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Secoiridoid glucosides (SGs) are monoterpenoids derived from the iridoid cyclopentane-C-pyran skeleton with β -D glucose linked at C1 position. Coordinated metabolic processes, such as biosynthesis and catabolism of SGs, ensure constitutive presence of these bitter tasting compounds in plant tissues, which plays a decisive role in the defense against pathogens and herbivores. These compounds are susceptible to hydrolysis mediated by enzymes β -glucosidases, and the resulting aglycones are subsequently directed toward different metabolic pathways in plants. Function of two β -D-glucosidases (named Ce BGlu1 and Ce BGlu2) from centaury (Centaurium erythraea Rafn; fam. Gentianaceae), belonging to the glycoside hydrolase 1 (GH1) family, was confirmed using in vitro assays with recombinant proteins, following their heterologous expression in E. coli and His-tag affinity purification. Although they show slightly differential substrate preference, both isoforms display high specificity toward SGs and the organ-specific distribution of transcripts was positively correlated with the content of SGs in diploid and tetraploid C. erythraea plants. Transient overexpression of Ce BGlu1 and Ce BGlu2 in C. erythraea leaves induced changes in metabolite profiles. The effectiveness of transgene overexpression has been altered by plant ploidy. UHPLC/DAD/(±)HESI − MS2 profiling of leaves of diploid and tetraploid C. erythraea genotypes revealed that the amounts of major SGs; sweroside, swertiamarin, and gentiopicrin was decreased in agroinfiltrated leaves, especially when Ce BGlu1 and Ce BGlu2 were co-expressed with transgene silencing suppressor p19. The work demonstrates that in planta metabolic engineering adopting transient overexpression of Ce BGlu1 and Ce BGlu2 is a suitable tool for the modulation of SGs content and glucosides/aglycones ratio, which might have substantial effects on overall phytochemistry of C. erythraea. [ABSTRACT FROM AUTHOR]

Secoiridoid glucosides (SGs) are monoterpenoids derived from the iridoid cyclopentane-C-pyran skeleton with β-D glucose linked at C1 position. Coordinated metabolic processes, such as biosynthesis and catabolism of SGs, ensure constitutive presence of these bitter tasting compounds in plant tissues, which plays a decisive role in the defense against pathogens and herbivores. These compounds are susceptible to hydrolysis mediated by enzymes β-glucosidases, and the resulting aglycones are subsequently directed toward different metabolic pathways in plants. Function of two β-D-glucosidases (named CeBGlu1 and CeBGlu2) from centaury (Centaurium erythraea Rafn; fam. Gentianaceae), belonging to the glycoside hydrolase 1 (GH1) family, was confirmed using in vitro assays with recombinant proteins, following their heterologous expression in E. coli and His-tag affinity purification. Although they show slightly differential substrate preference, both isoforms display high specificity toward SGs and the organ-specific distribution of transcripts was positively correlated with the content of SGs in diploid and tetraploid C. erythraea plants. Transient overexpression of CeBGlu1 and CeBGlu2 in C. erythraea leaves induced changes in metabolite profiles. The effectiveness of transgene overexpression has been altered by plant ploidy. UHPLC/DAD/(±)HESI − MS2 profiling of leaves of diploid and tetraploid C. erythraea genotypes revealed that the amounts of major SGs; sweroside, swertiamarin, and gentiopicrin was decreased in agroinfiltrated leaves, especially when CeBGlu1 and CeBGlu2 were co-expressed with transgene silencing suppressor p19. The work demonstrates that in planta metabolic engineering adopting transient overexpression of CeBGlu1 and CeBGlu2 is a suitable tool for the modulation of SGs content and glucosides/aglycones ratio, which might have substantial effects on overall phytochemistry of C. erythraea.

Four new saponins, camelliagenin A and B derivatives, and one new secoiridoid glucoside were isolated from the stem bark of Aptandra zenkeri Engl. (Aptandraceae) together with two known secoiridoid glucosides. Their structures were determined based on a combination of 1D- and 2D-NMR experiments techniques and HR-ESI-MS analysis. This is the first report on saponins in genus Aptandra. [ABSTRACT FROM AUTHOR]

