Banksialactones and banksiamarins

isochromanones and isocoumarins from an Australian fungus, Aspergillus banksianus

Nirmal K. Chaudhary, John I. Pitt, Ernest Lacey, Andrew Crombie, Daniel Vuong, Andrew M. Piggott, Peter Karuso*

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Chemical 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.

Original languageEnglish
Pages (from-to)1517-1526
Number of pages10
JournalJournal of Natural Products
Volume81
Issue number7
DOIs
Publication statusPublished - Jul 2018

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