Anti-Nociceptive and Anti-Inflammatory Activities of the Ethyl Acetate Extract of Belamcanda chinensis (L.) Redouté in Raw 264.7 Cells in vitro and Mouse Model in vivo

PURPOSE: Inflammation and accompanying pain is a common global health problem that seriously affects human quality of life worldwide. Here, we aimed to investigate the anti-nociceptive and anti-inflammatory activities of the ethyl acetate extract of B. chinensis (EAEBc) along with the underlying mechanisms of action. METHODS: The in vitro anti-inflammatory activity of EAEBc was explored using an LPS-induced RAW264.7 cell inflammatory model. Nitric oxide (NO) production, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 levels were evaluated. In vivo anti-nociceptive and anti-inflammatory activities of EAEBc were assessed with the aid of classical experimental mouse models. In addition, LPS-induced biomarker contents (TNF-α, IL-1β, IL-6, NO, iNOS, and PGE2) and formalin-induced serum inflammatory factors (NO, PGE2, 5-HT, β-EP, substance P, and NE) were determined in mice. RESULTS: In vitro, EAEBc significantly reduced LPS-induced NO generation and suppressed the production of TNF-α, IL-1β, and IL-6 in RAW264.7 cells in a concentration-dependent manner. In vivo, EAEBc downregulated serum TNF-α, IL-1β, IL-6, NO, iNOS, and PGE2 contents in mice with LPS-induced inflammation in a dose-dependent manner. EAEBc displayed anti-inflammatory activity in carrageenan-induced paw edema and xylene ear edema tests. Intragastric administration of EAEBc at test doses of 100 and 200 mg/kg led to inhibition of nociception and capillary permeability induced by acetic acid to varying degrees. Similarly, EAEBc exerted analgesic effects in the formalin and hot plate tests. In particular, the administration of EAEBc reversed the changes in the levels of inflammatory indicators NO, PGE2, 5-HT, β-EP, substance P, and NE in a mouse model of formalin-induced pain. CONCLUSION: Our findings provide considerable evidence to support the extensive application of B. chinensis in traditional medicine and demonstrate the utility of this plant species as an effective candidate for prevention or treatment of various pain and inflammation-related conditions.