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The failure to improve the five-year survival rate of cancer patients, from one in three in the 1960s to one in two in the 1970s, stimulated awareness of the importance of primary prevention of cancer. Korean investigators carried out extensive long-term anticarcinogenicity experiments with 2000 newborn mice to investigate whether Panax ginseng C.A. Meyer inhibited carcinogenesis induced by several chemical carcinogens in 1978. There was a 22% decrease (p<0.05) in the incidence of urethane induced lung adenoma by the combined use of red ginseng extract. In the group sacrificed at 56 weeks after the treatment with aflatoxin B1, the incidence of hepatoma significantly decreased to 75% by the addition of red ginseng extract (p<0.05). The result showed that natural products can provide hope for human cancer prevention. By the newly established '9 week medium-term anticarcinogenicity test model of lung tumors in mice' (Yun's model), we confirmed significant anticarcinogenic effects of powders and extracts of the 6- yr-old dried fresh ginseng, 5- and 6-yr old white ginsengs, and 4-, 5-, and 6-yr old red ginseng. We also demonstrated that the anticarcinogencity of ginseng was more prominent in aged or heat treated extracts of ginseng and red ginseng made by steaming. To investigate the active components for cancer prevention, several fractions of 6-yr old fresh ginseng and red ginseng, four semi-synthetic ginsenoside Rh1, Rh2, Rg3 and Rg5, major saponin components in red ginseng, were prepared. Among the ginsenosides, Rg3 and Rg5 showed statistically significant reduction of lung tumor incidence and Rh2 had a tendency of decreasing the incidence. Ginsenoside Rg3, Rg5 and Rh2 were found to be active anticarcinogenic compounds. Rg3, Rg5 and Rh2 are active components in red ginseng, and they prevent cancer either singularly or synergistically.

We examined the effects of the purified ginseng components, panaxadiol (PD) and panaxatriol (PT), on the expression of matrix metalloproteinase-9 (MMP-9) in highly metastatic HT1080 human fibrosarcoma cell line. A significant down-regulation of MMP-9 by PD and PT was detected by Northern blot analysis. However, the expression of MMP-2 was not changed by treatment with PD and PT. Quantitative gelatin based zymography confirmed a markedly reduced expression of MMP-9, but not MMP-2 in the treatment of PD and PT. To investigate whether the reduced level of MMP-9 by PD and PT affects the invasive capacity of HT1080 cells, we conducted an in vitro invasion assay with PD and PT treated cells. The results of the in vitro invasion assay revealed that PD and PT reduced tumor cell invasion through a reconstituted basement membrane in the transwell chamber. Because of the similarity of chemical structure between PD, PT and dexamethasone (Dexa), a synthetic glucocorticoid, we investigated whether the down-regulation of MMP-9 by PD and PT were mediated by the nuclear translocation of glucocorticoid receptor (GR). Increased GR in the nucleus of HT1080 human fibrosarcoma cells treated by PD and PT was detected by immunocytochemistry. Western blot and gel retardation assays confirmed the increase of GR in the nucleus after treatment with PD and PT. These results suggest that GR-induced down-regulation of MMP-9 by PD and PT contributes to reduce the invasive capacity of HT1080 cells.

In ginsenoside Rh2-treated rat glioma C6Bu-1 cells, apoptotic morphological changes, such as cell shrinkage, chromatin condensation and pyknosis were confirmed by means of electron microscopy. To evaluate whether induction of apoptosis by ginsenoside Rh2 is mediated by the members of Bcl-2 family, we first established C6Bu-1 cells overexpressing Bcl-2. It was demonstrated that the expression of Bcl-2, Bcl-xL and Bax was not altered in ginsenoside Rh2-treated C6Bu-1 cells. Bcl-2 overexpressing C6Bu-1 cells failed to prevent from ginsenoside Rh2-induced cell death. These results suggest the existence of other apoptotic pathway that requires induction of apoptosis by ginsenoside Rh2 rather than the pathway through Bcl-2, Bcl-xL or Bax in C6Bu-1 cells.

Ginseng sapogenins were produced from ginseng saponins, isolated from Korean ginseng roots. Ginseng saponins very mildly inhibited acyl-CoA:cholesterol acyltransferase (ACAT) in vitro, however, the sapogenins showed strong inhibitory activity on microsomal ACAT. Therefore, the sapogenins will be one of key ingredients of ginseng affected a lowering of the serum total cholesterol level.

