Theaflavins from black tea, especially theaflavin-3-gallate, reduce the incorporation of cholesterol into mixed micelles.
Tea is one of the most widely consumed beverages in the world and may be associated with reduced heart disease rates. Theaflavins, which are formed in the production of black tea, have been suggested being responsible for the blood-cholesterol-lowering (BCL) effects of tea. We hypothesized that the effect of theaflavins on BCL could be through interference in the formation of dietary mixed micelles, which could result in reduced intestinal cholesterol absorption. Micelles were produced by mixing oleic acid, bile acids, lyso-phosphatidylcholine, and cholesterol. Theaflavin-treated micelles/particles were analyzed using electron microscopy (cryo-TEM), high-performance liquid chromatography (HPLC) analysis, and light-scattering particle size measurements. A dose-dependent inhibitory effect of theaflavins on the incorporation of (14)C-labeled cholesterol into micelles and a theaflavin-dependent increase in particle size was found. These particles consisted of insoluble large multilamellar vesicles with onion-like structures. Ultracentrifugation and HPLC analysis revealed that the pellets contained mainly theaflavin-3-gallate, while the remaining theaflavins were found to be present in the supernatant. Using purified theaflavin subtypes confirmed that mainly theaflavin-3-gallate is responsible for multilamellar vesicle formation. These results show that theaflavins can play a role in decreased intestinal cholesterol absorption via inhibition of micelle formation.
Vermeer
Mario A
MA
Unilever Food and Health Research Institute, Olivier van Noortlaan 120, P. O. Box 114, 3130 AC, 3133 AT Vlaardingen, The Netherlands. mario.vermeer@unilever.com
Mulder
Theo P J
TP
Molhuizen
Henri O F
HO
D044946:Biflavonoids / Q000737:chemistry* / Q000494:pharmacology; D002392:Catechin / Q000737:chemistry* / Q000494:pharmacology; D002784:Cholesterol / Q000737:chemistry* / Q000378:metabolism; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology; D011108:Polymers / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*
D044946:Biflavonoids; D008823:Micelles; D010936:Plant Extracts; D011108:Polymers; D013662:Tea; C088983:theaflavine gallate; D005707:Gallic Acid; D002392:Catechin; D002784:Cholesterol