Baicalin and baicalein attenuate renal fibrosis in vitro via inhibition of the TGF-β1 signaling pathway

Baicalin and baicalein are flavonoid compounds derived from Scutellaria baicalensis Georgi. These compounds have been used in the treatment of numerous diseases, including fibrotic diseases. However, research regarding their antifibrotic effects and mechanism of action in renal fibrosis is limited. In the present study, normal rat kidney interstitial fibroblast (NRK-49F) cells were stimulated with transforming growth factor (TGF)-β1, with or without baicalin/baicalein, and assessed for proliferation, apoptosis, extracellular matrix (ECM) accumulation, collagen expression, TGF-β1 expression and mothers against decapentaplegic homolog 3 (SMAD3) protein activation. The results revealed that baicalin and baicalein exhibited antifibrotic effects in vitro, whereas baicalein had a stronger inhibitory action compared with baicalin on TGF-β1-induced NRK-49F cell proliferation, deposition of ECM, collagen synthesis, endogenous TGF-β1 expression and phosphorylation of SMAD3. In conclusion, the findings of the present study indicate that baicalin and baicalein, particularly baicalein, exhibit antifibrotic effects in vitro by inhibiting the TGF-β1 pathway. Therefore, these compounds have the potential to be developed as novel agents to treat renal fibrosis.