The phytochemical constituents and protective effect of Fritillaria hupehensis on acute lung injury

Acute lung injury (ALI), a severe respiratory disorder, frequently develops into acute respiratory distress syndrome (ARDS) without timely treatment and scores highly in terms of morbidity and mortality rates. Fritillaria hupehensis is a famous traditional Chinese medicine with antitussive, expectorant and anti-asthmatic effect. Here, the effects of F. hupehensis extracts on lipopolysaccharide (LPS)-induced ALI mice were evaluated for the first time. We showed ethyl acetate fraction (EAF) significantly reduced the leukocytes and neutrophils of bronchoalveolar lavage fluid (BALF) and the lung index as well as pro-inflammatory cytokines (TNF-α and IL-6) of lung homogenates but increasing the anti-inflammatory cytokines (IL-4 and IL-10). Additionally, the alleviation of EAF treatment on lung injury was verified through histopathological observations. Subsequent phytochemical investigation on bioactive fraction led to isolation of 17 compounds including two new, in which compounds 2, 5 and 6 exhibited better anti-inflammatory effect on LPS-induced 16 human airway epithelial (16HBE) cells model by inhibiting the production of CRP and PCT. Furthermore, compound 2 suppressed the LPS-induced upregulation of proteins containing p-p65, COX-2, Caspase-1 and IL-18. In summary, F. hupehensis alleviating LPS-induced ALI in mice may be associated with the anti-inflammatory activity of steroidal alkaloids by suppressing the NF-κB-regulated pro-inflammatory proteins.