Geniposide, an iridoid glucoside derived from Gardenia jasminoides, protects against lipopolysaccharide-induced acute lung injury in mice.

Geniposide, a main iridoid glucoside component of gardenia fruit, has been shown to possess anti-inflammatory activity. However, its potential use for acute lung injury (ALI) has not yet been studied. The aim of this study was to evaluate the anti-inflammatory properties of geniposide using a mouse ALI model. ALI was induced by intranasal injection of lipopolysaccharide (LPS). Pretreatment of mice with geniposide (20, 40, or 80 mg/kg) resulted in a marked reduction in inflammatory cells and total protein concentration in the bronchoalveolar lavage fluid (BALF) of mice. Levels of inflammatory mediators, including tumour necrosis factor- α (TNF- α), interleukin-6 (IL-6), and interleukin-10 (IL-10), were significantly altered after treatment with geniposide. Histological studies using hematoxylin and eosin (H&E) staining demonstrate that geniposide substantially inhibited LPS-induced alveolar wall changes, alveolar haemorrhage, and neutrophil infiltration in lung tissue, with evidence of reduced myeloperoxidase (MPO) activity. In addition, we investigated potential signal transduction mechanisms that could be implicated in geniposide activity. Our results suggest that geniposide may provide protective effects against LPS-induced ALI by mitigating inflammatory responses and that the compound's mechanism of action may involve blocking nuclear factor-kappaB (NF- κB) and mitogen-activated protein kinases (MAPK) signalling pathway activation.