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At least 19 recordsLinked to original sources
PubMed1998

Iridoid glycoside biosynthesis in Penstemon secundiflorus. Another H-5, H-9 trans-iridoid glycoside.

Isolation and characterization of the new iridoid 10-hydroxy-(5 alpha H)-6-epidihydrocornin from Penstemon secundiflorus (Scrophulariaceae) is described. In biosynthetic experiments, deoxyloganic acid was incorporated into the trans-fused iridoid glycosides (5 alpha H)-6-epidihydrocornin and 10-hydroxy-(5 alpha H)-6-epidihydrocornin in P. secundiflorus. Formation of the trans-fused compounds is therefore a late event in the biosynthesis and does not occur during iridoid formation by cyclization of the open chain monoterpene precursor. In the same plant, 8-epideoxyloganic acid was not incorporated into the trans-iridoids. Deoxyloganic acid was also incorporated into 10-hydroxyhastatoside (which bears an 8 beta-methyl group), while 8-epideoxyloganic acid was incorporated into penstemoside (with an 8 alpha-methyl group). Thus, iridoid biosynthetic pathways leading from both deoxyloganic acid and 8-epideoxyloganic acid were found in the same plant.

Glucosides↗
PubMed1980

Pharmacological studies on iridoid compounds. II. Relationship between structures and choleretic actions of iridoid compound.

The relationship between the structures and the choleretic actions of iridoid compounds was examined. Only patrinoside and villoside accelerated bile secretion among the iridoid glucosides but all of the iridoid aglycones increased it after intravenous administration rats. The choleretic effects of villoside, patrinoside aglycone, and 11-deoxy patrinoside aglycone were far weaker in comparison with those of other active iridoid compounds. When an equimolar amount of patrinoside, its aglycone, or 11-deoxy patrinoside aglycone was administered intravenously, their periodical patterns of choleretic activities nearly paralleled with those of isovaleric acid excreted in the bile. Patrinoside was partly hydrolyzed into its aglycone by the artificial gastric juice or the intestinal content. After intraduodenal administration of patrinoside (1 g/kg), the amount of patrinoside enough to exert a choleretic action was detected in the portal blood. These findings indicate that the hemiacetal moiety of iridoid compounds plays an important role in exerting a strong choleretic action and that patrinoside shows the same action following saponification of isovalerate of C-1 position in the liver.

Animals↗
PubMed1988

Studies on iridoid-related compounds. V. Antitumor activity of iridoid dervs. periodate oxidation products.

In the course of a modification study of iridoid glucosides to investigate their antitumor and antimicrobial activity, we found that about all metaperiodate oxidation products of iridoid glucosides which had no antitumor activity showed potent activity against the leukemia P388 in mice. They were found to be more active than the corresponding aglycones obtained by enzymic hydrolysis of iridoid glucosides. Among them, periodate oxidation product of sweroside showed the most potent activity, of which the maximum total/control (T/C) value was 198% at 200 mg/kg.

Animals↗
PubMed1981

Pharmacological studies on iridoid compounds. III. The choleretic mechanism of iridoid compounds.

We made a study on choleretic property and mechanism of action of iridoid compounds as well as dehydrocholate (DHC), cholate (CA), and salicylate (SA), examining their effects on factors such as bile flow, bile acids, electrolytes (Na+, K+, Cl-, and HCO3-), and their metabolites. Each sample showed a characteristic property, respectively. Genipin and patrinoside decreased biliary concentrations of bile acids, Na+, Cl-, and HCO3-, corresponding to their rapid choleretic actions which were due to bile acids independent fraction. The choleretic action of DHC is approximately twice as potent as that of CA. Their actions were due to bile acids-dependent fraction. CA gave a marked increase in Na+ concentration but DHC did not. And both compounds gave a marked diminution in Cl- concentration and weakly decreased HCO3- concentration. SA showed a weak and durable choleretic action and also gave a marked increase in HCO3- concentration. The main metabolite detected from the bile given genipin was genipin-1-O-glucuronic acid (GGA). The periodical pattern of GGA level in bile was in agreement with that of genipin- induced choleretic action, and quantitatively cation, anion gap produced was nearly compensated by biliary concentration of GGA. From out various results, the choleretic mechanism of iridoid compounds is considered to be as follows: The hemiacetal moiety of them undergoes conjugation in the liver to give glucuronide. Glucuronide thus formed is secreted into the biliary tree being coupled mainly with Na+ and water is passively excreted.

Animals↗
PubMed1999

Iridoid and seco-iridoid glucosides from Chioccoca alba (Rubiaceae).

