Iridoid glucosides from Veronica pectinata var. glandulosa

A new highly oxygenated iridoid glucoside, urphoside B (1) was isolated from the Veronica pectinata var. glandulosa together with seven known iridoid glucosides, aucubin, catalpol, veronicoside, catalposide, verproside, amphicoside and 6-O-veratroyl catalpol. The planar as well as the stereo structures of the isolated compounds were determined by means of extensive 1D- and 2D-NMR spectroscopy and confirmed by HR-Mass.     

Acylated iridoid glucosides from Veronica anagallis-aquatica

Three new (1-3) and four known iridoid glucosides (4-7) as well as a known phenylethanoid glycoside (8) were isolated from the aerial parts of Veronica anagallis-aquatica and their structures were determined as 6'-O-benzoyl-8-epiloganic acid named aquaticoside A (1), 6'-O-p-hydroxybenzoyl-8-epiloganic acid named aquaticoside B (2), 6'-O-benzoyl-gardoside named aquaticoside C (3), veronicoside (4), catalposide (5), verproside (6), verminoside (7) and martynoside (8) on the basis of 1D and 2D NMR spectral analysis.     

Iridoid glucosides of Paederota lutea and the relationships between Paederota and Veronica

In a chemical investigation of the water soluble compounds in Paederota lutea eight known iridoids were isolated together with a new one with a 8,9-double bond, namely paederotoside (10-O-benzoyl-6'-O-alpha-arabino(1-->6)-beta-glucopyranosyl arborescosidic acid) and the 6-hydroxy-flavone glucoside 4'-O-methylscutellarein 7-O-beta-glucopyranoside. The known iridoid glucosides were 8-epiloganic acid, gardoside, aucubin, catalpol and the 6-O-esters of catalpol: veronicoside, catalposide, amphicoside and verproside. The compounds isolated show that Paederota has a glycoside content almost identical to that of a general Veronica species, and this is in good agreement with the results from recent investigations of the phylogeny of Veronica and its closest relatives, where Paederota is placed as a sister-group next to Veronica. In an analysis of the iridoid glucosides from some of these relatives, it is shown that Veronica, Paederota, Picrorhiza and Veronicastrum are all characterized by containing 6-O-esters of catalpol. Some less closely related taxa namely: Lagotis, Wulfenia, Plantago, Aragoa and Globularia instead contain 10-O-esters of catalpol or aucubin.     

Iridoid glycosides and insect feeding preferences: gypsy moths (Lymantria dispar, Lymantriidae) and buckeyes (Junonia coenia, Nymphalidae)

Abstract. 1. The effect of increasing concentrations of an iridoid glycoside, catalposide, was tested on a generalist and an adapted specialist lepidopteran, using artificial diets.
2. Two strains of the gypsy moth, Lymantria dispar (L.) (Lymantriidae), were tested. Larvae of a wild strain showed a negative dose-dependent response to increasing concentrations of catalposide (up to 7.2% dry weight), while a laboratory strain showed no such pattern. Choice tests using the laboratory strain showed that these larvae often preferred diets relatively low in catalposide over those with higher concentrations.
3. In contrast, larvae of the iridoid glycoside specialist, the buckeye, Junonia coenia Hübner (Nymphalidae), showed a positive dose-dependent response and grew better on diets with higher doses of catalposide.
4. We tested whether the improved growth of J. coenia at higher concentrations of catalposide may have been due to extra glucose yielded by hydrolysis of catalposide. Larvae were fed increasing doses of glucose equivalent to the amount potentially obtained by hydrolysing the quantities of catalposide used in the previous experiment. However, added glucose did not effect growth, suggesting that increased growth at higher catalposide concentrations was due to increased feeding rates.     

