Lyngbyabellin Q, an Antimalarial Cyclic Peptide, and Its Acyclic Analog from a Cyanobacterial Biomat Dominated by Moorena sp.

Two new lyngbyabellin analogs, Q (1) and R (2), were isolated from a marine cyanobacterial biomat dominated by Moorena sp. Their structures were established primarily through a combination of spectroscopic analyses and degradation reactions. Lyngbyabellin Q (1) inhibited the growth of HeLa cells and disrupted actin dynamics. In addition, lyngbyabellin Q (1) exhibited potent antimalarial activity with an IC₅₀ value of 22 nM, and a new structure-activity relationship enhancing selectivity for the growth inhibition of Plasmodium falciparum over mammalian cells was identified.