Chemical Progress in Cyclopeptide-containing Traditional Medicines Cited in Chinese Pharmacopoeia

Plant cyclopeptides, cyclic compounds formed mainly by the peptidic bonds of 237 protein and non-protein amino acids (mainly L-amino acids) and found in higher plants, have been attractive for their extensive bioactivities and distinctive molecular architectures. During the last half century's study, about 500 cyclopeptides divided into eight types have been isolated from over 120 species, which belong to over 20 families and 60 genera. Some cyclopeptides showed potential anti-tumor, sedative, immunosuppressive, and uterotonic activities. In the Chinese Pharmacopoeia (CP, 2010 Version), 23 species (14 families, 18 genera) containing cyclopeptides have been recorded in the origins of 24 traditional Chinese medicines (TCMs). Heterophyllin B (64), first reported by us from Pseudostellaria heterophylla in 1993 was cited for the first time in CP as the standard substance of cyclopeptides for quality control. In this review, we highlight the progress in the chemical studies of these cyclopeptide-containing TCMs, in particular recent results in our group's publications.