Roasted Coffee Reduces ß-Amyloid Production by Increasing Proteasomal ß-Secretase Degradation in Human Neuroblastoma SH-SY5Y Cells.

SCOPE: Epidemiological studies have shown that coffee consumption may be associated with a lower risk of developing several neurological disorders, including Alzheimer's disease (AD). Caffeine is a prominent candidate component underlying the preventive effects of coffee; however, the contribution of other constituents is unclear. To clarify this issue, the effect of roasting coffee beans on ß-secretase (BACE1) expression in human neuroblastoma SH-SY5Y cells is investigated. METHODS AND RESULTS: Coffee (2%) reduces Aß accumulation in culture medium to 80% of control levels after 24 h. Accordingly, BACE1 expression is decreased to 70% of control levels at 12 h. Experiments using cycloheximide and MG132, a proteasome inhibitor, reveal that coffee enhanced BACE1 degradation through activation of proteasomal activity. Furthermore, coffee activates cAMP-dependent protein kinase, and consequently, phosphorylation of a serine residue of proteasome 26S subunit, non-ATPase 11 (PSMD11). Pyrocatechol, a strong antioxidant known as catechol or 1,2-dihydroxybenzene, produced from chlorogenic acid during roasting, also reduces BACE1 expression by activation of proteasomal activity. Furthermore, pyrocatechol reduces Aß production in SH-SY5Y cells. CONCLUSION: The data suggest that the roasting process may be crucial for the protective effects of coffee consumption in AD.

Effect of hesperetin derivatives on the development of selenite­induced cataracts in rats.

Cataracts are a major cause of blindness worldwide. As anti­cataract pharmaceutical therapies require long­term treatment, identifying anti­cataract compounds that are ubiquitous in the human diet, have no adverse effects and are affordable, is of paramount importance. The present study focused on hesperetin and its derived compounds, hesperetin stearic acid ester (Hes­S) and hesperetin oleic acid ester (Hes­O), in order to investigate their therapeutic potential to treat cataracts in a selenite animal model. Thirteen­day­old Sprague Dawley rats were divided into 12 groups. Animals in groups 1 and 7 were subcutaneously injected with vehicle, those in groups 2 and 8 were administered hesperetin, those in groups 3 and 9 received stearic acid, those in groups 4 and 10 were injected with oleic acid, those in groups 5 and 11 were administered Hes­S, and those in groups 6 and 12 received Hes­O (10 nmol/kg body weight on days 0, 1 and 2). Animals in groups 7 to 12 were treated with sodium selenite (20 µmol/kg body weight given 4 h following the test compound treatment on day 0) to induce cataract. On day 6, rats had less severe central opacities and lower stage cataracts than rats in the selenite treatment­only control groups. The levels of glutathione (GSH) and ascorbic acid (AsA) in lenses with selenite­induced cataracts declined to one­third of that of controls, and the reduction in GSH and AsA levels was rescued following hesperetin, Hes­S or Hes­O treatment, with concentrations remaining to 70­80% of that of controls. However, there were no changes in the plasma levels of GSH and AsA following treatments. Administration of either hesperetin or hesperetin­derived compounds prevented the reduction of chaperone activity in the lens, and rats treated with Hes­S or Hes­O treatment had significantly greater chaperone activity than hesperetin­treated rats. Collectively, these results suggested that hesperetin and hesperetin­derived compounds may be novel drug compounds that have the potential to prevent or delay the onset of cataracts.