Exploring the Potential Immunomodulatory Properties of Noni Juice on Human Monocytes and Macrophages

Abstract Noni, also known as Morinda citrifolia, is a plant that has been widely used for treating various pathologies due to its allegedly anti-inflammatory and immunomodulating properties. Macrophages and monocytes are critical immune cells that initiate inflammation and generate an immune response against various aggressors, regardless of their causative agent. However, it is not well investigated how noni fruit components affect the behavior or phenotype of these cells. Hence, studies in this direction could potentially demonstrate the therapeutic effects of this fruit, which is consumed worldwide. This study aimed to investigate the therapeutic properties of noni fruit juice in modulating the behavior and phenotype of human monocytes and macrophage cells in vitro. The results show that noni fruit juice inhibited the production of nitric oxide (NO) and inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-4, while stimulating the production of the anti-inflammatory cytokine IL-10 in monocytes. In addition, it negatively modulated the expression of toll-like receptor 4 (TLR4). In macrophages, noni fruit juice enhanced the secretion of all cytokines and NO, and inhibited the expression of TLR4. The contrasting results observed could be attributed to the joint stimuli of PMA (Phorbol 12-myristate 13-acetate), which was used to induce macrophage differentiation and noni Juice. Overall, the data indicate that noni may act as an anti-inflammatory agent and may aid in the treatment of uncontrolled inflammatory diseases as a complementary treatment to conventional therapies, under medical supervision. GRAPHICAL ABSTRACT