Some analogues of Ginseng diyne were synthesized and tested for antiproliferative activity against L1210 cells. The epoxy moiety of panaxydol, isolated from the root of Panax ginseng, proved to be in the cis-form on comparison with synthetic specimens. Analysis of structure-activity relationship revealed that the presence of the heptadec-1-ene-4,6-diyn-3-ol moiety in the structure of the analogues was essential for their antiproliferative activity and that the epoxy and alkyl groups in the structure contributed to enhancement of the antiproliferative activity.

A new dammarane glycoside named ginsenoside Rf2 has been isolated from Korean red ginseng (Panax ginseng) and its chemical structure has been elucidated as 6-O-[alpha-L-rhamnopyranosyl (1-->2) beta-D-glucopyranosyl]dammarane-3 beta, 6 alpha, 12 beta, 20(R), 25-pentol by chemical and spectral methods.

The anticomplementary activity of ginseng saponins and their degradation products obtained by chemical treatment of Korean red ginseng saponins was investigated. The total saponin and its major components showed strong anticomplementary activity and their structure-activity relationship was evaluated.

Ginseng saponins and their degradation products have been screened for antagonist activity towards [3H]PAF (platelet activating factor) in washed rabbit platelet receptor binding studies. 20(S)- and delta20-ginsenosides Rg3, protopanaxadiol-type saponins, were found to be relatively potent PAF antagonists (IC50 = 4.9 x 10(-5) M and 9.2 x 10(-5) M, respectively).

Glycosylation of 12beta-acetoxy-dammar-24-en-3beta,20(S)-diol (4), with hepta-O-acetyl-alpha-sophorosyl bromide (5) under catalysis by Ag2CO3 or Ag2O afforded a chromatographically unseparated mixture of the alpha- and beta-linked octaacetates 6 and 7 in an approximately 2.5:1 ratio. After deprotection and chromatographic purification, the free alpha- (8) and beta-glycosides (9) were obtained. Sophoroside 9 was identical in all respects with ginsenoside Rg3, the minor component of Ginseng Radix rubra. All compounds were fully characterized by 1H and 13C NMR spectroscopy.

The involvement of ginsenosides in the signal cascade that stimulates cellular growth was investigated. It was found that ginsenosides Rh1 and Rh2 extracted from the root of Panax ginseng inhibited cellular proliferation in NIH 3T3 fibroblasts. Both ginsenosides Rh1 and Rh2 effectively reduced phospholipase C activity resulting in a decrease in the intracellular level of diacylglycerol, an endogenous activator of protein kinase C. The treatment of cells with Rh1 or Rh2 was thus found to reduce intracellular protein kinase C activity. We also observed that the phosphorylation of myristoylated alanine-rich C kinase substrate, one of the major substrates of protein kinase C in cells, was inhibited by the ginsenosides. Data suggest that the ginsenoside Rh1 or Rh2 exerts antiproliferative effects by inhibiting phospholipase C, which produces second messengers necessary for the activation of protein kinase C.

A possible role of cytochrome P450 (P450) inhibition by red ginseng saponins in carbon tetrachloride (CCl4)-induced lipid peroxidation was investigated in liver microsomes prepared from male Sprague Dawley rats. The total saponin of red ginseng standardized on ginsenosides-Rb1, -Rb2, -Rc, -Rd, -Re, and -Rg1 whose composition was studied in our previous report was used in the present study. The standardized saponin of red ginseng showed inhibitory effects on P450-associated monooxygenase activities in a dose-dependent manner, particularly p-nitrophenol hydroxylase activity which has been known to represent CCl4-activating P450 2E1 enzyme. Meanwhile, silymarin enhanced the activity of P450 2E1 enzyme in liver microsomes. When the lipid peroxidation was induced by incubating rat liver microsomes with CCl4 in the presence of NADPH, the standardized saponin significantly blocked the formation of thiobarbituric acid-reactive substances at the same concentrations showing P450 inhibition in liver microsomes. Silymarin revealed more potent protection against CCl4-induced lipid peroxidation. When the lipid peroxidation was induced by FeCl3, in which metabolic activation may not be required, only silymarin could protect the lipid peroxidation in liver microsomes. Taken together, our present results indicated that the inhibitory effects of red ginseng saponin on P450 enzymes may have a critical role in CCl4-induced lipid peroxidation in rat liver microsomes and that the mechanism of hepatoprotection by red ginseng saponin may be distinct from that of silymarin.

