Psammosilenin C, a New Cyclic Peptide from Psammosilene tunicoides

Phytochemical investigation of Psammosilene tunicoides led to isolation of a new cyclicpeptide, psammosilenin C (1) and three known compounds, 1-O-(beta-D-glucopyranosyl)-(2S,3R,4E,8E)-2-[(2R)-2-hydroxypentadecanoylamino]-4,8-octadecadiene-1,3-diol (2), dihydroferulic acid (3) and vanillylacetone (4). Their structures were elucidated by comprehensive spectroscopic methods, including 1D and 2D NMR spectroscopic, and HR-ESI-MS spectrometric data. Compounds 1, 2 and 4 showed inhibitory activities on lipopolysaccharide (LPS)-induced NO release in RAW 264.7 cells.