Integrated in vitro and in silico assessment of antimicrobial, chemical antioxidant, and cytotoxic activities of endophytic Aspergillus sp. GK1 isolated from Mentha spicata roots

Abstract

Medicinal plants are a source of structurally diverse endophytic fungi which harbor significant pharmaceutical potential. In the present research, the antimicrobial, chemical antioxidant, and cytotoxic properties of the ethyl acetate extract of endophytic Aspergillus sp. GK1 isolated from Mentha spicata roots were evaluated using both in vitro and in silico assessments. The crude extract was subjected to GC–MS profiling, which tentatively identified several metabolites, followed by molecular docking, drug-likeness, pharmacokinetic and toxicity prediction analyses. The crude extract has shown broad spectrum antibacterial activity with inhibition zone of 15.66 ± 0.57 mm against Escherichia coli , 14.66 ± 1.52 mm against Staphylococcus aureus , 14.00 ± 0.00 mm against Staphylococcus epidermidis and 13.33 ± 0.57 mm against Bacillus subtilis . Minimum inhibitory concentration values were 16, 32, 64, and 64 μg/mL, while minimum bactericidal concentration values were 32, 32, 64, and 128 μg/mL, respectively. The extract showed concentration-dependent responses in chemical antioxidant assays, including DPPH radical-scavenging, hydrogen peroxide-scavenging, reducing-power and total antioxidant-capacity assays. A strong correlation between chemical antioxidant capacity and total phenolics (R2 = 0.9752–0.9986) and total flavonoids (R2 = 0.9814–0.9956) content was found. The extract exhibited concentration-dependent cytotoxicity against MCF-7 cells with an IC50 value of 69.20 μg/mL that had positive correlation with the phenolics and flavonoids content. The analysis of GC–MS points to the presence of several metabolites, including 2-Buten-1-one, 1,3-diphenyl- (dypnone, a β-methyl2-Buten-1-one, 1,3-diphenyl-; CID 95329) which showed the highest binding affinity to selected protein targets, along with favourable drug-likeness, in silico pharmacokinetic and toxicity properties. The extract demonstrated antibacterial activity, measurable chemical antioxidant/ radical-scavenging properties, and cytotoxic effects under the experimental conditions. Integrated experimental and computational studies highlighted the tentatively identified 2-Buten-1-one, 1,3-diphenyl- as a compound of interest for further investigation. These findings provide preliminary indication for the possible biological activity of the Aspergillus sp. GK1 extract and support further bioassay- guided fractionation, isolation, structural characterization, mechanistic studies, and in vivo analysis of its active constituents.