Phytochemical investigation of Chioccoca alba afforded three new iridoids, alboside I, alboside II and alboside III, and a new seco-iridoid alboside V. Alboside IV showed moderate activity towards the DNA repair-deficient mutant RS321 of Saccharomyces cerevisiae. The structural elucidation of the new compounds was performed by ES-MS and by 1D and 2D NMR spectroscopic methods.

Glucosides↗
PubMed2001

Selective sequestration of iridoid glycosides from their host plants in Longitarsus flea beetles.

We investigated in eight species of the flea beetles genus Longitarsus (Coleoptera, Chrysomelidae) whether the beetles take up iridoid glycosides from their host plants of the Lamiaceae, Plantaginaceae, and Scrophulariaceae. Five of the beetle species, L. australis, L. lewisii, L. melanocephalus, L. nigrofasciatus, and L. tabidus, could be shown to sequester iridoid glycosides in concentrations between 0.40 and 1.55% of their dry weight. Eight different iridoid glycosides, acetylharpagide, ajugol, aucubin, catalpol, 8-epi-loganic acid, gardoside, geniposidic acid, and harpagide could be identified in the host plants, yet only aucubin and catalpol are sequestered by the beetles. No iridoid glycosides could be detected in the beetles if neither aucubin nor catalpol were present in the host plant, as in L. minusculus on Stachys recta (acetylharpagide only) and in L. salviae on Salvia pratensis (no iridoid glycosides). In one beetle species, L. luridus, we could not detect any iridoid glycosides although its field host, Plantago lanceolata, had considerable amounts of aucubin and catalpol plus two further iridoids. The five sequestering Longitarsus species differ in their capacity to store the compounds and in their affinity for catalpol relative to aucubin.

Journal Article↗
PubMed2001

Determination of iridoid glycosides by micellar electrokinetic capillary chromatography-mass spectrometry with use of the partial filling technique.

A fast and easy method was sought for determination of the iridoid glycosides catalpol, ketologanin, verbenalin, loganin, 8-epi-loganic acid, geniposidic acid and 10-cinnamoyl catalpol in plant samples. The method involved micellar electrokinetic capillary chromatography (MEKC) coupled on-line to mass spectrometry. The partial filling technique and electrospray ionization were used. Seven iridoid glycosides could be separated with use of MEKC under basic conditions. However, 8-epi-loganic acid and geniposidic acid could not be detected simultaneously with the five neutral iridoid glycosides by mass spectrometry. Therefore, only the neutral iridoid glycosides were screened from plant samples. Catalpol, verbenalin, loganin and possibly 10-cinnamoyl catalpol were found in an examination of seven plant species in the genera Plantago, Veronica, Melampyrum, Succisa, and Valeriana. Aucubin, which was not included in the sample mixture used in method development because of overlapping with catalpol in MEKC, was also detected. The limits of detection for the iridoid glycosides, both at the UV and at the mass spectrometer, are given.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2000

Chemotaxonomy of Plantago. Iridoid glucosides and caffeoyl phenylethanoid glycosides.

Data for 34 species of Plantago (Plantaginaceae), including subgen. Littorella (= Littorella uniflora), have been collected with regard to their content of iridoid glucosides and caffeoyl phenylethanoid glycosides (CPGs). In the present work, 21 species were investigated for the first time and many known compounds were found together with three new iridoid glucosides. Of these, arborescoside and arborescosidic acid, both of the uncommon type with an 8,9-double bond, were present in several species, while 6-deoxymelittoside was found only in P. subulata. The known compounds deoxyloganic acid, caryoptoside and rehmannioside D were isolated from the genus for the first time. The earlier reported occurrence of sorbitol in the family was confirmed, and this compound was shown by NMR spectroscopy to be the main sugar in the three species investigated for this. The combined data show that CPGs are present in all species investigated. With regard to the iridoids, the distribution patterns showed a good correlation with the classification of Rahn. Thus, aucubin is typical for the whole genus, while bartsioside and catalpol as well as 5-substituted iridoids are each characteristic for a subgenus in the family. Finally, the close relationship between Plantago and Veronica suggested by chloroplast DNA sequence analysis. could be corroborated by the common occurrence of the rare 8,9-unsaturated iridoids in these two genera.

Glucosides↗
PubMed2000

The distribution of iridoids in Bignoniaceae.

The distribution of iridoids among the tribes of Bignoniaceae is shown. In the present work, 18 species from the tribes Bignonieae and Tecomeae as well as one from Eccremocarpeae have been investigated. These data combined with those obtained through a literature review were analysed and showed that iridoids occur predominantly in the tribe Tecomeae. In this tribe, a chemical distintion between the genera Tabebuia and Tecoma was observed: The iridoids in Tabebuia are decarboxylated whereas in Tecoma they are C-4 formylated. The species from Bignonieae are poorly investigated and only few reports have been published, however, the iridoids found are mainly C-4 carboxylated. The only exception, Dolichandra cynanchoides (=Macfadyena cynanchoides), with decarboxylated iridoids, is also morphologically abnormal in Bignonieae.

