Three New Dipeptide and Two New Polyketide Derivatives from the Mangrove-Derived Fungus sp.: Antioxidant Activity of Two Isolated Substances.

Five new metabolites, including three cyclic dipeptide derivatives (-) and two new polyketides (-), together with nine known ones (- and -), were isolated from the mangrove-sediments-derived fungus sp. SCSIO 41431. Their structures were determined using detailed NMR, MS spectroscopic analyses, and quantum chemical calculations. X-ray single-crystal diffraction analysis of was described. Compounds - demonstrated activity against , with MIC values ranging from 25 to 50 µg/mL. Compound showed activity against , , and , with an MIC value of 100 µg/mL. In addition, compounds and showed DPPH radical scavenging activity, with the EC of 27.62 and 29.34 µg/mL, compared to the positive control (ascorbic acid, EC, 12.74 µg/mL).