Neuroprotective effect of standardized Vitex pubescens Vahl bark extract and its n-butanol fraction against scopolamine-induced cognitive impairment in Sprague-Dawley rats in relationship to its isolated phytochemicals

Abstract

Introduction Alzheimer’s disease (AD), marked by gradual cognitive decline and memory deterioration, poses a major global health concern and ranks as the fourth leading contributor to disability-adjusted life years. Genus Vitex is one of the largest genera of the family Lamiaceae, with reported neuroprotective activity attributed to the abundance of diverse bioactive metabolites. The current study aimed to investigate the phytochemical constituents of the defatted methanol extract of Vitex pubescens bark as well as evaluate its neuroprotective activity. Methods The neuroprotective assessment includes histopathological examination, behavior tests, and biochemical analysis, viz, in vivo acetylcholinesterase (AChE) concentration via enzyme-linked immunosorbent assay (ELISA) and AChE inhibitory activity using Ellman’s microplate assay. Results The phytochemical investigations revealed the isolation of six compounds, viz . betulinic acid, vanillic acid, p -hydroxybenzoic acid, orientin-2´ˊ- O-α -L-rhamnoside, isoorientin, and orientin. Histopathological examination indicated notable hippocampal recovery in the n -BuOH and orientin groups, exceeding improvements observed with other treated groups with defatted methanol extract. Discussion The neuroprotective evaluation using behavioral and biochemical analyses demonstrated dose-dependent neuroprotective effects of the defatted methanol extract, with the n -BuOH fraction showing the strongest anti-dementia activity, reflected by enhanced AChE inhibition and improved neuronal integrity. Conclusion The findings of this study reveal the potential of the defatted methanolic extract and n -buOH fraction of Vitex pubescens bark as a natural candidate for managing the progression of Alzheimer’s disease.