C15 acetogenins with antistaphylococcal activity from the red alga Laurencia glandulifera

Five new C15 eight-membered cyclic ethers (1, 3-6) with a characteristic terminal cis ene-yne moiety, along with the previously reported acetylenic chloro diol (2) were isolated from the organic extract of the red alga Laurencia glandulifera, collected at Crete island in South Greece. Full assignment of all 1H and 13C resonances were carried out by extensive analysis of their NMR spectra. All metabolites were tested for their antistaphylococcal activity and the minimum inhibitory concentrations (MICs) of 2-5 were in the range of 8-256 μg/ml.

Graphical abstractFive new eight-membered cyclic ethers, typified by 1, have been isolated from Laurencia glandulifera collected in Greece. Full assignment of all 1H and 13C data were carried out by means of spectral data analysis. All metabolites were tested for their antistaphylococcal activity.