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PubMed1991

Mechanism of action of ginsenoside Rh2: uptake and metabolism of ginsenoside Rh2 by cultured B16 melanoma cells.

The uptake and metabolism of ginsenoside Rh2 (Rh2) by B16 melanoma cells were studied. In a medium containing 2% fetal calf serum, the uptake of Rh2 reached a maximum of 3 nmol/10(6) cells at 3-6 h after Rh2 (12.5 microM) was added, but gradually decreased to 0.8 nmol/10(6) cells. In these cells, protopanaxadiol (PPD), which is an aglycon of Rh2, increased inversely with the decrease in Rh2 as a result of deglycosylation by the cells. When PPD (8 microM) was added to the medium, the uptake reached a plateau of 2.4 nmol/10(6) cells, within 0.5 h. The association constant of Rh2 (1.74 +/- 1.08 x 10(6) M-1) for bovine serum albumin (BSA) was significantly higher than that of PPD (9.90 +/- 1.10 x 10(4) M-1). In a serum-free medium, both Rh2 and PPD were incorporated within 1.5 h. The uptake rate constant of Rh2 (1.20 +/- 0.20 h-1) was not significantly different from that of PPD (1.02 +/- 0.15 h-1), but the release rate constant of PPD (2.12 +/- 0.38 h-1) was significantly lower than that of Rh2 (3.03 +/- 0.57 h-1). These differences in affinity for BSA and the release rate constants were thought to be the cause of the difference in uptake kinetics between these drugs. The effects of Rh2 and PPD on the cells were identical, and there was no difference in the lag periods before the appearance of their effects, despite their differing rates of uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Detection and quantification of ginsenoside Re in ginseng samples by a chromatographic immunostaining method using monoclonal antibody against ginsenoside Re.

A chromatographic immunostaining method has been developed for the determination of ginsenoside Re (G-Re) in ginseng samples on a polyethersulphone (PES) membrane. G-Re standard and the extracts of ginseng roots were applied to a PES membrane and developed by methanol-water-acetic acid (45:55:1, by volume). G-Re was clearly detected by an immunostaining method using a monoclonal antibody against G-Re. The coloring spots of G-Re were analyzed quantitatively using NIH Image software indicating at least 0.125 microg of G-Re was detectable. G-Re can be analyzed quantitatively between 0.25 and 4.0 microg.

Animals↗
PubMed2000

Metabolism of ginsenoside Rg1 by intestinal bacteria. II. Immunological activity of ginsenoside Rg1 and Rh1.

AIM: To compare the effect of ginsenoside Rg1 and its metabolite Rh1 on proinflammatory cytokines and their mRNA expression by THP-1 cells. METHODS: Human peripheral blood mononuclear cells (PBMC) were incubated with Rg1 and Rh1 at concentrations of 0.1, 1, 10, and 100 mg/L, and the cell proliferation was measured 24 h after incubation. Radioimmunoassay (RIA) was used to detect the production of proinflammatory cytokines, TNF alpha, IL-1 alpha, and IL-8. TNF alpha mRNA level was detected by reverse transcription polymerase chain reaction (RT-PCR) after administration of Rg1 and Rh1. RESULTS: Rg1 and Rh1 (at concentration of 0.1, 1, 10, 100 mg/L) had no effect on PBMC proliferation. Rh1 1 mg/L could upregulate the productions of TNF (and IL-8 induced by lipopolysaccharides (LPS) 10 mg/L plus phorbol myristate acetate (PMA) 200 nmol/L, however, Rg1 showed an inhibitory effect on TNF alpha production induced by LPS 100 mg/L. Rg1 1 mg/L and Rh1 100 mg/L enhanced the production of IL-1 alpha level in THP-1 cells in the presence of LPS 10 mg/L. RT-PCR revealed that Rh1 stimulated TNF alpha mRNA expression in suitable stimulatory conditions. CONCLUSION: Rg1 and Rh1 have different effects on the production of cytokines produced THP-1 cells stimulated by LPS and PMA.

