Dammarane saponin

Besso, H., Kasai, R., Saruwatari, Y., Fuwa, T., and Tanaka, O. (1982). Ginsenoside-Raj and ginsenoside-Ra2, new dammarane saponins of ginseng roots. Chem. Pharm. Bull. 30, 2380-2385. 

Kuwahara, M., Kawanishi, F., Komiya, T., and Oshio, H. (1989). Dammarane saponins of Gynostemma pentaphyllum Makino and isolation of malonylginsenosides-Rbl,- Rd, and malonylgypenoside V. Chem. Pharm. Bull. 37,135-139. 

Tanaka, O., and Yahara, S. (1978). Dammarane saponins of leaves of Panax pseudo-ginseng subsp. himalaicus. Phytochemistry 17,1353-1358. 

Ginsenosides, notoginsenosides Dammarane saponins Panax notoginseng Analytical RPC ELSD, MS SPE, IR, 1H-, and 13C-NMR 168... 

Key Word Index—Vietnamese ginseng, Panax vielmmensis, dammarane saponins, vina-ginsenosides- R15 — R24. 

In our previous papers, we reported the identification and structure elucidation of twenty-four known saponins and fourteen new saponins named vina-ginsenosides -R1 — R14 which were isolated from the underground part of P. vietnamensis. We now summarize the result of our further study on the saponin composition of Vietnamese ginseng, which led to the isolation and structure elucidation of two known saponins, pseudo-ginsenoside-RCi (1) and gypenoside-IX (2), and ten new dammarane saponins named vina-ginsenosides-Rl5 — R24 (3 -12, respectively). 

Figure 2. Known Dammarane Saponins from Pcauix vietnamensis. 

Figure 3. New Dammarane Saponins from Panax vietnamenss. 

Since 1958, Shibata and his successors have conducted chemical studies on the saponins of the crude drug. After many twists and turns, it was determined that the major saponins of Ginseng were not oleanane oligoglycosides which are very common in nature, but that the genuine sapogenins were represented by triterpenes of the dammarane type. This was the first example of the occurrence of dammarane saponins in nature. The complications encountered in the isolation and structure determination were mainly due to an unexpected acid catalyzed epimerization of the tertiary hydroxyl group on c-20 of the carbon skeleton which was followed by cyclization of the side chain. This undesirable reaction accompanied acid hydrolysis of the saponins to the sapogenins. 

Studies on the chemical constituents of Ginseng and its relatives have also shown that the characteristic dammarane saponins are found in most other Panax species as well. 

Komori et al. 50) and recently, Schulten and Soldati 51) reported that the field desorption (FD) mass spectra of dammarane saponins exhibited a fairly strong M+Na ion without the need for any prior derivatization. This appears to be of promise for determining the molecular weight and the homogeneity of saponins. 

Rai, Ra2 and Ra3 are the most polar dammarane saponins because of the presence of five monosaccharide units. 

Chemical studies on most of these Panax spp. have only been carried out recently. The saponins of Group A species are mainly oligoglycosides of dammarane type triterpenes, while the rhizomes of Group B contain large amounts of the common oleanolic acid saponins (C-V etc. Table III) along with dammarane saponins which are characteristic of each species. 

This well-known Chinese traditional crude drug which consists of the roots of P. notoginseng cultivated in Yunnan has been used as a tonic and a hemostatic. Recently, it has attracted much attention because of its action in preventing and curing coronary disease. Several Ginseng dammarane saponins, Rb (1.62% yield), Rd (0.32%), Re (0.51%) and Rgi (2.07%) have been isolated from this drug, while the oleanolic acid saponin C-V (= ginsenoside-Ro) could not be detected (85, 88, 89). 

A Chinese-Japanese cooperative chemical study 104) of the rhizomes of this plant from Zhaotong, Yunnan at 2100m led to isolation of the oleanolic acid saponins, G-IV, C-IVa, and C-V in yields of 3.4, 2.8, and 3.1%. In this respect, then Zhujie-shen is very similar to Japanese Chikusetsu-ninjin. However, the composition of the dammarane saponin fraction of Zhujie-shen which consisted of Rd (0.04% yield). Re (0.12%), Rgi(0.15%), Rg (0.05%), NG-R2(0.02%, see Chapter VIII-2, Table II) and pseudo-ginsenoside-Fii (PG-Fn, 0.04%, an ocotillol-type saponin from leaves of Himalayan Panax and also from leaves of American Ginseng, see Chapter IX-2), was significantly different from that of the Japanese plant. 

This medicinal plant grows wild in the southern region of Yunnan at altitude of about 2000 m. From ginger-like rhizomes of this plant, Yang, Zhou et al. (106) recently isolated the oleanolic acid saponins, C-IV (0.28% yield), -IVa (0.025%) and -V (2.1%) (see Table 111) along with the dammarane saponins, Rgi (0.59%) and Rhj (trace) (see Table II). A new saponin named zingibroside-Ri (Z-Ri) based on oleanolic acid was also isolated in 0.078% yield (see Table III). 

From the rhizomes of Himalayan Panax collected near Khosa (1800m) in western Bhutan, the oleanolic acid saponins, C-IV, -IVa and -V were isolated in yields of 0.3, 0.6 and 7.25%, respectively (107, 108). One of the major dammarane saponins of Ginseng, Rb was also isolated in somewhat higher yield (1.05%) than from Ginseng roots. 

Recently, Acanthopanax senticosus Harms (Araliaceae), so-called Siberian-Ginseng , and Pfaffia paniculata (Matius) Kuntze (Acantha-ceae), so-called Brazilian-Ginseng , have been sold as health foods or for medicinal use similar to that of real Ginseng. It should be noted that the chemical constituents of these two plants are completely different from those of Ginseng and other Panax spp. and that dammarane saponins could not be detected in either of them. 

Leaves and flower buds of Panax spp. have been practically unutilized for medicinal purposes. To find better and cheaper sources of biologically active dammarane saponins and to find evidence for possible taxonomic relationships, the saponins of the aerial parts of this genus have also been investigated recently. 

Flower buds of P. ginseng are usually removed before ripening for the better growth of roots. Rbi, Rb2, Rc, Rd, Re, Rgi and F3 were isolated from the flower buds in yields of 0.2, 0.2, 0.2, 0.5, 2.8, 0.2 and 0.03%, respectively, whereas the fruits gave Rb2, Rc, Rd, Re and Rg in yields of 0.2, 0.1, 0.1, 6.0 and 0.04% (55, 110). In addition to these saponins, a new dammarane saponin named ginsenoside-M7cd with an oxygenated side chain was isolated in 0.0039% yield from the flower buds as a minor saponin its structure was elucidated by C-NMR spectrometry as shown in Chart 13 (55). 

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