Phenylethanoids, iridoids and a spirostanol saponin from Veronica turrilliana

From the aerial parts of Veronica turrilliana two phenylethanoid glycosides, turrilliosides A and B and a steroidal saponin, turrillianoside were isolated and their structures elucidated as beta-(3,4-dihydroxyphenyl)ethyl-4-O-E-caffeoyl-O-[beta-glucopyranosyl-(1-->4)-alpha-rhamnopyranosyl-(1-->6)]-beta-glucopyranoside, beta-(3,4-dihydroxyphenyl)ethyl-4-O-E-caffeoyl-[6-O-E-feruloyl-beta-glucopyranosyl-(1-->4)-alpha-rhamnopyranosyl-(1-->6)]-beta-glucopyranoside and (23S,25S)-12beta,23-dihydroxyspirost-5-en-3beta-yl O-alpha-rhamnopyranosyl-(1-->4)-beta-glucopyranoside, respectively. Furthermore, eight known glucosides are reported namely, catalpol, catalposide, verproside, amphicoside, isovanilloylcatalpol, aucubin, arbutin, and 6-O-E-caffeoylarbutin, the latter two for the first time in the genus Veronica. The two phenylethanoid glycosides were found to be potent DPPH radical scavengers. All of the tested compounds were inactive against the representative species of fungi and bacteria.     

Catalposide is a natural agonistic ligand of peroxisome proliferator-activated receptor-α

Peroxisome proliferator-activated receptor-alpha (PPARα) is a nuclear receptor that regulates the expression of genes related to cellular lipid uptake and oxidation. Thus, PPARα agonists may be important in the treatment of hypertriglyceridemia and hepatic steatosis. In this study, we demonstrated that catalposide is a novel natural PPARα agonist, identified from reporter gene assay-based activity screening with approximately 900 natural plant and seaweed extracts. Results of time-resolved fluorescence resonance energy transfer analyses suggested that the compound interacted directly with the ligand-binding domain of PPARα. Cultured hepatocytes stimulated with catalposide exhibited significantly reduced cellular triglyceride concentrations, by 21%, while cellular uptake of fatty acids was increased, by 70% (P<0.05). Quantitative PCR analysis revealed that the increase in cellular fatty acid uptake was due to upregulation of fatty acid transporter protein-4 (+19% vs. the control) in cells stimulated with catalposide. Additionally, expression of genes related to fatty acid oxidation and high-density lipoprotein metabolism were upregulated, while that of genes related to fatty acid synthesis were suppressed. In conclusion, catalposide is hypolipidemic by activation of PPARα via a ligand-mediated mechanism that modulates the expression of in lipid metabolism genes in hepatocytes.     

A chemosystematic study of Veronica: Iridoid glucosides

Caffeoyl-catalpol, isoferuloyl-catalpol, protocatechuoyl-catalpol, benzoyl-catalpol, p-hydroxybenzoyl catalpol (catalposide), vanilloyl-catalpol and cinnamoyl-aucubin have been isolated from several Veronica species (Scrophulariaceae) in a more or less pure state. The first four compounds have never been recorded in plants before. A PC survey of forty-three species of the genus sensu lato has shown a general presence of aucubin and catalpol. They are accompanied in many of the species by a complex mixture of esters, especially esters of catalpol with aromatic acids. In only one species have aucubin esters been found. Loganin has been identified in five species, this being the first time that this compound has been found in the Scrophulariaceae. Loganin is accompanied by unidentified loganin esters in the same five species. From the systematic point of view the complex mixtures of esters of catalpol in Veronica seem to be noteworthy. Species of Globularia, Erinus, Scrophularia Verbascum, Wulfenia, Catalpa and Plantago investigated either totally lacked ester glucosides in leaves or contained mainly different types of esters. The possible systematic meaning of these results is briefly discussed.     

Iridoid glucosides from Satureja Vulgaris

Satureja vulgaris was shown to contain two new iridoid glucosides, 5-deoxylamiol and 4-methylantirrhinoside, as well as the known iridoid glucosides lamiol and 5-deoxylamioside. The structures of the new glucosides were established by spectroscopic studies and chemical evidence.     

