New cyclic peptides with osteoblastic proliferative activity from Dianthus superbus

Two new cyclic peptides, dianthins G-H (1 and 2), and a known cyclic peptide, dianthin E (3), were isolated from the traditional Chinese medicinal plant Dianthus superbus and the structures were established by NMR spectroscopic techniques in combination with ESI tandem mass fragmentation analysis and X-ray diffraction. All cyclic peptides showed potent osteoblastic proliferative activities on MC3T3-E1 cell of rat in vitro.