Secoiridoid Glycosides Research Articles

The in vitro Immunomodulatory Activity of Oleuropein, a Secoiridoid Glycoside from Olea europaea L

Oleuropein, a secoiridoid glycoside, is a potential antioxidant and antimicrobial agent. The aim of the present study was to investigate the in vitro effects of oleuropein and Olea europaea extracts on unstimulated lymphocytes. Oleuropein did not produce any significant cytotoxic effects on lymphocytes. On the contrary, it had a stimulatory effect, and was capable of inducing and maintaining high proliferation rates in lymphocytes. The stimulatory effects of oleuropein and extracts were concentration-dependent with a range of median stimulatory concentration 1 mM at 48 h. The cytotoxicity effect of oleuropein and extracts increased with time resulting in a greater cytotoxic effect on already-stimulated lymphocytes at 96 h even though dose dependence was not demonstrated. Morphological observations showed that oleuropein and extracts induced blastogenesis similar to that of phytohaemagglutinin (PHA). In fact, from lymphocyte activation studies, oleuropein exhibited a high degree of lymphocyte aggregation, which is an indicator of cell activation and proliferation.

The chemical constituents of fresh Gentian Root

We isolated and characterized 23 compounds, including a new iridoid named gentiolutelin and its dimethyl acetal, and a new lignan named gentioluteol from fresh roots (including small amounts of rhizome) of Gentiana lutea cultivated in Japan (Hokkaido). The structures of gentiolutelin and gentioluteol were determined as (1S,2R,3S,5R)-3-hydroxy-2-methyl-5-(2-oxoethyl)-cyclopentanecarboxylic acid methyl ester and (7R,8S,8′S)-4,4′,8,9-tetrahydroxy-3,3′,5-trimethoxy-7,9′-epoxylignan, respectively, on the basis of chemical and spectroscopic evidence. It was noteworthy that gentiopicroside, known to be a major secoiridoid glycoside in Gentian root, was not detected from the fresh roots of 3-year-old G. lutea.

Two New Secoiridoid Glycosides from Tripterospermum chinense

AbstractTwo new secoiridoid glycosides, tripterospermumcin A (1) and B (2), were isolated from the EtOH extract of the aerial parts of Tripterospermum chinense (Migo) H. Smith, along with three known compounds, secologanin, secologanol, and sweroside. Their structures were established on the basis of UV, IR, MS, and extensive 1D‐ and 2D‐NMR analyses, as well as by literature comparison of spectroscopic data.

Secoiridoid glycosides from the leaves of Hydrangea macrophylla subsp. serrata

Seven secoiridoid glycosides, secologanin dimethyl acetal (1), n-butyl vogeloside (2), n-butyl epi-vogeloside (3), (7R)-n-butyl morroniside (4), hydrangenoside A (5), hydrangenoside C (6), and hydrangenoside A dimethyl acetal (7), have been isolated from the leaves of Hydrangea macrophylla subsp. serrata (Thunb.) Makino (Saxifragaceae). The structures were elucidated on the basis of spectral data.

Liquid chromatography/tandem mass spectrometric study and analysis of xanthone and secoiridoid glycoside composition of Swertia chirata, a potent antidiabetic

Swertia chirata is a bitter plant, used in the Indian system of medicine (Ayurveda) for various human ailments. The bioactive constituents include the xanthone and secoiridoid glycosides consisting of mangiferin, amarogentin, amaroswerin, sweroside and swertiamarin. Methanolic extracts of S. chirata possess constituents with antidiabetic activities, which was investigated by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). Preliminary HPLC analyses were performed on a reversed-phase C18 column using gradient elution. In the LC/ESI-MS spectra, predominant [M+H]+ and [M+Na]+ ions were observed in positive ion mode and provided molecular mass information. The five components of S. chirata were structurally correlated and confirmed based on the fragmentation characteristics and information available in the literature. The fragmentation behavior of [M+H]+/[M+Na]+ ions of these components were deduced from the collision-induced dissociation (CID) spectra obtained from the selective on-column information-dependant acquisition (IDA) approach. Xanthone-C-glycoside showed characteristic fragment ions due to fragmentation in the C-glycosidic unit while iridoid-O-glycosides showed characteristic fragment ions due to cleavage in the glycoside linkage and retro-Diels-Alder (RDA) cleavage within an iridoid aglycone. Furthermore, on the basis of this information, an analytical assay was developed and validated to determine relative concentrations of mangiferin, amarogentin, amaroswerin, sweroside and swertiamarin. The detection was carried out using multiple reaction monitoring (MRM) in positive ionization mode with a total analysis time of 3.5 min. The method was successfully applied to standardize four different batches of herbal preparation on the basis of relative concentration of five bioactive components.