Triterpenoids and glycosides from Geum japonicum

Two new glucosides and two known ester glucosides have been isolated from Geum japonicum. The two new glucosides were isolated by formation of their acetates and were identified as glucosides of 2-isopropyl-5-methylhydroquinone by chemical and spectral studies. The two known ester glucosides were identified as niga-ichigoside F1 and suavissimoside F1 by direct comparison with authentic samples. 2α,19α-Dihydroxyursolic acid and the known glycoside, gein, were also isolated from the same plant, in addition to a mixture of 2α-hydroxyursolic acid and 2α-hydroxyoleanolic acid.     

Glucosides from the roots of Capparis tenera

Two new lignan glucosides, compounds 2 and 3, two new 1H-indole-alkaloid glucosides, 5 and 6, as well as two new phenolic glucosides, 7 and 10, were isolated from the roots of Capparis tenera, together with five known compounds. Their structures were characterized by chemical and spectroscopic methods. Most of these isolates were obtained for the first time from Capparidaceae. The antioxidant and anti-inflammatory activities of the new compounds were investigated.     

Unique cholesteryl glucosides in Helicobacter pylori: composition and structural analysis.

A chloroform-methanol-extracted lipid of Helicobacter pylori was studied. Three kinds of glycolipids, accounting for about 25% (wt/wt) of the total lipid, were detected and identified to be cholesteryl glucosides. The structures of two of them were determined to be cholesteryl-alpha-D-glucopyranoside and cholesteryl-6-O-tetrade-canoyl-alpha-D-glucopyranoside, and the plausible structure of the third one was identified as cholesteryl-6-O-phosphatidyl-alpha-D-glucopyranoside. Cholesteryl glucosides are very rare in animals and bacteria. Furthermore, those in H. pylori had an alpha-glycosidic linkage, which is rather unusual for natural glycosides, and a phosphate-linked cholesteryl glycoside like the cholesteryl-6-O-phosphatidyl-alpha-D-glucopyranoside has not been reported previously. As the cholesterol glucosides were detected in strains obtained from diverse geographical locations, the presence of cholesteryl glucosides in H. pylori is a very unique and a characteristic feature of the species. These findings add a new facet to the physiology and biochemistry, especially the cholesterol and glucose metabolism, of H. pylori. Furthermore, the cholesteryl glucosides of H. pylori showed hemolytic activities.     

Three secoiridoid glucosides from Ligustrum japonicum

Three new secoiridoid glucosides, ligustaloside A, ligustaloside B and 10-hydroxyoleuropein, along with two known glucosides, oleuropein and ligstrosid     

Furanoflavonoid glycosides from Pongamia pinnata fruits

Pongamia pinnata fruits afforded three new furanoflavonoid glucosides, pongamosides A-C (1-3), and a new flavonol glucoside, pongamoside D (4). The structures of these compounds were established on the basis of spectroscopic studies. This is the first time that furanoflavone glucosides have been found as naturally occurring compounds.     

Three new secoiridoid glucosides from Eustoma russellianum

Three new secoiridoid glucosides, eustomoside, eustoside and eustomorusside, have been isolated along with three known glucosides, sweroside, swertiamarin and gentiopicroside, as well as one unknown glycoside from Eustoma russellianum.     

Two new iridoid glucosides from Osmanthus fragrans

Two new iridoid glucosides, 10-acetoxyligustroside and 10-acetoxyoleuropein, along, with two known glucosides, acteoside and phillyrin, have been isolated from the leaves of Osmanthus fragrans Lour and their structures have been determined.     

Kaempferol Glycosides in the Seed-Coat of Ophiopogon jaburan (Kunth) Lodd.

Blue seed-coats of Ophiopogon jaburan have been found to contain kaempferol, kaempferol 3-glucoside (astragalin), two new glucosides of kaempferol, and a trace amount of an unknown flavonol-like compound. One of the new glucosides was determined to be kaempferol 4′-glucoside and the other to be kaempferol 3, 4′-diglucoside by means of paper-chro-matographic and spectral analyses.     

