Journal of Medicinal Plant and Herbal Therapy Research
ISSN: 2053-1826
Vol. 10(2), pp. 10-21, April 2023
doi.org/10.33500/jmphtr.2023.10.002

Acetylcholinesterase inhibition and metal chelating potentials of fractions and compounds isolated from Cola hispida

Onoja O. J. ^1,2* and Elufioye T. O.³

¹Department of Pharmacognosy and Environmental Medicine, Faculty of Pharmaceutical Sciences, University of Nigeria, Nsukka, Nigeria.
²Institute of Drug-Herbal Medicine-Excipient Research and Development, University of Nigeria, Nsukka, Nigeria.
³Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria.

*To whom correspondence should be addressed. E-mail: jojogbane@yahoo.com.

Received 16 September, 2022; Received in revised form 04 March, 2023; Accepted 08 March, 2023.

Abstract

Keywords:
Cola hispida, acetylcholinesterase inhibition, metal chelating activity, molecular docking, bioactive compounds, chromatography.

Alzheimer’s disease (AD) is an age-related, neurodegenerative disorder characterized by cognitive impairment. Acetylcholinesterase terminates the action of acetylcholine through catalytic hydrolysis. Inhibition of acetylcholinesterase enzymes is considered a promising strategy for AD treatment. In Nigerian ethnomedicine, it was mentioned that the seeds of Cola hispida can enhance mental capacity. The present study is therefore aimed at identifying and isolating inhibitors of AChE and metal chelation potential of C. hispida seed. C. hispida seed was macerated in methanol and partitioned into various solvents of increasing polarity. Ellman colorimetric assay method was used to determine the acetylcholinesterase inhibitory activity in vitro. Chromatographic methods were used to isolate and purify bioactive compounds from most active fraction. Their structures were determined by spectroscopic analysis including 1D and 2D NMR. Molecular docking was done using software (MOE 2015.010). The selected PDB was modeled using PDB ID: 10CE (pacific electric ray). Chromatographic analyses afforded four compounds identified as Daucosterol, β-sitosterol, 2-hydroxyquinoline-4-carboxylic acid, which are reported for the first time, and 5-hydroxymethylfurfural previously reported. 2-hydroxyquinoline-4-carboxylic acid isolated from ethyl acetate fraction of C. hispida seed demonstrated good AChE inhibitory activity (IC₅₀=1.070±0.09 mg/mL) at 1 mg/mL compared to eserine (IC₅₀=0.009±0.00 mg/mL). 5-hydroxymethylfurfural showed good metal chelating potential (IC₅₀ value of 0.2951±0.01 mg/mL) at 1 mg compared to EDTA (IC₅₀ = 0.045±0.11 mg/mL). Molecular docking reveals hydrophobic and hydrogen bonding interactions. β-sitosterol and 2-hydroxyquinoline-4-carboxylic acid are a possible source of potential lead for new acetylcholinesterase inhibitors.