Novel immunomodulatory effects of phytanic acid and its related substances in mice

• Phytanic acid and its related substances inhibited IFN-γ production.
• Phytanic acid and phytol showed inhibitory activity on IL-17A production.
• Phytanic acid elicited immunomodulatory effects at its concentration in healthy humans.

Phytanic acid is one of the constituents of animal products with possible health benefits through improving lipid and glucose metabolism; however, its immunomodulatory effects remain undetermined. The in vitro effects of phytanic acid and its related substances on T-cell functions were investigated. Mouse splenocytes were stimulated by T-cell mitogens and incubated with phytanic acid, phytol, and pristanic acid followed by evaluation of cell proliferation and cytokine production. All phytanic acid-related substances significantly reduced IFN-γ, IL-4, and IL-10 production, with varying potencies, and had no significant effects on IL-2 production. Moreover, IL-17A production was inhibited by phytol and phytanic acid. Phytanic acid elicited immunomodulatory effects without inhibition of T-cell proliferation, and its effective concentration was less than 10 µM, which corresponds to the serum concentration of healthy humans. The present study suggests that phytanic acid has a potentially beneficial effect for amelioration of T-cell mediated autoimmune diseases.