Tocotrienol‐rich fraction of palm oil exhibits anti‐inflammatory property by suppressing the expression of inflammatory mediators in human monocytic cells

Abstract

Tocotrienol-rich fraction (TRF) of palm oil has been shown to possess potent antioxidant, anticancer, and cholesterol lowering activities. In this study, our aim was to examine the effects of TRF on LPS-induced inflammatory response through measuring the production of inflammatory mediators, namely nitric oxide (NO), prostaglandin E(2) (PGE(2)), inducible nitric oxide synthase (iNOS), cytokines (TNF-alpha, IL-4, and IL-8), cyclooxygenase-1 and -2 (COX-1 and COX-2), and nuclear factor-kappaB (NF-kappaB) in human monocytic (THP-1) cells. At concentrations 0.5-5.0 microg/mL, TRF dose-dependently protected against LPS-induced cell death. At same concentrations, TRF also showed potent anti-inflammatory activity as demonstrated by a dose-dependent inhibition of LPS (1 microg/mL)-induced release of NO and PGE(2), and a significant decrease in the transcription of proinflammatory cytokines. TRF at 1.0 microg/mL significantly blocked the LPS induction of iNOS and COX-2 expression, but not COX-1. This anti-inflammatory activity was further supported by the inhibition of NF-kappaB expression. These results conclude that TRF possesses potent anti-inflammatory activity, and its mechanism of action could be through the inhibition of iNOS and COX-2 production, as well as NF-kappaB expression.