Cuscutic acids

Cuscutic acids A (tetradecanoic acid, (115)-[(0-6-deoxy-a-L-mannopyranosyl-(l- 3)-(9-6-deoxy-a-L-mannopyranosyl-(1 2)-0-/l-D-glucopyranosyl-(1 2)-)S-... 

Cuscutic acid A R = C2H5 Cuscutic acid A2. R = H Cuscuta australis... 

Fig. 8.1 Glycosidic acids (cuscutic acids), unique acylated trisaccharides without cyclization to a macrolactone structurally closely related to resin glycosides (cus-1, cus-2), and a real resin glycoside (cuscutic resinoside A) from the seeds of Cuscuta spp. (clearing up of the abbreviations concerning sugar units and acyl residues see Table 8.2)...

It was only detected in three glycosidic acids, cuscutic acid B from Cuscuta chin-ensis as well as operculinic acids D and F from Operculina macrocarpa. Interestingly, - by pure chance or not - to date no resin glycosides corresponding to these three glycosidic acids could be identified. 

Cuscutic resinoside A (1 tetradecanoic acid, (115)-[[6-deoxy-3-(9-(6-deoxy-a-L-mannopyranosyl)-4-0-[(2/ ,3R)-3-hydroxy-2-niethyl-l-oxobutyl]-a-L-nianno-pyranosyl]oxy]-intramol. l,2 -ester) was obtained from the ethyl acetate-soluble fraction of a methanol extract prepared from the seeds of Cuscuta chinensis Lam. The purification of this compound employed a combination of column and preparative-scale HPLC. The structure was deduced from spectroscopic evidence and acid hydrolysis 14). The degradative process gave convolvuUnolic acid, nilic acid, and L-rhamnose. The sugar components were identified by GC analysis after being converted to their thiazolidine derivatives. This disaccharide has a unique macrocyclic lactone, which is placed between C-1 and C-2 of the first rhamnose moiety. 

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