Discovery of a Dimeric Zinc Complex and Five Cyclopentenone Derivatives from the Sponge-Associated Fungus Aspergillus ochraceopetaliformis

In devotion to investigating
structurally novel and biologically
active marine natural products, a dimer of a zinc complex, dizinchydroxyneoaspergillin
(1), aspernones A–E (2–6), five cyclopentenone derivatives together with known polyketides
(7–10), and neoaspergillic acid analogues
(11–14) were isolated from the sponge-associated
fungus Aspergillus ochraceopetaliformis SCSIO 41018. Their structures were elucidated on the basis of spectroscopic
analysis, electronic circular dichroism (ECD) analysis, and X-ray
diffraction. Dizinchydroxyneoaspergillin (1) displayed
significant bactericide effects toward methicillin-resistant Staphyloccocus aureus, Staphyloccocus
aureus, Enterococcus faecalis, Acinetobacter baumannii, and Klebsiella pneumonia with MIC values of 0.45–7.8
μg/mL and moderate in vitro cytotoxic activities against the
K562, BEL-7402, and SGC-7901 cell lines with IC50 values
of 12.88 ± 0.14, 15.83 ± 0.23, and 15.08 ± 0.62 μM,
respectively. This is the first time to report the dimer of the zinc
complex of hydroxyneoaspergillic acid conjunction at Zn–N-4
by a coordination bond. Additionally, compound 1 displayed
significant antibacterial and cytotoxic activities, which would be
a promising drug lead and could attract much attention from both chemists
and pharmacists.