B-seco Limonoids with anti-inflammatory activity from Tetradium fraxinifolium (Hook.) T.G.Hartley.

Fraxinifolines A-F (1 – 6), six new B- seco limonoids, together with four known A,D-di- seco ones, were isolated from the twigs with leaves of Tetradium fraxinifolium. Their structures with absolute configurations were elucidated on the basis of analysis of MS, NMR, single-crystal X-ray diffraction and biogenetic pathway. An anti-inflammatory bioassay in vitro showed limonoids 1 – 3 had significant immunosuppressive effect against the production of pro-inflammatory cytokines (IL-1 β and/or TNF-α) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. [Display omitted] • Ten limonoids were isolated from the twigs with leaves of Tetradium fraxinifolium. • Fraxinifolines A-F are the first examples of B- seco limonoids from Rutaceae plant. • Fraxinifolines A-D are unusal 7,8- seco -7,8-epoxide type limonoids. • Fraxinifolines A, B and C had significant immunosuppressive effect. [ABSTRACT FROM AUTHOR]