The protective effects of red ginseng saponins against carbon tetrachloride-induced hepatotoxicity were investigated in male Sprague Dawley rats. The total saponins of red ginseng standardized on ginsenosides-Rb1, -Rb2, -Rc, -Rd, -Re, and -Rg1 were used in the present study. The rats were administered the standardized saponins of red ginseng orally at 50, 100, and 200 mg/kg for 7 consecutive days, followed by an administration of carbon tetrachloride at 0.4 ml/kg in corn oil intraperitoneally for 24 h. The administration of saponin changed neither body and organ weights nor hematological and serum clinical parameters. The elevation of SGPT and SGOT activities induced by carbon tetrachloride was partially recovered by the administration of the saponin. The liver vacuolization and lymphoid cell aggregation by carbon tetrachloride were clearly recovered by the red ginseng saponins as examined histologically. The present results indicated that the standardized saponins of red ginseng used in these studies may partially recover the hepatotoxicity induced by carbon tetrachloride in male Sprague Dawley rats.

The aim of this study was to determine the ability of the ginsenosides, extracts of Panax ginseng C.A. Meyer, to cause differentiation of F9 teratocarcinoma stem cells as a model system. F9 stem cells cultured in the presence of the ginsenosides together with dibutyryl cyclic AMP (dbcAMP) became parietal endoderm-like cells. Moreover, the expression of differentiation marker genes, such as laminin B1 and type IV collagen, was increased after treatment with the ginsenosides. Among the various purified ginsenosides, Rh1 and Rh2 were the most effective at causing differentiation of F9 cells. Since ginsenosides and glucocorticoid hormone have similar chemical structures, we examined the possibility of the involvement of a glucocorticoid receptor (GR) in the differentiation process induced by the ginsenosides. According to Southwestern blot analysis, a 94 kDa protein regarded as a GR was detected in F9 cells cultured in the medium containing the ginsenosides Rh1 or Rh2. In addition, F9 stem cells treated with the ginsenosides Rh1 or Rh2 and with RU486, a glucocorticoid antagonist with a high affinity for the GR, did not differentiate into endoderm cells morphologically, and the expression of laminin B1 gene was not induced in these cells. In a gel mobility shift assay, protein factors capable of binding to the glucocorticoid responsive element (GRE) specifically were detected in nuclear extracts of the ginsenoside-treated F9 cells. Moreover, overexpression of GR by cotransfection of GR expression vector and GRE-luciferase vector enhanced the transactivation activity of GRE promoter in the presence of ginsenosides Rh1 or Rh2 and was further augmented by dbcAMP. In addition, ginsenosides Rh1 and Rh2 bound to a GR assessed by whole-cell binding assay, even though the specific binding affinity was weaker compared to dexamethasone. Based on these data, we suggest that the ginsenosides Rh1 and Rh2 cause the differentiation of F9 cells and the effects of ginsenosides might be exerted via binding with a GR or its analogous nuclear receptor.

A genuine glycoside, named ginsenoside Rh4, was isolated from Korean red ginseng (Panax ginseng C. A. Meyer) through repeated column chromatography, and its chemical structure was established to be 6-O-beta-D-glucopyranosyldammar-20(22),24-diene-3 beta,6 alpha,12 beta-triol by spectral and chemical methods. The stereochemistry of a double bond at C-20(22) of ginsenoside Rh4 was characterized as (E) from a NOESY experiment in the 1H-NMR of the aglycone. Cytotoxic activities of ginsenoside Rh4 and its aglycone against cancer cell lines were evaluated by use of the SRB method.

Two new polyines showing good cytotoxic activity against L1210 cells were isolated from Korean ginseng root. These were 3-acetyloxy-9,10-epoxy-heptadec-1-en-4,6-diyne(acet ylpanaxydol, ED50 = 0.52 microgram/ml) and 10-chloro-3,9-dihydroxyheptadec-1-en-4,6-diyne(Panaxydolc hlorohydrin, ED50 = 0.50 microgram/ml).