Ginsenosides↗
PubMed2001

Effects of ginsenosides from Panax ginseng on cell-to-cell communication function mediated by gap junctions.

Gap junctions have been shown or are believed to be involved in the pathogenesis of many inherited and acquired human diseases. Agents that regulate the gap junction-mediated intercellular communication (GJIC) function may facilitate prevention and treatment of GJIC-involved diseases. In the present study we examined the effects of 27 ginsenosides isolated from Panax ginseng on GJIC. The results show that compounds 1 (oleanolic acid), 2 (ginsenoside-R0), 3 (ginsenoside-Rb1), 5 (ginsenoside-Rb2), 7 (ginsenoside-Rd), 8 (ginsenoside-Rg3), 12 (panaxadial), 13 (notoginsenoside-R4), 17 [ginsenoside-Rg2 (20S)], 18 (ginsenoside-Rf), and 26 (ginsenoside-F3) did not obviously affect GJIC, whereas compounds 4 (ginsenoside-Rc), 6 (ginsenoside-Rb3), 9 (ginsenoside-Rd2), 10 (notoginsenoside-Fe), 11 (ginsenoside-Rh2),14 (ginsenoside-Ra1), 15 (ginsenoside-Re), 16 [ginsenoside-Rg2 (20R)], 19 (ginsenoside-Ia), 20 [ginsenoside-Rh1 (20S)], 21 [ginsenoside-Rh1 (20R)], 22 (ginsenoside-F1), 23 (protopanaxatriol), 24 (panaxatriol), 25 (ginsenoside-Rg1), and 27 (chikusetsaponin-L8) induced GJIC reductions at various degrees. Compounds 2, 7, and 8 protected against the tyrosine phosphatase inhibitor vanadate-induced GJIC reduction, while compounds 1, 5, 7, and 17 inhibited the cytokine interleukin 1 alpha (IL-1alpha)-induced reduction in GJIC. Nevertheless, no compounds protected against the protein kinase C (PKC) activator 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced GJIC inhibition. On the other hand, GJIC reductions induced by compounds 6, 9,10, 20, 21, 22, 24, and 25 were inhibited by the tyrosine kinase (TK) inhibitor genistein, while GJIC reductions induced by compounds 6, 9, 14, 16, 19, 21, and 24 were attenuated in the presence of the PKC inhibitor calphostin C. However, GJIC reductions induced by compounds 4, 23, and 27 were not inhibited either by genistein or by calphostin C. These data indicate that various mechanisms are responsible for effects of ginsenosides on GJIC.

Cell Communication↗
PubMed2005

Metabolism of ginsenoside Re by human intestinal microflora and its estrogenic effect.

To understand the relationship between the metabolism and biological activity of ginsenoside Re, a main protopanaxatriol saponin in Panax ginseng C. A. MEYER, its metabolic pathway and estrogenic effect by human intestinal microflora were investigated. All human fecal specimens metabolized ginsenoside Re, mainly to ginsenoside Rh1 and ginsenoside F1, via ginsenoside Rg1, with protopanaxadiol as a minor component. Almost all isolated ginsenoside Re-metabolizing intestinal bacteria (GHIB) also metabolized ginsenoside Re, mainly to ginsenosides Rh1 and F1, via ginsenoside Rg1. Alpha-Rhamnosidase and beta-glucosidase, partially purified from the most potent GHIB, Bacteroides JY-6, hydrolyzed ginsenoside Re and ginsenoside Rg1, respectively; however, they did not hydrolyze ginsenosides Rh1 and F1. These findings suggest that the ginsenosides Rh1 and/or F1 may not be suitable substrates of intestinal bacteria, particularly Bacteroides JY-6. The estrogenic effects of ginsenoside Re and its main metabolites, ginsenosides Rg1 and Rh1, were also investigated. Ginsenoside Rh1 showed the greatest estrogenic effect in human breast carcinoma MCF-7 cells. Based on these findings, the estrogenic effect of ginsenoside Re may be expressed by intestinal microflora.