Iridoid glucosides from Phlomis rotata

Two new iridoid glucosides, dehydropentstemoside and 7-epiphlomiol have been isolated from the aerial parts of Phlomis rotata and their structures elucidated by means of chemical and spectral methods. Shanzhiside methyl ester and barlerin have also been isolated and identified     

Quercetin glucosides promote ischemia-induced angiogenesis,but do not promote tumor growth

Aims

Dietary flavonoid intake shows a significant inverse association with mortality from coronary heart disease, incidence of myocardial infarction and stroke. Quercetin is one of the most common flavonoids in our diet and has several favorable biological activities. Quercetin glucosides, which are enzymatically trans-glycosylated isoquercitrin, have high water-solubility and bioavailability compared with quercetin. Here, we investigated the effects of quercetin glucosides on collateral development in a murine hindlimb ischemia model.

Main methods

We induced hindlimb ischemia in 24- to 32-week-old male C3H/HeJ mice by resecting the right femoral artery. Then, 0.5% carboxymethyl cellulose (control) or quercetin glucosides (100 mg/kg/day) were administered daily by gavage. Blood flow was monitored weekly by laser Doppler imaging.

Key findings

Recovery of blood flow to the ischemic leg was significantly enhanced by quercetin glucosides (blood flow ratio at 4 weeks: control, 0.57 ± 0.11; quercetin glucosides, 0.95 ± 0.10, p < 0.05). Furthermore, anti-CD31 immunostaining revealed that quercetin glucosides increased capillary density in the ischemic muscle (control, 200 ± 24/mm²; quercetin glucosides, 364 ± 41/mm², p < 0.01). Quercetin glucosides did not promote tumor growth. The beneficial effect of quercetin glucosides was abrogated in eNOS-deficient mice.

Significance

These results suggest that quercetin glucosides may have therapeutic potential to promote angiogenesis in ischemic tissue.     

Hairy root cultures of Rehmannia glutinosa and production of iridoid and phenylethanoid glycosides

Hairy root lines through the infection of Agrobacterium rhizogenes strain (A4) were established from shoot tips and leaves of Rehmannia glutinosa Libosch. Ten lines of hairy roots were selected on the basis of biomass increase in half-strength Gamborg medium (¹/₂ B5). Transgenic status of the roots was confirmed by polymerase chain reaction using rolB and rolC specific primers. Iridoid glycosides (catalposide, loganin, aucubin and catalpol) and phenylethanoid glycosides (verbascoside and isoverbascoside) identified using HPLC?CESI?CMS, and their contents were compared with untransformed root culture and roots of 1-year-old field-grown plants of R. glutinosa by RP-HPLC. The growth and production of secondary metabolites in ten hairy root lines varied considerably as to the media. Woody plant (WP) medium displayed higher growth in terms of fresh (FW) and dry weights (DW) compared to ¹/₂ B5 medium. High-yielding hairy root lines produced higher amounts of loganin, catalposide, verbascoside and isoverbascoside in comparison to the untransformed root culture and roots of 1-year-old field-grown plants. The highest amounts of catalposide and loganin in transformed roots were 4.45?mg?g^?1 DW (RS-2 hairy root line) and 4.66?mg?g^?1 DW (RS-1 hairy root line), respectively. Aucubin and catalpol were detected in some lines in trace amounts. The highest amounts of verbascoside (16.9?mg?g^?1 DW) and isoverbascoside (3.46?mg?g^?1 DW) were achieved in RS-2 root line. The contents of catalposide, verbascoside and isoverbascoside in high-producing lines were several times higher than in untransformed root culture and roots of R. glutinosa plants grown in soil. Loganin and aucubin could not be detected in roots of field-grown plants. However, the levels of catalpol were much lower in the in vitro roots.     

Abeliosides A and B,secoiridoid glucosides from Abelia grandiflora

Twp new secoiridoid glucosides, abeliosides A and B, were isolated along with cantleyoside and sylvestroside II from Abelia grandiflora. On the basis of spectral and chemical evidence, these new glucosides were identified as esters of secologanic acid with an iridoid lactone which may arise from loganin. Cantleyoside was also isolated from A. spathulata and A. serrata.