Cyclopeptides, also known as cyclic peptides, are polypeptides formed from amino acids arranged in a cyclic ring structure.

The present review mainly focuses on the anticancer efficacies, mechanisms of action and chemical structures of 236 cyclopeptides with natural origins. Additionally, studies of the structure–activity relationship, total synthetic strategies as well as bioactivities of natural cyclopeptides are also included in this article. Herein, we provide an overview of anticancer cyclopeptides that were discovered in the past 20 years. Full contents of the review report can be found in International Journal of Molecular Sciences 2021, 22(8), 3973; https://doi.org/10.3390/ijms22083973.