Latrunculin A is a bicyclic macrolide natural product comprising a 16-membered bicyclic lactone linked to a rare 2-thiazolidinone group. Isolated from the Red Sea sponge *Latrunculia magnifica* and the Fiji Islands sponge *Cacospongia mycofijiensis*, it inhibits actin polymerization, microfilament organization, and microfilament-mediated processes. It functions as a toxin, metabolite, and actin polymerization inhibitor. Chemically, it is a cyclic hemiketal, oxabicycloalkane, thiazolidinone, and macrolide.
