NEUROPROTECTIVE AND MEMORY-ENHANCING PROPERTIES OF EXTRACTS OF POLYSCIAS GUILFOYLEI (W. BULL) L.H. BAILEY AND POLYSCIAS FILICIFOLIA (C. MOORE EX E. FOURN.) L.H. BAILEY CULTIVATED IN VIETNAM

Ethanolic extracts of leaves, stems, and roots of Polyscias guilfoylei L.H. Bailey (P. guilfoylei) and Polyscias filicifolia (Merr.) L.H. Bailey (P. filicifolia) collected from several regions of Vietnam were screened for neuroprotective activity against glutamate toxicity in HT22 mouse hippocampal neuronal cells. Extracts from leaves and roots of P. filicifolia and leaves of P. guilfoylei exhibited pronounced neuroprotective effects in HT22. Among active samples, extracts from P. guilfoylei leaves and from P. filicifolia roots cultivated in Nam Dinh province were subsequently evaluated for their ability to enhance short-term memory in a Drosophila melanogaster transgenic human amyloid precursor protein (hAPP) model of Alzheimer’s disease. This finding highlights the difference between the two species and suggests that extracts of P. guilfoylei leaves and P. filicifolia roots are good candidates for further studies in rodent models to define bioactive metabolites and related mechanisms for neuroprotection of Alzheimer’s and related dementias.