Bacteroides↗
PubMed2004

Transformation of ginseng saponins to ginsenoside Rh2 by acids and human intestinal bacteria and biological activities of their transformants.

When ginseng water extract was incubated at 60 degrees C in acidic conditions, its protopanaxadiol ginsenosides were transformed to ginsenoside Rg3 and delta20-ginsenoside Rg3. However, protopanaxadiol glycoside ginsenosides Rb1, Rb2 and Rc isolated from ginseng were mostly not transformed to ginsenoside Rg3 by the incubation in neutral condition. The transformation of these ginsenosides to ginsenoside Rg3 and delta20-ginsenoside Rg3 was increased by increasing incubation temperature and time in acidic condition: the optimal incubation time and temperature for this transformation was 5 h and 60 degrees C resepectively. The transformed ginsenoside Rg3 and delta20-ginsenoside Rg3 were metabolized to ginsenoside Rh2 and delta20-ginsenoside Rh2, respectively, by human fecal microflora. Among the bacteria isolated from human fecal microflora, Bacteroides sp., Bifidobacterium sp. and Fusobacterium sp. potently transformed ginsenoside Rg3 to ginsenoside Rh2. Acid-treated ginseng (AG) extract, fermented AG extract, ginsenoside Rh2 and protopanaxadiol showed potent cytotoxicity against tumor cell lines. AG extract, fermented AG extract and protopanaxadiol potently inhibited the growth of Helicobacter pylori.

Animals↗
PubMed2002

Metabolism of 20(S)- and 20(R)-ginsenoside Rg3 by human intestinal bacteria and its relation to in vitro biological activities.

When ginsenoside Rg3 was anaerobically incubated with human fecal microflora, all specimens metabolized ginsenoside Rg3 to ginsenoside Rh2 and protopanaxadiol. The main metabolite was ginsenoside Rh2. 20(S)-ginsenoside Rg3 was quickly transformed to 20(S)-ginsenoside Rh2 or 20(S)-protopanaxadiol in an amount 19-fold that compared with the transformation of 20(R)-ginsenoside Rg3 to 20(R)-ginsenoside Rh2 or 20(R)-protopanaxadiol. Among the bacteria isolated from human fecal microflora, Bacteroides sp., Eubacterium sp., and Bifidobacterium sp. metabolized ginsenoside Rg3 to protopanaxadiol via ginsenoside Rh2. However, Fusobacterium sp. metabolized ginsenoside Rg3 to ginsenoside Rh2 alone. Among ginsenoside Rg3 and its metabolites, 20(S)-protopanaxadiol and 20(S)-ginsenoside Rh2 exhibited the most potent cytotoxicity against tumor cell lines, 20(S)- and 20(R)-protopanaxadiols potently inhibited the growth of Helicobacter pylori, and 20(S)-ginsenoside Rh2 inhibited H+/K+ ATPase of rat stomach.

Animals↗
PubMed2005

In vitro metabolism of ginsenosides by the ginseng root pathogen Pythium irregulare.

