Antihyperlipidemic effect of iodine egg: Search for active ingredients and their iodine contents

Abstract

Active fractions that possess the hypocholesterolemic effect of iodine egg yolk lipid fraction have been investigated with male Wistar strain rats fed on a cholesterol-rich diet. Iodine egg yolk lipid was extracted by Folch's (chloroform: methanol) method and was refractionated into a neutral lipid (IEYNL) fraction and a polar lipid (IEY-PL) fraction. The iodine content in each fraction was determined. The animals were kept on the cholesterol-rich diet for 5 days, and then they were fed the fractions in addition to the above diet for 10 more days. The hypocholesterolemic effect was seen most significantly with the IEY-NL fraction. The serum total cholesterol level in rats receiving this fraction was 70% as compared with that of the Ch group (fed on the cholesterol diet). However, the liver total cholesterol level was not affected or rather increased by the IEY-NL fraction. Another fraction (IEY-PL) showed no such effect. Iodine content in the IEY-NL fraction was quite low (0.2ppm) compared with the other fractions. The daily dose in terms of iodine in the IEY-NL fraction was only the amount equivalent to 1/50 of the reported daily requirement for the rat. The IEY-NL fraction induced the hypocholesterolemic effect, though it contained only a trace of iodine.