Effects of riboflavin and fatty acid methyl esters on cholesterol oxidation during illumination.
The effect of riboflavin or fatty acid methyl esters on cholesterol photooxidation was studied. Samples containing cholesterol, either alone or in combination with riboflavin or fatty acid methyl esters, were illuminated at 25 degrees C in an incubator for 28 days. The various cholesterol oxidation products (COPs) and cholesterol were analyzed by gas chromatography-mass spectrometry (GC-MS), and riboflavin was determined by HPLC. Results showed that the presence of riboflavin or fatty acid methyl esters facilitated production of COPs and degradation of cholesterol, and the degradation fits a first-order model. The COPs formed during light storage included 7 alpha-OH, 7 beta-OH, 7-keto, 3,5-cholestadien-7-one, 5,6alpha-EP, and 5,6beta-EP. The addition of riboflavin caused formation of 3,5-cholestadien-7-one through dehydration of 7-keto, whereas in the presence of docosahexaenoic acid methyl ester, the formation of 5,6alpha-EP or 5,6beta-EP was favored. Riboflavin was more effective for generation of COPs than fatty acid methyl esters.
Hu
Po Chen
PC
Department of Nutrition and Food Science, Fu Jen University, Taipei, Taiwan 242.
Chen
Bing Huei
BH
D002784:Cholesterol / Q000032:analysis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D005227:Fatty Acids / Q000494:pharmacology*; D008401:Gas Chromatography-Mass Spectrometry; D008027:Light; D008041:Linoleic Acids / Q000494:pharmacology; D010777:Photochemistry; D012256:Riboflavin / Q000737:chemistry / Q000494:pharmacology*; D013229:Stearic Acids / Q000494:pharmacology
D005227:Fatty Acids; D008041:Linoleic Acids; D013229:Stearic Acids; C005575:methyl linoleate; D004281:Docosahexaenoic Acids; C059579:methyl docosahexaenoate; C031183:stearic acid; D002784:Cholesterol; D012256:Riboflavin