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Eight iridoid glucosides were reported from the aerial parts of Wendlandia ligustroides. 10-deoxygeniposidic acid (1), 7-deoxygardoside (2), geniposidic acid (3), 7-deoxy-8-epi-loganic acid (4), deacetyl-daphylloside (5), scandoside methyl ester (6), 6-O-methyl-deacetyl-daphylloside (7), 6-O-methyl-scandoside methyl ester (8). Compounds 3 – 8 were isolated as a pure form while 1 and 2 as a mixture. The structures of the compounds 1 – 8 were established by spectroscopic methods including 1D-NMR (1H NMR, 13C NMR, DEPT-135), 2D-NMR (COSY, NOESY, HSQC, HMBC) and HRMS.

The content of glycosides in Kirengeshoma palmata and Jamesia americana (Hydrangeaceae) have been investigated. The former contains loganin and secoiridoids, including the alkaloid demethylalangiside. The latter contains no iridoids, but the known glucosides arbutin, picein and prunasin. In order to futher investigate the chemotaxonomy of the family Hydrangeaceae, the distribution of the iridoid and secoiridoid glucosides as well as the known biosynthetic pathways to these compounds have been reviewed. However, only a few genera of the family has been investigated. Loganin, secologanin, and derivatives of these are common. The genus Deutzia is characteristic in containing more structurally simple iridoids in which C-10 has been lost during biosynthesis. Such compounds have so far only been reported from the genus Mentzelia (Loasaceae). The taxonomic relationships between Hydrangeaceae and the closely related Cornaceae and Loasaceae is discussed and found to agree well with recent DNA sequence results.

From Veronica longifolia were isolated three chlorinated iridoid glucosides, namely asystasioside E (6) and its 6-O-esters 6a and 6b, named longifoliosides A and B, respectively. The structures of 6a and 6b were proved by analysis of their spectroscopic data and by conversion to the catalpol ester verproside (5a) or to catalpol (5), respectively. The configuration of the previously known vanilloyl analogue, urphoside B, was shown to be the 6-epimer (6c) of the structure originally reported. Longifoliosides A (6a) and B (6b) were found to exhibit radical-scavenging activity against nitric oxide (NO), superoxide (SO), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals.

Snow hebes are the alpine cushion-forming plants of New Zealand Veronica, formerly classified as Chionohebe. The chemical composition of Veronica pulvinaris and Veronica thomsonii was studied and 33 water-soluble compounds were isolated. The structure of 14 previously unknown esters of phenylethanoid glycosides were elucidated by spectroscopic analyses. Further, eight known phenylethanoids, nine iridoids, 6'-feruloyl-sucrose and mannitol are also reported. It was found that the iridoid profile of the snow hebes was different from the other species of Veronica in New Zealand but similar to the alpine Northern Hemisphere representatives of the genus.

From the aerial parts of Eremostachys moluccelloides, a new iridoid glucoside, lamalbidic acid (7), was isolated together with six known iridoid glucosides, 5-desoxysesamoside (1), 6β-hydroxy-7-epi-loganin (2), lamalbide (3), shanzhiside methyl ester (4), sesamoside (5) and 5-deoxypulchelloside I (6). Lamalbidic acid was isolated as its choline salt. Its structure was elucidated by spectroscopic (UV, IR, 1D- and 2D-NMR, and ESI-MS) methods.

Phytochemical investigations on the above ground parts of Lamium garganicum subsp. laevigatum resulted in the isolation of seven iridoid glucosides, shanzhiside methyl ester (1), barlerin (8-O-acetylshanzhiside methyl ester; 2), 6-O-syringyl-8-O-acetylshanzhiside methyl ester (3), 6β-hydroxyipolamiide (4), lamalbide (5), dehydropenstemoside (6), and sesamoside (7). The structure of the iridoids was elucidated by spectroscopic (UV, IR, 1D- and 2D-NMR, and ESI-MS) evidence.

