New Hybrid Phenalenone Dimer, Highly Conjugated Dihydroxylated C 28 Steroid and Azaphilone from the Culture Extract of a Marine Sponge-Associated Fungus, Talaromyces pinophilus KUFA 1767.

An undescribed hybrid phenalenone dimer, talaropinophilone ( 3 ), an unreported azaphilone, 7- epi -pinazaphilone B ( 4 ), an unreported phthalide dimer, talaropinophilide ( 6 ), and an undescribed 9 R ,15 S -dihydroxy-ergosta-4,6,8 (14)-tetraen-3-one ( 7 ) were isolated together with the previously reported bacillisporins A ( 1 ) and B ( 2 ), an azaphilone derivative, Sch 1385568 ( 5 ), 1-deoxyrubralactone ( 8 ), acetylquestinol ( 9 ), piniterpenoid D ( 10 ) and 3,5-dihydroxy-4-methylphthalaldehydic acid ( 11 ) from the ethyl acetate extract of the culture of a marine sponge-derived fungus, Talaromyces pinophilus KUFA 1767. The structures of the undescribed compounds were elucidated by 1D and 2D NMR as well as high-resolution mass spectral analyses. The absolute configuration of C-9' of 1 and 2 was revised to be 9' S using the coupling constant value between C-8' and C-9' and was confirmed by ROESY correlations in the case of 2 . The absolute configurations of the stereogenic carbons in 7 and 8 were established by X-ray crystallographic analysis. Compounds 1 , 2 , 4 - 8 , 10 and 11 were tested for antibacterial activity against four reference strains, viz. two Gram-positive ( Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212) and two Gram-negative ( Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853), as well as three multidrug-resistant strains, viz. an extended-spectrum β-lactamase (ESBL)-producing E. coli , a methicillin-resistant S. aureus (MRSA) and a vancomycin-resistant E. faecalis (VRE). However, only 1 and 2 exhibited significant antibacterial activity against both S. aureus ATCC 29213 and MRSA. Moreover, 1 and 2 also significantly inhibited biofilm formation in S. aureus ATCC 29213 at both MIC and 2xMIC concentrations.