Anti-Inflammatory Effects and Macrophage Activation Induced by Bioavailable Cinnamon Polyphenols in Mice

ScopeCinnamon is a commonly used spice and herb that is rich in polyphenols. Due to the limited bioavailability of oral polyphenols, it remains unclear to which extent they can reach cells and exert a biological effect. This study aims to investigate the impact of bioavailable cinnamon polyphenols on lipopolysaccharide (LPS)-stimulated macrophages.Methods and resultsA polyphenol fraction is prepared from cinnamon (Cinnamomi ramulus) (CRPF) by boiling cinnamon in water and adsorbing the extract onto a hydrophobic resin. Mice are orally administered CRPF for 7 days and then subjected to three independent experiments: endotoxemia, serum collection, and macrophage isolation. Upon intraperitoneal lipopolysaccharide challenge, CRPF decreases serum levels of inflammatory cytokines, involving suppression of liver and spleen macrophages. When normal macrophages are cultured in serum obtained from CRPF-treated mice, they exhibit an anti-inflammatory phenotype. However, macrophages from CRPF-treated mice show an increased production of inflammatory cytokines when cultured in fetal bovine serum and stimulated with LPS.ConclusionThe study provides evidence for the presence of bioavailable cinnamon polyphenols with anti-inflammatory properties and macrophage activation. These findings suggest that cinnamon polyphenols have the potential to modulate macrophage function, which could have implications for reducing inflammation and improving immune function. Polyphenols demonstrate anti-inflammatory functions in vitro but they are transformed in vivo, raising concerns regarding their low bioavailability. Following the oral administration of cinnamon polyphenols, bioavailable polyphenols with anti-inflammatory properties are clearly observed. However, some of these polyphenols exhibit immunostimulatory effects, penetrating macrophages. These discoveries highlight the potential of cinnamon polyphenols in mitigating inflammation and enhance immune function. image