Karl Hiller

Four major saponins from Solidago canadensis

Four new bisdesmosidic saponins each containing eight carbohydrate units were isolated from Solidago canadensis. GC, GC-MS, FABMS analysis and mainly the use of 2D NMR techniques allowed their identification as bayogeninglycosides (canadensissaponins 1-4) 3-O- [beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-O-[alpha-L- rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[beta-D- apio-D-furanosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl- (1----]-bayogenin; -(1----2)-[beta-D-apio-D-furanosyl-(1----3)]-ara- binopyranosyl-(1----]-bayogenin; -[alpha-L-rhamnopyranosyl-(1----3)]-beta- D-6-deoxyglucopyranosyl-(1----]-bayogenin and - [alpha-L-rhamnopyranosyl- (1----3)]-arabinopyranosyl-(1----]-bayogenin.

Application of MS and NMR to the structure elucidation of complex sugar moieties of natural products: exemplified by the steroidal saponin from Yucca filamentosa L.

An approach, using well characterized procedures, is presented that should be of general applicability for the structural elucidation of complex sugar moieties of natural products. The methods used are exemplified by the structure elucidation of a new gitogenin-based steroidal saponin that has a strong leishmanicidal activity similar to preparations used in clinical practice and has been isolated by bioactivity-guided fractionation of the ethanolic extract of Yucca filamentosa L. leaves. The saponin has been characterized as 3-O-((beta-D-glucopyranosyl-(1-->3)- beta-D-glucopyranosy-(1-->2))(alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3))-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranosyl)-25R,5alpha-spirostan-2alpha,3beta-diol.

Bellissaponins BA1 and BA2, acylated saponins from Bellis perennis

Abstract Two novel acylated triterpenoid saponins were isolated from Bellis perennis . The structures of these have been elucidated as 3- O -α- l -rhamnopyranosyl- and 3- O -β- d -glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-oic acid-28- O -α- l -rhamnopyranosyl(1→3)-β- d -xylopyranosyl(1→4)-α- l -rhamnopyranosyl(1→2)-[ E -buta-2-enoic acid(1→4)]-β- d -fucopyranoside by means of high field 1D and 2D NMR spectroscopic methods without recourse to derivatization or comparison with previous data.

Enzymatic hydrolysis of the cytotoxic triterpenoid glycoside virgaureasaponin 1

The cytotoxic compound, virgaureasaponin 1, was converted using several optimized enzymecatalysed hydrolyses to the 28-O-beta-D-xylopyranosyl (1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-fucopyranoside (2), and the 28-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha- L- rhamnopyranosyl-(1-->2)-beta-D-fucopyranoside (3) and 28-O-beta-D-xylyopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2) - beta-D-fucopyranoside (4) both lacking the glucose moiety at C-3 of the aglycone. The terminal rhamnose of the acylglycosidic bonded tetrasaccharide was cleaved by naringinase to give compound 2. The new acylglycosides 3 and 4 were obtained with the help of a relatively crude beta-glucuronidase preparation, but the cleavage of the sapogenin bonded glucose was impossible using several beta-glucosidase preparations directly. These derivatives were used for the investigation of the relationship between the saponin carbohydrate structure and their cytotoxic activity.

Triterpenoid saponins from Bellium bellidioides

A new acylated triterpenoid saponin carrying the rare 2,3-branched glucose at C-28 of the aglycone bayogenin (2 beta, 3 beta, 23-trihydroxyolean-12-en-28-oic acid) was isolated from the whole plants of Bellium bellidioides. The structure was elucidated mainly by high field NMR experiments (1H and 13C NMR, HMBC, HMQC, COSY-45 at 600/150 MHz) as 3-O-beta-D-glucopyranosyl-28-O-[2-O-alpha-L-rhamnopyranosyl-3-O-beta-D- glucopyranosyl-6-O-acetyl-beta-D-glucopyranosyl]-23-O-acetylbayogenin . Additionally, three acylated derivatives of the known bellissaponin BS1 were obtained.

Bayogenin and asterogenic acid glycosides from Bellis perennis.

