Effects of genotype,habitat, and seasonal variation on iridoid glycoside content of Plantago lanceolata (Plantaginaceae) and the implications for insect herbivores

Summary We investigated the effects of genotype, habitat, and seasonal variation on production of the iridoid glycosides, aucubin and catalpol, in leaves of the common weed Plantago lanceolata. Two genotypes, one each from a lawn and an adjacent abandoned hayfield population, were clonally replicated in the greenhouse, and then planted back into the two habitats. One quarter of the plants from each treatment were harvested on each of four dates, at approximately two-week intervals. Over the course of the growing season, and in both habitats, we found a significant increase in the concentration of both aucubin and catalpol in P. lanceolata leaves. The genotypes differed in their response to environmental variation, both in time and between sites, as indicated by significant genotype x date and genotype x site interactions. Early in the season, habitat (lawn or field) had a greater effect on iridoid glycoside concentration than did plant genotype, but later in the season, plant genotype was more influential in determining the iridoid glycoside concentration. Thus, the relative palatability of Plantago genotypes to specialist and generalist herbivores may vary in time and space.     

Iridoid glycosides from Galium verum

From the aerial parts of Galium verum in flower, asperuloside and V₁ iridoid were isolated. From the mother liquor obtained on recrystallizatio     

Genetical and biochemical evidence that the hydroxylation pattern of the anthocyanin B-ring in Silene dioica is determined at the p-coumaroyl-coenzyme a stage

In petals of Silene dioica, gene P controls the 3′-hydroxylation of the anthocyanin B-ring and the hydroxylation pattern of the hydroxycinnamoyl acyl group bound to the 4″'-hydroxyl group of rhamnose of anthocyanidin 3-rhamnosyl(1→6)glucoside-5-glucoside. In this paper, experiments are presented which show that gene P is involved in the hydroxylation of p-coumaroyl-CoA to caffeoyl-CoA, which is then used both as a precursor in anthocyanin biosynthesis and as a substrate for the final acylation.     

Diosgenin saponins from Dioscorea floribunda

Five spirostanol glycosides and two furostanol glycosides were isolated from Dioscorea floribunda. In addition to the IR spectra of the free glycosides and the MS of the peracetates and permethyl ethers, the most effective method for structural determination proved to be the NMR spectra of the free saponins in pyridine-d₅.     

New steroidal saponins of Agave americana

Two new saponins, agavasaponin E and agavasaponin H have been isolated from the methanolic extract of Agave americana leaves and their structures elucidated. Agavasaponin E is 3-O-[β-d-xylopyranosyl-(1→2glc1)-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3glc 1)-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-(1→4)-α-d-galactopyranosyl]-(25R)-5α-spirostan-12-on-3β-ol, whereas agavasaponin H is 3-O-[β-d-xylopyranosyl-(1→2 glc 1)-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3 glc 1)-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-(1→4)-β-d-galactopyranosyl]-26-O-[β-d-glucopyranosyl]-(25R)-5α-furostan-12-on-3β,22α,26-triol.     

Steroidal saponins of Yucca filamentosa: Yuccoside C and protoyuccoside C

Two new saponins, yuccoside C and protoyuccoside C, have been isolated from the methanolic extract of Yucca filamentosa root and their structures elucidated. Yuccoside C is 3-O-[α-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, whereas protoyuccoside C is 3-O-[α-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosy]-(25S)-5β-furostan-3β,22α,26-triol.     

Die flavonolglykoside von Equisetum silvaticum

Ten glycosides of kaempferol and quercetin, including the hitherto unknown kaempferol and quercetin 3-rutinoside-7-rhamnosides, have been isolated from Equisetum silvaticum L.     

Dihydrofurocoumarin glucosides from Angelica archangelica and Angelica silvestris

A water-soluble root extract of Angelica archangelica subsp. litoralis afforded, in addition to adenosine, coniferin and the two known dihydrofurocoumarin glycosides, apterin and 1′-O-β-d-glycopyranosyl-(S)-marmesin (marmesinin), two new dihydrofuranocoumarin glycosides, 1′-O-β-d-glucopyranosyl-(2S, 3R)-3-hydroxymarmesin, and 2′-β-d-glucopyranosyloxymarmesin. For the latter a 2S-configuration was demonstrated, the stereochemistry at position 1′ remaining undefined. Roots of A. silvestris similarly afforded 1′-O-β-d-glucopyranosyl-(2S, 3R)-3-hydroxymarmesin. By correlation with the aglycone 2S,3R)-3-hydroxymarmesin obtained in this work, the absolute configurations (2S,3R) were established for the known dihydrofurocoumarin diesters smirniorin and smirnioridin.     

A new cryptic Sympistis from eastern North America revealed by novel larval phenotype and host plant association (Lepidoptera,Noctuidae, Oncocnemidinae)

A Triosteum-feeding species of Sympistis is described from eastern North America: Sympistis forbesi sp. n. Identity of the new species is most reliably determined from larval morphology and host plant association—both adult scaling and genitalic characters overlap with those of Sympisitis chionanthi, a Chionanthus and Fraxinus feeder.     

Sulphuretin glycosides of Coreopsis mutica

The anthochlor complement of Coreopsis mutica has been determined. The compounds observed were all glycosidic derivatives of sulphuretin, being the mono- and di-glucosides and two new glucosidic derivatives acylated with caffeic acid.