Sesame Oil and Rice Bran Oil Ameliorates Adjuvant-Induced Arthritis in Rats: Distinguishing the Role of Minor Components and Fatty Acids.

Though present in small amounts, the minor constituents of dietary oils may supplement the dietary therapies for rheumatoid arthritis (RA). Hence, in the present study, we assessed the effect of minor constituents from sesame oil (SO) and rice bran oil (RBO) and their fatty acids on the severity of adjuvant-induced arthritis in experimental rats. Rats were gavaged with 1 mL of SO or RBO or groundnut oil (GNO, control) with or without its minor components for a period 15 days before and 15 days after the induction of arthritis. Oxidative stress, markers of RA, eicosanoids, cytokines, paw swelling and joint integrity were measured in experimental and control rats. Results demonstrated that native SO and RBO but not SO and RBO stripped of their minor components decreased severity of paw inflammation, oxidative stress (lipid peroxides, protein carbonyls, nitric oxide), RA markers (RF and CRP), inflammatory eicosanoids (PGE2, LTB4 and LTC4) and cytokines (IL-1β, IL-6, MCP-1 and TNF-α) compared to control rats. Native SO and RBO inhibited hydrolytic enzymes (collagenase, elastase and hyaluronidase) in the synovial tissue compared to SO and RBO without minor components. The arthritic scores assessed based on the digital and X-ray images indicated that native oils but not those without their minor components reduced the paw swelling and bone loss. Our results indicated that minor components of SO and RBO possess a significant degree of an anti-arthritic effect and are responsible for down regulating inflammation in the experimentally induced arthritis in rats.