New Pyrroline Isolated from Antarctic Krill-Derived Actinomycetes Nocardiopsis sp. LX-1 Combining with Molecular Networking

Antarctic krill ( ) of the family comprise one of the largest biomasses in the world and play a key role in the Antarctic marine ecosystem. However, the study of -derived microbes and their secondary metabolites has been limited. Chemical investigation of the secondary metabolites of the actinomycetes sp. LX-1 (in the family of ), isolated from , combined with molecular networking, led to the identification of 16 compounds - (purple nodes in the molecular network) and the isolation of one new pyrroline, nocarpyrroline A ( ), along with 11 known compounds - . The structure of the new compound was elucidated by extensive spectroscopic investigation. Compound exhibited broad-spectrum antibacterial activities against , , , and antifungal activity against in a conventional broth dilution assay. The positive control was ciprofloxacin with the MIC values of