Palmyramide A, a Cyclic Depsipeptide from a Palmyra Atoll Collection of the Marine Cyanobacterium Lyngbya majuscula

Bioassay-guided fractionation of the extract of it consortium of it marine cyanobacterium and a red algii (Rhodophyta) led to the discovery of a novel compound, palmyramide A, along with the known compounds curacin D and malyngamide C. The planar structure of palmyramide A was determined by one- and two-dimensional NMR studies and Mass spectrometry. Palmyramide A is it cyclic depsipeptide that features an unusual arrangement of three amino acids and three hydroxy acids: one of the hydroxy acids is the rare 2,2-dimethyl-3-hydrohexanoic acid unit (Dmhha). The absolute configurations of the six residues were determined by Marfey's analysis, chiral HPLC analysis, and GUMS analysis of the hydrolysate. Morphological and phylogenetic studies revealed (lie sample to be composed of a Lyngbya majuscula-Centroceras sp. association. MALDI-imaging analysis of file cultured L. majuscula indicated that it wits file true producer of this new, depsipeptide. Pure palmyramide A showed sodium channel; blocking activity in neuro-2a ells and cytotoxic activity in H-460 human lung carcinoma cells.