Cytotoxic phenazine and antiallergic phenoxazine alkaloids from an arctic Nocardiopsis dassonvillei SCSIO 502F

Microbes well-adapted to the Arctic Ocean are promising for producing novel compounds, due to their fancy strategies for adaptation and being under-investigated. Two new phenazine alkaloids (1 and 2) and one new phenoxazine (3) were isolated from Nocardiopsis dassonvillei 502F, a strain originally isolated from Arctic deep-sea sediments. AntiSMASH analysis of the genome of Nocardiopsis dassonvillei 502F revealed the presence of 16 putative biosynthetic gene clusters (BGCs), including a phenazine BGC. Most of the isolated compounds were evaluated for their antibacterial, antiallergic, and cytotoxic activities. Among them, compounds 4 and 5 exhibited potent in vitro cytotoxic activities against osteosarcoma cell line 143B with IC(50) values 0.16 and 20.0 μM, respectively. Besides, the results of antiallergic activities of compounds 6–8 exhibited inhibitory activities with IC(50) values of 10.88 ± 3.05, 38.88 ± 3.29, and 2.44 ± 0.17 μg/mL, respectively (IC(50) 91.6 μM for the positive control loratadine). GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13659-023-00408-w.