Journal Article↗
PubMed1998

Trans-fused iridoid glycosides from Penstemon mucronatus.

Two new trans-fused iridoid glycosides (5 alpha H)-6 alpha-8-epidihydrocornin and (5 alpha H)-6 alpha-8-hydroxy-8-epiloganin, were isolated from Penstemon mucronatus, along with cornin, penstemoside and three hastatosides. The trans-fused iridoids are only the second and third known among over 900 described cis-fused iridoid glycosides. Two pairs of iridoids, identical except for the stereochemistry at C-8, were found. Structures were determined by spectroscopic methods.

Carbohydrate Conformation↗
PubMed2001

Iridoid glycosides from Globularia trichosantha.

A new iridoid glycoside, deacetylalpinoside (2), was isolated from the aerial parts of Globularia trichosantha together with nine known iridoid glycosides: catalpol, 10-O-benzoyl-catalpol, aucubin, asperuloside, deacetylasperuloside, asperulosidic acid, scandoside, geniposidic acid, and alpinoside (1). From the underground parts of the same plant, two new bisiridoid glycosides, globulosides A (3) and B (4); a known iridoid glycoside, globularidin; a lignan glycoside, liriodendrin; and seven phenylethanoid glycosides, arenarioside, verbascoside (= acteoside), isoacteoside, crenatoside, isocrenatoside, and trichosanthosides A and B, were isolated. Compounds 2-4 are new iridoids containing an 8,9 double bond representing a rare carbon skeleton. Their structures were established by spectroscopic methods.

Glucosides↗
PubMed2000

HPLC analysis of the seasonal and diurnal variation of iridoids in cultivars of Antirrhinum majus.

In this paper we show the seasonal and diurnal variation in the content of the four iridoids found in cultivars of Antirrhinum majus, antirrhinoside, antirrhide, 5-glucosyl-antirrhinoside and linarioside. The seasonal variation in total iridoid content showed a marked bimodal distribution with high total values (around 100mg/g dry matter) early and late in the season and a very low content of all iridoids coinciding with the onset of flowering at the beginning of August. The relative contribution of antirrhinoside was significantly higher before flowering than after bud break. The relative decrease in antirrhinoside was counteracted by an increase of antirrhide, which was significantly higher after the onset of flowering than before. This pattern indicates a change in biosynthesis, although no explanation can be given to the phenomenon. The diurnal variation showed a variation between 20 and 60mg/g dry weight, but there was no relation to light/darkness conditions, temperature patterns or water content. The analyses were performed by HPLC. The applied method has not previously been used in the quantification of iridoids, but was developed specifically for the analyses of cultivars of Antirrhinum majus. We have fully validated the method during its development. The limit of detection was calculated to 0.004mg/ml and the limit of quantification was 0.01mg/ml.

Journal Article↗
PubMed1996

Inhibitory effect of iridoids on Epstein-Barr virus activation by a short-term in vitro assay for anti-tumor promoters.

The in vitro anti-tumor promoting effect of the methanolic extracts of iridoids containing three plants and several pure iridoids isolated from other plants, has been evaluated. The alcoholic extracts of Paederia scandens, P. scandens var. mairei and the Ayurvedic herbal remedy Picrorhiza kurrooa were tested against the Epstein-Barr virus. Among the 15 iridoids evaluated, the glycoside, paederoside, displayed the highest order of anti-tumor promoting activity.

Anticarcinogenic Agents↗
PubMed2000

Bis-iridoid glucosides from Abelia chinensis.

Seven bis-iridoid glucosides have been isolated from Abelia chinensis and were characterized by having a secoiridoid residue as unit A esterifying a C(10)-iridoid or a delta-lactone iridoid as unit B. Among these, compounds 1-3 are new and correspond to 7-O-acetyllaciniatoside IV, 7-O-acetyllaciniatoside V, and 7-O-acetylabelioside B, respectively. The structures of 1-3 were elucidated by spectral methods.

Glucosides↗
PubMedDate not supplied

Iridoids from Scrophularia genus.

We report here an updated summary about iridoid composition of a series from the genus Scrophularia which have been investigated until now from a phytochemistry point of view. In addition a list is included about iridoids isolated in our laboratory from different plant parts of Scrophularia scorodonia L., which are compared with iridoids from some species of the Scrophularia genus. The present study may serve as a current information to researchers working on phytochemistry and pharmacological aspects from the Scrophularia genus and possibly to serve as a new starting point for future investigations.

Asteraceae↗