The role of ginseng saponins (ginsenosides) as modulators or inhibitors of disease is vague, but our earlier work supports the existence of an allelopathic relationship between ginsenosides and soilborne microbes. Interestingly, this allelopathy appears to significantly promote the growth of the important ginseng pathogen, Pythium irregulare while inhibiting that of an antagonistic non-pathogenic fungus, Trichoderma hamatum. Herein we report on the apparent selective metabolism of 20(S)-protopanaxadiol ginsenosides by an extracellular glycosidase from P. irregulare. Thus, when P. irregulare was cultured in the presence of a purified (> 90%) ginsenoside mixture, nearly all of the 20(S)-protopanaxadiol ginsenosides (Rb1, Rb2, Rc, Rd, and to a limited extent G-XVII) were metabolized into the minor ginsenoside F2, at least half of which appears to be internalized by the organism. No metabolism of the 20(S)-protopanaxatriol ginsenosides (Rg1 and Re) was evident. By contrast, none of the ginsenosides added to the culture medium of the non-pathogenic fungus T. hamatum were metabolized. The metabolism of 20(S)-protopanaxadiol ginsenosides by P. irregulare appears to occur through the hydrolysis of terminal monosaccharide units from disaccharides present at C-3 and/or C-20 of ginsenosides Rb1, Rc, Rb2, Rd and G-XVII to yield one major product, ginsenoside F2 and one minor product (possibly G-III). A similar transformation of ginsenosides was observed using a crude protein preparation isolated from the spent medium of P. irregulare cultures.

Carbohydrate Sequence↗
PubMed2003

Prevention of ginsenoside-induced desensitization of Ca2+-activated Cl- current by microinjection of inositol hexakisphosphate in Xenopus laevis oocytes: involvement of GRK2 and beta-arrestin I.

We demonstrated that ginsenosides, the active ingredient of Panax ginseng, enhance endogenous Ca(2+)-activated Cl(-) currents via Galpha(q/11)-phospholipase C-beta3 pathway in Xenopus laevis oocytes. Moreover, prolonged treatment of ginsenosides induced Cl(-) channel desensitization. However, the molecular mechanisms involved in ginsenoside-induced Cl(-) channel desensitization have not yet been determined precisely. To provide answers to these questions, we investigated the changes in ginsenoside-induced Cl(-) channel desensitization after intraoocyte injection of inositol hexakisphosphate (InsP(6)), which is known to bind beta-arrestins and interfere with beta-arrestin-induced receptor down-regulation, and cRNAs coding beta-arrestin I/II and G-protein receptor kinase 2 (GRK2), which is known to phosphorylate G protein-coupled receptors and attenuate agonist stimulations. When control oocytes were stimulated with ginsenosides, the second, third, and fourth responses to ginsenosides were 69.6 +/- 4.1, 9.2 +/- 2.3, and 2.6 +/- 2.2% of the first responses, respectively. Preintraoocyte injection of InsP(6) before ginsenoside treatment restored ginsenoside effect to initial response levels in a concentration-, time-, and structurally specific manner, in that inositol hexasulfate had no effect. The EC(50) was 13.9 +/- 8.7 microM. Injection of cRNA coding beta-arrestin I but not beta-arrestin II blocked InsP(6) effect on prevention of ginsenoside-induced Cl(-) channel desensitization. Injection of cRNA coding GRK2 abolished ginsenoside effect enhancing Cl(-) current. However, the GRK2-caused loss of ginsenoside effect on Cl(-) current was prevented by coinjection of GRK2 with GRK2-K220R, a dominant-negative mutant of GRK. These results indicate that ginsenoside-induced Cl(-) channel desensitization is mediated via activation of GRK2 and beta-arrestin I.

Animals↗
PubMed1998

Intestinal bacterial hydrolysis is required for the appearance of compound K in rat plasma after oral administration of ginsenoside Rb1 from Panax ginseng.

