Antidesma thwaitesianum Müll. Arg. fruit extract rich in ۵-hydroxymethylfurfural exhibits anti-inflammatory effects in lipopolysaccharide-stimulated RAW۲۶۴.۷ macrophages

Introduction: Antidesma thwaitesianum Müll. Arg is a tropical fruit, which has been commonly used for healthy food and traditional herbal medicine. This study aimed to investigate the anti-inflammatory effects of A. thwaitesianum fruit extract (AFE) rich in ۵-hydroxymethylfurfural (۵-HMF) in lipopolysaccharide (LPS)-stimulated RAW۲۶۴.۷ macrophages. Methods: The chemical composition of AFE was analysed by gas chromatography/mass spectrometry (GC/MS). RAW۲۶۴.۷ cells were used as an in vitro inflammatory response model. RAW۲۶۴.۷ cells were pre-treated with various concentrations of AFE or ۵-HMF and subsequently treated with LPS. Cell viability was assessed by the ۳-(۴,۵-dimethylthiazol-۲-yl)-۲,۵-diphenyltetrazolium bromide (MTT) assay. The production levels of pro-inflammatory cytokines and mediators, including nitric oxide (NO), interleukin (IL)-۱β, and tumour necrosis factor (TNF)-α were determined by the Griess assay and enzyme-linked immunosorbent assay. The protein expression of inducible nitric oxide synthase (iNOS) was examined by western blot analysis. Results: AFE had a high content of ۵-HMF (۶۱.۰۳% ± ۰.۴۹%). Pre-treatment with AFE and ۵-HMF markedly reduced LPS-induced pro-inflammatory mediators and cytokines, namely NO, IL-۱β, and TNF-α, in RAW۲۶۴.۷ cells; this reduction correlated with downregulation of iNOS expression. Conclusion: This study suggests that A. thwaitesianum fruit extract containing ۵-HMF could modulate the LPS-induced inflammatory response by inhibiting NO, IL-۱β, and TNF-α production and iNOS expression. A. thwaitesianum fruit extract rich in ۵-HMF could be considered a potential therapeutic agent for the prevention of inflammation.