Aspermicrones A-C, novel dibenzospiroketals from the seaweed-derived endophytic fungus Aspergillus micronesiensis

Chemical investigation of the Kappaphycus alvarezii-derived endophytic fungus Aspergillus micronesiensis lead to the isolation of three novel dibenzospiroketals, aspermicrones A-C (1-3). Their chemical structures were determined by extensive analysis of HR-ESI-MS and NMR spectral data. The absolute configurations of them were determined by experimental and TD-DFT theoretical calculated circular dichroism spectra. Compound 2 exhibited selective cytotoxic effect toward HepG2 cell line (IC50 = 9.9 μM). Additionally, both of compounds 2 and 3 displayed anti-microbial activity against Staphylococcus aureus (MIC = 123.2 μM for each compound). Compound 1 was inactivity in both cytotoxic and antimicrobial assays.Fil: Luyen, Nguyen Dinh. Vietnam Academy of Science and Technology; Vietnam. Graduate University of Science and Technology; VietnamFil: Huong, Le Mai. Vietnam Academy of Science and Technology; Vietnam. Graduate University of Science and Technology; VietnamFil: Thi Hong Ha, Tran. Vietnam Academy of Science and Technology; VietnamFil: Cuong, Le Huu. Vietnam Academy of Science and Technology; VietnamFil: Thi Hai Yen, Duong. Institute of Marine Biochemistry; VietnamFil: Nhiem, Nguyen Xuan. Graduate University of Science and Technology; Vietnam. Institute of Marine Biochemistry; VietnamFil: Tai, Bui Huu. Graduate University of Science and Technology; Vietnam. Institute of Marine Biochemistry; VietnamFil: Gardes, Astrid. Leibniz Centre for Tropical Marine Research; AlemaniaFil: Kopprio, Germán Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Leibniz Centre for Tropical Marine Research; AlemaniaFil: Van Kiem, Phan. Graduate University of Science and Technology; Vietnam. Institute of Marine Biochemistry; Vietna