Title : Neuroprotective effects of Chrysophyllum perpulchrum bark extract in AD like rats model of ?-amyloid 1-40 intrahippocampal injection
Background: Alzheimer Disease (AD) is a threatening disease of upcoming years among african populations because of the increase of their expectancy life. Because no therapeutic drugs existing, it is now worthwhile to investigate on new effective drugs derived from natural product of endemic traditional use plants.
Objective: we examine whether a methanolic bark extract of Chrysophyllum perpulchrum, rich in catechin and two new procyanidins (catechin dimers + hexose), could prevent some physiopathology mechanisms as well as cognitive changes in an AD-like rat model induced by intrahippocampal CA1 subfield Aβ1-40 injection.
Materials and Methods: Adult male Wistar rats were either microinjected with 1% ammonia as vehicle (10µL) or aggregated Aβ1-40 (10µg bilaterally). At 14th day post-surgery, a group of Aβ rats received treatments with melatonin (10 mg/kg i.p) or Chrysophyllum perpulchrum extract (300 mg/kg p.o), and sham-operated rats only with extract. Cognitive abilities were tested with Y-maze, object recognition test and Morris water Maze. Biochemical assay of pro-inflammatory and oxidative stress markers, as well as microglia cells activation with Iba 1 immunostaining in brain.
Results: we found microglia overactivation associated with high levels of nitric oxide (NO), Malondialdehyde (MDA), superoxide dismutase (SOD), but not thiol content in hippocampus, prefrontal cortex (PFC) and septum of AD-like rats. Aβ induced also significant recognition memory and spatial learning deficits. However, the treatment with Chrysophyllum perpulchrum extract improved significantly cognitive impairments through a mitigation of Aβ-induced microglial cells overactivation and subsequent neuroinflammation and oxidative stress processes. Interestingly, the neuroprotective actions of Chrysophyllum perpulchrum extract seem to be more effective than melatonin (10 mg/kg ip).
Conclusion: these findings should be strengthened by pharmacological studies such as bioactive compounds of Chrysophyllum perpulchrum’s action on the blockade of cdk 5/p35 complex and Aβo- induced Fyn signaling, before being proposed as promise drug against AD.