Apratoxin D, a potent cytotoxic cyclodepsipeptide from papua new guinea collections of the marine cyanobacteria Lyngbya majuscula and Lyngbya sordida.
Gutiérrez M, Suyama TL, Engene N, Wingerd JS, Matainaho T, Gerwick WH.
Cancer cell toxicity-guided fractionation of extracts of the Papua New Guinea marine cyanobacteria Lyngbya majuscula and Lyngbya sordida led to the isolation of apratoxin D (1). Compound 1 contains the same macrocycle as apratoxins A and C but possesses the novel 3,7-dihydroxy-2,5,8,10,10-pentamethylundecanoic acid as the polyketide moiety. The planar structures and stereostructures of compound 1 were determined by extensive 1D and 2D NMR and MS data analyses and by comparison with the spectroscopic data of apratoxins A and C. Apratoxin D (1) showed potent in vitro cytotoxicity against H-460 human lung cancer cells with an IC 50 value of 2.6 nM.