Sortase A-Inhibitory Metabolites from a Marine-Derived Fungus sp.

Seven alkaloidal compounds (-) and one polyketide () were isolated from a semisolid rice culture of the marine-derived fungus sp. F452. Structures of the isolated compounds were elucidated based on spectroscopic data and comparisons with previously reported data. The alkaloidal compounds (-) displayed weak to moderate inhibitory activities against -derived sortase A (SrtA) without affecting cell viability. Aspermytin A () strongly inhibited SrtA activity, with an IC value of 146.0 μM, and significantly reduced bacterial adherence to fibronectin-coated surfaces. The present results indicate that the underlying mechanism of action of compound is associated with the inhibition of SrtA-mediated . adhesion to fibronectin, thus potentially serving as an SrtA inhibitor.