Baicalein 5, 6, 7-trimethyl ether from Physalis pubescens L. leaves ameliorate the effect of epirubicin in HepG2 cancer cells by inducing apoptosis and autophagy

Abstract Context: flavonoids have a pivotal cytotoxic effect against hepatocellular carcinoma (HCC). Aims To reveal which flavonoid isolated from Physalis pubescens L. leaves exerts the most cytotoxic effect against HepG2 liver cancer cells and if it could ameliorate epirubicin efficacy and safety through regulating apoptosis and autophagy. Methods Baicalein trimethyl ether (BTE), rutin, quercitrin and myricitrin were isolated from Physalis Pubescens L. leaves. HepG2 cells were treated with the isolated flavonoids as well as a combination of BTE and epirubicin. Cell viability was assessed by MTT assay after 48hr treatment. In addition, the chromosomal DNA fragmentation in HepG2 cells, a biochemical hallmark of apoptosis, was assessed. Autophagy and apoptosis markers, ATG7 and TGF-β1, were determined by RT-qPCR. Results BTE showed the best cytotoxic effect against HepG2 cells (IC50 = 95.6 ± 5.849 µg/mL). Combination of epirubicin with (200µg/mL) BTE significantly decreased the IC50 of epirubicin from 2.79 ± 0.626 µg/mL to 0.76 ± 0.258 µg/mL (p = 0.04). Moreover, the same combination significantly increased the IC50 of BTE against WI-38 normal cells (p < 0.0001). DNA fragmentation was increased in HepG2 cells treated with BTE and BTE + epirubicin compared to untreated cells. BTE and BTE + epirubicin significantly downregulated gene expression of TGF-β1 while upregulated ATG7 gene expression. Conclusions BTE (200µg/mL) significantly increased the cytotoxicity of epirubicin against HepG2 cells and increased its safety profile. It could exert anti-hepatocarcinoma effect via increasing apoptosis and autophagy. It could be a promising adjuvant therapy to ameliorate epirubicin cytotoxicity against HCC with less adverse effects.