The Anti‐Arthritis Effect of Olive‐Derived Maslinic Acid in Mice is Due to its Promotion of Tissue Formation and its Anti‐Inflammatory Effects

SCOPE: A previous study demonstrated that intake of olive pomace extract containing maslinic acid (MA), a triterpene, effectively prevents and alleviates arthritis in animals and humans. Here, the molecular mechanisms involved in the anti-arthritis effect of MA have been elucidated by determining gene expression changes induced by olive-derived MA intake in collagen antibody-induced arthritis (CAIA) mice. METHODS AND RESULTS: Mice are divided into the untreated (CT), CAIA (CA), and CAIA administered MA (CA + MA) groups. The CA + MA mice are fed MA at a daily dose of 200 mg kg-1 of body weight from day 1. CAIA is then induced on day 8 and evaluated on day 12. Arthritis symptoms are alleviated, and the gene expression of inflammatory cytokines is reduced in the CA + MA group compared with the CA group. A DNA microarray analysis of synovial membranes reveals that MA alters the expression levels of genes related to inflammation, including glucocorticoid responses, immune responses, and the extracellular matrix. CONCLUSIONS: The preventive effect of MA on arthritis is attributable to the promotion of tissue formation as well as suppression of inflammation in the synovium via inactivation of Toll-like receptor signaling and downregulation of leukotrienes through the glucocorticoid receptor.