Panax Vietnamensis Research Articles

Cancer chemopreventive activity of majonoside-R2 from Vietnamese ginseng, Panaxvietnamensis

In the course of our continuing search for novel cancer chemopreventive agents from natural sources, several kinds of Panax plants were screened. Consequently, the ocotillol-type saponin, majonoside-R2 (MR2), was obtained from the rhizome and root of Panax vietnamensis (Vietnamese ginseng) as an active constituent. MR2 exhibited potent anti-tumor-promoting activity on two-stage carcinogenesis test of mouse hepatic tumor using N-nitrosodiethylamine (DEN) as an initiator and phenobarbital (PB) as a promoter. Further, MR2 exhibited the remarkable inhibitory effect on two-stage carcinogenesis test of mouse skin induced by nitric oxide (NO) donor/12- O-tetradecanoylphorbol-13-acetate (TPA) or peroxynitrite/TPA.

Anti-tumor-promoting activity of majonoside-R2 from Vietnamese ginseng, Panax vietnamensis Ha et Grushv. (I).

Seven saponins (1-7) isolated from the rhizomes and roots of Panax vietnamensis were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) induced by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), in Raji cells as a primary screening test for anti-tumor-promoters (cancer chemopreventive agents). The ocotillol-type saponin, majonoside-R2 (2), which is the major and characteristic constituent of this plant, exhibited a significant inhibitory effect on EBV-EA activation. Furthermore, the cell cycle analysis of 2 on Raji cells was also examined and strong inhibition was observed on the effect of the cell cycle induced by TPA. Compound 2 showed potent anti-tumor-promoting activity in two-stage carcinogenesis tests of mouse skin using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA or fumonisin B1 as a promoter. Consequently, these results suggest that majonoside-R2 (2) could be a valuable chemopreventive agent against chemical carcinogenesis.

Involvement of supraspinal GABA receptors in majonoside-R2 suppression of clonidine-induced antinociception in mice

Majonoside-R2 (MR2) is a major constituent of Vietnamese ginseng ( Panax vietnamensis, Ha et Grushv. Araliaceae) that is known to exhibit antagonistic activity against opioid-induced antinociception. In this study, we investigated the effect of MR2 on the antinociception caused in mice by the α2-adrenoceptor agonist clonidine, and elucidated the role of supraspinal GABAergic systems in this effect of MR2. The systemic administration of clonidine (0.5–2.5 mg kg , s.c.) dose-dependently suppressed the nociceptive response of mice in the tail-pinch and hot-plate tests. The intraperitoneal (i.p.), intracerebroventricular (i.c.v.) or intrathecal (i.t.) administration of idazoxan (a selective α2-adrenoceptor antagonist) significantly antagonized the antinociceptive effect of clonidine in both tests. MR2 administered systemically (1.5–6.2 mg kg , i.p.) or centrally (5–10 μg/mouse, i.c.v. or i.t) dose-dependently antagonized the clonidine (1 mg kg , s.c.)-induced antinociception in the tail-pinch test but not in the hot-plate test. The antagonistic effect of i.c.v. MR2 on the systemic clonidine-induced antinociception in the tail-pinch test was significantly reversed by i.c.v. administrations of the selective benzodiazepine receptor antagonist flumazenil (5 μg/mouse) and the GABA A antagonist picrotoxin (0.25 μg/mouse). These results suggest that the supraspinal GABA A/benzodiazepine receptors are involved in the antagonistic effect of MR2 on the clonidine-induced antinociception in the tail-pinch test in mice.

A Comparative Evaluation of Ginsenosides in Commercial Ginseng Products and Tissue Culture Samples Using HPLC

ABSTRACT A rapid, effective method for the determination of ginsenosides using reversed-phase high performance liquid chromatography (HPLC) was successfully developed and used to evaluate the ginsenoside content of more than 60 commercial ginseng products, roots, and tissue culture samples. The quality evaluations, using the major ginsenosides, Rg1, Re, Rf, Rb1, Rb2, Rc, and Rd as standards, included Panax ginseng C.A. Meyer (Chinese ginseng, Korean ginseng), Panax quinquefolius L. (American ginseng), and some products containing ginsenosides purportedly from Panax vietnamensis Ha et Grushu, Panax pseudoginseng Wall, and Gynostemma pentaphyllum Thunb Mak. The main ginsenosides, the panaxtriols and the panaxadiols, could be cleanly resolved in a single analysis. The various ginseng samples contain widely differing proportions of the constituent ginsenosides.

