Rivalosides A and B, two 19-Oxo triterpenoid saponins from Galium rivale.
Two new oleanene-type triterpene glycosides, rivaloside A (2alpha-acetoxy-3alpha-hydroxy-19-oxo-olean-12-en-28-o ic acid 28-O-beta-glucopyranosyl-(1-->6)-beta-D-glucopyranoside) (1) and rivaloside B (2alpha,3alpha-dihydroxy-19-oxo-olean-12-en-28-oic acid 28-O-beta-glucopyranosyl-(1-->6)-beta-D-glucopyranoside) (2), were isolated from aerial parts of Galium rivale. The structures were determined on the basis of spectroscopic data and chemical transformations. Under alkaline or acid hydrolysis, rivalosides A and B undergo allylic rearrangement with migration of the double bond. These compounds are the first representatives of 19-oxo substituted oleanenes, and they seem to be promising as taxonomic markers for G. rivale.
De Rosa
S
S
Istituto per la Chimica di Molecole di Interesse Biologico, CNR, Via Toiano 6, 80072 Arco Felice (Napoli), Italy. sderosa@icmib.na.cnr.it
Mitova
M
M
Handjieva
N
N
Popov
S
S
Anchev
M
M
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D009828:Oleanolic Acid / Q000031:analogs & derivatives*; D019666:Rubiaceae / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry / Q000302:isolation & purification*; D013057:Spectrum Analysis
D012503:Saponins; C413042:rivaloside A; C413043:rivaloside B; D009828:Oleanolic Acid