Potential Antidiabetic Inhibitors and Antimicrobials from the Fungus <i>Fusarium lichenicola</i> Isolated from the Cicada <i>Cryptotympana mandarina</i> Distant, 1891

Fungi are among the main producers of diverse bioactive secondary metabolites. This study aimed to characterize the chemical constituents and evaluate the antimicrobial and antidiabetic activities of metabolites produced by the fungal <i>Fusarium lichenicola</i> isolated from the cicada <i>Cryptotympana mandarina</i>. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the fungal ethyl acetate extract contained 23 metabolites, including hydrocarbons, esters, terpenoids, alcohols and ketones, fatty acids, aldehydes, phenolics, and sulfur-containing compounds. <i>In vitro</i> assays indicated the fungal extract exhibited weak antimicrobial activity against Gram-positive and Gram-negative bacteria, as well as pathogenic fungi, with minimum inhibitory concentrations (MICs) ranging from 128 to 512 μg/ml. Antidiabetic potential of the fungal extract was demonstrated by inhibition of α-amylase and α-glucosidase enzymes, with IC₅₀ values of 1202 ± 35 to 1347 ± 40 μg/ml, whereas representative metabolites demonstrated activities in the range of 285 ± 32 to 892 ± 85 μM. Molecular docking simulation identified the potential antidiabetic metabolites from the fungal extract. Further analyses revealed moderate correlation between docking scores and experimental activities, with regression R² values of 0.58-0.62 and Pearson correlation coefficients of 0.76-0.79. These results highlight the predictive value of docking for identifying active metabolites, while emphasizing the necessity of experimental confirmation. Overall, these findings suggest that <i>F. lichenicola</i> derived from a cicada host represents a potential source of antidiabetic agents.