Abstract From two species of Sutera (S. foetida and S. cordata) (Scrophulariaceae tribe Limoselleae) were isolated three known secoiridoid glucosides (12 – 14) as well as four iridoid congeners (8 – 11), all biosynthetically derived from iridodial glucoside (and/or deoxyloganic acid). In addition, two previously unknown compounds were found, namely a terpenoid glucoside lactone (suterolide, 21) and the phenylethanoid glycoside 2′′′′- O -acetyl-angoroside A (19) as well as verbascoside, echinacoside and tubuloside A(15 – 17 , respectively). Two other species, Jamesbrittenia dissecta and Lyperia antirrhinoides , previously considered to belong to the same genus (Sutera) were shown to be members of two different genera, respectively. Significantly, these two species contained iridoids derived from 8- epi -iridodial (and 8-epideoxyloganic acid), namely aucubin (2), melittoside (3) and acetylharpagide (4). In addition we investigated Melanospermum transvaalense , Lyperia tristis and Microdon dubius likewise from Limoselleae and all of these contained iridoid glucosides from the 8- epi -pathway. Thus, secoiridoid distribution confirms the DNA-based circumscription of Sutera and its sister-group relationship with Manulea. In addition, the results show that the clade including these two genera has a biosynthetic pathway to iridoids fundamentally different from the rest of the tribe and from the whole family Scrophulariaceae. Graphical abstract Two species of the genus Sutera (tribe Limoselleae) contain secoiridoid glucosides. This genus and the sister genus Manulea are both characterised by these compounds while the remaining genera in the tribe and the rest of the family contain iridoid glucosides like aucubin and catalpol which are formed by a different biosynthetic pathway. Image 1 Highlights • Secoiridoids were isolated from two species of Sutera (Scrophulariaceae). • A terpenoid lactone glucoside and a phenylethanoid were isolated and characterised. • Manulea and Sutera are the only genera of Scrophulariaceae with secoiridoids. • The chemotaxonomy of Scrophulariaceae is discussed. [ABSTRACT FROM AUTHOR]

Osmanthus fragrans (OF) is widely used as a flavour additive for tea and other beverages in China and some Asian countries. In this paper, phytochemical investigation on OF seed, the purple-brown ripe fruit of OF, resulted in the discovery of a new secoiridoid glucoside, fragranside A (1), together with nine known secoiridoid glucosides (2–10). Their structures were established through 1D and 2D NMR, HRESI-MS spectra, and compared with literature data. By HPLC analysis, nuzhennoside (4) and nuzhennoside G13 (6) were found to be the predominant compounds in OF seeds with a content of 0.87 and 1.23%, respectively. For quality control, they were simultaneously quantified from four representative species of OF seeds. Additionally, antioxidant and antiplatelet aggregation activity of OF seed extracts were first examined. Results showed that OF seed extracts and compounds 4 and 6 had obvious inhibiting effects on platelet aggregation induced by using adenosine 5′-diphosphate (ADP), collagen, and arachidonic acid (AA) as agonists. These findings suggest that OF seeds may have the potential to be developed into a novel inhibitor of platelet aggregation.

Two new secoiridoid glucosides, ilexpublignoside (1), pubzenoside (2), and a new lignan, ilexlignan B (3), along with seven known compounds (4-10) were isolated from the roots of Ilex pubescens for the first time. Their chemical structures were elucidated on the basis of extensive spectroscopic methods, including IR, UV, HR-ESI-MS, CD, NMR experiments, as well as comparison with the reported data. [ABSTRACT FROM AUTHOR]

Ligustrum lucidum secoiridoid glucosides have been demonstrated to treat various types of diseases such as inflammation, pain, hepatotoxicity and hyperlipidermic as well as tonic for liver and kidney. Matrix metalloproteinases (MMPs) play a key role upon the pathology of photoaging. The present computational study showed that among the six secoiridoid glucosides (ligustroside, lucidumoside A, lucidumoside C, neonuezhenide, oleoside dimethylester, and oleuropein), ligustroside and lucidumoside A competitively inhibit all MMP-1, MMP-3, and MMP-9 activities in the docking models. The molecular docking analysis revealed a network of interactions between MMP-1, MMP-3, and MMP-9 and the ligands; ligustroside and lucidumoside A, and oxygen-containing and hydrophobic functional groups appear to be responsible for these enhanced interactions. The effect of ligustroside and lucidumoside A on the transcription factor AP-1 action was also investigated using molecular docking and dynamics simulations. The experiments suggested that inhibition of an AP-1-DNA complex formation could be on account of the direct interference of AP-1 binding onto the DNA binding sequence by ligustroside and lucidumoside A. The results suggest that both compounds have the highest potential for application as an anti-aging agent with the MMP inhibitory and anti-transcriptional activities. [ABSTRACT FROM AUTHOR]

