Unusual sesquilignans with anti-inflammatory activities from the resin of Ferula sinkiangensis

Sinkianlignans A - D (1-4), four new sesquilignans with an unusual architectures was characterized with a rarely α-γ', β-γ', and γ-γ' linkage pattern, and sinkianlignans E - F (5 and 6), two lignans, were isolated from the Ferula sinkiangensis. Hypothetic biosynthetic pathway of compound 3 contain a newly formed six-membered C-ring by Diels-Alder cycloaddition. The structures of isolates were established by spectroscopic techniques and computational methods. Biological evaluation of all the isolated compounds revealed that compounds 2a and 2b could inhibit IL-6 and TNF-α production in lipopolysaccharide (LPS) induced RAW264.7 cells in a dose-dependent manner.