Polyacetylene Compound from Cirsium japonicum var. ussuriense Inhibited Caspase-1-mediated IL-1β Expression.

Our previous report showed that polyacetylene compound, 1-Heptadecene-11, 13-diyne-8, 9, 10-triol (PA) from the root of Cirsium japonicum var. ussuriense has anti-inflammatory activity. In this study we investigated the role of the PA as inhibitor of caspase-1, which converts prointerleukin-1β (proIL-1β) to active IL-1β and is activated by inflammasome involved in the inflammatory process. We tested the effect of PA on the production of pro-inflammatory cytokines, IL-1β in murine macrophage cell line, RAW264.7. PA inhibited lipopolysaccharide (LPS)-induced IL-1β production by macrophages at a dose dependent manner. PA also suppressed the activation of caspase-1. The mRNA level of ASC (apoptosis-associated spec-like protein containing a CARD), an important adaptor protein of inflammasome, was decreased in the PA treated group. Therefore our results suggest that the anti-inflammatory effect of PA is due to inhibit the caspase-1 activation.