Synergistic interaction means that the effect of two chemicals taken together is greater than the sum of their separate effect at the same doses. Synergism among chemo drugs has a great clinical significance, meaning two synergistic chemo drugs can be adminstered at lower concentrations but still achieve an efficacy equal to or higher than that with individual use at a standard concentraction. Low concentration also means low percentage of side and adverse effects associated with chemo drugs.

The drugs that have been most effective as systemic chemo in liver cancer are doxorubicin (Adriamycin), 5-fluorouracil, and cisplatin. Also, cyclophosphamide is sometimes used for refractory liver cancers.

A research published on CHINESE TRADITIONAL AND HERBAL DRUGS in 2010 reported that protopanaxadiol (PPD) is able to exert synergistic effect with cyclophosphamide on liver cancer cells. Also, it’s anti-cancer activity is additive to other chemo drugs including 5-fluorouracil and cisplatin.

In the study, PPD and other chemo drugs (cyclophosphamide, 5-fluorouracil, cisplatin) were added to liver cancer cells (Bel-7402、SMMC-7721) alone or in combination, and the growth curve was depicted to assess the anti-cancer activity. When PPD was added with cyclophosphamide, the inhibition of cancer cell growth were significantly increased on two types of liver cancer cells (Bel-7402、SMMC-7721), and greater than the simple addition of both activities. An additive effect of PPT and 5-fluorouracil was observed on these two types of liver cancer cells. Interestingly, the mild synergism between PPD and cisplatin was observed on SMMC-7721 liver cancer cells and a simple additive effect on Bel-7402 liver cancer cells.

Above results suggest PPT can be a potential drug to enhance the chemo response in liver cancer patients. Especially, when cyclophosphamide is considered to be the drug of choice for liver cancer, the use of PPD will deliver greater benefit to patients.