The ethyl acetate extract of PGP ( Phellinus linteus grown on Panax ginseng) suppresses B16F10 melanoma cell proliferation through inducing cellular differentiation and apoptosis

Phellinus linteus and Panax ginseng have been widely used as traditional herbal medicines to treat various diseases including cancer in East Asia. The present study sought to investigate the possible mechanism in anti-proliferative effect of Phellinus linteus that was grown on Panax ginseng (PGP) on B16F10 melanoma cells. The anti-proliferative effect of PGP on B16F10 was evaluated by CCK-8 assays. Apoptotic cells were detected by flow cytometry analysis. The proteins involved in apoptosis and cellular differentiation were assessed by immunoblot analysis. Ginsenosides contents of PG or PGP were analyzed using HPLC. The ethyl acetate fraction (EtOAc) of PGP exhibited the strongest anti-proliferative activity among PGP fractions (butanol or water) on B16F10 cells. PGP EtOAc extract showed stronger inhibitory effect than Panax ginseng (PG) or Phellinus linteus (PL) EtOAc extract on B16F10 melanoma cell proliferation. PGP EtOAc extract induced the dendrite-like structures and the melanin production in B16F10 cells. PGP EtOAc extract increased a sub-G1 cell population through inducing p53/p21 and activated caspase-8 protein expression in B16F10 cells. Notably, PGP EtOAc extract contained ginsenosides Rd, Rg3, Rb2, Rg1 and Rb1 more than PG EtOAc extract. Rd and Rg3 significantly inhibited B16F10 cell proliferation. Our data suggest that PGP EtOAc extract inhibits B16F10 cell proliferation through inducing apoptosis and cellular differentiation.