Oleanane-type triterpene saponins

Morikawa T, Miyake S, Miki Y, Ninomiya K, Yoshikawa M, Muraoka O (2012) Quantitative analysis of acylated oleanane-type triterpene saponins, chakasaponins I-III and florathea-saponins A-F, in the flower buds of Camellia sinensis from different regional origins. J Nat Med 66 608... 

Yoshikawa M, Monkawa T, Nakamura S et til (2(X)7) Bioactive saponins and glycosides. XXV.l) Acylated oleanane-type triterpene saponins from the seeds of tea plant (Camellia sinensis). Chem Pharm Bidl 55 57-63... 

Dammarane derivatives. Besides the isolation of oleanane -type triterpene glycosides several new dammarane-type saponins designated... 

A number of non-proteinaceous substances of plant origin are known that induce or inhibit the sensation of sweetness. Sweetness inducers and enhancers from plants include cynarin, chlorogenic acid, caffeic acid, and arabinogalactin (larch gum) (33). A synthetic compound, 2-(4-methoxyphenoxy)propanoic acid, which is also a constituent of roasted coffee beans, is currently on the market as a sweetness inhibitor (33). Several oleanane-type triterpene esters with sweetness-inhibitory activity occur in Gynmema sylvestre leaves (33,116,117), with dammarane-type saponins with similar effects having been reported recently from the leaves of Hovenia dulcis Thunb. (Rhamnaceae) (118) and Ziziphusjujuba Mill. (Rhamnaceae) (33,119,120). 

Matsuda H, Morikawa T, Ueda H, Yoshikawa M (2001) Medical foodstuffs. XXVII. Saponin constitutes of gotu kola(2) structures of new ursane-and oleanane-type triterpene oligogly-cosidase, centell. Chem Pharm Bull 49 1368-1371... 

Glycyrrhizin has been found to concentrate in the woody parts of the thickened root and stolon of G. glabra. Betulinic acid and soya-saponins have been previously reported from G. glabra cell cultures. Recently, soyasapo-nins (oleanane-type triterpene glycosides) have been reported in all parts of the intact plant, especially the seeds and young roots, particularly rootlets. ... 

Marsileagenin A (750) which is a hexahydroxylated oleanane type triterpene is a major sapogenol of the saponins obtained from Marsilea-minuata (Marsileaceae) 409), Such highly oxidized triterpenes are quite unusual in ferns though they occur frequently in seed plants. 

FIGURE 1.4 Proposed biosynthetic route for the biosynthesis of (A) squalene oxide (squalene-2,3-oxide) via the isoprenoid pathway and (B) triterpene saponins of the dammarane-type and oleanane-type from squalene oxide. PP, diphosphate group GPS, geranyl phosphate synthase FPS, farnesyl phosphate synthase NADPH, nicotinamide adenine dinucleotide phosphate. 

Since 1958, Shibata and his successors have conducted chemical studies on the saponins of the crude drug. After many twists and turns, it was determined that the major saponins of Ginseng were not oleanane oligoglycosides which are very common in nature, but that the genuine sapogenins were represented by triterpenes of the dammarane type. This was the first example of the occurrence of dammarane saponins in nature. The complications encountered in the isolation and structure determination were mainly due to an unexpected acid catalyzed epimerization of the tertiary hydroxyl group on c-20 of the carbon skeleton which was followed by cyclization of the side chain. This undesirable reaction accompanied acid hydrolysis of the saponins to the sapogenins. 

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