In a chemical investigation of the water soluble compounds in Paederota bonarota five known iridoid glucosides were isolated together with a compound with an 8,9-double bond, namely bonarotoside (10-O-benzoyl arborescosidic acid). The known iridoid glucosides were aucubin, catalpol and the 6-O-esters of catalpol: verproside, catalposide, amphicoside and veronicoside, compounds that are characteristic for many species of Veronica. The only other species in the genus Paederota, namely P. lutea contains an iridoid glucoside analogous to bonarotoside but with an additional arabinosyl moiety present. This common chemical attribute of Paederota distinguishes the genus from Veronica; it is in good agreement with the results from recent investigations of the phylogeny based on plastid DNA sequences of Veronica and its closest relatives, where Paederota is placed as a sister-group next to Veronica and not included in Veronica as previously suggested.

Two new iridoid glycosides, eriobioside (1) and lamerioside (2) were isolated from the aerial parts of Lamium eriocephalum subsp. eriocephalum, along with two known componds, lamiide (3) and ipolamiide (4). Their structures were elucidated by spectroscopic methods (UV, 1D- and 2D-NMR) and by mass spectrometry (HR-ESI-MS).

Structures of six different iridoid glucosides have been revised. Three compounds isolated from Eremostachys glabra and designated 6,9-epi-8-O-acetylshanziside (1), 5,9-epi-penstemoside (2), and 5,9-epi-7,8-didehydropenstemoside (3) have been shown to be identical to the known iridoids barlerin (4, 8-O-acetylshanziside), penstemoside (5), and 7,8-didehydropenstemoside (6), respectively. Another compound named harpagoside-B, isolated from Scrophularia deserti and proposed to be 9-epi-6-O-methyl-harpagoside (11), was demonstrated from the spectral data given to be the known harpagoside (10b). Finally, two alleged iridoid galactosides from Buddleja crispa named buddlejosides A and B (12a and 12b) have been shown to be the corresponding glucosides; the former is identical to agnuside (13a) while the latter is 3,4-dihydroxybenzoylaucubin (13b), an iridoid glucoside not previously published. It has again been shown that care should be taken with the interpretation of NOEs involving bridgehead protons in iridoid structures because they can be capricious and lead to mistaken structural assignments

In a continued chemosystematic investigation of the water-soluble compounds in Veronica sect. Hebe, four additional species were investigated. In comparison to other, Northern Hemisphere (NH) species of Veronica, those belonging to the New Zealand species in sect. Hebe are apparently more variable in chemical content. In addition to the compounds characteristic for NH Veronica, namely mannitol, aucubin, catalpol and 6-O-esters of catalpol as well as some caffeoyl phenylethanoid glucosides (CGPs), V. topiaria (syn. Hebe topiaria) in also gave an unusual 6-O-ester of aucubin named topiarioside. The former Hebe species V. cupressoides and V. stenophylla each provided one of the two previously undescribed disaccharide esters named hebitol I and II, respectively, and the former plant also a CPG named cuproside, a 6-O-b-glucopyranosyl derivative of the known hebeoside.The last species, namely V. hulkeana (syn. Heliohebe hulkeana) only contained compounds common to other species of Veronica. The taxonomic results are discussed and it is concluded that carbohydrate esters are common in sect. Hebe. The data so far obtained indicate that the occurrences of esters of 6-O-rhamnopyranosylcatalpol are confined to the most derived species in the section.

Decimation of cereal growth and yields by hemiparasitic Striga species cannot be accounted for entirely by the removal of host-plant resources. The production of toxic compounds by the parasite has been suggested. An investigation of three species of the economically important Striga and the related Alectra vogelii has now resulted in the isolation of eight iridoid glucosides (mussaenosidic acid, mussaenoside, gardoside methyl ester, bartsioside, isoaucubin, melittoside, aucubin and eurostoside), two caffeoyl phenylethyl glycosides (calceolarioside A and verbascoside) as well as shikimic acid and trigonelline, all identified by NMR spectroscopy. The iridoids are potent cytotoxins and probably represent an anti-herbivore defence system common to Scrophulariaceae (sensu lato). This has the potential to explain differences in tolerance apparent for contrasting host taxa and cultivars. The nature of the iridoids present also provides additional validation of the recent transferral of parasitic Scrophulariaceae (s.l.) to Orobanchaceae.

