Two new polyketone derivatives from the mangrove endophytic fungus GXNU TH4b.

Two new polyketones, exserone B () and cytosporone F (), along with three known metabolites, were isolated from the mangrove endophytic fungus TH4b. The structures of and were determined by detailed NMR, and MS spectroscopic data. The absolute configurations of and were determined by single crystal X-ray diffraction analysis and the combination of experimental ECD and computational ECD, respectively. Compounds have strong inhibitory activity against citrus Psyllid () with 95.4% and 93.7% lethal at 1000 mg/kg.