Pseudocercones A-C, three new polyketide derivatives from the endophytic fungus Pseudocercospora sp. TSS-1

Abstract

Chemical investigation of an EtOAc extract of the endophytic fungus Pseudocercospora sp. TSS-1 led to the isolation of three new polyketide derivatives, including one benzophenon derivative (1), two spirocyclic polyketides (4 and 5), along with four known compounds (2, 3, 6 and 7). Their structures and the absolute configurations were characterized by means of NMR, HRESIMS, ¹³C NMR and theoretical electronic circular dichroism calculations. Furthermore, all compounds were evaluated for their antibacterial activity against four microbial pathogens (Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli), and compounds 1, 2, 3 and 5 displayed significant selective antibacterial activity against S. aureus with MIC values ranging from 3.9 to 7.8 µg/mL.

Graphical Abstract

Keywords:

• Pseudocercospora sp. TSS-1
• endophytic fungi
• structure elucidation
• polyketides
• antibacterial activity

Disclosure statement

There are no conflicts of interest to declare.

Additional information

Funding

This project was funded by Natural Science Foundation of Hunan Province (No. 2021JJ30917), Key R&D Project of Hainan Province (No. ZDYF2022SHFZ048), the High-tech Industry Science and Technology Innovation Project of Hunan Province (2020GK4083), the Central South University Postgraduate Independent Exploration and Innovation Project (Nos. 2021zzts0978; 2021zzts0994), and the Open Sharing Fund for the Large-scale Instruments and Equipments of Central South University.