Ginsenoside Rb1 from Panax ginseng root is transformed into compound K via ginsenosides Rd and F2 by intestinal bacterial flora. Among 31 defined intestinal strains from man, only Eubacterium sp. A-44 transformed ginsenoside Rb1 into compound K via ginsenoside Rd. The ginsenoside Rb1-hydrolysing enzyme isolated from Eubacterium sp. A-44 was identical to a previously purified geniposide-hydrolysing beta-D-glucosidase. When ginsenoside Rb1 (200 mg kg-1) was administered orally to germ-free rats, neither compound K nor any other metabolite was detected in the plasma, intestinal tract or cumulative faeces 7 or 15 h after administration. Most of the ginsenoside Rb1 administered was recovered from the intestinal tract, especially the caeca, and cumulative faeces indicating poor absorption of ginsenoside Rb1. When ginsenoside Rb1 was administered orally to gnotobiote rats mono-associated with Eubacterium sp. A-44, a significant amount of compound K was detected in the plasma and considerable amounts were found in the caecal contents and cumulative faeces 7 and 15 h after administration. A small amount of ginsenoside Rb1 was detected in the caecal contents only 7 h after administration. These results indicate that orally administered ginsenoside Rb1 is poorly absorbed from the gut but that its metabolite compound K, produced by ginsenoside Rb1-hydrolysing bacteria such as Eubacterium sp. A-44 in the lower part of intestine, is absorbed.

Administration, Oral↗
PubMed2003

Effects of ginsenosides on glycine receptor alpha1 channels expressed in Xenopus oocytes.

Ginsenosides, major active ingredients of Panax ginseng, are known to regulate the excitatory ligand-gated ion channel activity. Recent reports showed that ginsenosides attenuate nicotinic acetylcholine and NMDA receptor channel activity. However, it is not known whether ginsenosides also affect the inhibitory ligand-gated ion channel activity. We investigated the effect of ginsenosides on human glycine alpha1 receptor channel activity expressed in Xenopus oocytes using a two-electrode voltage clamp technique. Treatment of ginsenoside Rf enhances glycine-induced inward peak current (IGly) with dose dependent and reversible manner but ginsenoside Rf itself did not elicit membrane currents. The half-stimulatory concentrations (EC50) of ginsenoside Rf was 49.8 +/- 8.9 microM. Glycine receptor antagonist strychnine completely blocked the inward current elicited by glycine plus ginsenoside Rf. Cl- channel blocker 4,4'-disothiocyanostilbene-2,2'-disulfonic acid (DIDS) also blocked the inward current elicited by glycine plus ginsenoside Rf. We also tested the effect of eight individual ginsenosides (i.e., Rb1, Rb2, Rc, Rd, Re, Rg1, Rg2, and Ro) in addition to ginsenoside Rf. We found that five of them significantly enhanced the inward current induced by glycine with the following order of potency: Rb1 > Rb2 > Rg2 > or = Rc > Rf > Rg1 > Re. These results indicate that ginsenosides might regulate gylcine receptor expressed in Xenopus oocytes and this regulation might be one of the pharmacological actions of Panax ginseng.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1980

American ginseng. III. Pharmacokinetics of ginsenosides in the rabbit.

The pharmacokinetics of ginsenosides A1, A2, B2, and C were studied in rabbits and were best described with a one-component open model. Ginsenoside C (protopanaxadiol group ginseng saponin) showed a significantly longer half-life, higher plasma protein binding, and lower metabolic and renal clearance than ginsenosides A1, A2, and B2 (protopanaxatriol group ginseng saponins). All ginsenosides except ginsenoside A1 were slowly absorbed after intraperitoneal administration. Ginsenosides were not found in rabbit plasma or urine samples after oral administration. The observed differences in the pharmacokinetics of the ginsenosides may be ascribed to differences in protein binding. Ginsenoside C was more toxic than ginsenoside A2 after intraperitoneal administration to mice. Toxicity was not observed after oral administration of any of the ginsenosides. The genins, panaxadiol and panaxatriol, were more toxic and had larger volumes of distribution than the ginsenosides.

Animals↗
PubMed2006

Simultaneous enantiomer determination of 20 (R)- and 20 (S)-ginsenoside-Rg2 in rat plasma after intravenous administration using HPLC method.

