BIOLOGICAL ACTIVITIES OF SAPONIN COMPONENTS FROM DUPUITS AND LAHONTAN ALFALFA¹

Abstract

Saponins of DuPuits and Lahontan alfalfa cultivars were extracted and fractionated by preparative thin‐layer chromatography. The ten relatively well‐defined saponin fractions obtained from each cultivar were chemically characterized by major aglycone and carbohydrate moieties. Lahontan contained considerably more soyasapogenol A than DuPuits, but medicagenic acid predominated in DuPuits. The near absence of medicagenic acid from Lahontan fractions was the most significant difference in composition of Lahontan and DuPuits saponins. Based on mass‐spectrometric analyses, four unidentified sapogenins were classified as the same pentacyclic triterpenoids as medicagenic acid or soyasapogenol. Six Lahontan fractions incorporated varying quantities of galactose, which was present in only two DuPuits fractions, but more arabinose was found in DuPuits than in Lahontan saponins. Simplified saponins of DuPuits and Lahontan were then bioassayed by survival of potato leafhopper (Empoasca fabae (Harris)), survival of pea aphid (Acyrthosiphon pisutn (Harris)), hemolysis of human blood cells, and inhibition of Trichoderma viride Pers. ex Fr. A crude‐saponin mixture and a commercially available saponin from Yucca sp. were included in all assays as controls. Certain fractions containing medicagenic acid were responsible for toxic properties in all assays. Presence or absence of medicagenic acid seemed to explain most of the differences in biological activity of DuPuits and Lahontan cultivars. However, medicagenic acid apparently is, not the only acid sapogenin strongly active toward pathogens. An unidentified acid sapogenin chemically related to medicagenic acid inhibited fungal growths markedly, but did not affect insects tested. Potato leafhopper and pea aphid appeared to be appropriate test insects for saponin differentiation. Zusammenfassung BIOLOGISCHE WIRKSAMKEIT VON SAPON1NFRAKTIONEN DER LUZERNESORTEN DUPUITS UND LAHONTAN Saponine sind Glykoside, welche auch in Luzerne (Medicago sativa L.) vorkommen. Obschon sie biologisch ungewöhnlich, wirksam sind, ist deren Bedeutung für die Pflanzen noch nicht abgeklärt. Unsere Untersuchungen bezweckten herauszufinden, ob es die gleichen oder verschiedene Saponine sind, welche für die unterschiedliche biologische Wirksamkeit verschiedener Saponingemische, wie sie in bestimmten Luzernesorten vorkommen, verantwortlich sind; ferner ob und wie jene in Zusammenhang mit der relativen Resistenz oder Anfälligkeit dieser Sorten gegenüber Krankheiten oder Schädlinge gebracht werden können. In der vorliegenden interdisziplinären Zusammenarbeit wurden die gereinigten Saponine der Luzeraesorten DuPuits und Lahontan zuerst charakterisiert und dann, in den folgenden drei Abschnitten, ihre biologische Wirksamkeit gegenüber 2 Insektenarten und einem Pilz, sowie die haemolytische Wirkung auf menschliches Blut dargestellt. Die Saponine der Sorten DuPuits und Lahontan wurden nach der Extraktion mithilfe präparativer Dünnschichtchromatographie fraktionniert. Die 10 verhältnismässig gut definierten Saponinfra...

Biologically active secondary metabolites in white clover (Trifolium repens L.) – a review focusing on contents in the plant, plant–pest interactions and transformation

“…Cloversaponin I-V methyl ester Soyasaponin I Soyasaponin I methyl ester Soyasaponin II methyl ester Azukisaponin II methyl ester Astragaloside VIII Toxic to fungi (Wolters, 1968), insects (Horber et al, 1974), molluscs (Agarwal and Rastogi, 1974;Mølgaard et al, 2000) and ruminants (Agarwal and Rastogi, 1974). Health-promoting activities (Rao and Gurfinkel, 2000).…”

“…Saponins are toxic to fungi (Wolters, 1968), insects (Horber et al, 1974;Adel et al, 2000), molluscs (Agarwal and Rastogi, 1974;Mølgaard et al, 2000), nematodes (Argentieri et al, 2007) and ruminants (Agarwal and Rastogi, 1974), but can have health-promoting activities (Rao and Gurfinkel, 2000). Soyasaponin I is toxic to the plant-parasitic nematode Xiphinema index (Argentieri et al, 2007), causes prolongation of the larval and pupal stages, retards growth, increase mortality, and reduce fecundity and fertility of the insect Spodoptera littoralis (Adel et al, 2000), but stimulates the growth of wheat (Triticum aestivum L.) (Oleszek, 1993).…”

“…Of 19 saponins and saponin fractions originating from various plant species, all were active in different degrees towards 15 species of fungi, mostly plant pathogens (Wolters, 1968). Acid saponins from alfalfa are strongly toxic to potato leafhopper larvae (Empoasca fabae (Harris)) and pea aphids (Acyrthosiphon pisum (Harris)) (Horber et al, 1974), and water-extracted saponins from the Endod plant berries are lethal to snails (Mølgaard et al, 2000). Six of the nine described saponins from white clover contains the saponin aglycones soyasapogenol B and soyasapogenol E, both of which are much less active (almost inactive) towards the insect Spodoptera littoralis than soyasaponin I (Adel et al, 2000).…”

Phytochemical screening and effect of aqueous extract of Ficus sycomorus L. (Moraceae) stembark on muscular activity in laboratory animals

“…Sandabe (2002), using thin layer chromatography, detected two types of saponins. Zimmer et al (1967) reported selective toxicity of saponins on microorganisms, indicating that not all saponins do affect the growth of microorganisms and individual saponins might be responsible for the differences in the growth inhibitory activities (Horber et al, 1974). The natives may be using the plant for wound dressing not because of its antibacterial action but probably because of the presence of tannins in the extract.…”

Taux de reproduction du puceron du pois (Acyrthosiphon pisum Harris) et teneur en acide médicagénique de la luzerne (Medicago sativa L)

“…Les recherches ont également mis en œuvre des milieux holidiques reproduisant la composition de cette sève . Les (Bournoville, 1993) (Horber et al, 1974 ;Krzymanska et Waligora, 1986 (Bournoville, 1993), à savoir que la résistance des génotypes de luzerne vis-à-vis du puceron du pois n'apparaît pas liée à ce composé. En utilisant d'autres plantes de luzerne, nous avons récemment montré (Girousse et Bournoville, 1994) …”