The Resveratrol Trimer Miyabenol C Inhibits β-Secretase Activity and β-Amyloid Generation

Accumulation and deposition of amyloid-beta peptide (A beta) in the brain is a primary cause of the pathogenesis of Alzheimer's disease (AD). Aa is generated from amyloid-beta precursor protein (APP) through sequential cleavages first by beta-secretase and then by.-secretase. Inhibiting a-secretase activity is believed to be one of the most promising strategies for AD treatment. In the present study, we found that a resveratrol trimer, miyabenol C, isolated from stems and leaves of the small-leaf grape (Vitisthunbergii var. taiwaniana), can markedly reduce Aa and sAPP beta levels in both cell cultures and the brain of AD model mice. Mechanistic studies revealed that miyabenol C affects neither protein levels of APP, the two major alpha-secretases ADAM10 and TACE, and the gamma-secretase component Presenilin 1, nor gamma-secretase-mediated Notch processing and TACE activity. In contrast, although miyabenol C has no effect on altering protein levels of the beta-secretase BACE1, it can inhibit both in vitro and in vivo beta-secretase activity. Together, our results indicate that miyabenol C is a prominent beta-secretase inhibitor and lead compound for AD drug development.