Experimental and epidemiological evidence on non-organ specific cancer preventive effect of Korean ginseng and identification of active compounds.

Panax ginseng C.A. Meyer has been the most highly recognized medicinal herb in the Orient. The prolonged administration of red ginseng extract significantly inhibits the incidence of hepatoma and also proliferation of pulmonary tumors induced by aflatoxin B(1) and urethane. Statistically significant anticarcinogenic effects were in aged or heat treated extracts of ginseng and red ginseng made by steaming in a 9 weeks medium-term anticarcinogenicity test using benzo[a]pyrene. In case-control studies, odds ratios (OR) of the cancer of lip, oral cavity and pharynx, larynx, lung, esophagus, stomach, liver, pancreas, ovary, and colorectum were significantly reduced. As to the type of ginseng, the ORs for cancer were reduced in user of fresh ginseng extract intakers, white ginseng extract, white ginseng powder, and red ginseng. In a cohort study with 5 years follow-up conducted in a ginseng cultivation area, ginseng users had a decreased relative risk (RR) compared with non-users. The relative risks (RRs) of ginseng users were decreased in gastric cancer and lung cancer. These findings strongly suggest that Panax ginseng C.A. Meyer cultivated in Korea has non-organ specific cancer preventive effects against various cancers. To investigate the active components for cancer prevention, several fractions of fresh and red ginseng and four semi-synthetic ginsenoside Rh(1), Rh(2), Rg(3) and Rg(5), the major saponin components in red ginseng, were prepared among the ginsenosides. By using Yun's model, Rg(3) and Rg(5) showed statistically significant reduction of lung tumor incidence and Rh(2) had a tendency to decrease the incidence. In conclusion, these results strongly suggested that Panax ginseng C.A. Meyer cultivated in Korea is a non-organ specific cancer preventive against human cancers and also indicated that the anticarcinogenicity or human cancer preventive effect of Panax ginseng is due to ginsenoside Rg(3), Rg(5) and Rh(2).