Bioactive Polyketides from the Natural Complex of the Sea Urchin-Associated Fungi Penicillium sajarovii KMM 4718 and Aspergillus protuberus KMM 4747.

The marine-derived fungal strains KMM 4718 and KMM 4747 isolated from sea urchin Scaphechinus mirabilis as a natural fungal complex were identified as Penicillium sajarovii and Aspergillus protuberus based on Internal Transcribed Spacer ( ITS ), partial β-tubulin ( BenA ), and calmodulin ( CaM ) molecular markers as well as an ribosomal polymerase two, subunit two ( RPB2 ) region for KMM 4747. From the ethyl acetate extract of the co-culture, two new polyketides, sajaroketides A ( 1 ) and B ( 2 ), together with (2'S)-7-hydroxy-2-(2'-hydroxypropyl)-5-methylchromone ( 3 ), altechromone A ( 4 ), norlichexanthone ( 5 ), griseoxanthone C ( 6 ), 1,3,5,6-tetrahydroxy-8-methylxanthone ( 7 ), griseofulvin ( 8 ), 6-O-desmethylgriseofulvin ( 9 ), dechlorogriseofulvin ( 10 ), and 5,6-dihydro-4-methyl-2H-pyran-2-one ( 11 ) were identified. The structures of the compounds were elucidated using spectroscopic analyses. The absolute configurations of the chiral centers of sajaroketides A and B were determined using time-dependent density functional theory (TDDFT)-based calculations of the Electronic Circular Dichroism (ECD) spectra. The inhibitory effects of these compounds on urease activity and the growth of Staphylococcus aureus , Escherichia coli , and Candida albicans were observed. Sajaroketide A, altechromone A, and griseofulvin showed significant cardioprotective effects in an in vitro model of S. aureus -induced infectious myocarditis.