AUTHOR=Shi Huajun , Jiang Jinyan , Zhang Hang , Jiang Haimei , Su Zijie , Liu Dandan , Jie Ligang , He Fei 

TITLE=Antibacterial spirooxindole alkaloids from Penicillium brefeldianum inhibit dimorphism of pathogenic smut fungi

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1046099

DOI=10.3389/fmicb.2022.1046099

ISSN=1664-302X

ABSTRACT=<p>Three new antibacterial spirooxindole alkaloids, spirobrefeldins A–C (1–3), together with four known analogs, spirotryprostatin M (4), spirotryprostatin G (5), 12β-hydroxyverruculogen TR-2 (6), and 12α-hydroxyverruculogen TR-2 (7), were isolated from terrestrial fungus <italic>Penicillium brefeldianum.</italic> All the new compounds were elucidated extensively by the interpretation of their NMR (1D and 2D) spectra and high-resolution mass data, and their absolute configurations were determined by computational chemistry and CD spectra. The absolute configurations of spiro carbon C-2 in spirotryprostatin G (5) and spirotryprostatin C in literature were reported as <italic>S</italic>, which were revised to <italic>R</italic> based on experimental and calculated CD spectra. All the compounds were evaluated for their antimicrobial activities toward <italic>Pseudomonas aeruginosa</italic> PAO1, <italic>Dickeya zeae</italic> EC1, <italic>Staphylococcus epidermidis</italic>, <italic>Escherichia coli</italic>, and <italic>Sporisorium scitamineum</italic>. Compound 7 displayed moderate inhibitory activity toward dimorphic switch of pathogenic smut fungi <italic>Sporisorium scitamineum</italic> at 25 μM. Compounds 3 and 6 showed weak antibacterial activities against phytopathogenic bacterial <italic>Dickeya zeae</italic> EC1 at 100 μM.</p>