Myxopyrum serratulum ameliorates the airway inflammation in LPS stimulated RAW 264.7 murine macrophages and OVA induced murine model of allergic asthma.

Myxopyrum serratulum (M.serratulum) is an important medicinal plant traditionally used for the treatment of asthma and cough, and many inflammatory diseases. In this study, the protective effects of M. serratulum was investigated through airway inflammation in an ovalbumin (OVA)-induced asthma murine model and lipopolysaccharide (LPS)-stimulated inflammation in RAW 264.7 murine macrophages and possible mechanism were studied.Phytochemicals in the methanolic extract of M. serratulum (MEMS) were identified using RP-HPLC analysis. For evaluating in vitro anti inflammatory activity, LPS stimulated RAW 264.7 murine macrophage method was adopted and to estimate the levels of nitric oxide (NO), reactive oxygen species (ROS) and group of proinflammatory cytokines by ELISA. Allergic asthma was induced in Female BALB/c mice by intraperitoneal injection of OVA on days 0 and 14 and then challenged with OVA from days (21-23). The MEMS at 200 & 400 mg/kg was administered by oral gavage 1 h before the OVA challenge. The airway hyperresponsiveness (AHR) was measured after 24 h OVA challenge, bronchoalveolar lavage fluid (BALF) & lung tissues were collected after 48 h last OVA challenge. Total cell count, differential cell eosinophil peroxidase assay, NO, Prostoglandin (PGE2), ROS assay and the cytokine release (IL-4, IL-5 & IL-13), were performed in BALF. Serum total IgE level and histopathological changes of lung tissues and cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were detected by Western blot.From the chromatographic identification, the gallic acid, protocatechuic acid, catechin, ellagic acid, rutin, p-coumaric acid, quercetin, naringenin, apigenin were found in MEMS. In LPS stimulated RAW 264.7 cells, MEMS (125,250 μg/mL) treatment significantly reduced the levels of NO, ROS and proinflammatory cytokines including IL1α, IL1β, IL-2, IL-4, IL-6, IL-10, IL-12, IL-17A, IFN-γ, TNF-α, G-CSF and GM-CSF). MEMS (200 & 400 mg/kg) significantly reduced the number of inflammatory cells, NO,PGE2, ROS and L-4, IL-5, IL-13 in BAL fluid, IgE in serum of OVA-sensitized/challenged mice and also inhibit the COX-2 & iNOS protein expression in lung tissues of OVA-sensitized/challenged mice.From this finding it was suggested that the MEMS exhibited significant effects on airway inflammation by reducing the level of oxidative stress, pro-inflammatory cytokines and inhibiting the COX-2, iNOS protein expression.