Anti-inflammatory Effects of a Sesquiterpene Lactone Extract from Chicory ( Cichorium intybus L.) Roots

Abstract

A chicory root extract rich in sesquiterpene lactones significantly reduced inflammation in two animal models. In a rat paw edema model, chicory extract at 50 and 100 mg/kg significantly reduced inflammation by 58 and 76%, respectively, 24 h after carrageenan injection. In a mouse collagen induced arthritis model, chicory extract (200 mg/kg) reduced paw edema by 71% while the extract was being administered, and 31% 48 h after extract administration was discontinued. Two possible modes of action were investigated, pro-inflammatory gene expression and nitric oxide production by LPS-elicited macrophages. Chicory root extract down-regulated COX-2, TNF-α, IL1β, and iNOS expression and reduced nitric oxide production in a dose dependant manner. Several compounds were isolated from the chicory extract and tested in vitro to confirm activity. Dihydrolactucopicrin and 8-deoxylactucin showed particularly high nitric oxide inhibitory activity (IC₅₀ = 13 μM for both). Dihydrolactucopicrin also was shown to down-regulate pro-inflammatory gene expression. These data demonstrate that chicory extracts rich in sesquiterpene lactones have potent anti-inflammatory activity with potential therapeutic use.