Structural elucidation and antimicrobial activity of a diketopiperazine isolated from a Bacillus sp. associated with the marine sponge Spongia officinalis

Abstract

A diketopiperazine (3S, 6S)-3,6-diisobutylpiperazine-2,5-dione was isolated from a sponge-associated microbe for the first time and characterized by FTIR, HRESI-MS, ¹H, ¹³C NMR and 2D NMR. The source is novel for this compound. Single crystal XRD of this diketopiperazine obtained as a natural product was analysed for the first time and its melting point was determined to be 262 °C. MICs of this cyclic dipeptide against Escherichia coli and Staphylococcus aureus subsp. aureus were 16 µg mL⁻¹ and 22 µg mL⁻¹ respectively, the first report of antibacterial activity of this diketopiperazine.

Supplemental data for this article can be accessed at https://doi.org/10.1080/14786419.2019.1672684.

Graphical Abstract

KEYWORDS:

• Bacillus sp.
• sponge
• diketopiperazine
• antibacterial

Disclosure statement

The authors declare that there is no conflict of interest regarding the publication of this article.

Additional information

Funding

This work was supported by Department of Biotechnology (DBT), Ministry of Science and Technology, India under Grant BT/PR12490/AAQ/3/7/16/2015.