavenumber range from 400 to 4000 cm-1 at room temperature. CLA-induced shifts were observed to the C=O and CH3 lipid group wavenumbers (Table 1). This result indicates CLA preferential location in the ASO chain. The wavenumber decrease in C=O can result from hydrogen bonding to the ester carbonyls induced by CLA. The shifts in the lipid CH3 wavenumber suggest an increase in gauche conformers in the system, reducing the order of the liposome bilayers.