The components of Flemingia macrophylla attenuate amyloid β-protein accumulation by regulating amyloid β-protein metabolic pathway

Abstract

Flemingia macrophylla (Leguminosae) is a popular traditional remedy used in Taiwan as anti-inflammatory, promoting blood circulation and antidiabetes agent. Recent study also suggested its neuroprotective activity against Alzheimer's disease. Therefore, the effects of F. macrophylla on A production and degradation were studied. The effect of F. macrophylla on A metabolism was detected using the cultured mouse neuroblastoma cells N2a transfected with human Swedish mutant APP (swAPP-N2a cells). The effects on A degradation were evaluated on a cell-free system. An ELISA assay was applied to detect the level of A1-40 and A1-42. Western blots assay was employed to measure the levels of soluble amyloid precursor protein and insulin degrading enzyme (IDE). Three fractions of F. macrophylla modified A accumulation by both inhibiting -secretase and activating IDE. Three flavonoids modified A accumulation by activating IDE. The activated IDE pool by the flavonoids was distinctly regulated by bacitracin (an IDE inhibitor). Furthermore, flavonoid 94-18-13 also modulates A accumulation by enhancing IDE expression. In conclusion, the components of F. macrophylla possess the potential for developing new therapeutic drugs for Alzheimer's disease. Copyright © 2012 Yun-Lian Lin et al.