Potential of Slime Molds as a Novel Source for the Cosmetics Industry

Nowadays, the flourishing development of modern cosmetics, and of "green cosmetics" especially, leads to rapid product innovation, with the increasing use of novel natural ingredients from unusual sources. A peculiar group of slime molds that have long been controversially classified as plants, fungi, or animals represents such an uncommon resource. In this regard, it is strange that these fascinating low-eukaryotic organisms are conspicuously absent from the current reviews of natural cosmetic sources and have no industrial cosmetics utilization. Chemical analyses have confirmed that the slime molds produce a plethora of novel or rare secondary metabolites of interest for cosmetics (127 substances), many of which exhibit biological activity. Interestingly, novel compounds were isolated from 72% of the 53 checked species. At the same time, the number of studied species, from a total of more than 900 currently recognized, is strikingly low (0.06). Such great unexplored biodiversity leaves a space wide open for new discoveries, presenting the slime molds as a reservoir of new biologically active substances that may provide valuable natural ingredients (pigments, lipids, aromatic substances, etc.) for application in modern cosmetics. Therefore, the current review aims to provoke a stronger interest in this neglected aspect, outlining the knowledge that has been obtained so far and indicating some challenges and perspectives for the future.