Saponins rhamnose

The difficulty of separating L-arabinose from L-rhamnose has already been noted, and, in a model study directed towards the analysis of steroidal saponins, it was found that a column of (cyanoethyl)sili-cone (XF-1105) was particularly suitable for resolving L-arabinose, D-xylose, and L-rhamnose.31... 

FIG. 4 Structure of representative saponins found in soybeans (triterpenoid) and eggplant (steroid). The R group represents one or more carbohydrate linkages that may contain rhamnose, xylose, arabinose, galactose, glucose, or glucuronic acid. 

About 130 saponins have been described in Astragalus spp. untill now. Table (2). D-xylose (xyl), D-glucose (g c), L-rhamnose (rha), L-arabinose (ara) represent the carbohydrate components of these glycosides pentoses are more frequent then hexoses. Apiose (apio), in the furanosic form, occurs only in cycloaraloside C, named also astrailienin A [140,61]. Glucuronic acid has been found only in pentacyclic triterpene saponins (as in soyasaponins). Astragalus saponins of cycloartane series... 

The carbohydrate moiety usually contains one to six monosaccharide units, the most common of these being glucose, galacto.se, rhamnose, arahinose, facose, xylose, glucuronic and galacturonic acid. The horse chestnut saponins are partly esterified with aliphatic acids. 

A. NMR of a non derivatized saponin in CD3OD (recorded at 300 MHz). At high field, one distinguishes the methyl resonances. The large peak at 4.7 ppm is OH (fi-om solvent and saponin). The 5.3 ppm signal is fi-om the triterpene double bond other signals in this area are anomeric protons from arabinose (5.7), rhamnose (5), xylose (4.5) and glucose (4.4 ppm). 

D. HOHAHA experiment performed on the imderivatized saponin (256 experiments of 2K, spin lock 250 ms MLEV16 sequence reverse mode experiment is phased). Horizontal lines cross the correlation peaks of each sugar. On the column corresponding to rhamnose H-6 are indicated the correlations observed between Me-6, H-1, 2 and 3 (superimposed), H-4 and H-5. 

Isolation of the quillaja saponin component fractions QS-7, QS-17, QS-18, and QS-21 has allowed some correlations of the role of different structural features with immunomodulatory properties. QS-17, QS-18, and QS-21 all induce similar humoral [87] and, presumably, CMI. These findings suggest that the terminal rhamnose of QS-17 and the terminal glucose of QS-17 and QS-18 are not critical for adjuvanticity [87]. 

Triosides The trioses solatriose and /S-chacotriose are the glycoside components of numerous Solanum steroid alkaloids and are thus widely distributed in the Solanaceae genus Solanum. They are composed of 1 mol each of D- galactose, D- glucose, and L- rham-nose (yS-solatriose) or 1 mol of D-glucose and 2 mol of L-rhamnose OS-chacotriose). The steroid saponin dioscin is also a /3-chacotrioside. 

---