Antioxidant and Antidiabetic Enzyme Inhibitory Activities of the Ethyl Acetate Fraction of Ocimum gratissimum Leaf Methanol Extract

Tajudeen Afolayan Lawal¹, Qazeem Oyeniyi Sholadoye²

Keywords: Ocimum gratissimum, α-amylase inhibition, α-glucosidase inhibition, antioxidant activity, molecular docking, rosmarinic acid, xanthine oxidase

DOI: 10.63475/yjm.v4i3.0244

DOI URL: https://doi.org/10.63475/yjm.v4i3.0244

Publish Date: 31-12-2025

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Pages: 613 - 623

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Downloads: 3

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Author Affiliation:

1 Lecturer, Biochemistry and Forensic Science Department, Faculty of Science, Nigeria Police Academy, Wudil, Kano, Nigeria
2 Lecturer, Chemistry Department, Faculty of Science, Nigeria Police Academy, Wudil, Kano, Nigeria

Abstract

Background: Natural products remain an important source of bioactive compounds for the management of metabolic disorders. This study aimed to investigate the antidiabetic and antioxidant potential of the ethyl acetate fraction of Ocimum gratissimum leaves (EAFOGL) through in vitro enzyme inhibition assays, antioxidant assays, and molecular docking analyses, to identify the phytochemicals responsible for the observed bioactivities.

Methods: EAFOGL was evaluated for α-amylase and α-glucosidase inhibitory activities and antioxidant potential using radical scavenging and metal chelation assays. Molecular docking was performed for selected phytochemicals against α-amylase (PDB ID: 1B2Y), α-glucosidase (PDB ID: 2QMJ), and xanthine oxidase (PDB ID: 3NVY). Docking protocol validation was achieved by re-docking native ligands, and binding affinities and protein–ligand interactions were analysed.

Results: EAFOGL exhibited moderate inhibition of α-amylase (IC50 = 87.17 ± 5.20 μg/mL) and α-glucosidase (IC50 = 49.84 ± 6.72 μg/mL) compared with acarbose (IC50 = 52.12 ± 2.74 and 40.94 ± 3.44 μg/mL, respectively). The fraction also demonstrated notable radical scavenging (IC50 = 90.32 ± 9.91 μg/mL) and metal chelating (IC50 = 98.58 ± 13.29 μg/mL) activities, although less potent than ascorbic acid and Ethylenediaminetetraacetic acid (EDTA). Docking validation yielded root mean square deviation values below 2.0 Å, confirming docking reliability. Among the screened compounds, rosmarinic acid isomers showed favourable binding energies and strong interactions with key catalytic residues of all three enzymes. Notably, cis-rosmarinic acid exhibited the highest affinity toward xanthine oxidase (−7.558 kcal/mol), exceeding that of the native ligand quercetin.

Conclusions: The findings demonstrate that EAFOGL possesses moderate antidiabetic and antioxidant activities, supported by molecular docking results identifying rosmarinic acid derivatives as key contributors to enzyme inhibition. These results highlight EAFOGL as a promising source of bioactive compounds for managing oxidative stress and postprandial hyperglycaemia.

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