20 (R,S)-Ginsenoside-Rg2, an anti-shock agent, is prescribed as a racemate. To analyze simultaneously the enantiomers of 20 (R)-ginsenoside-Rg2 and 20 (S)-ginsenoside-Rg2 in plasma, a simple and reproducible high-performance liquid chromatographic (HPLC) method has been developed. The enantiomeric separation and determination were successfully achieved using a Diamonsil ODS C18 reversed-phase column (5 microm, 250 mm x 4.6 mm) with an RP18 (5 microm) guard column and a mobile phase of MeOH-aq. 4% H3PO4 (65:35, v/v, pH 5.1) with UV detection at 203 nm. Both enantiomers, 20 (R)-ginsenoside-Rg2 and 20 (S)-ginsenoside-Rg2, were well separated at 14.5 min and 13.6 min, respectively. The linear ranges of the standard curves were 2.0-250 microg/ml. The intra- and inter-day precision (R.S.D.) were <or=1.59% and <or=0.54% and the mean extraction recoveries were 95.8% and 96.5% for 20 (R)-ginsenoside-Rg2 and 20 (S)-ginsenoside-Rg2 in rat plasma, respectively. The limits of detection and quantification were 2.0 microg/ml and 7.8 microg/ml (S/N=3:1) for 20 (R)-ginsenoside-Rg2, and 2.0 microg/ml and 3.9 microg/ml (S/N=3:1) for 20 (S)-ginsenoside-Rg2, respectively. This validated method was applicable to pharmacokinetic studies in rat plasma after intravenous administration of 20 (R,S)-ginsenoside-Rg2. A pharmacokinetic study in rat plasma indicated that the enantiomers were rapidly absorbed and eliminated. These assay results are necessary for the evaluation of the metabolism of ginsenoside-Rg2 in vivo.

Animals↗
PubMed2006

Inhibitory effects of Korean red ginseng and its genuine constituents ginsenosides Rg3, Rf, and Rh2 in mouse passive cutaneous anaphylaxis reaction and contact dermatitis models.

The inhibitory effects of the Korean red ginseng (steamed root of Panax ginseng C.A. MEYER, family Araliaceae) saponin fraction (KRGS) and its constituents ginsenosides Rg3, Rf, and Rh2 in mouse passive cutaneous anaphylaxis (PCA) and contact dermatitis models were measured. Orally administered KRGS and its genuine ginsenosides potently inhibited the PCA reaction induced by IgE. However, when these ginsenosides were intraperitoneally administered, ginsenoside Rh2 showed the most potent inhibition. The ginsenoside Rh2 also the most potently inhibited the beta-hexosaminidase release from RBL-2H3 cells induced by IgE with antigen. KRGS administered topically at a dose of 0.1% suppressed ear swelling in an oxazolone-induced mouse contact dermatitis model by 38.8%. Its constituents ginsenosides Rg3, Rf, and Rh2 at a concentration of 0.05% also potently suppressed mouse ear swelling by 47.5%, 34.8%, and 49.9% at 16 d, respectively. These ginsenosides also significantly reduced mRNA expression levels of cyclooxygenase (COX)-2, interleukin (IL)-1beta, tumor necrosis factor-alpha and interferon-gamma induced by oxazolone applied to mouse ears. However, the ginsenosides, except for ginsenoside Rh2, almost did not notably reduce IL-4 levels. The ginsenoside Rh2 also potently inhibited COX-2 and inducible NO synthetase protein expression in liphopolysaccharide-stimulated RAW264.7 cells. Based on these findings, KRGS and its ginsenosides are suggested to improve atopic and contact dermatitis by regulating expression of cytokines.

Animals↗
PubMed1991

[Studies on antinephritic effects of plant components in rats (2): Effects of ginsenosides on original-type anti-GBM nephritis in rats and its mechanisms].

