Six New Dammarane-type Triterpene Saponins from the Leaves of Panax ginseng

Abstract

Panax ginseng, an ancient and famous herbal drug in traditional chinese medicines, has been used in Chinese folklore for more than 4000 years. In the course of our studies to find bioactive saponins from natural medicines, a number of dammarane-type triterpene oligoglycosides having anti-cancer, anti-arrhythmia and inhibitory effects on reducing sideeffects of steroid hormones were found.1,2) In a continuing study, further systematic research on chemical constituents from the leaves of P. ginseng, we now report the isolation and structural elucidation of six new saponins, together with 14 known ones among which, majoroside-F 2 was the first isolated from P. ginseng.The 70% EtOH extract from the dried leaves of P. ginseng were separated by a macro-reticular resin column to give the 50% EtOH eluates which upon drying afforded the total saponins. The total saponins were chromatographed on silica gel, a reversed-phase column and finally on HPLC to afford ginsenoside-Rh 5 (1, 8 mg), -Rh 6 (2, 9 mg), -Rh 7 (3, 10 mg), -Rh 8 (4, 5 mg), -Rh 9 (5, 9 mg), -Rg 7 (6, 10 mg), majoroside-F 2 (7, 9 mg), ginsenoside-Rh 1 (8, 100 mg), chikusetsusaponin-L 8 3) (9, 15 mg), notoginsenoside-Fe 4) (10, 10 mg), majoroside- H COSY and HMBC experiments of 1. In the HMBC spectrum, a methyl proton signal at d 1.83 showed long-range correlations between d 51.0 (C-17), d 142.4, and 122.2. So this methyl signal can be assigned to the proton of C-21, and the two olefinic carbon signals can be assigned for C-20 and C-22, respectively. Similarly, the HMBC spectrum also revealed long-range correlations between the following protons and carbons: H-23 and C-20, 22, 24; H-27 and C-24, 25, 26 (Fig. 1). In addition, in the 1 H-1 H COSY spectrum, the signals at d 2.41, 2.55 (H-23) showed a correlation with each other, and the correlations between H-23 with d 5.69 (t like, Jϭ7.5 Hz, H-22) and d 4.37 (dd, Jϭ3.5, 8.5 Hz,. The stereochemistry of the double bond at C-20 (22) was proposed to be (E) since the signal for C-21 was observed at d 13.2 in the 13 C-NMR spectrum of 1, while the methyl carbon of a (Z)-type structure is usually observed at about d 20-30. 7,8) From the above results, the structure of 1 was determined as 3b,6a,12b,24x-tetrahydroxy-dammar-20 (22)

Peroxy natural products

“…Floralginsenoside ka displayed potent scavenging activity with the inhibition value of 64% at 10 μM. 279,280 The same species contained six dammarane-type triterpene diglycosides, floralginsenosides A-F 470-475, five dammarane triterpene triglycosides, floralginsenosides G-K 476-480, and a dammarane triterpene obligoglycoside, ginsenoside SF 481. [281][282][283] Six dammarane triterpenes, named probosciderols D-I 482-487, have been found in Proboscidea louisiana.…”

New Dammarane Saponins from the Steamed Ginseng Leaves

“…1 Especially, biologically active constituents of ginseng leaves have been studied and dammarane-type triterpene oligoglycosides have been characterized as the principal ingredients as ginseng roots. 2,3 Consequently, ginseng leaf is a valuable production of ginseng saponins.…”

Ginsenoside Rg8, a New Dammarane-Type Triterpenoid Saponin from Roots of Panax quinquefolium

“…P. ginseng (Asian ginseng), P. quinquefolium (American ginseng), and P. notoginseng (Sanchi ginseng), have been widely used throughout the world for the treatment of a number of diseases, including anaemia, diabetes, gastritis, insomnia, and sexual impotence.1) Triterpenoid saponins are considered the main principal constituents for the clinical effects of the Panax species, and various bioactivities have been reported.2) Previously, we have investigated the saponins of P. ginseng [3][4][5] and their effects on type 1 and type 2 cytokines production 6) and protein tyrosine kinase activation. 7) In P. quinquefolium, another important Panax species, mainly growing in North America, difference in the content and type of ginsenosides from those of P. ginseng has been found.…”

“…2) Previously, we have investigated the saponins of P. ginseng [3][4][5] and their effects on type 1 and type 2 cytokines production 6) and protein tyrosine kinase activation. 7) In P. quinquefolium, another important Panax species, mainly growing in North America, difference in the content and type of ginsenosides from those of P. ginseng has been found.…”