Ethyl acetate fraction of Terminalia bellirica (Gaertn.) Roxb. fruits inhibits proinflammatory mediators via down regulating nuclear factor-κB in LPS stimulated Raw 264.7 cells

Abstract

Inflammation has been considered as a major risk factor for various kinds of human diseases. Macrophages play substantial roles in host defense against infection. It can be activated by lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria. The current study aims to investigate the anti-inflammatory effects of ethyl acetate fraction isolated from T. bellerica (EFTB) in LPS stimulated RAW 264.7 macrophage cell lines. The inhibitory effects of EFTB on total cyclooxygenase (COX), 5-lipoxygenase (5-LOX) activity, nitrate and inducible nitric oxide synthase (iNOS) level, reactive oxygen species (ROS) production were studied. The gene level expression of COX-2, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and Nuclear factor-κB (NF-κB) were also studied in LPS stimulated RAW 264.7 cells. EFTB (100μg/mL) inhibited all inflammatory markers in dose dependent manner. Moreover, EFTB down regulated the mRNA expression of TNF-α, IL-6, COX-2 and NF-κB against LPS stimulation. Our results demonstrated that EFTB is able to attenuate inflammatory response possibly via suppression of ROS and NO species, inhibiting the production of arachidonic acid metabolites, proinflammatory mediators and cytokines release.

Keywords: Inflammation; Interleukin-6; Nuclear factor-κB; Reactive oxygen species; Terminalia bellirica.