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. Transcriptome analysis is performed to investigate the gene expression changes induced by olive‐derived maslinic acid intake in the synovium of collagen antibody‐induced arthritic mice. The anti‐arthritis effect of maslinic acid is attributable to the promotion of tissue formation as well as suppression of inflammation via inactivation of Toll‐like receptor signaling pathways, and downregulation of leukotrienes. These gene expression changes would have a preventive effect on arthritis.