Two unique 2-(3,4-dihydroxyphenyl)ethyl glycosides, namely, dopaol beta-D-2-ketoglucopyranoside and dopaol beta-D-2,3-diketoglucopyranoside, were isolated from Chelone obliqua together with the iridoid glucoside catalpol, dopaol beta-D-glucopyranoside, descaffeoylverbascoside, and verbascoside. Glycosides with a diketosugar have not so far been isolated from natural sources.

Two unique 2-(3,4-dihydroxyphenyl)ethyl glycosides, namely, dopaol beta-D-2-ketoglucopyranoside and dopaol beta-D-2,3-diketoglucopyranoside, were isolated from Chelone obliqua together with the iridoid glucoside catalpol, dopaol beta-D-glucopyranoside, descaffeoylverbascoside, and verbascoside. Glycosides with a diketosugar have not so far been isolated from natural sources.

Vejbred slægten har været imponerende god til at kolonisere nye områder og der findes i dag over 200 arter udbredt over hele verden. Her fortæller vi historien om hvordan planternes kemiske forsvarsstoffer og DNA-profiler kan bruges til at opnå kendskab til arternes indbyrdes slægtskab og til slægtens oprindelse og evolution.

In continuation of our investigations of the genus Plantago L. (Plantaginaceae), sixteen species were investigated with respect to watersoluble glycosides. The iridoids auroside, strictoloside and globularicisin, as well as poliumoside, 3-[(4-beta-D-glucopyranosyloxy)phenyl]propionic acid and 2-[4-(beta-D-glucopyranosyloxy)phenyl]acetic acid were isolated from Plantago for the first time. The latter compound has not previously been isolated as a natural product. Sorbitol was the main carbohydrate in all the species investigated. The distribution of iridoids correlates well with the morphological classification of Rahn and also with a recently published molecular phylogenetic study of nuclear ribosomal and plastid DNA sequences. A new chemotaxonomic finding is an abundance of iridoid glucosides present in one of the two groups within subgenus Coronopus section Coronopus, while the other group lacks iridoids, supporting a subdivision of this section. Moreover, in subgenus Albicans, 10-benzoylcatalpol is a characteristic constituent of section Gnaphaloides, while the corresponding cinnamoyl ester globularin occurs in section Lanceifolia. In biosynthetic experiments, labelled epideoxyloganic acid and deoxygeniposidic acid were incorporated into aucubin and geniposidic acid in Plantago ovata, consistent with earlier findings, but no incorporation into asperuloside was observed. The evolution of biosynthetic pathways in Plantago is discussed.

Acid treatment of an iridoid glycoside results in the cleavage of the acetal bond between the sugar unit and the monoterpenoid aglycon. Iridoids possessing non-conjugated enol ether systems, however, undergo the hydration of the iridoid enol ether functionality in acid medium, as well as the hydrolysis of the bond. We examined the acid rearrangement of secoiridoids such as oleuropein (1) and secologanin (2) and their reduction products oleuropeinol (3) and secologaninol (4), to examine whether similar behaviour also occurs in this case.

A survey of the flavonoid glycosides of selected taxa in the genus Veronica yielded two new acylated 5,6,7,3',4'-pentahydroxyflavone (6-hydroxyluteolin) glycosides and two rare allose-containing acylated 5,7,8,4'-tetrahydroxyflavone (isoscutellarein) glycosides. The new compounds were isolated from V. liwanensis and V. longifolia and identified using NMR spectroscopy as 6-hydroxyluteolin 4'-methyl ether 7-O-alpha-L-rhamnopyranosyl(1'''->2'')[6''-O-acetyl-b-D-glucopyranoside] and 6-hydroxyluteolin 7-O-(6''-O-(E)-caffeoyl)-beta-D-glucopyranoside, respectively. Isoscutellarein 7-O-(6'''-O-acetyl)-beta-D-allopyranosyl(1'''->2'')-beta-D-glucopyranoside was obtained from both V. intercedens and V. orientalis and its 4'-methyl ether from V. orientalis only. Complete 1H and some revised 13C NMR spectral assignments are presented for the known isoscutellarein glycosides. Two iridoid glucosides new to the genus Veronica (melittoside and globularifolin) were also isolated from V. intercedens.