Cenchrus ciliaris L. ameliorates cigarette-smoke induced acute lung injury by reducing inflammation and oxidative stress.

Acute lung injury (ALI) and its more severe form acute respiratory distress syndrome (ARDS) is a critical respiratory condition characterized by a sudden respiratory collapse, accumulation of fluid in lungs leading to reduced blood oxygenation. ALI/ARDS management is mainly supportive, as no specific anti-inflammatory therapy exists for lung injury. Recently, several medicinal plants and natural products have gained attention for their antimicrobial, antioxidant, immunomodulation and anti-inflammatory activities. Cenchrus ciliaris L. (Buffel grass), is native to Africa and Asia where it is traditionally used for several inflammatory disorders, wounds and pain. Cigarette smoke induces inflammation and oxidative stress in respiratory system which can damage lungs and augment respiratory disorders that can progress to ALI/ARDS. We described antioxidant and anti-inflammatory potential of C. ciliaris L. which ameliorates acute lung injury induced by exposure to cigarette smoke. Total phenolic, flavonoid, tannin and saponin contents were quantified in 70 % methanolic extract of C. ciliaris (Cc.Cr). Phytochemical characterization was performed by UHPLC which indicated the presence of furoic acid, longistylin A, scandenin, salicylic acid, piscidic acid, 3-hydroxybenzaldehyde, pheophorbide and chrysoeriol reported for their antioxidant, anti-inflammatory and antimicrobial activities. ALI was induced in mice by exposure to cigarette smoke, followed by the collection of broncho alveolar lavage fluid (BALF) and lung tissues. Total inflammatory cells, differential leukocyte count, total protein contents, nitrite levels, interleukins, total oxidative stress and antioxidant capacity were assessed in BALF. MDA and catalase levels were assessed in lung tissue and histopathology was performed to assess the integrity of lung tissue architecture. Cc.Cr showed good antioxidant activity in CUPRAC and FRAP assays while it effectively scavenged free radicals in DPPH, ABTS and nitric oxide assay. Cc.Cr inhibited cycloxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) with IC 50 values 29.23 ± 9.73 μ g/ml and 24.12 ± 6.0 μ g/ml respectively. In mice, Cc.Cr improved total antioxidant capacity, lung tissue integrity, and hematological parameters while it reduced inflammation, oxidative stress, lung edema and tissue damage. Graphical abstract [Display omitted] • C. ciliaris L. possess good antioxidant and free radical scavenging activity. • It inhibits COX-2 and 5-LOX enzymes. • C. ciliaris L. improves total antioxidant capacity, lung tissue integrity and hematological parameters. • C. ciliaris L. reduced inflammation, oxidative stress, lung edema and tissue damage in acute lung injury. [ABSTRACT FROM AUTHOR]