Five New Steroidal Glycosides from the Stems of Solanum sodomaeum

Abstract

NotesSolanum sodomaeum L. is a solanaceous plant native to the Libyan Desert. There exist reports on the antineoplastic activity of a mixture of glycoalkaloids extracted from the fruits of this plant against Sarcoma 180 in mice.1) Furthermore, it has been reported that a cream formulation containing purified glycoalkaloids isolated from the fruits was effective in the treatment of malignant human skin tumors; basal cell carcinomas, squamous cell carcinomas, and benign tumors; and keratoses and keratoacanthomas.2) Fruit constituents such as steroidal glycosides and pyrrole alkaloids were also studied. 3,4) In the preceding paper, we had reported the isolation and structural elucidation of eight steroidal glycosides obtained from the methanol (MeOH) extract of the underground parts of this plant. Additionally, we had reported on the antiproliferative activity of these eight steroidal glycosides against human promyelocytic leukemia (HL-60) cells.5) As a continuation to this study, we now describe the isolation and structural elucidation of 5 new steroidal glycosides obtained from the MeOH extract of the stems of S. sodomaeum L., along with 12 known glycosides. In the process, the structure of one of these glycosides was corrected.The MeOH extract of the stems of S. sodomaeum was suspended in H 2 O and extracted with ethyl acetate (EtOAc). The aqueous layer was partitioned between H 2 O and n-butanol (BuOH). The BuOH soluble fraction was then subjected to silica gel, Chromatorex octadecyl silica (ODS), and Diaion HP20 column chromatography and HPLC on ODS to afford 17 glycosides (1-17).Compounds 7-17 were identified as Pd (7), 5) abutiloside O (8), 5) solamargine (9), 5) solasonine (10), 6) sycophantine (11), 6) protodioscin (12), 5) anguivioside XV (13), 10) respectively, based on the comparison of their physical and spectral data with authentic samples or those already reported (Fig. 1), although NMR spectral data of 16 and 17 have not been reported in the literature.Compound 1, tentatively named solasodoside B, was obtained as an amorphous powder, exhibiting an [MϩNa] ϩ ion peak at m/z 969 in the positive FAB-MS. The molecular formula of 1 was determined to be C 45 H 70 O 21 by high-resolution (HR)-positive FAB-MS. The IR spectrum of 1 displayed strong absorption bands at 3415 cm Ϫ1 due to hydroxyl groups and at 1768 cm Ϫ1 due to g-lactone group. The Table 1. Thus, the planar structure of 1, a steroidal glycoside possessing one g-lactone ring between C-22 and C-16 and one tetraglycosyl group at C-3 of aglycone, could be determined. On acidic hydrolysis, 1 afforded L-rhamnose, D-xylose, and D-glucose, which were confirmed by optical rotation using chiral detection in HPLC analysis. The 1 H-and 13 C-NMR data of the sugar moiety and of the C-1-C-11 of the aglycone moiety of 1 were superimposable on those of 14, 5) indicating that the sugar chain attached to the b-hydroxyl group at C-3 of aglycone was identical to the sugar chain of 14. The stereochemistry at C-16, C-17, and C-20 of aglycone was defined on the bas...

Indiosides G–K: Steroidal Glycosides with Cytotoxic and Anti-inflammatory Activities from Solanum violaceum

“…Moreover, ROESY correlations (Figure ) were observed between H-23 (δ H 4.56) and H 3 -27 (δ H 0.96) and between H-26 (δ H 4.86) and H 3 -27 (δ H 0.96). The 1D NMR assignments were analogous to those of anguivioside XI and solasodoside F; however, the O -glucosyl group attached to C-26 in solasodoside F was absent, while an n -propyl group was present in 4 . Accordingly, the structure of compound 4 (indioside J) was elucidated as 3- O -{α- l -rhamnopyranoside-(1→2)- O -[α- l -rhamnopyranoside-(1→4)]-β- d -glucopyranosyl}-(22 S ,23 S ,25 R ,26 S )-23,26-epoxy-26β-propoxy-3β,22α,26-trihydroxyfurost-5-ene.…”

Glycoalkaloid isolation fromSolanum linnaeanumberries

“…Thus, finding a new and/or good source of glycoalkaloids, and discovering efficient methods for isolation are strategic. Different extraction methods can be performed with ethanol [24] or methanol via either maturation [21,26], reflux [25], alkalinisation after acidic hydrolysis [20,22,23] or ammonium hydroxide precipitation [24]. Methanol can be considered as the most efficient extraction solvent.…”

“…Chromatographic methods are applied for purfication of glycoalkaloids. Generally column chromatography with alumina [20,22,24] or silica [25,26] is used for separation and purification. In addition, droplet counter current chromatography (DCCC) [21] or fast centrifugal partition chromatography (FCPC) [23] can be used.…”

“…Another important factor in determining the efficiency of isolation is the source of the glycoalkaloids. Different nightshade species have been investigated to date including S. sycophanta [20], S. aculeastrum [21], S. khasianum [22], S. xanthocarpum [23], S. lycocarpum [24,25] and S. sodomaeum [26]. In this work, we used S. linneaenum berries and obtained glycoalkaloids in higher quantities compared to all other nightshade species except S. khasianum (table II).…”

Open-chain steroidal glycosides, a diverse class of plant saponins

“…Solanum sodomaeum L.). 66 One saponin has also been reported based on the 5a analogue of krypotgenin, 94 isolated from Solanum lycopersicum. 64 Saponin 94 has six accompanying monosaccharide units, which are arranged as a branched tetrasaccahride at linked position C-3 and an unusual disaccharide unit at C-26; this is to date the greatest number of attached sugar units for a plant open-chain glycoside.…”