Natural Occurring β-Peptides: A Fascinating World of Bioactive Molecules

Background: Living organisms are a natural source of β-amino acids and peptides containing them. Many marine organisms and plants are able to produce by themselves such compounds, e.g. depsi-peptides and macrocyclic molecules, which possess different biological activities, mostly concerned to the treatment of human diseases. Methods: Literature has been collected ranging from 1980 until now; both reviews and research articles have been carefully considered and cited in our paper. Results: Literature revealed an increased interest in natural bioactive peptides incorporating β-amino acids. Several papers focused their attention on structural characteristics of depsipeptides and cyclic compounds incorporating them in marine organisms, which may influence and determine the specific biological activity in vivo. Conclusion: In this brief review, we collect a series of naturally occurring peptides incorporating β- amino acids, with the aim to update the arsenal of bioactive compounds available, highlighting the significant structural modifications which are the base of the exerting biological properties.