Volume 20, Issue 46, July - December, 2026

In Vitro Evaluation and Molecular Docking Studies of α-Glucosidase and α-Amylase Inhibitory and Antioxidant Activities of Anacardium occidentale Leaves

Tajudeen Afolayan Lawal^♦

Biochemistry and Forensic Science Department, Faculty of Science, Nigeria Police Academy, Wudil, Kano, Nigeria

^♦Corresponding Author
Tajudeen Afolayan Lawal, Biochemistry and Forensic Science Department, Faculty of Science, Nigeria Police Academy, Wudil, Kano, Nigeria

ABSTRACT

The rising global prevalence of diabetes mellitus highlights the need for new plantbased therapeutic agents with both antidiabetic and antioxidant properties. The ethyl acetate subfraction (SF5) of the methanolic leaf extract of Anacardium occidentale was evaluated for its ability to inhibit α-amylase and α-glucosidase. The study also assessed its antioxidant activity, phytochemical composition, and predicted molecular interactions. The fractions were evaluated using in vitro enzyme-inhibition and antioxidant assays. At the same time, the phytoconstituents of the most potent subfraction were characterized by LC-MS. The methanolic extract of Anacardium occidentale leaves (MEAOL) was fractionated by column chromatography to obtain pooled fractions (PF1 to PF8). PF5 exhibited the strongest enzyme-inhibitory activity and was further fractionated into six subfractions (SF1 to SF6). SF5 exhibited the strongest antidiabetic and antioxidant activities among the subfractions tested. The IC50 of SF5 for α-amylase inhibition is 23.84±2.42 μg/mL, for α-glucosidase inhibition is 19.54±1.05 μg/mL, for DPPH radical scavenging activity is 28.63±1.78 μg/mL, and for metal chelating activity is 21.87±1.92 μg/mL. The result of FTIR analysis indicates the presence of phenolic, hydroxyl, and carbonyl functionalities. These functional groups are commonly associated with antidiabetic and antioxidant bioactive compounds. The LC-MS analysis results revealed the presence of gallic acid, protocatechuic acid, methyl gallate, methyl ursolate, quercetin-3-O-arabinose, luteolin-7-O-glucoside, and amentoflavone. These compounds are composed of biologically active compounds such as phenolic acids, flavonoids, and triterpenoids. Molecular docking was used to assess the affinities and interactions between the compounds and the target proteins. Luteolin-7-O-glucoside (-6.91 kcal/mol), quercetin-3-O-arabinoside (-6.26 kcal/mol), and amentoflavone (-7.11 kcal/mol) showed favorable interactions with important residues of α-amylase and α- glucosidase, compared with the reference inhibitor acarbose (-8.47 and -7.09 kcal/mol, respectively). Hydrogen bonds involving His299, Asp300, Glu233, and Asp443 were observed in the docked complexes, indicating possible contributions to enzyme inhibition. The compounds also showed binding affinities of −7.26 to −7.10 kcal/mol toward HO-1, which were consistent with the antioxidant activity observed in vitro. Generally, the results indicate that the SF5 fraction of Anacardium occidentale leaves has antidiabetic and antioxidant activities. The activity may be associated, at least in part, with its polyphenolic and flavonoid constituents. The results provide evidence for the potential of Anacardium occidentale leaves as a source of compounds with enzyme-inhibitory and redox-related activities. Further work involving enzyme kinetics, mechanistic studies, and in vivo models would be useful for establishing the mechanisms underlying these activities and evaluating the prospects for phytotherapeutic formulation.

Keywords: Anacardium occidentale, α-amylase, α-glucosidase, antioxidant, molecular docking, LC-MS, HO-1

Drug Discovery, 2026, 20(45), e19dd3107

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Published: 09 October 2026