Abstract:
Four compounds (1–4) were isolated from the extracts of Streptomyces sp. CT37 using
bioassay in conjunction with mass spectrometric molecular networking (MN) driven isolation. Their
complete structures were established by high-resolution electrospray ionization mass spectrometry
(HR-ESIMS), and 1D and 2D nuclear magnetic resonance (NMR) data. Legonimide 1 was identified
as a new alkaloid containing a rare linear imide motif in its structure, while compounds 2–4 were
already known and their structures were elucidated as 1H-indole-3-carbaldehyde, actinopolymorphol
B, (2R,3R)-1-phenylbutane-2,3-diol, respectively. The biosynthetic pathways of 1–4 were proposed
based on the reported biogenesis of indole alkaloids in literature. Bioactivity tests for 1 and 2 revealed
moderate growth inhibition activity against Candida albicans ATCC 10231 with MIC95 values of
21.54 g/mL and 11.47 g/mL, respectively.
