Macrosphelide, a Novel Inhibitor of Cell-cell Adhesion Molecule

I. Taxonomy, Fermentation, Isolation and Biological Activities

Abstract

Potent anti-adherent activity was detected in fermentation extracts of microbial strain FO-5050. Active compounds designated macrosphelide A and B were isolated and the structure was determined to be 16-membered macrolide antibiotics possessing three ester bonds in the ring structure. Macrosphelide A dose-dependently inhibited the adhesion of HL-60 cells to LPS-activated HUVEC monolayer (IC₅₀, 3.5μM); macrosphelide B also inhibited HL-60 adhesion but to a lesser extent (IC₅₀, 36μM). Macrosphelide A did not show any antimicrobial and cytocidal activities at the concentration of 1000μg/ml and 100μg/ml, respectively.