5-Hydroxymethylfurfural Mitigates Lipopolysaccharide-Stimulated Inflammation via Suppression of MAPK, NF-B and mTOR Activation in RAW 264.7 Cells

5-Hydroxymethylfurfural (5-HMF) is found in many food products including honey, dried fruits, coffee and black garlic extracts. Here, we investigated the anti-inflammatory activity of 5-HMF and its underlying mechanisms in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. 5-HMF pretreatment ranging from 31.5 to 126.0 g/mL reduced the production of nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokines (TNF-, IL-1 and IL-6) in a concentration-dependent manner in LPS-stimulated cells. Moreover, 5-HMF-pretreated cells significantly down-regulated the mRNA expression of two major inflammatory mediators, nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and suppressed the production of pro-inflammatory cytokines, as compared with the only LPS-stimulated cells. 5-HMF suppressed the phosphorylation of extracellular regulated protein kinases (ERK1/2), c-Jun N-terminal kinase (JNK), IB, NF-B p65, the mammalian target of rapamycin (mTOR) and protein kinase B (Akt). Besides, 5-HMF was proved to inhibit NF-B p65 translocation into nucleus to activate inflammatory gene transcription. These results suggest that 5-HMF could exert the anti-inflammatory activity in the LPS-induced inflammatory response by inhibiting the MAPK, NF-B and Akt/mTOR pathways. Thus, 5-HMF could be considered as a therapeutic ingredient in functional foods.