Anti-Inflammatory Effects of Morinda citrifolia Extract against Lipopolysaccharide-Induced Inflammation in RAW264 Cells

Leaves of Morinda citrifolia (noni) have been used in Polynesian folk medicine for the treatment of pain and inflammation, and their juice is very popular worldwide as a functional food supplement. This study aimed to demonstrate that M. citrifolia seed extract exerts anti-inflammatory effects on RAW264 cells stimulated by lipopolysaccharide. To confirm the inhibitory effect of M. citrifolia seed extract, we assessed the production of nitric oxide (NO) and inflammatory cytokines. The M. citrifolia seed extract showed a significant inhibition of NO production, with no effect on cell viability, and was more active than M. citrifolia seed oil, leaf extract, and fruit extract. The M. citrifolia seed extract was found to reduce the expression of inducible NO synthase and tumor necrosis factor-alpha of pro-inflammatory cytokines. These results suggest that the anti-inflammatory effect of M. citrifolia seed extract is related to a reduction in the expression of inflammatory mediators and support its potential therapeutic use.