Novel Cyclic Tetrapeptides as Neuraminidase Inhibitors from a Sponge-Associated <i>Penicillium</i> sp. SCSIO41035.

ABSTRACT: Four new compounds and three new natural products (1-7), including three novel cyclic tetrapeptides (penicopeptides B-D), along with three known spiroquinazoline analogs (8-10), were isolated from rice medium cultures of a sponge-associated Penicillium sp. SCSIO41035. The structural elucidations, including the determination of absolute configurations, were accomplished by comprehensive analyses utilizing NMR spectroscopy, HRESIMS, optical rotation data, X-ray crystallography experiments and electronic circular dichroism calculations. Differential NMR signals between symmetric units in cyclotetrapeptides 1 and 2 arise from the asymmetric solution conformations as investigated through conformational searching and theoretical calculations. The

SUBMITTER: Chen W 

PROVIDER: S-EPMC12565300 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature