Cucurbitane Glycosides from Unripe Fruits of <i>Siraitia grosvenori</i>

Abstract

Siraitia grosvenori SWINGLE (formerly Momordica grosvenori SWINGLE), a traditional Chinese fruit, belongs to the family cucurbitaceae and has been used as a pulmonary demulcent and emollient for the treatment of dry cough, sore throat, dire thirst, and constipation in folk medicine.1) A number of cucurbitane triterpene saponins from the ripe fruits were previously obtained. [2][3][4][5][6][7][8][9][10] On the basis of its characteristic that the ripe fruit is very sweet, its extract is commercially utilized as a sweet component in sugar substitute; it is widely used as additive and ingredient in health foods and beverages. Meanwhile, owing to the influence of cold weather during winter, some fruits cannot mature naturally. The unripe fruits have a bitter taste, and at the place of cultivation, these may amount to one quarter of total production. We have isolated seven cucurbitane triterpene glycosides: 20-hydroxy-11-oxo-mogroside I A 1 (1), 11-oxomogroside II E (2), 11-oxomogroside I A 1 (3), mogroside II E (4), mogroside III (5), mogroside IV (6), mogroside V (7) and two flavonoid glycosides: kaempferol 7-a-L-rhamnopyranoside (8) and kaempferol 3,7-a-L-dirhamnopyranoside (9), from the unripe fruits of S. grosvenori.11) In our continuing study of this fruit, three new cucurbitane triterpene glycosides, 11-oxomogroside III (10), 11-dehydroxymogroside III (11), and 11-oxomogroside IV A (12), were isolated. This paper deals with the isolation and structure elucidation on the basis of detailed 1D, 2D-NMR spectroscopic analyses. All of the compounds isolated from the unripe fruits of S. grosvenori were tested for cytotoxic activities against HCT-116 and SMMC-7721 cell lines.Fresh unripe fruits were extracted with methanol. A suspension of methanol-extract in water was subjected to a highly-porous polystyrene gel, Diaion HP-20, which was successively eluted with H 2 O and 30%, 80%, and 100% methanol. The 80% methanolic eluate was chromatographed on silica gel, Sephadex LH-20, and reverse-phase silica gel to afford three glycosides, compounds 10-12 (Fig. 1), in yields of 0.0019%, 0.0014%, and 0.00019%, respectively.Compound 10, a white amorphous powder, [a] D ϩ56.7°( MeOH), showed a quasi-molecular ion peak at m/z 983.5261 [MϩNa] ϩ in the positive HR-FAB-MS, corresponding to the molecular formula C 48 H 80 O 19 Na, which was supported by the 13 C-NMR spectrum and its distortionless enhancement by polarization transfer (DEPT) measurement ( 9, 18.4, 18.2, 28.3, 20.2, 26.9, 24.2, 25.8, 87.1, 92.5, and 118.5, respectively, in the heteronuclear multiple quantum coherence (HMQC). In the 1 H-NMR spectrum (Table 1) 03, 4.15, 4.16, 3.92, 3.98, 4.86; 4.01, 4.18, 4.20, 4.15, 4.33, 4.52, and 4.02, 4.17, 4.23, 4.16, 4.30, 4.47 (each 1H), which correlated with the carbon signals at d 106. 2, 75.0, 78.0, 72.0, 76.4, 70.3; 104.8, 75.4, 78.7, 71.8, 78.4, 62.6, and 107.2, 75.5, 78.5, 71.5, 78.1, 63.2, respectively, Studies on the constituents of the unripe fruits of Siraitia grosvenori led to the isolation of three new cucurb...

Studies on chemical fingerprints of Siraitia grosvenorii fruits (Luo Han Guo) by HPLC

“…Eleven reference compounds (4)(5)(6)(8)(9)(10)(11)(12)(13)(14)(15) were extracted, isolated, and purified from fresh fruits of S. grosvenorii in our laboratory. Their chemical structures are shown in Fig.…”

“…The purity was found to be [98%, based on the percentage of total peak area by HPLC analysis. The detailed procedures for isolation and spectrometric identification have been reported in another paper [8,9].…”

“…The chromatographic analysis was carried out on a ZOR-BAX SB-C 18 column (4.6 mm 9 150 mm, 5 lm; Agilent, USA), and the mobile phase was 0.05% phosphoric acid in (4)(5)(6)(8)(9)(10)(11)(12)(13)(14)(15) were identified on chromatograms, and retention time and spectral characteristics of the corresponding peak were matched to those of external standards. The HPLC chromatograms of these samples were further quantitatively expressed in terms of the absolute peak areas of the eleven reference components (Table 2), which may reflect the quantitative expression of the present HPLC fingerprints.…”

“…In addition, we have obtained a total of ten cucurbitane triterpene glycosides and five flavonol glycosides from the fruits of S. grosvenorii. Five compounds are new cucurbitane glycosides [8,9]. In bioactivity research on this herb, cucurbitane triterpene glycosides have attracted a great deal of attention from pharmacologists, and some interesting findings have been reported.…”

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

“…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.…”