Papers of the Week

Citrus grandis (L.) Osbeck is a popular fruit cultivated around the world and its peels are sometimes used for the treatment of cough, abdominal pain and indigestion in China. However, the peel is discarded after fruits consumption in most cases and its chemical constituents and biological activities haven't been validated before. The present study focused on evaluation of the chemical and pharmacological profile of coumarins from peels of C. grandis against inflammation. The extracts and phytochemicals from peels of C. grandis were prepared and anti-inflammatory activities were carried out in vivo and in vitro, including inhibiting xylene-induced ear edema, carrageenan-induced paw edema in mice, and the production of inflammatory cytokines (IL-1β, PGE2, TNF-α) in lipopolysaccharide (LPS) induced RAW 264.7 cells. Results indicated that methanolic extract (ME), ethyl acetate fraction (EAC) and four major coumarins (compounds 7, 8, 13, and 16) inhibited swelling induced by xylene and carrageenan respectively in vivo. Furthermore, 18 coumarins inhibited inflammatory factors secretion in macrophages primed by LPS, in which compounds 4, 6, 7, 10, 17 showed the most pronounced change, which were comparable to dexamethasone (DXM). In summary, peel of C. grandis showed an anti-inflammatory effect, and coumarins compounds were responsible for the regulating inflammatory mediators and cytokines, which might provide a novel nutritional strategy for inflammatory diseases.