Ochrolines A-C, three new indole diketopiperazines from cultures of endophytic fungi Bionectria ochroleuca SLJB-2

Yuting Zheng; Siyu Qin; Li Xu; Zihuan Sang; Chen Chen; Jianbing Tan; Yuantao Huang; Meifang Li; Zhenxing Zou

doi:10.1016/j.fitote.2023.105809

Ochrolines A-C, three new indole diketopiperazines from cultures of endophytic fungi Bionectria ochroleuca SLJB-2

Fitoterapia. 2024 Mar:173:105809. doi: 10.1016/j.fitote.2023.105809. Epub 2023 Dec 31.

Authors

Yuting Zheng¹, Siyu Qin¹, Li Xu¹, Zihuan Sang¹, Chen Chen¹, Jianbing Tan¹, Yuantao Huang², Meifang Li², Zhenxing Zou³

Affiliations

¹ Xiangya School of Pharmaceutical Sciences, Central South University, Changsha 410013, China; Hunan Key Laboratory of Diagnostic and Therapeutic Drug Research for Chronic Diseases, Central South University, Changsha 410013, China.
² Affiliated Haikou Hospital of Xiangya School of Medicine, Central South University, Haikou 570100, China.
³ Xiangya School of Pharmaceutical Sciences, Central South University, Changsha 410013, China; Hunan Key Laboratory of Diagnostic and Therapeutic Drug Research for Chronic Diseases, Central South University, Changsha 410013, China. Electronic address: zouzhenxing@csu.edu.cn.

PMID: 38168565
DOI: 10.1016/j.fitote.2023.105809

Abstract

Three new indole diketopiperazines, ochrolines A-C (1-3), along with three known compounds (4-6), were isolated and identified from the EtOAc extract of the solid fermentation of Bionectria ochroleuca SLJB-2. Notably, compound 1 featured a natural rarely-occurring caged skeleton with a 6/5/6/7 heterotetracyclic bridged ring system. The structures including absolute configurations of 1-3 were fully accomplished by extensive spectroscopic analyses, DFT GIAO ¹³C NMR and electronic circular dichroism (ECD) calculations. The plausible biogenetic pathways of these new indole diketopiperazines were also proposed. Moreover, the cytotoxic activity screening revealed that compound 2 exhibited moderate inhibitory effect against A549 with inhibition rate of 57.44% at the concentration of 50 μM and compound 1 exhibited mild inhibitory activities against A549, Hela and MCF-7.

Keywords: Bionectria ochroleuca; Endophytic fungi; Indole diketopiperazine; Quantum chemistry calculation; Secondary metabolites.

MeSH terms

Diketopiperazines* / chemistry
Fungi
Hypocreales* / chemistry
Indoles / pharmacology
Molecular Structure

Substances

Diketopiperazines
Indoles

Supplementary concepts

Clonostachys rosea