Interaction of α-Tocopherol and Soybean Oil with Phosphatidylcholine and Their Formation of Small Dispersed Particles

✍ Scribed by Yasuyuki Asai; Teruko Nomura; Sumio Watanabe

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 86 KB
• Volume: 214
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1999.6168

✦ Synopsis

In this study, ␣-tocopherol (␣-T) was dispersed by cosonication with soybean phosphatidylcholine (PC). The particle size in the dispersion was increased to 250 nm up to the ␣-T mole fraction (X T ) 0.4. At X T ‫؍‬ 0.5, the ␣-T/PC mixture was difficult to disperse and the macroscopic oil/water phase separation was observed. By the addition of soybean oil (SO) to ␣-T (molar ratio ␣-T:SO ‫؍‬ 1:1), stable aqueous dispersions (diameter 50 -70 nm) were obtained in the mole fraction range for the ␣-T and SO mixture (X M ) 0.1-0.8. In order to clarify the dispersal mechanism, the dispersed particles were characterized and the interaction among ␣-T, SO, and PC was investigated using several physicochemical techniques. The trapped aqueous volume inside the ␣-T/PC particles was determined using the aqueous space marker calcein, and this volume was increased with the addition of ␣-T into small unilamellar vesicles of PC. The trapped aqueous volume of ␣-T/SO/PC particles was decreased remarkably with an increase in X M , and the decline in the fraction of vesicular particles was also confirmed by fluorescence quenching of N-dansylhexadecylamine in the PC membrane by the addition of the quencher CuSO 4 . These results indicate that the interaction of ␣-T with PC bilayers and the structure of the ␣-T/PC mixture will be changed by the addition of SO.