Baicalin, a
flavonoid monomer derived from Scutellaria baicalensis called Huangqin in mandarin, is the main active ingredient contributing to S. baicalensis' efficacy. It is known in China that
baicalin has potential
therapeutic effects on inflammatory diseases. However, its anti-inflammatory mechanism has still not been fully interpreted. We aim to investigate the anti-inflammatory effect of
baicalin on
lipopolysaccharide (LPS)-induced
inflammation in HBE16 airway epithelial cells and also to explore the underlying signaling mechanisms. The anti-inflammatory action of
baicalin was evaluated in human airway epithelial cells HBE16 treated with LPS. Airway epithelial cells HBE16 were pretreated with a range of concentrations of
baicalin for 30 min and then stimulated with 10 μg/ml LPS. The secretions of
interleukin-6 (IL-6),
interleukin-8 (IL-8), and
tumor necrosis factor-α (TNF-α) in cell culture supernatants were quantified by
enzyme-linked
immunosorbent assay (ELISA). The
messenger RNA (
mRNA) expressions of
IL-6,
IL-8, and TNF-α were tested by quantitative real-time polymerase chain reaction (real-time RT-PCR). Furthermore, Western blotting was used to determine whether the signaling pathway NF-κB was involved in the anti-inflammatory action of
baicalin. The inflammatory cell model was successfully built with 10 μg/ml LPS for 24 h in our in vitro experiments. Both the secretions and the
mRNA expressions of
IL-6,
IL-8, and TNF-α were significantly inhibited by
baicalin. Moreover, the expression levels of phospho-IKKα/β and phospho-NF-κB p65 were downregulated, and the phospho-IκB-α level was upregulated by
baicalin. These findings suggest that the anti-inflammatory properties of
baicalin may be resulted from the inhibition of
IL-6,
IL-8, and TNF-α expression via preventing signaling NF-κB pathway in HBE16 airway epithelial cells. In addition, this study provides evidence to understand the
therapeutic effects of
baicalin on inflammatory diseases in clinical practice.