2,5-Diketopiperazines From a Sponge-Derived Fungus Aspergillus sclerotiorum

Chao-Yi Wang; Xiao-Han Liu; Yao-Yao Zheng; Xing-Yan Ning; Ya-Hui Zhang; Xiu-Mei Fu; Xin Li; Chang-Lun Shao; Chang-Yun Wang

doi:10.3389/fmicb.2022.808532

2,5-Diketopiperazines From a Sponge-Derived Fungus Aspergillus sclerotiorum

Front Microbiol. 2022 May 20:13:808532. doi: 10.3389/fmicb.2022.808532. eCollection 2022.

Authors

Chao-Yi Wang^{1

2}, Xiao-Han Liu^{1

2}, Yao-Yao Zheng^{1

2}, Xing-Yan Ning^{1

2}, Ya-Hui Zhang^{1

2}, Xiu-Mei Fu^{1

2}, Xin Li^{1

2}, Chang-Lun Shao^{1

2}, Chang-Yun Wang^{1

2

3}

Affiliations

¹ Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.
² Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
³ Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.

Abstract

Three new 2,5-diketopiperazines, speramide C (1), 3,21-epi-taichunamide F (2), and 2-epi-amoenamide C (3), along with four known analogs (4-7), were obtained from the sponge-derived fungus Aspergillus sclerotiorum GDST-2013-0501 collected from the South China Sea. The chemical structures of new compounds were elucidated by analyzing NMR and MS spectroscopy data, and their absolute configurations were determined by electronic circular dichroism (ECD) calculations. Compound 1 represents the first prenylated indole alkaloid with an ethylene oxide ring at the isopentenyl side chain. Compound 4 displayed DNA topoisomerase I inhibitory activity and antibacterial activity against Staphylococcus epidermidis. The low cytotoxic or non-cytotoxic compound 4 displayed DNA topoisomerase I inhibitory activity, which could provide a starting point for the development of antitumor agents.

Keywords: 2; 5-diketopiperazines; Aspergillus sclerotiorum; DNA topoisomerase I; bicyclo[2.2.2]diazaoctane; sponge-derived fungus.