Cytotoxic and Hepatoprotective Effects of Bupleurum flavum Flavonoids on Hepatocellular Carcinoma HEP-G2 Cells

Aims: In this study, we aimed at investigating the possible cytotoxic and hepatoprotective effects of crude extract, flavonoid mixture and pure flavonoids isolated from the aerial parts of Bupleurum flavum Forsk. (Apiaceae) native to Bulgaria.

Methods: For the first time flavon C-glycoside vicenin-2 was isolated from B. flavum. Its structure was identified by LC-ESI/MS/MS analysis in positive ion mode. Cytotoxic effects of vicenin-2, as well as the known flavonoid narcissin and B. flavum crude extract at concentrations ranging from 25 to 400 μg/ml were tested on cultured hepatocellular carcinoma HEP-G2 cells for 72 h by MTT assay. In vitro hepatoprotective activities of B. flavum flavonoid mixture (BFF), and rutin and narcissin isolated from BFF, were evaluated on epirubicin-induced damage.

Results: IC50 of 141.7 μM, 195.7 μM and 369.3 μg/ml was calculated for vicenin-2, narcissin and crude extract, respectively. Curcumin was used as positive control with IC50 17.90 μM. At a concentration 0.4 mg/ml of rutin, the strongest cytoprotective effect was verified, discerned by statistically significant (P = 0.05) increase in cell viability by 43.5%. However, incubation with narcissin had no significant hepatoprotective activity.

Conclusions: Vicenin-2 showed the most prominent cytotoxic effect at the highest tested concentration. Rutin in BFF had function for the observed protection against oxidative damage caused by the epirubicin. Therefore, B. flavum flavonoids are worth investigating for the potential development of agents against hepatocellular carcinoma.