Screening of Ethyl Acetate Fraction of Ocimum gratissimum Leaf Methanol Extract for Antioxidant Potentials and Alpha-Amylase and Alpha-Glucosidase Inhibitors

Type 2 diabetes mellitus (T2DM) is a global health challenge characterised by impaired carbohydrate metabolism

and oxidative stress, necessitating safer plant-based therapeutic alternatives. This study evaluated the

antidiabetic and antioxidant potential of the ethyl acetate fraction of Ocimum gratissimum leaf extract (EAFOGL)

using in vitro and in silico approaches. Enzyme inhibition assays revealed that EAFOGL moderately suppressed

α-amylase and α-glucosidase activities, with IC 50 values of 87.17 ± 5.20 and 49.84 ± 6.72 μg/mL, respectively,

relative to acarbose (52.12 ± 2.74 and 40.94 ± 3.44 μg/mL). Antioxidant evaluations demonstrated radical

scavenging and metal chelating activities with IC₅₀ values of 90.32 ± 9.91 and 98.58 ± 13.29 μg/mL, respectively,

which were lower than standard antioxidants but still significant. LC-MS profiling identified five predominant

compounds, namely lariciresinol, nitrendipine, eupatilin, 6,7-dimethoxy-2-(1-piperazinyl)-4-quinazolinamine, and

N-succinoyl anthranilic acid. Molecular docking indicated strong binding affinities of these phytochemicals for α-

amylase, α-glucosidase, and the Keap1 protein, with nitrendipine showing notable interactions with α-amylase

(−6.91 kcal/mol) and Keap1 (−6.54 kcal/mol), and lariciresinol binding effectively to α-glucosidase (−6.98

kcal/mol). Key interactions involved hydrogen bonding and hydrophobic contact with catalytic residues such as

His305 and Arg416. In conclusion, EAFOGL exhibited promising dual antidiabetic and antioxidant properties,

supporting its potential use in mitigating hyperglycaemia and oxidative stress associated with T2DM. Further in

vivo studies and mechanistic investigations are recommended to validate its therapeutic efficacy and establish its

safety profile.