Fragilides K and L, New Briaranes from the Gorgonian Coral Junceella fragilis

Two new briarane metabolites—fragilides K (1) and L (2)—along with five known analogues—gemmacolide X, praelolide, juncins P and ZI, and gemmacolide V (3–7)—were extracted and purified from Junceella fragilis, a gorgonian coral. Based on data obtained via spectroscopic techniques, the structures of new briaranes 1 and 2 were determined and the cyclohexane rings in 1 and 2 were found to exist in chair and twist boat conformation, respectively. Additionally, anti-inflammatory analysis showed that briaranes 2, 3, and 6 inhibited pro-inflammatory inducible nitric oxide synthase protein expression and briaranes 3 and 7 suppressed the cyclooxygenase-2 level, in LPS-stimulated murine macrophage-like RAW264.7 cells.