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Banksialactones and Banksiamarins: Isochromanones and Isocoumarins from an Australian Fungus, Aspergillus banksianus
journal contribution
posted on 2018-06-19, 14:23 authored by Nirmal
K. Chaudhary, John I. Pitt, Ernest Lacey, Andrew Crombie, Daniel Vuong, Andrew M. Piggott, Peter KarusoChemical investigation of an Australian
fungus, Aspergillus
banksianus, led to the isolation of the major metabolite
banksialactone A (1), eight new isochromanones, banksialactones
B–I (2–9), two new isocoumarins,
banksiamarins A and B (10 and 11), and the
reported compounds, clearanol I (12), dothideomynone
A (13), questin (14), and endocrocin (15). The structures of 1–11 were established by NMR spectroscopic data analysis, and the absolute
configurations were determined from optical rotations and ECD spectra
in conjunction with TD-DFT calculations. The secondary metabolite
profile of A. banksianus is unusual, with the 11
most abundant metabolites belonging to a single isochromanone class.
Conjugation of 1 with endocrocin, 5-methylorsellinic
acid, 3,5-dimethylorsellinic acid, mercaptolactic acid, and an unknown
methylthio source gave rise to five unprecedented biosynthetic hybrids, 5–9. The isolated compounds were tested
for cytotoxicity, antibacterial, and antifungal activities, with hybrid
metabolites 7–9 displaying weak cytotoxic
and antibiotic activities.
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Keywords
methylthio sourcebiosynthetic hybridsNMR spectroscopic data analysiscompoundantifungal activitiesantibiotic activitiesAspergillus banksianusisochromanone classmetabolite profileAspergillus banksianus Chemical investigationmercaptolactic acidTD-DFT calculationsAustralian Fungusmetabolite banksialactoneECD spectraAustralian fungusendocrocin5- methylorsellinic acid