To clarify the antinephritic effects of ginsenosides, we investigated the effects of crude ginsenoside and ginsenosides Rg1 and Rb1 on original-type anti-GBM nephritis in rats. Crude ginsenoside at 1.0 mg and 5.0 mg/kg, i.p., and ginsenoside Rg1 at 1.0 mg/kg, i.p., prevented urinary protein excretion and elevation of serum cholesterol content, as well as histopathological changes such as hypercellularity and adhesion. On the other hand, ginsenoside Rb1 only inhibited the histopathological parameters. In order to clarify the antinephritic mechanisms of ginsenosides on this model, we investigated the effect of ginsenosides on platelet aggregation and renal blood flow. Crude ginsenoside markedly enhanced the renal blood flow. Ginsenoside Rg1 inhibited the platelet aggregation in vivo and enhanced the renal blood flow on the 1st day. These results suggest that crude ginsenoside and Rg1 exert their antinephritic action via increased renal blood flow.

Animals↗
PubMed2006

Analytical application of acetate anion in negative electrospray ionization mass spectrometry for the analysis of triterpenoid saponins--ginsenosides.

Ginsenosides containing different numbers of glycosyl groups can be easily differentiated based on the formation of characteristic ginsenoside-acetate adduct anions and deprotonated ginsenosides generated by electrospray ionization (ESI) of methanolic solutions of ginsenosides (M) and ammonium acetate (NH4OAc). Ginsenosides containing two glycosyl groups gave a characteristic mass spectral pattern consisting of [M+2OAc]2-, [M-H+OAc]2- and [M-2H]2- ions with m/z values differing by 30 Th, while this mass spectral pattern was not observed for ginsenosides containing one glycosyl group. Formation of [M+2OAc]2- was influenced by the chain length of glycosyl groups and was used to differentiate the ginsenosides containing different combinations of monosaccharide and disaccharide units in the glycosyl groups. Under identical collisional activation conditions, [M+OAc]-, [M-H+OAc]2- and [M+2OAc]2- underwent proton abstractions predominantly to generate [M-H]-, [M-2H]2- and [M-H+OAc]2- ions, respectively. The ion intensity ratios, I[M-H](-/I) [M+OAc]-, I[M-2H](2-/I) [M-H+2OAc]2- and I[M-H+OAc](2-/I) [M+OAc]2-, being sensitive to the structural differences of ginsenosides, could differentiate the isomeric ginsenosides, including (i) Rf, F11 and Rg1, (ii) Rd and Re, and (iii) Rb2 and Rc. Additionally, NH4OAc was found to enhance the sensitivity of detection of ginsenosides in the form of [M-H]- down to the femtomole level.

Acetates↗
PubMed2003

Effects of ginsenosides on GABA(A) receptor channels expressed in Xenopus oocytes.

Ginsenosides, major active ingredients of Panax ginseng, are known to regulate excitatory ligand-gated ion channel activity such as nicotinic acetylcholine and NMDA receptor channel activity. However, it is not known whether ginsenosides affect inhibitory ligand-gated ion channel activity. We investigated the effect of ginsenosides on human recombinant GABA(A) receptor (alpha1beta1gamma2S) channel activity expressed in Xenopus oocytes using a two-electrode voltage-clamp technique. Among the eight individual ginsenosides examined, namely, Rb1, Rb2, Rc, Rd, Re, Rf, Rg1 and Rg2, we found that Rc most potently enhanced the GABA-induced inward peak current (I(GABA)). Ginsenoside Rc alone induced an inward membrane current in certain batches of oocytes expressing the GABA(A) receptor. The effect of ginsenoside Rc on I(GABA) was both dose-dependent and reversible. The half-stimulatory concentration (EC50) of ginsenoside Rc was 53.2 +/- 12.3 microM. Both bicuculline, a GABA(A) receptor antagonist, and picrotoxin, a GABA(A) channel blocker, blocked the stimulatory effect of ginsenoside Rc on I(GABA). Niflumic acid (NFA) and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), both Cl- channel blockers, attenuated the effect of ginsenoside Rc on I(GABA). This study suggests that ginsenosides regulated GABA(A) receptor expressed in Xenopus oocytes and implies that this regulation might be one of the pharmacological actions of Panax ginseng.

Animals↗