Saponins from Vietnamese ginseng, Panax vietnamensis Ha et Grushv. collected in central Vietnam. III.

Five new dammarane saponins derived from four new aglycones were isolated from the rhizomes and roots of Panax vietnamensis Ha et Grushv. On the basis of physicochemical and spectral evidence, the structures of these compounds were established as 6-O-beta-D-glucopyranosyl 20(S),25-epoxydammarane-3 beta,6 alpha,12 beta,24 alpha-tetrol (1), 6-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranosyl 20(S),25-epoxydammarane-3 beta,6 alpha,12 beta,24 alpha-tetrol (2), 6-O-beta-D-glucopyranosyl dammarane-3 beta,6 alpha,12 beta,20(S),24 xi,25-hexol (5), 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]-20-O-beta-D- glucopyranosyl dammarane-3 beta,12 beta,20(S),24 xi,25-pentol (8) and 6-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranosyl 20(S),24(S)-epoxydammarane-3 beta,6 alpha,12 beta,25 xi,26-pentol (10). The trivial names, vina-ginsenoside-R10, -R11, -R12, -R13 and -R14, respectively, were assigned to the new saponins.

Saponins from Vietnamese Ginseng, Panax vietnamensis HA et Grushv. Collected in central Vietnam. II.

Further investigation on the saponin composition of rhizomes and roots of Panax vietnamensis HA et GRUSHV. has resulted in the isolation and structural elucidation of seven new dammarane saponins named vina-ginsenosides-R3 (12), -R4 (11), -R5 (16), -R6 (17), -R7 (6), -R8 (20), -R9 (22), together with the identification of six known saponins including 20-gluco-ginsenoside-Rf (10), ginsenoside-Rc (4), notoginsenoside-R6 (9), quinquenoside-R1 (5), gypenoside XVII (2) and majoroside F1 (21). The structures of the novel saponins were established on the basis of chemical and spectral evidence. Vina-ginsenoside-R3 is the first naturally occurring glycoside of dammarenediol II, while vina-ginsenosides-R5 and -R6, two ocotillol-type saponins, are two other examples of saponins having the rare alpha-glucosyl linkage.

Saponins from Vietnamese ginseng, Panax vietnamensis Ha et Grushv. Collected in central Vietnam. I.

From rhizomes and roots of Panax vietnamensis Ha et Grushv., Araliaceae, commonly known as Vietnamese Ginseng, two new acetylate saponins named vina-ginsenoside-R1 (13) and vina-ginsenoside-R2 (15) were isolated. On the basis of chemical and spectral data, 13 was formulated as monoacetyl 24(S)-pseudo-ginsenoside-F11 and 15 was proved to be monoacetyl majonside-R2. Besides the two new saponins and beta-sitosteryl-3-O-beta-D-glucopyranoside, sixteen known saponins were also isolated and identified. Dammarane saponins:ginsenoside-Rh1 and 20(R)-ginsenoside-Rh1 (1), ginsenosides-Rg1 (2), -Re (3), -Rd (6), -Rb3 (7), -Rb2 (8), -Rb1 (9), pseudo-ginsenoside-RS1 (= monoacetyl ginsenoside-Re, 4), notoginsenosides-R1 (5) and -Fa (10). Ocotillol-type saponins:pseudo-ginsenoside-RT4 (11), 24(S)-pseudo-ginsenoside-F11 (12), majonosides-R1 (16) and -R2 (14). Oleanolic acid saponins:ginsenoside-Ro (= chikusetsusaponin V, 17) and hemsloside-Ma3 (18), a saponin previously isolated from a cucurbitaceous plant, Hemsleya macrosperma C. Y. Wu. Despite having large horizontally elongated rhizomes, the underground part of this plant contains mainly dammarane saponins and a small amount of oleanolic acid saponins. In addition, the yield of ocotillol-type saponins, especially majonoside-R2, is surprisingly very high (more than 5% and ca. half of the total yield of saponin). This characteristic saponin composition has made Vietnamese Ginseng an interesting species among Panax spp.