Oleanane saponins

The distribution and structural elucidation of saponins have been reviewed. Glucuronides with a free carboxy-group and carbohydrate residues at C-2 and C-4 are readily cleaved with acetic anhydride in refluxing pyridine to give the genuine aglycone (see Vol. 7, p. 145). Details of the mass spectra of a series of permethylated oleanane saponins have been discussed. 

Table 2. Astragalus species studied for their cycloartane and oleanane saponins... 

Three new oleanane saponins from Zahna africana (63-65) were active against a TPA-induced ear oedema, exhibiting ID50 of 14, 20 and 79 i.g/ear, respectively [90]. Tubeimoside III, natural analog of tubeimoside I (5) also had an antiinflammatory effect on mouse oedema induced by arachidonic acid and TPA [39],... 

Abstract— Hemiaria fcmUoKsU Gay (caiyophyllaceae) is widespread in the Mediterranean area. In the traditional pharmacopoda of Morocco, the aerial parts of this plant are used for the treatment of lithiasis. We have studied the title plant and now we report the isolation and identification of tree flavonoids and four oleanane saponins. The mixture of glycosides was isolated from the methanol extract of the aerial parts of H.fontanesii and separated by multiple chromatographic steps. The structure of the pure glycosids was elucidated by means of mass spectrometry (FAB-MS), NMR technics ( H, C, 2D homo and heteronuclear COSY) and chemical analysis (methanolysis, methylation, alkaline hydrolysis). The flavonoids isolated are (-) catechine 1 3-0-robinobioside Isorhamnetine 2 and a new one 3 feniloyl-3-O-robinobioside Isorhamnetine 3. 

The four saponins are new oleanane saponins. Thdr structures were established as Hemiaria saponin A 28-o- [ a-L-rhamnopyranosyl (l->2) [a-L-rhanmopyranosyl (l->3)]-P-D-xylopyranosyl (l->2)-P-D-fucopyranosyl esto of 3-0-P-D-glucopyranosyluronic (l->4) a-L- rhamnopyranosyl] 2 p, 3 P-dihydroxy oleanl2-en 23,28-dioic... 

Stimulated by the use in moroccan folk medicine of the aerial parts of Hemiariafontanesii Gay (Catyophyllaceae) for the treatement of lithiasis or as a diuretic, we have undertaken the phytochemical study of this mediterranean endemic species. This led us to isolate three flavonoids [1] and four oleanane saponins [2-4] whose structures are described in this paper. 

Zoubida Charrouf Addi Nait M Bark Dominique Guillaume Yves Leroy and Ossarath Kol. Hemiaria saponin B, a new Oleanane saponin from Hemiaria fontanesii. In Saponins used in Food and Agriculture. Edited by G. R. Waller and K. Yamasaki Plenum Publishing Co., New York City. 1996, 241-245... 

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