A new asperitaconic acid (1) and an undescribe cyclotetrapeptide (2), together with nine known compounds (3–11), were isolated from the endophytic fungus Pseudallescheria boydii XL-0256 obtained from the leaves of Dimocarpus longan Lour. The structures of the new compounds have been successfully assigned based on the NMR spectroscopic data and the mass spectrometric analysis. Compound 3 was confirmed to significantly reduce B16–F10 cell viability in a dose- and time-dependent manner, as well as promoting cell apoptosis and inhibiting cell migration in B16–F10 cell. In addition, compound 3 was hypothesized to have an anti-melanoma effect through target proteins (ADAM17 and ADAMTS5) based on network pharmacological target prediction and molecular docking studies. Display omitted