A new xanthostatin analogue from the marine sponge-associated actinomycete Streptomyces sp. SCSIO 40064

Abstract

A new cyclo-heptadepsipeptide xanthostatin B (1), together with isobutyryl hexapeptide (2), xanthostatin (3), TXS-1 (4) and TXS-2 (5), were isolated from the marine sponge derived Streptomyces sp. SCSIO 40064. The structures were elucidated by comprehensive spectroscopic data analyses and comparison with the literatures. The D-Val unit in 1 was assigned by Marfey’s method. The absolute configuration of 4 was determined by X-ray crystallographic analysis. Compounds 1‒5 were evaluated for the inhibitory activities against four pharmaceutical targets and six antibacterial indicator strains. Compound 5 displayed α-glucosidase inhibitory activity with IC₅₀ value of 18.67 ± 1.27 µM.

Graphical Abstract

Keywords:

• xanthostatin B
• isobutyryl hexapeptide
• marine sponge-associated actinomycete
• α-glucosidase inhibitory activity

Acknowledgements

We appreciate Prof. Tianyu Zhang of Guangzhou Institutes of Biomedicine and Health in antibacterial activities test of Mycobacterium tuberculosis H37Ra. We appreciate Shilan Zhai, Jing Peng and Huixin Xu for their assistance in enzyme inhibitory activities testing assays. We are grateful to Zhihui Xiao, Xiaohong Zheng, Aijun Sun, Xuan Ma and Yun Zhang in the analytical facilities of SCSIO.

Disclosure statement

Authors report no conflict of interest.

Additional information

Funding

This work was financially supported by Chinese Academy of Sciences (XDA13020302, QYZDJ-SSW-DQC004), the National Natural Science Foundation of China (31630004, 41911530078) and the Guangdong Province Foundation (2019B030302004).