Tocotrienols Suppress Proinflammatory Markers and Cyclooxygenase‐2 Expression in RAW264.7 Macrophages

AbstractTocotrienols are powerful chain breaking antioxidant. Moreover, they are now known to exhibit various non‐antioxidant properties such as anti‐cancer, neuroprotective and hypocholesterolemic functions. This study was undertaken to investigate the anti‐inflammatory effects of tocotrienol‐rich fraction (TRF) and individual tocotrienol isoforms namely δ‐, γ‐, and α‐tocotrienol on lipopolysaccharide‐stimulated RAW264.7 macrophages. The widely studied vitamin E form, α‐tocopherol, was used as comparison. Stimulation of RAW264.7 with lipopolysaccharide induced the release of various inflammatory markers. 10 μg/ml of TRF and all tocotrienol isoforms significantly inhibited the production of interleukin‐6 and nitric oxide. However, only α‐tocotrienol demonstrated a significant effect in lowering tumor necrosis factor‐α production. Besides, TRF and all tocotrienol isoforms except γ‐tocotrienol reduced prostaglandin E2 release. It was accompanied by the down‐regulation of cyclooxygenase‐2 gene expression by all vitamin E forms except α‐tocopherol. Collectively, the data suggested that tocotrienols are better anti‐inflammatory agents than α‐tocopherol and the most effective form is δ‐tocotrienol.