Methanol extract of the aerial parts of barley (Hordeum vulgare) suppresses lipopolysaccharide-induced inflammatory responses in vitro and in vivo

Context: Recently, there has been renewed interest in barley (Hordeum vulgare L. Poaceae) as a functional food and for its medicinal properties. Objective: This study examines the anti-inflammatory potential of the active fractions of barley and the mechanisms involved. Materials and methods: The macrophages were exposed to 100 mg/mL of each of the barley extracts in the presence of 1 mg/mL lipopolysaccharide (LPS) and after 24 or 48 h of incubation, cells or culture supernatants were analyzed by various assays. The anti-inflammatory potential of barley fractions was also investigated using the LPS-injected septic mouse model. The active constituents in the fractions were identified using gas chromatography-mass spectrometry (GC-MS). Results: The active fractions, named F₄, F₇, F₉ and F ₁₂, inhibited almost completely the LPS-induced production of nitric oxide (NO) and inducible NO synthase. Pre-treatment with these fractions at 100 mg/mL diminished the tumor necrosis factor-a (TNF-a) levels to 19.8, 3.5, 1.2 and 1.7 ng/mL, respectively, compared to LPS treatment alone (41.5 ng/mL). These fractions at 100 mg/mL also suppressed apparently the secretion of interleukin (IL)-6 and IL-1b and the DNA-binding activity of nuclear factor-kB in LPS-stimulated cells. Mice injected intraperitoneally with LPS (30 mg/kg BW) showed 20% survival at 48 h after injection, whereas oral administration of the fractions improved the survival rates to 80%. GC-MS analysis revealed the presence of the derivatives of benzoic and cinnamic acids and fatty acids in the fractions. Discussion and conclusion: The aerial parts of barley are useful as functional food to prevent acute inflammatory responses.