The present study was principally aimed at ascertaining the differences in metabolomics profiles and biological activities between non-hydrolyzed (ME) and hydrolyzed methanol extract (HME) of Centaurium erythraea Rafn. UHPLC–MS/MS Orbitrap analysis showed that the enzymatic hydrolysis of the extract caused changes in β- d -glycoside/aglycone ratio of both flavonoid and secoiridoid compounds. UHPLC/DAD/+HESI − qqqMS characterization and/or quantification of secoiridoid glucosides (SGs) and their aglycones in both ME and HME revealed gentiopicral and erythrocentaurin as the major aglycones, the same metabolic products which appear after the hydrolysis of pure swertiamarin, the dominant secoiridoid glucoside of C. erythraea . SGs played an antioxidant role only in ABTS assay, whilst the remarkable antioxidant potential of C. erythraea methanol extract is ascribed chiefly to phenolics detected in it. Interestingly, antioxidant activities of swertiamarin and sweroside recorded in ABTS assay increased after the compounds have been hydrolyzed, which highlighted their possible antioxidant role during ingestion. Strong antimicrobial activities of ME and HME against a vast array of pathogens, which exceed the effects of the reference antibiotics and antimycotics, largely depended on the amount of secoiridoids in either of the glycosylation forms. Extracts and pure secoiridoids were especially effective against most of the tested Penicillium species. On the other hand, P. funiculosum has evolved an efficient mechanism of detoxification of sub-lethal concentrations of secoiridoid glucosides, involving their biotransformation and complete digestion. The presented findings will contribute to clarify the fate and role of the SGs after C. erythraea ingestion within in vivo systems, and to further promote this remarkable plant as a food preservation additive with significant health benefits. [ABSTRACT FROM AUTHOR]

A simple and specific high-performance liquid chromatographic method has been developed and validated to simultaneously determine seven secoiridoid glucosides for the first time. Three of them were separated from the ethanolic extract of the roots of Ilex pubescens for the first time, namely nuezhenide A, ligusides B and oleonuezhenide. In quantitative analysis, all of the calibration curves showed good linear regression ( r > 0.999) within the tested ranges, and the mean recoveries of three different concentrations ranged from 97.6 to 101.2%. The limit of detection and limit of quantification were <4.18 and 11.63 ng mL−1, respectively. The relative standard deviation for repeatability and the precision of seven analytes were <3.4 and 1.9%, respectively. The established method was successfully applied to simultaneous determination of seven secoiridoid glucosides in 11 batches of samples collected from different habitats in China. [ABSTRACT FROM AUTHOR]

In our continued investigation of plants from the family Oleaceae we have now investigated Picconia azorica endemic to the Azores. Like most species within the family it contains the oleoside-based secoiridoid glucosides ligstroside and oleuropein as the main compounds and in addition verbascoside and echinacoside. As with the previously investigated Picconia excelsa , it also contained the carbocyclic iridoid glucosides involved in the biosynthetic pathway to the oleoside derivatives. However, while P. excelsa contained loganin esterified with some monoterpenoid acids, P. azorica contains similar esters of 7- epi -loganic acid named Picconioside A and B. In addition were found the two 7- O - E / Z -cinnamoyl esters of 7- epi -loganic acid named Picconioside C and D. [ABSTRACT FROM AUTHOR]

From Manulea altissima (Scrophulariaceae) were isolated five known secoiridoid glucosides sweroside, eustomoside, eustoside, secoxyloganin and secologanoside as well as the 4″- O -rhamnopyranosyl-feruloyl ester of adoxosidic acid, named altissimoside. Also, the caffeoyl phenylethanoid glycoside verbascoside was isolated. In addition two previously unknown terpenoid esters of 6β-hydroxy 8- epi -boschnaloside, named manucoside A and B were isolated from a formerly obtained fraction from the work-up of Manulea corymbosa . The distribution of iridoid glucosides in the Scrophulariaceae is discussed. [ABSTRACT FROM AUTHOR]

A phytochemical investigation on crude extract of Gentianella azurea led to the isolation of ten new ( 1 – 10 ) and one known ( 11 ) secoiridoid glycosides. Their structures were unambiguously elucidated by analysis of 1D and 2D NMR. Compounds 2 , 5 and 11 were found to inhibit nitric oxide (NO) production in RAW 264.7 macrophages with IC 50 values of 52.78 ± 8.61, 0.69 ± 0.23 and 5.18 ± 1.33, respectively, while indomethacin, the positive control, showed an IC 50 value of 1.25 ± 0.52 μM. [ABSTRACT FROM AUTHOR]

