Salvianic borneol ester reduces β-amyloid oligomers and prevents cytotoxicity

The destabilization of β-amyloid (Aβ) peptide aggregates and the protection of functional cells are the attractive therapeutic strategies for Alzheimer's disease (AD). Some active ingredients of Salvia miltiorrhiza f. alba C.Y.Wu & H.W.Li (Lamiaceae) (SM) have attracted increasing attention for the treatment of neurodegenerative diseases.

Salvianic borneol ester (SBE) is a new compound based on SM formulas. The present study was designed to examine the anti-amyloid effects and neuroprotection of SBE in vitro.

The destabilizing effects of SBE and its related compounds (salvianic acid A and borneol) on preformed Aβ oligomers were measured by using fluorescence spectroscopy with thioflavin T (ThT) and the destabilizing effects of SBE were further confirmed visually by transmission electron microscopy (TEM). The neuroprotective effects of SBE against hydrogen peroxide (H(2)O(2))-induced toxicity in human neuroblastoma cells (SH-SY5Y) and motor neuron hybridoma cells (VSC 4.1) were shown by MTT assay and morphological observation.

SBE showed the most significant destabilizing effect, though the mixture of salvianic acid A and borneol also destabilized Aβ1-40 oligomers. The destabilizing activity of salvianic acid A or borneol alone was not significant. SBE destabilized Aβ1-40 oligomers in dose- and time-dependent manners and the destabilizing effect could also be seen in the photographs of TEM. Furthermore, SBE could protect SH-SY5Y cells and VSC 4.1 cells against H(2)O(2)-induced toxicity in a dose-dependent manner.

SBE had the bifunctional activities of anti-amyloid and neuroprotection. It may have therapeutic potential for AD and be an alternative lead compound for developing new drugs against AD.