Four novel triterpenoid saponins were isolated from the underground parts of Bellis perennis. The structures were elucidated as 3-O-beta-D-glucopyranosides of 2 beta,3 beta,16 alpha-trihydroxyolean-12-ene-28-oic acid-28-alpha-L- rhamnopyranosyl(1----2)-[beta-D-glucopyranosyl(1----6)]-beta-D- glucopyranoside, 2 beta,3 beta,23-trihydroxyolean-12-ene-28-oic acid-28-O-beta-D-xylopyranosyl (1----2)-[beta-D-glucopyranosyl (1----6)]- beta-D-glucopyranoside and 2 beta,3 beta,23-trihydroxyolean-12-ene-28-oic acid-28-O-alpha-L-rhamnopyranosyl(1----2)-[beta-D-glucopyranosyl(1----6) ]- beta-D-glucopyranoside and as 3-O-alpha-L-rhamnopyranosyl-2 beta,3 beta,23-trihydroxyolean-12-ene-28-oic acid-28-O-beta-D-glucopyranosyl(1----2)-[beta-D-glucopyranosyl(1----6)]- beta-D-glucopyranoside by means of high field 1D and 2D NMR spectroscopic methods without recourse to derivatization or comparison with previous data.

Triterpenoid saponins from Aster bellidiastrum

Seven triterpenoid saponins were isolated from both the aerial and the underground parts of Aster bellidiastrum. Five of the compounds were common to both parts. The structures were elucidated mainly from their NMR and mass spectral data, and showed significant similarity to the corresponding data for the saponins from plants of the Bellis genus. Two of the saponins are novel compounds with the structures 3-O-beta-D-xylopyranosyl-2 beta,3 beta, 23-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranoside and 3-O-beta-D-glucopyranosyl-2 beta,3 beta,16 alpha, 23-tetrahydroxyolean-12-en-28-oic acid 28-O-alpha-L-arabinofuranosyl(1-->3)-[alpha-L-rhamnopyranosyl(1-->2)]-be ta- D-fucopyranoside.

Triterpenoid saponins from Bellium bellidioides. structures of the minor deacylsaponins

A new deacylsaponin of polygalacic acid, desacylbellidioside B4, was obtained from the whole plants of Bellium bellidioides L. The structure has been elucidated by a general strategy involving mass spectrometry (ESI-MS, including tandem MS, and GC-MS) and high-field one- and two-dimensional NMR spectroscopy (1H and 13C NMR, COSY-45, HMQC, HMBC) as 3-O-alpha-L-rhamnopyranosyl-2 beta, 3 beta, 16 alpha, 23-tetrahydroxyolean-12-en-28-oic acid 28-O-alpha-L-rhamnopyranosyl(1-->3)-beta-D-xylopyranosyl(1-->4)-alpha-L- rhamnopyranosyl(1-->2)-[alpha-L-arabinofuranosyl(1-->3)-beta-D-fucopyran oside. Moreover, bellissaponin BS2 and besysaponin C12 have also been isolated, demonstrating the close chemical relationship of B. bellidioides to the Bellis genus.

Triterpenoid saponins from the aerial parts of Aster bellidiastrum

Four major triterpenoid saponins were isolated from the aerial parts of Aster bellidiastrum. The structures were elucidated from their NMR and mass spectral data, and from derivatization. One is a new compound with the structure 3-O-beta-D-glucopyranosyl-2 beta,3 beta,16 alpha,23-tetrahydroxyolean-12-en-28- oic acid 28-O-beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->2)-beta- D-fucopyranoside, while the three others have been previously identified in extracts from various Bellis species.

Virgaureasaponin 3, a 3,28-bisdesmosidic triterpenoid saponin from Solidago virgaurea

A new 3,28-bisdesmosidic triterpenoid glycoside was isolated from the mixture of deacylated saponins from the aerial parts of Solidago virgaurea. The structure of virgaureasaponin 3 was determined as 3-O-beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosylpolygalacic++ + acid 28-O-beta-D-fucopyranosyl-(1----2)-alpha-L-rhamnopyranosyl-(1----3)-beta -D- xylopyranosyl-(1----4)-alpha-L-rhamnopyranosyl-(1----2)-beta-D-fucopyran oside mainly by various 2D NMR techniques.