The wewakpeptins, cyclic depsipeptides from a Papua New Guinea collection of the marine cyanobacterium Lyngbya semiplena.

Bingnan Han, Doug Goeger, Claudia S Maier, William H Gerwick

College of Pharmacy and Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA.

The Journal of organic chemistry 2005 Apr 15

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Four new depsipeptides have been isolated from the marine cyanobacterium Lyngbya semiplena collected from Papua New Guinea. The amino and hydroxy acid partial structures of wewakpeptins A-D (1-4) were elucidated through extensive spectroscopic techniques, including HR-FABMS, 1D (1)H and (13)C NMR, as well as 2D COSY, HSQC, HSQC-TOCSY, and HMBC spectra. The sequence of the residues was determined through a combination of multifaceted approaches including ESI-MS/MS, HMBC, ROESY, and a modified 1D HMBC experiment. The absolute stereochemistry of each residue was determined by chiral HPLC and chiral GC-MS methods. The wewakpeptins represent an unusual arrangement of amino and hydroxy acid subunits relative to known cyanobacterial peptides and possess a bis-ester, a 2,2-dimethyl-3-hydroxy-7-octynoic acid (Dhoya) or 2,2-dimethyl-3-hydroxyoctanoic acid (Dhoaa) residue, and a diprolyl group reminiscent of dolastatin 15. Wewakpeptin A and B were the most cytotoxic among these four depsipeptides with an LC(50) of approximately 0.4 muM to both the NCI-H460 human lung tumor and the neuro-2a mouse neuroblastoma cell lines.

Citation

Bingnan Han, Doug Goeger, Claudia S Maier, William H Gerwick. The wewakpeptins, cyclic depsipeptides from a Papua New Guinea collection of the marine cyanobacterium Lyngbya semiplena. The Journal of organic chemistry. 2005 Apr 15;70(8):3133-9