ABSTRACT
Plant-based small peptides are also referred to as plant hormones, where their sizes, according to different definitions, range from 5 to 75 chains of amino acids. Peptides are a very important requirement for the signaling system in plants, enabling growth and various responses to their abiotic and biotic environments. Many studies have only focused on their phytochemicals and antioxidants; however, plants are a rich source for many other molecules that currently have not gained attention. One of the many other molecules that are less studied are cyclic plant-based peptides; such peptides hold massive potential for drug development and delivery because of their compatibilities in the presence of proteolytic enzymes. Furthermore, these peptides have biological activities such as anti-inflammatory, antitumor, antimalaria, anticancer and antimicrobial, among many others. Plant peptides such as cyclopeptides are part of plant defensive system that are innate in nature, but unfortunately, not all plants possess this type of plant peptide. Cyclopeptides were originally classified into two main plant subfamilies of short proteins; namely, the Mobius and the Bracelet; classification is structurally based on the occurrence or absence of cis-proline in loop 5 of their circular backbone. This review is aimed at providing information on short, cyclic plant-based peptides.
