Exploring the Pharmacognostic Characteristics, Antioxidant Potential, and Anticholinesterase Activity of Piliostigma thonningii (Schum.) Milne-Redh.: Implications for Neuroprotection and Cognitive Health

Aim: The aim of this research is to investigate the pharmacognostic characteristics, antioxidant potential, and anticholinesterase activity of Piliostigma thonningii (Schum.) Milne-Redh. This study seeks to evaluate its potential applications for neuroprotection and cognitive health enhancement. Place and Duration of Study: This study was carried out in Nigeria by the Department of Medicinal Plant Research and Traditional Medicine, National Institute for Pharmaceutical Research and Development, Idu – Abuja, Nigeria between January 2024 and March 2024. Methodology: Physicochemical studies, including total Ash value and moisture content, were assessed using the powdered leaf sample. Leaf microscopy was conducted to examine the epidermal layer of the leaves. Anti-oxidant assays (Total phenol, total flavonoid and 2,2- diphenyl-1-picrylhydrazyl [DPPH] free radical scavenging activity), as well as acetylcholinesterase (AchE) inhibition assay was carried out on the methanolic leaf extract of the plant. Results: The powdered leaves of P. thonningii contained a total ash of 5.00% ± 0.00 and 7.74% ± 0.01 moisture. The alcohol- and water-soluble extractive values were 8.51% ± 0.24 and 9.77% ± 0.31, respectively. Leaf microscopic analysis showed the presence of polygonal cell walls, unicellular multiseriate trichomes, trichome base, xylem vessels, rosette-type calcium oxalate crystals, parenchyma, and collenchyma cells. The methanolic leaf extract exhibited antioxidant capacity, inhibiting DPPH in a dose-dependent manner, with total phenolics and flavonoids of 53.74(GAE) ± 1.59 and 42.51mg QE/g ± 0.38, respectively. The methanolic extract of P. thonningii in this study showed an AchE inhibition of between 5.89 % at 10 mg/ml to 16.56 % at 20 mg/ml Conclusion: The study reveals significant pharmacognostic characteristics, robust antioxidant potential, and notable anticholinesterase activity of P. thonniingii, suggesting its promising role in neuroprotection. These findings highlight its potential application in enhancing cognitive health and preventing neurodegenerative diseases.