Evaluation of the Neuroprotective Effects of Diospyros discolor and Diospyros ebenum Leaf Bioactive Fractions In Vivo...

Species of Diospyros L. genus (Ebenaceae family) are known for their economic, nutritional, and pharmacological values. This study aimed to compare the neuroprotective effects of Diospyros discolor and Diospyros ebenum against dementia, with reference to their phytochemical composition. Chemical composition of both species was unveiled through ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS). Promising fractions of both species were standardized against the major identified active constituent(s) via high-performance liquid chromatography-photodiode array detector (HPLC-PDA). Both Diospyros species were evaluated for their neuroprotective activity in vivo using scopolamine-induced dementia in animal model. UPLC-ESI-MS/MS of the EtOAc fractions of D. discolor and D. ebenum resulted in identification of 14 and 48 compounds, respectively, which belong to different classes, namely, organic acids, phenolics, naphthoquinones, triterpenoids, and sterols. Gallic acid contents in EtOAc fractions of D. discolor and D. ebenum were 295.95 and 1.5 µg/mg fraction, respectively. In elevated plus-maze (EPM) test, a tendency towards reduction in the inflexion ratio (IR) was noticed in scopolamine-injected group, however, groups treated with EtOAc fractions of D. discolor, D. ebenum, and pure gallic acid displayed a counteraction pattern. In novel object recognition (NOR) test, tested groups showed the same discrimination index. In brain histological study, treated groups with D. discolor, D. ebenum, and pure gallic acid revealed amelioration compared to scopolamine. In alignment, both EtOAc fractions and gallic acid counteracted the scopolamine-induced dementia in rats and significantly lowered the levels of acetylcholinesterase. Thus, Diospyros species demonstrated a significant ameliorative effect on neurotoxicity induced by scopolamine.