Anti-oxidant activity and protective effects of Lindera obtusiloba flower teas on inflammatory response in Raw 264.7 macrophages induced by lipopolysaccharide

We investigated the in vitro anti-oxidant activity and protective effects of Lindera obtusiloba flower tea extract (LFE) on lipopolysaccharide (LPS)-induced inflammatory response in Raw 264.7 macrophages.The polyphenol and flavonoid contents of LFE were 32.32 mg GAE/g and 213.83 mg QE/g, respectively.The LFE exhibited the highest 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities at a concentration of 100 μg/mL among stem and leaf of Lindera obtusiloba extracts.When treated with LFE at concentrations of 10-100 μg/mL, it dose-dependently reduced the production of nitric oxide (NO) in LPS-induced Raw 264.7 macrophages.The treatment of LFE significantly inhibited inflammatory cytokines such as interleukin (IL)-1β and IL-6 in Raw 264.7 macrophage induced by LPS.In particular, treatment of LFE showed a high suppression of IL-1β expression.To evaluate the anti-inflammatory mechanisms of LFE, we investigated protein expressions such as phospho-nuclear factor kappa-lightchain-enhancer of activated B cells (p-NF-B), inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2).The LFE inhibited the expression of p-NF-B, iNOS, and COX-2 compared with LPS-treated cells, resulting anti-inflammatory effects of LFE by inhibiting protein expression involved in NF-B signaling.Therefore, LFE could be a considered as a functional material with anti-oxidant and anti-inflammatory properties.