Anti-inflammatory cyclopeptides from exocarps of sugar-apples.

Two new cyclic peptides, fanlizhicyclopeptide A, cyclo(Pro(1)-Pro(2)-Tyr(3)-Leu(4)-Pro(5)-Gly(6)-Val(7)) (1), and fanlizhicyclopeptide B, cyclo(Pro(1)-Ile(2)-Tyr(3)-Ala(4)-Gly(5)) (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.