posted on 2010-09-24, 00:00authored byLilibeth A. Salvador, Valerie J. Paul, Hendrik Luesch
A Phormidium spp. collection from Key West, Florida, afforded caylobolide B (1), an analogue of the known macrolactone caylobolide A, previously isolated from a Lyngbya majuscula collection from the Bahamas. The planar structure of 1 was determined using NMR and MS experiments. The relative configuration for subunits C7−C9 and C25−C29 was assigned using Kishi’s Universal NMR Database. Caylobolide B (1) displayed cytotoxic activity against HT29 colorectal adenocarcinoma and HeLa cervical carcinoma cells with IC50 values of 4.5 and 12.2 μM, respectively.