Anti-inflammatory cyclopeptides from exocarps of sugar-apples

Two new cyclic peptides, fanlizhicyclopeptide A, cyclo(Pro1-Pro2-Tyr3-Leu4-Pro5-Gly6-Val7) (1), and fanlizhicyclopeptide B, cyclo(Pro1-Ile2-Tyr3-Ala4-Gly5) (2), were isolated along with six known kaurane diterpenoids and a known clovane sesquiterpene from the exocarps of sugar-apples, the fruit of Annona squamosa. Their structures were elucidated by ESI MS/MS experiments, 1D and 2D NMR data and chemical degradation. In the anti-inflammatory assay, both 1 and 2 showed in vitro inhibitory effects on the production of pro-inflammatory cytokines, TNF-α and IL-6, in LPS-stimulated RAW 264.7 macrophages.