New Cyclic Peptides from the Seeds of Annona squamosa L. and Their Anti-inflammatory Activities
journal contributionposted on 23.01.2008, 00:00 by Yu-liang Yang, Kuo-feng Hua, Pei-Hsuan Chuang, Shih-hsiung Wu, Kuen-yuh Wu, Fang-Rong Chang, Yang-chang Wu
Two new cyclic peptides, cyclosquamosin H (1) and I (2), together with six known cyclic peptides, squamin A (3), squamin B (4), cyclosquamosin A (6), cyclosquamosin D (7), cyclosquamosin E (8), and cherimolacyclopeptide B (9), were isolated from the seeds of Annona squamosa. All structures were confirmed by 2D nuclear magnetic resonance, chemical evidence, and electrospray ionization−mass spectromotry/mass spectrometry (ESI-MS/MS). Compound 9 was isolated from this plant for the first time. In the anti-inflammatory assay, compound 7 showed an inhibitory effect on the production of pro-inflammatory cytokines within lipopolysaccharide and Pam3Cys-stimulated J774A.1 macrophages.