New triterpenic saponins from the aerial parts of Medicago arabica (L.) huds.

The reinvestigation of saponin composition from Medicago arabica from Italy allowed the detection of nineteen (1-19) saponins. All of them were purified by reverse-phase chromatography and their structures elucidated by spectroscopic and spectrometric (1D and 2D NMR; ESI-MS/MS) and chemical methods. Fourteen were known saponins, previously found in other plants including other Medicago species.

[The effect of Medicago spp. on growth of Trichophyton mentagrophytes in microculture].

The study aimed at assessing effect of dried root and aerial parts of Medicago spp. on growth of Trichophryton mentagrophytes. Fungus strains were inoculated onto microcultures with Sabouraud agar supplemented each with 1 g of dried and pulverised roots or aerial parts of 3 species: Medicago arabica, M.

Antimicrobial activity of saponins from Medicago sp.: structure-activity relationship.

The antimicrobial activity of saponins from Medicago sativa, M. arborea and M. arabica against a selection of medically important yeasts, Gram-positive and -negative bacteria was investigated.

Triterpene saponins from the roots of Medicago hybrida.

Fourteen triterpene saponins (1-14) have been isolated from the roots of Medicago hybrida and their structures elucidated by FAB-MS and NMR analysis. Two of them are new compounds and were identified as hederagenin 3-O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-28-O-beta-D-glucopyranoside (7) and oleanolic acid 3-O-[beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyranosyl]-28-O-[alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranoside] (14). Seven saponins being mono- and bidesmosides of hederagenin (1, 5, 6, 9), one bidesmoside of bayogenin (2), and two bidesmosides of 2beta,3beta-dihydroxyolean-12-en-23-al-28-oic acid (11) and oleanolic acid (13) are known compounds but not previously reported as saponin constituents of Medicago, whereas five other saponins, being mono- and bidesmosides of medicagenic acid (3, 4, 8, 10, 12), and one monodesmoside of hederagenin (8) have been previously isolated from other Medicago species.

Chromatographic determination of plant saponins--an update (2002-2005).

The developments during 2002-2005 in the methods used for saponin analyses in plant material are presented. There were number of papers published on isolation and identification of new saponins by chromatographic techniques. Some new developments can be found in separation techniques or solid and mobiles phases used.

Triterpenoid glycosides from leaves of Medicago arborea L.

Eighteen triterpene saponins (1-18) from Medicago arborea leaves have been isolated and their structures elucidated by spectroscopic, spectrometric (1D and 2D NMR, FAB-MS, ESI-MS/MS), and chemical methods. They have been identified as glycosides of medicagenic, zanhic, and 2beta-hydroxyoleanolic acids, soyasapogenol B, bayogenin, and 2beta,3beta-dihydroxyolean-12-en-23-al-28-oic acid. Twelve of them, identified as 3-O-beta-D-glucopyranosyl-28-O-[alpha-L-arabinopyranosyl(1-->3)-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside] zanhic acid (3), 3-O-beta-D-glucopyranosyl-28-O-[beta-D-xylopyranosyl(1-->4)-[alpha-L-arabinopyranosyl-(1-->3)]-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside] zanhic acid (4), 3-O-[alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->2)-beta-D-glucopyranosyl]-2beta-hydroxyoleanolic acid (5), 3-O-beta-D-glucuronopyranosyl-28-O-[alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside]medicagenic acid (6), 3-O-beta-D-glucuronopyranosyl-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside]bayogenin (9), 3-O-beta-D-glucuronopyranosyl-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside]-2beta,3beta-dihydroxyolean-12-en-23-al-28-oic acid (10), 3-O-beta-D-glucuronopyranosyl-28-O-[beta-D-xylopyranosyl(1-->4)-[beta-D-apiofuranosyl(1-->3)]-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside]zanhic acid (12), 3-O-beta-D-glucuronopyranosyl-28-O-[beta-D-xylopyranosyl(1-->4)-[alpha-L-arabinopyranoside(1-->3)]-alpha-L-rhamnopyrano-syl(1-->2)-alpha-L-arabinopyranoside]zanhic acid (13), 3-O-beta-D-glucuronopyranosyl-28-O-[beta-D-xylopyrano-syl(1-->4)-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside]zanhic acid (14), 3-O-[alpha-L-arabinopyranosyl-(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-28-O-[beta-D-xylopyranosyl(1-->4)-[beta-D-apiofurano-syl(1-->3)]-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside]zanhic acid (16), 3-O-[beta-D-glucopyrano-syl(1-->2)-beta-D-glucopyranosyl]-28-O-[beta-D-xylopyranosyl(1-->4)-[alpha-L-arabinopyranosyl(1-->3)]-alpha-L-rhamno-pyranosyl (1-->2)-alpha-L-arabinopyranoside]zanhic acid (17), and 3-O-beta-D-glucuronopyranosyl-28-O-[beta-D-xylopyranosyl(1-->4)-[beta-D-apiofuranosyl(1-->3)]-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyrano-side]medicagenic acid (18), are reported as new natural compounds.