Medicinal properties of mangiferin, amaroswerin and amarogentin are well documented in literature,Swertia chirayitais main source of these compounds. However, scarcity ofSwertia chirayitain natural habitat, it becomes necessary to identify new sources of these compounds. Samples ofSwertia ciliatawere collected from Gulaba (9000 ft), Himachal Pradesh, India, and analyzed for the presence of bioactive compounds. Presence of C-glucoxanthone mangiferin along with bitter secoiridoid glucosides (amaroswerin and amarogentin) increased importance ofS. ciliataand open new avenues for further investigations. ThusS. ciliatamay be used as a source of mangiferin, amaroswerin and amarogentin for medicinal exploitation. [ABSTRACT FROM AUTHOR]

One new iridoid glucoside, 4″- O- β- D-glucosyl-6′- O-(4- O- β- D-glucosylcaffeoyl)linearoside ( 1), and two new secoiridoid glucosides, 6′- O-acetylsweroside ( 2) and 6′- O-acetyl-3′- O-[3-( β- D-glucopyranosyloxy)-2-hydroxybenzoyl]sweroside ( 3), were isolated from the dried roots of Gentiana manshurica (Gentianaceae), together with 11 known ones, including one iridoid glucoside, five secoiridoid glucosides, and five triterpenes. The structures of the new compounds were determined on the basis of detailed spectroscopic analyses and acidic hydrolysis. [ABSTRACT FROM AUTHOR]

The genus Gentiana extends across the temperate regions of Asia, Europe and North and South America, largely in mountainous areas. The Willow Gentian (Gentiana asclepiadea L.) extends from the mountainous areas of Spain through the Balkan States to the Ukraine in their more temperate regions. The plant characteristics are described, including roots, seed germination, the blue-violet flowers and their altitudinal variability, together with uses of the plant in traditional medicine. The dried roots and rhizomes are used as remedies for poor appetite and digestive problems. The Willow Gentian is also popular as an ornamental due to its late flowering time, when few other plants are in the generative phase. The popularity of this plant has led to instances of overharvesting and it is now strictly protected in Poland. The authors recommend special attention to this species in the field and close management of existing stands and surrounding areas. Further development of in vitro techniques will provide an excellent tool to support in situ plant protection. However, methods for in vitro micropropagation of this species require further development. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To develop high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) for the analysis and identification of secoiridoid glucosides in Jasminum lanceolarium Roxb. Methods: The ultraviolet (UV) chromatogram, total ion current chromatogram (TIC) and extracted ion chromatogram (EIC) of the sample and ESI/MS/MS spectra of the peaks in the chromatograms were obtained in order to identify the structure of secoiridoid glucosides. Results: The six identified secoiridoid glucosides were Jasminoside, Jaslanceoside A, Jaslanceoside B, Jaslanceoside C, Jaslanceoside D and Jaslanceoside E. The structures of another four unknown secoiridoid glucosides were speculated. Conclusion: The developed simple and rapid method was useful to isolate the new secoiridoid glycoside from Jasminum lanceolarium quickly and to authenticate the species of the herb. [Copyright &y& Elsevier]

Hairy roots of Centaurium erythraea were obtained by infection with Agrobacterium rhizogenes strain LBA 9402. They spontaneously regenerated adventitious shoots in Woody Plant liquid medium without growth regulators. The shoots were grown continuously in Murashige and Skoog (MS) liquid or agar solidified media supplemented with 0.1 mg l−1 indole-3-acetic acid and 1.0 mg l−1 6-benzylaminopurine. These shoots produced roots 4 weeks after transfer into agar-solidified MS medium without phytohormones. Regenerated plants grown and flowered under greenhouse conditions. The transgenic value of the regenerated plants was confirmed by the polymerase chain reaction amplification. Transformation by Agrobacterium rhizogenes alters plant morphology and production of secoiridoid glucosides. The level of secoiridoids was also modified by development stage of transformed plants. The total content of the compounds (expressed as the sum of gentiopicroside, sweroside and swertiamarin) in 10-week old pRi-transformed regenerants was 280 mg g−1 dry weight and was 8-times the content in the sample of commercially available C. erythraea herb. [ABSTRACT FROM AUTHOR]

