Polyphenolics from Syzygium brachythyrsum Inhibits Oxidized Low-Density Lipoprotein-Induced Macrophage-Derived Foam Cell Formation and Inflammation

Evidence suggests that the immunomodulatory property of polyphenols may also contribute to the reduction of cardiovascular risk. In the present study, we investigated the polyphenol extraction (PE) from Syzygium brachythyrsum, a functional food resource in south China, regarding the protective effect on inhibiting foam cell formation and the underlying molecular mechanism based on an ox-LDL-induced RAW264.7 macrophage model. The results of Oil Red O staining, Dil-ox-LDL fluorescent staining, and cholesterol efflux experiments showed that PE, and its two phenolics brachythol B (BB) and ethyl gallate (EG), significantly inhibited the foam cell formation, which may be associated with reducing the expression of SR-A1 and CD36 while increasing expression of SR-B1, ABCG1, and PPARγ. In addition, BB and EG also reduce the inflammatory response by down-regulating the expression of NF-κB and MAPK signal pathway proteins, thereby inhibiting the expression of inflammatory factors. Altogether, PE and its two components BB and EG attenuated foam cell formation and macrophage inflammation response.