Anti-inflammatory effects of Nelumbo leaf extracts and identification of their metabolites

Abstract

BACKGROUND/OBJECTIVES: Nelumbo leaves have been used in traditional medicine to treat bleeding, gastritis, hemorrhoids, and halitosis. However, their mechanisms have not been elucidated. MATERIALS/METHODS: The present study prepared two Nelumbo leaf extracts (NLEs) using water or 50% ethanol. Inflammatory response was induced with LPS treatment, and expression of pro-inflammatory mediators (inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-alpha (TNF-alpha), interleukin (1L)-1 beta, and IL-6 and nitric oxide (NO) and prostaglandin E-2 (PGE(2)) productions were assessed. To determine the anti-inflammatory mechanism of NLEs, we measured nuclear factor-kappa B (NF-kappa B) activity. Major metabolites of NLEs were also analyzed and quantified. RESULTS: NLEs effectively reduced the expression and productions of pro-inflammatory mediators such as IL-1 beta, IL-6, TNF-alpha, PGE(2), and NO. NLEs also reduced NF-kappa B activity by inhibiting inhibitor of NF-kappa B phosphorylation. Both extracts contained catechin and quercetin, bioactive compounds of NLEs. CONCLUSIONS: In this study, we showed that NLEs could be used to inhibit NF-kappa B-mediated inflammatory responses. In addition, our data support the idea that NLEs can ameliorate disease conditions involving chronic inflammation.