Isolation and structure of koshikalide, a 14-membered macrolide from the marine cyanobacterium Lyngbya sp

A 14-membered macrolide, koshikalide (1), was isolated from the marine cyanobacterium Lyngbya sp., and its planar structure was elucidated by spectroscopic analysis. The relative stereochemistry of C-11 and C-13 was elucidated by NOESY experiments and by an analysis of 1H–1H coupling constants. Koshikalide (1) exhibited weak cytotoxicity against HeLa S3 cells.