Novel sarsasapogenin-triazolyl hybrids as potential anti-Alzheimer's agents: Design, synthesis and biological evaluation.

Sarsasapogenin, an active ingredient in Rhizoma anemarrhenae, is a promising bioactive lead compound in the treatment of Alzheimer's disease. To search for more efficient anti-Alzheimer agents, a series of novel sarsasapogenin-triazolyl hybrids were designed, synthesized, and evaluated for their Aβ aggregation inhibitory activities. Most of these new hybrids displayed potent Aβ aggregation inhibition. In particular, the promising compounds 6j and 6o displayed a better ability to interrupt the formation of Aβ fibrils than curcumin. Moreover, 6j and 6o exhibited moderate neuroprotective effects against HO-induced neurotoxicity in SH-SY5Y cells. To investigate whether 6j and 6o could improve cognitive deficits, we performed behavioral tests to examine the learning and memory impairments induced by intracerebroventricular injection of Aβ (ICV-Aβ) in mice and TUNEL staining to observe neuronal apoptosis in the hippocampus. The results obtained indicated that oral treatment with 6j and 6o significantly ameliorated cognitive impairments in behavioral tests and TUNEL staining showed that 6j and 6o attenuated neuronal loss in the brain. Taken together, the results we obtained showed that the sarsasapogenin skeleton could be a promising structural template for the development of new anti-Alzheimer drug candidates, and compounds 6j and 6o have the potential to be important lead compounds for further research.