New Tetramic Acid Derivatives From the Deep-Sea-Derived Fungus Penicillium sp. SCSIO06868 With SARS-CoV-2 Mpro Inhibitory Activity Evaluation
Xiaoyan Pang, Weihao Chen, Xin Wang, Xuefeng Zhou, Bin Yang, Xinpeng Tian, Junfeng Wang, Shi‐Hai Xu, Yonghong Liu
Abstract
Three new tetramic acid derivatives ( 1 – 3 ) and a new polyketide ( 4 ) along with eight known compounds ( 5 – 12 ) were isolated from cultures of the deep-sea-derived fungus Penicillium sp. SCSIO06868. Four new structures were elucidated by analysis of one-dimensional/two-dimensional nuclear magnetic resonance (NMR) data and high-resolution electrospray ionization mass spectrometry. Their absolute configurations were established by X-ray crystallography analysis and comparison of the experimental and reported electronic circular dichroism (ECD) values or specific optical rotation. Compound 3 exhibited potent, selective inhibitory activities against Staphylococcus aureus and methicillin-resistant S. aureus with minimum inhibitory concentration values of both 2.5 μg/ml. Also, compound 3 showed weak antiviral activity against severe acute respiratory syndrome coronavirus 2 main protease, which was responsible for the coronavirus disease 2019 pandemic.