The Effect of Terpenoids of Dipsacus Asperoides Against Alzheimer's Disease and Development of Simultaneous Analysis by High Performance Liquid Chromatography

Dipsaci Radix has been proved to represent an effective treatment strategy for Alzheimer's disease (AD), but the potential active components in Dipsaci Radix have not been evaluated by an AD-related bioassay. In this study, water fraction of Dipsaci Radix had been shown to have highest inhibitory effect on the AD-related activity tests, including inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), β-site amyloid precursor protein cleaving enzyme 1 (BACE1), and advanced glycation end-product (AGE) formation. Therefore, a bioassay-guided approach yielded eleven terpenoid compounds (DR1-11) isolated from water fraction of Dipsaci Radix. Compounds (DR2,3,7 and 11) were stronger inhibitors of AChE. The BChE inhibitory effect of saponins was more positive than that of iridoids (DR1,4). Compounds (DR6,7,9-11) were good inhibitors of BACE1. Compounds (DR7-11) were more effective than positive control on the inhibition of AGE formation. Moreover, we firstly suggested concomitant new connections between the structure of Dipsaci Radix's isolated terpenoid compounds with AChE inhibitory activities and AGE formation. The study also represented that Dipsaci Radix was therapeutic for treating AD and dipsacus saponin XI (DR11) might be one of its active components. Our findings significantly provided the new foundation of the potential capacity bioactive components from Dipsaci Radix for AD remedy.