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

[Display omitted] • Four unusual sesquilignans compounds were isolated from the resin of Ferula sinkiangensis. • Hypothetic biosynthetic pathways of compound 3 contain a newly formed six-membered C-ring by Diels-Alder cycloaddition. • Biological assay revealed that 2a and 2b could inhibit IL-6 and TNF-α production in LPS induced RAW264.7 cells in a dose-dependent manner. 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. [ABSTRACT FROM AUTHOR]