Triterpene saponins from aerial parts of Medicago arabica L.

Eight major triterpene saponins have been isolated from the aerial parts of Medicago arabica and their structures elucidated by FAB-MS and NMR analysis. Three of them are new compounds and are identified as 3-O-(alpha-L-arabinopyranoside) bayogenin, 3-O-(alpha-L-arabinopyranosyl), 28-O-(beta-D-glucopyranoside) bayogenin, and 3-O-[alpha-L-arabinopyranosyl(1-->2)-beta-D-glucuronopyranosyl], 28-O-beta-D-glucopyranoside 2-beta-hydroxyoleanolic acid. Two saponins, identified as 3-O-(alpha-L-arabinopyranoside) hederagenin and 3-O-(alpha-L-arabinopyranosyl), 28-O-(beta-D-glucopyranoside) hederagenin are known compounds but not previously reported as saponin constituents of Medicago species, while three other saponins, being mono- and bidesmosides of hederagenin, have been previously isolated from roots of M.

Stability of saponins in alcoholic solutions: ester formation as artifacts.

Saponins containing a free carboxylic group in the molecule give the corresponding esters as artifacts when stored for a long time in alcoholic solutions. Two saponins from Medicago sativa L., chosen on the basis of their different positions of the carboxylic group in the molecule, were refluxed with methanol and ethanol under neutral conditions.

Saponins in alfalfa (Medicago sativa L.) root and their structural elucidation.

Twenty-four saponins have been identified in alfalfa roots, including 13 medicagenic acids, 2 zanhic acids, 4 hederagenins, 1 soyasapogenol A, 2 soyasapogenol B's, 1 soyasapogenol E, and 1 bayogenin glycoside. Ten of the identified compounds, including 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-glucopyranosyl]-28-O-beta-D- glucopyranoside medicagenate, 3-O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta -D-glucopyranoside] medicagenic acid, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D -glucopyranosyl]-28-beta- D-glucopyranoside medicagenate, 3-O-[beta-D-glucuronopyranosyl methyl ester]-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1--> 2)-alpha-L-arabinopyranoside] medicagenate, 3-O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-be ta-D-glucuronopyranosyl]-21-O-alpha-L-rhamnopyranoside soyasapogenol A, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)glucopy ranosyl]-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyranosyl (1- ->2)-alpha-L-arabinopyranoside] medicagenate, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)glucopy ranosyl]-28-O-¿beta-D-xylopyranosyl(1-->4)-)-[beta-D-apiofurano syl-(1 -->3)]- alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside¿ medicagenate, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D -glucopyranosyl]-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyra nosyl(1-->2)-alpha-L-arabinopyranoside] zanhic acid, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D -glucopyranosyl]-28-O-¿beta-D-xylopyranosyl(1-->4)-[beta-D-apiofurano side-(1-->3)]- alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside¿zanhic acid, and 3-O-[beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyranosyl]-28- O-b eta-D-glucopyranoside bayogenin, were not reported before, and their structures were established by spectral (FAB-MS and NMR) techniques. In addition, 3-O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-be ta-D-glucuronopyranoside] soyasapogenol E was identified in the roots for the first time.