AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
The title compound which was isolated as its 3β-sophoroside from the defensive secretion of Chrysomela varians (Coleoptera: Chrysomelidae) has been synthesized from diosgenin in 8 steps.
The defensive secretions of adults of eight species of Doryphorina beetles have been analyzed. Four Leptinotarsa one Labidomera species (L. trimaculata) produce amino acid derivatives, whereas two Calligrapha species produce cardiac glycosides. On the other hand, Zygogramma suturalis is so far unique in simultaneously producing cardiac glycosides and amino acid derivatives. The secretions of all species studied contain ethanolamine. Besides seven known compounds, (3Z)-2-aminohexa-3,5-dienoic acid and four new cardiac glycosides have been isolated and their structures determined by spectroscopic methods. The implications of these results for the taxonomy of the Chrysomelini are discussed, as well as the evolution of chemical defences in this group of beetles.
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
La composition des sécrétions défensives de quatre espèces de coléoptères du genre Chrysolina inféodées au millepertuis (Hypericum perforatum), a été étudiée. Alors que les autres membres de ce genre produisent des glycosides cardiaques, ces quatre espèces contiennent des glycosides stéroïdiques polyoxygénés. Les structures de sept d'entre eux (3–9) ont été déterminées.v51b
The composition of the defence secretions of six species of chrysomelid beetles (Chrysolina polita, C. americana, C. grossa, C. herbacea, C. fastuosa, and Oreina gloriosa) belonging to the sub-tribe Chrysolinina has been investigated. Two known cardenolide aglycones, sarmentogenin (1) and oleandrigenin (23), and fourteen new cardiac glycosides (7–20) have been isolated and their structure established by spectral and chemical methods. Three of the glycosides (18, 19, and 20) are based on a new cardenolide aglycone, namely Δ11-digitoxigenin. All the new glycosides but 17 contain monosaccharides (e. g. lyxose, ribose, allose) which are rarely encountered in secondary metabolites. Ethanolamine was shown to be present in the secretions of the six species examined, as well as in C. hyperici and in C. coerulans. In the latter, ethanolamine is accompanied by its N-(γ-glutamyl) derivative.
AbstractOreina cacaliae (Coleoptera, Chrysomelidae) produces in its elytral and pronotal defensive secretion seneciphylline N‐oxide together with small amounts of another pyrrolizidine alkaloid tentatively identified as senecionine N‐oxide. This is a strong departure from the chemical composition of the defensive secretions in related species, characterized by complex mixtures of cardenolides, synthesized by the beetles from cholesterol. It is suggested that O. cacaliae sequesters the alkaloids from its host‐plant, Adenostyles leucophylla. Other specimens of O. cacaliae from far distant populations feeding on Senecio nemorensis, Petasites paradoxus or P. album also produced pyrrolizidine alkaloids, but not O. speciosissima feeding on the same food plants and producing cardenolides. In addition to pyrrolizidine alkaloids, O. cacaliae secretes ethanolamine, which is also found in all the cardenolide‐producing species.
