Incorporation of carotenoid esters into liposomes.
Carotenoid esters are investigated for their interaction with liposomal membranes and compared with their corresponding free (non-esterified) carotenoids. A monoester (beta-cryptoxanthin) and two diesters (zeaxanthin and lutein) were chosen. Egg yolk phosphatidylcholine liposomes served as the membrane model. We measured the sizes of the liposomes by photon correlation spectroscopy. The incorporation yields were determined spectrophotometrically. From liposomes simultaneously doped with the fluorescent dye Laurdan, fluidity changes of the liposomes were obtained. In summary, the results indicate that the carotenoid esters: (i) get incorporated, but at a lower yield than their corresponding free carotenoids, (ii) also increase the membrane rigidity as do the free carotenoids, and (iii) increase the liposome sizes significantly, but after extrusion through an 0.1 mum filter the sizes resemble with the exception of the liposomes incorporated with lutein diesters, they remain bigger indicating an elastic property due to two different accessible locations in the membrane.
Department of Chemistry and Biochemistry, University of Agricultural Sciences and Veterinary Medicine, Str. Manastur 3, RO-400372 Cluj-Napoca, Romania.
Adela
A
Pintea
Horst A
HA
Diehl
Carmen
C
Momeu
Lisa
L
Aberle
Carmen
C
Socaciu
D000975:Antioxidants / Q000008:administration & dosage; D002338:Carotenoids / Q000008:administration & dosage / Q000737:chemistry*; D065366:Cryptoxanthins; D004548:Elasticity; D004952:Esters / Q000737:chemistry*; D005456:Fluorescent Dyes; D008081:Liposomes / Q000737:chemistry*; D014975:Lutein / Q000737:chemistry; D008560:Membrane Fluidity; D010316:Particle Size; D010539:Permeability; D010713:Phosphatidylcholines / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene / Q000031:analogs & derivatives / Q000737:chemistry
D000975:Antioxidants; D065366:Cryptoxanthins; D004952:Esters; D005456:Fluorescent Dyes; D008081:Liposomes; D010713:Phosphatidylcholines; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene; D002338:Carotenoids; D014975:Lutein