Two New Cucurbitane-Type Glycosides Obtained from Roots of Siraitia grosvenori SWINGLE

Abstract

Siraitia grosvenori SWINGLE belongs to the cucurbitaceae family. This plant is a special product found in the southern part of China, Guangxi province, and is greatly expected to be used as a sweetener in the near future. We have studied the seasonal variation of the chemical constituents of the fruits of this plant. [1][2][3] As part of a series of studies on this plant, we present the chemical constituents of its roots. The roots of this plant are used as raw material in cultivated areas. It is used as a folk medicine for the treatment of rheumatoid arthritis. Pharmacological tests have revealed that its extract exhibits antiinflammatory, analgesic, and anticarcinogenic activities. 4) In this paper, we report two novel norcucurbitane triterpene glycosides.The roots of Siraitia grosvenori were extracted with MeOH to obtain an extract, which was then passed through Diaion HP-20 with water, 50% MeOH, and MeOH, successively. The MeOH eluate was chromatographed on silica gel with a mixture of CHCl 3 , MeOH, and water and on octadecyl silica (ODS) with 60% MeOH to give compounds 1 and 2. 74.2, 78.5, 70.8, 77.9, 69.5, 105.3. 75.1, 78.4, 71.4, 78.5, 62.5 (glc I C-1Ј-6Ј, glc II C-1Љ-6Љ, respectively) and the following signals arising from the sapogenol moiety: five methyl groups at d 8. 4, 12.5, 16.6, 18.2, 19.9; five methine carbons at d 35. 8, 44.8, 45.5, 49.5 50.3; nine methylene carbons at d 19.9, 25.6, 25.8, 28.1, 33.8, 34.8, 35.9, 39.9, 50.6; three quaternary carbons at d 48.7, 49.1, 59.9; an oxygen-bearing quaternary carbon at d 90.1; an oxygen-bearing methylene carbon at d 74.6; an a,bunsaturated carboxylate system at d 144.6, 127.5, 167.1; and two carbonyl carbons at d 209.8. The heteronuclear multiple bond connectivity (HMBC) from five methyl groups to the respective neighboring carbons established that the skeleton of the sapogenol to be 29-nor-cucurbit-24-ene-27-oic acid. Moreover, the HMBC examination revealed the occurrence of an epoxy function group between C-19 and C-5 and two carbonyl groups at C-3 and C-11. Next, the sequential C-NMR to be 5b,19b-epoxy-29-nor-3,11-dioxo-cucurbit-24-ene-27-oic acid methyl ester, whose desmethyl compound was identical with siraitic acid B isolated from the same source and determined by X-ray analysis by Wang et al.4) The connection of the sugar moiety to the sapogenol was also apparent due to the fact that the signal due to H-1Ј at d 6.44 correlated to that of C-27 at d 167.1. Therefore, the structure of 1 was characterized as 5b ,19b -epoxy-29-nor-3,11-dioxo-cucurbit-24-ene-27-oic

The generally useful estimate of solvent systems method facilitates off‐line two‐dimensional countercurrent chromatography for isolating compositions from Siraitia grosvenorii roots

“…The CCC solvent systems of ChMWat (10:4:6, v/v/v) and (10:5:5, v/v/v) correspond to TLC solvent systems of ChMWa (90:10:0.5, v/v/v) and (85:15:0.5, v/v/v), respectively [21]. The ChMWat solvent mixtures have been applied to the separation of several compounds obtained from S. grosvenorii by solid-support chromatography in a series of chemical studies that we conducted on the plant [7]. In the present experiment, we used a solvent composed of ChMWat (9:1:0.1, v/v/v) to monitor fractionation when preparing the CCC-tested sample by solid-support chromatography.…”

“…A key issue in the research on herbal medicine involves the clarification of the pharmacodynamic material basis. A few chemical investigations of the ethanolic extract of the roots have reported the isolation of some cucurbitacin compounds, including siraitic acids A-F and two cucurbitane-type glycosides [3][4][5][6][7][8]. These compounds are usually separated through multidimensional solid-based column chromatography, an extremely time-consuming process.…”

A Review of the Phytochemistry and Pharmacology of the Fruit of Siraitia grosvenorii (Swingle): A Traditional Chinese Medicinal Food

“…Recently, researchers have gained new insights into siraitic acids, the methyl group at C-26 is oxidized to a carboxyl group. The forms of siraitic acid present in S. grosvenorii are divided into two kinds: one is in the form of free acid, such as siraitic acid A-F ( 57–58 , 60–63 ) [ 29 , 30 , 31 ]; the other exists in the form of glycoside combined with sugar group, such as siraitic acid IIA ( 65 ), IIB ( 59 ) and IIC ( 64 ) [ 32 ]. They were isolated from the roots of S. grosvenorii.…”

Triterpenoids

“…A glycoside from the fruit of Momordica cymbalaria has the new genin 165. 78 New glycosides with known genins have been reported from the roots of Siraitia grosvenor 79 and the stems of Dendrosicyos socotrana (socotroside). 80…”