Antiinflammatory Constituents in Noni (Morinda citrifolia) Fruits

Abstract

Morinda citrifolia (Noni) is a tropical plant whose leaves, barks, roots and fruits have been used as traditional remedy for various diseases. Although inflammation was considered as one of the indications for noni fruits, and fruit extract was demonstrated to have immunomodulatory activity in vitro, no principle has been identified. In our study, we attempted to identify constituents that may be responsible for anti-inflammatory activity, and to elucidate the possible roles on anti-inflammatory mediators for interested compounds. Solvent extraction and column chromatography were major techniques used for isolation of compounds, while structures were elucidated by integration of data from UV, IR, MS and NMR analysis. Anti-inflammatory activity was assessed by mouse ear edema model. Subsequent Elisa analysis was carried out for their effects on anti-inflammatory mediators such as IL-1β, IL-6, PGE 2 and myeloperoxidase. Scopoletin, quercetin, ursolic acid were identified as major anti-inflammatory constituents. Since ursolic acid was known to have anti-inflammatory activity, we characterized the mode of action of scopoletin and quercetin in mouse ear inflammation model. The most potent inhibition occurred at 0.5 μmol level for both quercetin (62.3%) and scopoletin (50.4%). Scopoletin mainly inhibited production of myeloperoxidase and PGE 2 while quercetin had significant suppressing effect on IL-6 production. Both compounds showed moderate inhibition on IL-1β production.