secondary metabolites from marine cyanobacteria and algae inhibit LFA-1/ICAM-1 mediated cell adhesion

An assay for inhibitors of LFA-1/ICAM-1 mediated cell-cell adhesion has been employed to identify new pharmacologically active compounds from marine cyanobacteria and algae. From a panel of sixty unusual marine natural products, seventeen compounds inhibited LFA-1/ICAM-1-based cell aggregation without showing significant cytotoxicity in the primary assay. Six compounds inhibited the cell-cell adhesion of HL-60 cells to CHO-ICAM-1 cells. The unusual oxylipin Cymathere aldehyde methyl ester (IC50 3.5 muM), cyanobacterial lipopeptides microcolins B (IC50 0.15 muM) and D (IC50 0.9 muM), bromophenol avrainvilleol (IC50 2.2 muM), sesquiterpene cymopol (IC50 2.7 muM), and cryptophyte derived compound styrylchromone hormothamnione diacetate (IC50 1.5 muM) significantly inhibited LFA-1/ICAM-1 mediated cell adhesion. The pharmacological activity and structure-activity relationships of selected marine algal metabolites are described.