Shoots of Centaurium erythraea Rafn were cultivated in 5 l mist trickling bioreactor for 21 and 28 days increasing their dry weight from 0.54 g to 13.7 g and 18.3 g, respectively. About 6880 shoots from 223 initial shoot-tips in 21-day bioreactor producing cycle were produced. The shoots could be successfully rooted and transferred to soil. Secoiridoid accumulation (expressed as a sum of gentiopicroside, sweroside and swertiamarin) in shoots after 21 days of culture reached about 303 mg l−1. [ABSTRACT FROM AUTHOR]

Abstract: An efficient shoot multiplication method from shoot tips of Centaurium erythraea using liquid Murashige and Skoog (MS) medium supplemented with indole-3-acetic acid (IAA) (0.1mgl-1) and 6-benzylaminopurine (BAP) (1.0mgl-1) was developed. Under these conditions, almost 60 microshoots per explant were produced within 4 weeks. This is three times more as compared to shoots obtained on agar-solidified medium. Shoots taken from liquid culture were rooted with frequency 85% and 77% on hormone-free full-strength and half-strength MS medium, respectively within 6 and 4 weeks. The plantlets were transferred into soil and they survived acclimatization with 90% success, producing healthy plants, morphologically similar to plants derived from shoots grown on solid culture during their multiplication stage. The shoots of 10-week-old micropropagated plants of C. erythraea accumulated secoiridoid glucosides (gentiopicroside, swertiamarin and sweroside) up to 149mgg-1 dry weight. The value was significantly higher than those achieved for other tested plant materials, such as shoot cultures and aerial parts of wild-grown plants. It is hoped, that the system using liquid shoot culture could be useful for large-scale micropropagation of C. erythraea plants with high production of pharmacologically important products. [Copyright &y& Elsevier]

Phytochemical investigation of the dried leaves of Syringa afghanica, has led to the isolation of nine secoiridoid glucosides, safghanosides A–H and 2″-epi-frameroside, as well as an iridoid glucoside, syringafghanoside along with nineteen known compounds. The structures were elucidated by spectroscopic and chemical means. [Copyright &y& Elsevier]

Methanolic extracts from aerial parts and capsules of plants of 5 populations of Blackstonia perfoliata and 99 populations of nine European and two American Centaurium species ( Gentianaceae) have been screened by means of TLC for the secoiridoid glucosides: sweroside, swertiamarin, gentiopicroside and the m-hydroxybenzoyl esters of sweroside, namely centapicrin, desacetylcentapicrin, decentapicrin A and B as well as for the xanthones: 1,8-dihydroxy-3,5-dimethoxyxanthone, 1,8-dihydroxy-3,7-dimethoxyxanthone, 1,8-dihydroxy-3,5,6,7-tetramethoxyxanthone and xanthone-β-mono-glucosides. The taxonomical significance of the results is discussed. On the basis of chemotaxonomical evidence two Centaurium species, C. pulchellum and C. tenuiflorum, are placed in sect. Parviflora instead of sect. Centaurium subsect. Parviflora. [ABSTRACT FROM AUTHOR]

A new secoiridoid glucoside, oleuropein-4″-methyl ether, was isolated, together with two known secoiridoid glucosides, ligstroside and oleuropein, from the leaves of Fraxinus rhynchophylla Hance by repeated column chromatography over Sephadex LH-20. The structure of the new compound has been characterized on the basis of spectroscopic evidence. [ABSTRACT FROM AUTHOR]

Centaurium erythraea Rafn produces and accumulates various biologically active specialized metabolites, including secoiridoid glucosides (SGs), which help plants to cope with unfavorable environmental conditions. Specialized metabolism is commonly modulated in a way to increase the level of protective metabolites, such as SGs. Here, we report the molecular background of the wounding-induced changes in SGs metabolism for the first time. The mechanical wounding of leaves leads to a coordinated up-regulation of SGs biosynthetic genes and corresponding JA-related transcription factors (TFs) after 24 h, which results in the increase of metabolic flux through the biosynthetic pathway and, finally, leads to the elevated accumulation of SGs 96 h upon injury. The most pronounced increase in relative expression was detected for secologanin synthase (CeSLS), highlighting this enzyme as an important point for the regulation of biosynthetic flux through the SG pathway. A similar expression pattern was observed for CeBIS1, imposing itself as the TF that is prominently involved in wound-induced regulation of SGs biosynthesis genes. The high degree of positive correlations between and among the biosynthetic genes and targeted TFs expressions indicate the transcriptional regulation of SGs biosynthesis in response to wounding with a significant role of CeBIS1, which is a known component of the jasmonic acid (JA) signaling pathway. [ABSTRACT FROM AUTHOR]