A triterpenoid saponin from Cyclamen coum

Making a Virtue of Necessity: The Use of Wild Edible Plant Species (Also Toxic) in Bread Making in Times of Famine According to Giovanni Targioni Tozzetti (1766)

In 1766, the agricultural scientist Giovanni Targioni Tozzetti described for the Grand Duchy of Tuscany, the wild and cultivated plant species that could be used, in times of famine, to increase the quantity of flour or vegetable mass in bread making. These wild plants can be defined as wild edible plants (WEPs) or "alimurgic species", a concept usually traced back to Giovanni Targioni Tozzetti himself. The 342 plant names mentioned in the text are in the Tuscan vernacular, so a research work was done on bibliographic sources from the 1800s in order to match them with their current nomenclature. This process led to an "alimurgic flora" repertoire based on the writing of Targioni Tozzetti; and a comparison with our AlimurgITA database of 1103 wild edible plants used in Italy. It is particularly interesting that in his short treatise, Giovanni Targioni Tozzetti identified eight toxic plants (corresponding to 14 species), indicating how to eliminate the poisonous substances from their useful roots. We treat them in detail, examining their current and past use, their geographical distribution in Italy, and their eventual toxicity. We obtained 343 matches, of which 198 were reliable (certain matches) and 145 possessed some degree of uncertainty (due to generic or collective vernacular names). Among the 198 certain identifications, 140 species are present in the AlimurgITA database (92 mentioned for Tuscany) and 58 are not; for bread-making there are only documentary traces of 53 species for Italy and 7 for Tuscany. Moreover, among the total 198 species, 84 showed some degree of hazard. Researching edible toxic spontaneous species allows: (1) investigation, from an unusual perspective, of a historical period in which the poor conditions of some social strata led to finding unusual solutions to food provision; (2) idea generation to re-enable potentially useful WEPs whose use has been lost. Making a virtue of necessity!

A new cytotoxic triterpene saponin from Lysimachia nummularia L

A new glycosylated triterpene 1 (named nummularoside) was isolated from the underground parts of Lysimachia nummularia L. Its chemical structure was elucidated as 3-O-β-{{[β-D-xylopyranosyl-(1→2)]-[β-D-xylopyranosyl-(1→4)]-β-D-glucopyranosyl-(1→4)}-[β-D-glucopyranosyl-(1→2)-]-α-L-arabinopyranosyl]}, protoprimulagenin A on the basis of extensive NMR and MS spectral data. The saponin showed significant activity against prostate cancer cells DU145 and PC3 (EC50 1.2 and 7.4 μg/mL, respectively), while it did not affect normal cells (EC50 30 μg/mL), in contrast to the reference compound (mitoxanthrone, EC50 0.45 μg/mL). Glioblastoma cells were also significantly affected by the tested saponin (EC50 6.0 μg/mL), whereas the activity against melanoma cells was moderate (EC50 17.5-23.2 μg/mL).

Triterpene saponins from Cyclamen hederifolium

Five triterpene saponins never reported before, hederifoliosides A-E, and four known triterpene saponins were isolated from the tubers of Cyclamen hederifolium. The structures of hederifoliosides A-E were determined as 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-[β-D-glucopyranosyl-(1 → 6)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,30-trihydroxyolean-12-en-28-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,28,30-tetrahydroxyolean-12-en 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. The cytotoxic activity of the isolated compounds was evaluated against a small panel of cancer cell lines including Hela, H-446, HT-29, and U937. None of the tested compounds, in a range of concentrations between 1 and 50 μM, caused a significant reduction of the cell number.

Saponins, classification and occurrence in the plant kingdom

Saponins are a structurally diverse class of compounds occurring in many plant species, which are characterized by a skeleton derived of the 30-carbon precursor oxidosqualene to which glycosyl residues are attached. Traditionally, they are subdivided into triterpenoid and steroid glycosides, or into triterpenoid, spirostanol, and furostanol saponins. In this study, the structures of saponins are reviewed and classified based on their carbon skeletons, the formation of which follows the main pathways for the biosynthesis of triterpenes and steroids. In this way, 11 main classes of saponins were distinguished: dammaranes, tirucallanes, lupanes, hopanes, oleananes, taraxasteranes, ursanes, cycloartanes, lanostanes, cucurbitanes, and steroids. The dammaranes, lupanes, hopanes, oleananes, ursanes, and steroids are further divided into 16 subclasses, because their carbon skeletons are subjected to fragmentation, homologation, and degradation reactions. With this systematic classification, the relationship between the type of skeleton and the plant origin was investigated. Up to five main classes of skeletons could exist within one plant order, but the distribution of skeletons in the plant kingdom did not seem to be order- or subclass-specific. The oleanane skeleton was the most common skeleton and is present in most orders of the plant kingdom. For oleanane type saponins, the kind of substituents (e.g. -OH, =O, monosaccharide residues, etc.) and their position of attachment to the skeleton were reviewed. Carbohydrate chains of 18 monosaccharide residues can be attached to the oleanane skeleton, most commonly at the C3 and/or C17 atom. The kind and positions of the substituents did not seem to be plant order-specific.

Analgesic and antiinflammatory activity ofCyclamen repandum S. et S

According to folk medicine some species belonging to the genus Cyclamen were used for their biological activities. Early investigation of the different species of the genus resulted in the isolation of triterpenic saponins. No phytochemical and biological data are available on C. repandum. As part of a series of phytochemical investigations for bioactive compounds from medicinal plants, Cyclamen repandum S. et S. was investigated. The present study sought to find the antiinflammatory and antinociceptive activities of C. repandum tubers in rats and mice. A preliminary screening was conducted with three different extracts in the tests used, particularly the paw edema and the writhing tests. Subsequently some saponins isolated from the ME extract, the more effective one, have been identified. This paper also describes the results of fractionation and bioassay guided chemical studies. Chemical investigation of the active extract afforded the isolation and characterization of six triterpenic saponins. The possible antiinflammatory and analgesic properties were investigated as the saponin content of the fractions allows to speculate on such aspect.

Biological activities and distribution of plant saponins

Plant saponins are widely distributed amongst plants and have a wide range of biological properties. The more recent investigations and findings into their biological activities were summarized. Isolation studies of saponins were examined to determine which are the more commonly studied plant families and in which families saponins have been identified.