Antitumoral Activity of (20R)- and (20S)-Ginsenoside Rh2 on Transplanted Hepatocellular Carcinoma in Mice

Hepatocellular carcinoma is one of the leading causes of malignancy-related death in China. Its therapy in clinics is a big challenge. Ginsenoside Rh2 is one of the most notable cancer-preventing components from red ginseng and it has been reported that ginsenoside Rh2 exhibited potent cytotoxicity against human hepatoma cells. Rh2 exists as two different stereoisomeric forms, (20S)-ginsenoside Rh2 and (20R)-ginsenoside Rh2. Previous reports showed that the Rh2 epimers demonstrated different pharmacological activities and only (20S)-ginsenoside Rh2 showed potent proliferation inhibition on cancer cells in vitro. However, the in vivo anti-hepatoma activity of (20R)-ginsenoside Rh2 and (20S)-ginsenoside Rh2 has not been reported yet. This work assessed and compared the anti-hepatoma activities of (20S)-ginsenoside Rh2 and (20R)-ginsenoside Rh2 using H22 a hepatoma-bearing mouse model in vivo. In addition, hematoxylin and eosin staining, the deoxynucleotidyl transferase dUTP nick-end labeling assay, and the semiquantitative reverse transcriptase polymerase chain reaction method were used to further study the apoptosis of the tumors. The results showed that both (20S)-ginsenoside Rh2 and (20R)-ginsenoside Rh2 suppressed the growth of H22 transplanted tumors in vivo, and the highest inhibition rate could be up to 42.2 and 46.8 %, respectively (p < 0.05). Further, hematoxylin/eosin staining and the deoxynucleotidyl transferase dUTP nick-end labeling assay indicated that both (20R)-ginsenoside Rh2 and (20S)-ginsenoside Rh2 could induce H22 hepatoma tumor cell apoptosis, with apoptosis indexes of 3.87 %, and 3.80 %, respectively (p < 0.05). Moreover, this effect was accompanied by downregulating the level of Bcl-2 mRNA. In conclusion, both (20S)-ginsenoside Rh2 and (20R)-ginsenoside Rh2 can suppress the growth of H22 hepatomas without causing severe side effects, and this effect is associated with the induction of apoptosis.