Macrolactins: Antitumor Antibiotics as Marine Drug Lead

Macrolactins are secondary metabolites mainly from marine microorganisms bearing a unique 24-membered lactone core structure. Since their first occurrence in 1989, they have attracted considerable attention from natural product chemists, organic chemists, and pharmacologists due to their chemical complexity, potent antimicrobial and antitumor activities. Some of them are serving as lead compounds for drug discovery. Although a number of synthetic approaches have been developed, sample supply remains a big issue which precludes further investigation of pharmacological application and mechanisms of action. This review summarizes current knowledge about macrolactins including their chemical diversity, biological activities, synthetic studies, and efficient preparation.