Cordatols A–D, four new anti-inflammatory bis-monoterpenoids from Illigera cordata

Abstract Cordatols A–D (1–4), four new limonene-derived bis–monoterpenoids plausibly biosynthesized via hetero-Diels-Alder cyclization and sequential hydrolyses of their monoterpene precursors, were isolated from the aerial parts of Illigera cordata . The structures, including absolute configuration, were established by spectroscopic analysis and further confirmed by a two-steps bioinspired chemical transformation. Moreover, compounds 1 – 4 exhibited moderate in vitro anti-inflammatory activity with IC 50 values ranging from 17.5 to 24.6 μM. This study may provide a novel structural template for potential anti-inflammatory agent discovery.