No abstract

Significant plasma dose-dependence was observed in flavan-3-ol metabolites of the AGSE group and in Mal, Del and Cyn galactosides and Pet, Peo, and Cyn glucosides of the bilberry groups. In the brain, a significant dose dependence was found in the cerebellum and frontal cortex in all major flavan-3-ol metabolites. All anthocyanidin glycosides, except for delphinidin, showed a dose-dependent increase in the cerebellum.

Scope Metabolic syndrome has become an epidemic and poses tremendous burden on the health system. People with metabolic syndrome are more likely to experience cognitive decline. As obesity and sedentary lifestyles become more common, the development of early prevention strategies are critical. In this study, we explore the potential beneficial effects of a combinatory polyphenol preparation composed of grape seed extract, Concord purple grape juice extract and resveratrol, referred to as Standardized Grape Polyphenol Preparation (SGP), on peripheral as well as brain dysfunction induced by metabolic syndrome. Methods We found dietary fat content had minimal effects on absorption and metabolites of major polyphenols derived from SGP. Using a diet-induced animal model of metabolic syndrome (DIM), we found that brain functional connectivity and synaptic plasticity are compromised in the DIM mice. Treatment with SGP not only prevented peripheral metabolic abnormality but also improved brain synaptic plasticity. Conclusion Our study demonstrated that SGP comprised of multiple bioavailable and bioactive components targeting a wide range of metabolic syndrome-related pathological features provides greater global protection against peripheral and central nervous system dysfunctions and can be potentially developed as novel prevention/treatment for improving brain connectivity and synaptic plasticity important for learning and memory.

Despite the presence of bioactive catechin B-ring auto-oxidation dimers in tea, little is known regarding their absorption in humans. Our hypothesis for this research is that catechin auto-oxidation dimers are present in teas and are absorbable by human intestinal epithelial cells. Dimers [theasinensins (THSNs) and P-2 analogs) were quantified in commercial teas by HPLC-MS. (−)-Epigallocatechin (EGC) and (−)-epigallocatechin gallate (EGCG) homodimers were present at 10-43 and 0-62 µmol/g leaf, respectively. EGC-EGCG heterodimers were present at 0-79 µmol/g. The potential intestinal absorption of these dimers was assessed using Caco-2 intestinal cells. Catechin monomers and dimers were detected in cells exposed to media containing monomers and preformed dimers. Accumulation of dimers was significantly greater than monomers from test media. Three h accumulation of EGC and EGCG was 0.19-0.55% and 1.24-1.35% respectively. Comparatively, 3h accumulation of the EGC P-2 analog, and THSNs C/E was 0.89 ± 0.28% and 1.53 ± 0.36%. Accumulation of P-2, and THSNs A/D was 6.93 ± 2.1%, and 10.1 ± 3.6%. EGCG-EGC heterodimer P-2 analog, and THSN B 3h accumulation was 4.87 ± 2.2%, and 4.65 ± 2.8% respectively. One h retention of P-2, and THSNs A/D was 171 ± 22%, and 29.6 ± 9.3% of accumulated amount suggesting intracellular oxidative conversion of THSNs to P-2. These data suggest that catechin dimers present in the gut lumen may be readily absorbed by intestinal epithelium.

Recently, interest in the application of natural pigments to replace synthetic dyes in beverages has grown. The present study investigates the stability of anthocyanin-rich grape and purple sweet potato (PSP) extracts to photo- and thermostresses in ready-to-drink (RTD) beverage models including hot fill beverages with various concentrations of ascorbic acid, a preserved beverage, and a vitamin-enriched water beverage. Thermo- and photostresses were induced at 40, 60, and 80 °C and 250, 500, and 750 W/m(2), respectively. Qualitative and quantitative data on anthocyanin content were collected by pH differential assay and LC-MS. Increasing concentration of ascorbic acid caused more rapid degradation through thermostress, but had a protective effect through photostress. Additionally, PSP was significantly less stable than grape extract in the vitamin-enriched water model beverage through photostress. Furthermore, photostress caused the formation of monoacylated peonidins from diacylated peonidins.