Black-Tea Polyphenols Decrease Micellar Solubility of Cholesterol in Vitro and Intestinal Absorption of Cholesterol in Rats

Abstract

Administration of black-tea polyphenols (BTP) simultaneously reduced lymphatic recovery of both (3)H-cholesterol and (14)C-trioleoylglycerol in rats that were cannulated in the thoracic duct. BTP decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. When purified theaflavins, which are components of BTP, were used, theaflavin-monogallates (TFMGs), theaflavin-3-gallate (TF3G), and theaflavin-3'-gallate (TF3'G) were effective in eliminating cholesterol from bile salt micelles in vitro. Theaflavin (TF) and theaflavin-3,3'-digallate (TFDG) had no effect on the micellar solubility of cholesterol. The concentration of bile acid in the micelles was not influenced by the addition of any BTPs or theaflavins. These results suggest that the reduction of micellar cholesterol by BTP could be important to reducing cholesterol absorption.

Simulated gastrointestinal digestion, intestinal permeation and plasma protein interaction of white, green, and black tea polyphenols

“…The polyphenolic pattern of white, green and black tea extracts have been reported previously (Almajano, Carbó, López Jiménez, & Gordon, 2008;Ikeda et al, 2010;Wu et al, 2012). White and green tea leaves are characterised by higher levels of catechins than black tea, since the postharvest treatments, specifically fermentation, convert these compounds to other higher molecular mass compounds, mainly, theaflavins ( Fig.…”

“…HPLC separation and quantification of phenolic compounds in tea extracts and samples obtained from in vitro digestion, transepithelial permeation, and plasma protein binding experiments, were performed according to earlier studies (Ikeda et al, 2010;Wu, Xu, Héritier, & Andlauer, 2012) with some modifications, as follows. Identification of individual polyphenols was achieved by recording chromatograms at 280 nm and comparison with spectra and retention times for the standards and those reported in the literature.…”

“…(-)-Epigallocatechin-3-gallate (EGCG) has been identified as the major polyphenol in both white and green teas, but (-)-epigallocatechin (EGC) and (-)-epicatechin-3-gallate (ECG), along with gallic acid, caffeine, and theobromine, are present at higher concentrations in white tea (Santana-Rios et al, 2001). EGCG is thought to be responsible primarily for many of the health benefits associated with tea consumption, including reduced oxidation (Mildner-Szkudlarz, Zawirska-Wojtasiak, Obuchowski, & Golinski, 2009) and inflammatory (Cao et al, 2007) processes, glucose/insulin regulation (Nishiumi et al, 2010) and lipid metabolism (Ikeda, Yamahira, Kato, & Ishikawa, 2010). The higher concentrations of several white tea constituents compared with black and green teas may be responsible for the apparent increase in biological activity (Santana-Rios et al, 2001).…”

In vitro bioaccessibility, bioavailability and plasma protein interaction of polyphenols from Annurca apple (M. pumila Miller cv Annurca)

“…Other works reveal the possibility that oligomeric procyanidins may be effective in reducing plasma cholesterol concentration and suppressing activity on postprandial hypertriacylglycerolemia. Actually, such effects were mainly demonstrated for grape seed, red wine and tea polyphenolic extracts (Leifert & Abeywardena, 2008;Ikeda, Yamahira, Kato, & Ishikawa, 2010;Kobayashi et al, 2009), but no studies reporting such bioactivities for apple procyanidins are available in literature so far.…”

Hypolipidemic mechanism of gypenosides via inhibition of pancreatic lipase and reduction in cholesterol micellar solubility

“…Compared to micelles without gypenosides, cholesterol in the supernatants obtained after ultracentrifugation decreased, and then it was revealed that gypenosides inhibited the incorporation of cholesterol into mixed micelles. A series of experiments have shown that polyphenol as an approach to a potential reduction in cholesterol absorption was correlated with the inhibitory effect of cholesterol micelle solubility [20,33]. Adisakwattana revealed that grape seed extracts inhibited pancreatic lipase Each measurement was repeated three times, and data are presented as mean ± SD in dose-dependent manner and also inhibited the formation of cholesterol micelles [34].…”