Stereocalpin B, a new cyclic depsipeptide from the Antarctic lichen Ramalina terebrata
- Author:
- Lee S., Jeong S.Y., Nguyen D.L., So J.E., Kim K.H., Kim J.H., Han S.J., Suh S.-S., Lee J.H. & Youn U.J.
- Year:
- 2022
- Journal:
- Metabolites
- Pages:
- 12: 141 [11 p.]
- Url:
- https://doi.org/10.3390/metabo12020141
Stereocalpin B, a new cyclic depsipeptide (1), and a new dibenzofuran derivative (3), were
isolated from the Antarctic lichen, Ramalina terebrata (Ramalinaceae), along with a known cyclic
depsipeptide (2). The structures of new compounds were characterized by comprehensive spectrometric
analyses; high-resolution fast atom bombardment mass spectrometry (HR-FABMS) and liquid
chromatography-tandem mass spectrometry (LC-MS/MS). Stereocalpin B (1) existed in a rotameric
equilibrium, which was confirmed using nuclear Overhauser effect spectroscopy (NOESY)/
exchange spectroscopy (EXSY) spectrum. Absolute configurations of the amino acid units in
1 were assigned using the advanced Marfey’s method and subsequent NOESY analysis of the 5-
hydroxy-2,4-dimethyl-3-oxo-decanoic acid residue confirmed the complete stereochemistry of 1.
Compounds 1-3 exhibited moderate antimicrobial activities against E. coli, with the IC50 values ranging
from 18‒30 μg/mL. Compound 2 exhibited cell growth inhibition against HCT116 cell lines, with
the IC50 value of 20 ± 1.20 μM, and compounds 1 and 2 also showed potent anti-inflammatory activities
against lipopolysaccharide (LPS)-induced RAW264.7 macrophages with the IC50 values
ranging from 5‒7 μM.
Keywords: Ramalina terebrata; cyclic depsipeptides; dibenzofuran; antimicrobial; cytotoxicity; antiinflammation.
- Id:
- 34137
- Submitter:
- zdenek
- Post_time:
- Saturday, 05 February 2022 19:38