A New Neuroprotective Compound ofLigustrum japonicumLeaves

A new secoiridoid glycoside characterized as (8 Z)-nuezhenide A along with five known glycosides, (8 E)-nuezhenide, (8 Z)-nuezhenide, oleonuezhenide, osmanthuside B and osmanthuside D, were isolated from the n-BuOH fraction of Ligustrum japonicum leaves. All six compounds significantly protected human neuroblastoma SH-SY5Y cells from 6-hydroxydopamine-induced neurotoxicity.

Novel Secoiridoid Glucosides inOlea europaeaLeaves Suffering from Boron Deficiency

From the methanol extract of boron deficient Olea europaea leaves, two secoiridoid glycosides, not detected in leaf extracts of untreated plants, 6'-E-p-coumaroyl-secologanoside and 6'-O-[(2E)-2,6-dimethyl-8-hydroxy-2-octenoyloxy]-secologanoside, were isolated together with three known secoiridoid glycosides, oleuropein, oleoside dimethyl ester, and secologanoside. The structures of the isolated compounds were established by means of NMR and MS spectral analyses. The above novel secoiridoids were synthesized by the plant as a physiological response to nutrient stress.

Modified secoiridoid from Acicarpha tribuloides and inhibition of nitric oxide production in LPS-activated macrophages

Bioassay-guided fractionation of Acicarpha tribuloides Juss. resulted in the isolation of an uncommon non-glycosylated secoiridoid, tribulolide ( 1), two known secoiridoid glycosides named secologanic acid ( 2) and vogeloside ( 3) as well as two natural chromones, 6,7-dimethoxychromone ( 4) and 7-hydroxy-6-methoxy-chromone ( 5). Compounds 1– 3 showed inhibition of nitric oxide production in lipopolysaccharide-activated macrophages; their activity is comparable to that of aminoguanidine, a classic inhibitor.

P.084 Inhibition of duck hepatitis B virus replication by peptide nucleic acids (PNAs) coupled to a transporter peptide

Jasminum officinale L. var. grandiflorum (JOG) is a folk medicine used for the treatment of hepatitis in south of China. Phytochemical studies showed that secoiridoid glycosides are the typical constituents of this plant.The present study was undertaken to evaluate the effect of oleuropein (Ole) derived from the flowers of JOG on hepatitis B virus (HBV) replication in HepG2 2.2.15 cell line in vitro and duck hepatitis B virus (DHBV) replication in ducklings in vivo.The extracellular hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) concentrations in cell culture medium were determined by ELISA. DHBV in duck serum was analyzed by dot blot.Ole blocks effectively HBsAg secretion in HepG2 2.2.15 cells in a dose-dependent manner (IC50 = 23.2 μg/ml). Ole (80 mg/kg, intraperitoneally, twice daily) also reduced viremia in DHBV-infected ducks.Ole therefore warrants further investigation as a potential therapeutic agent for HBV infection.

Secoiridoid Glycosides fromSwertia mileensis

From the MeOH extract of the aerial parts of Swertia mileensis, four new secoiridoid glycosides were isolated, 4′-O-[(E)-caffeoyl]swertiamarin (1), 4′-O-[(Z)-coumaroyl]swertiamarin (7), 6′-O-[(E)-coumaroyl]swertiamarin (8), and 6′-O-[(Z)-coumaroyl]swertiamarin (9), together with five known compounds. Their structures were elucidated by NMR spectroscopy and tandem mass spectrometry. Detailed HPLC/MS analyses and MS/MS fragmentation pathways are discussed for the identification of the swertiamarin-derived (E)/(Z) isomers 6/7 and 8/9.

Isolation of iridoid and secoiridoid glycosides and comparative study on Radix gentianae and related adulterants by HPLC analysis

HPLC profile guided study led to the isolation of an acylated secoiridoid glycoside, named gentiotrifloroside ( 1), together with six known compounds, i.e., loganic acid ( 2), 6- O-β- d-glucopyranosylgentiopicroside ( 3), swertiamarin ( 4), gentiopicroside ( 5), sweroside ( 6) and 2 -( o, m-dihydroxybenzyl)-sweroside ( 7) from Gentiana triflora and Gentiana rigescens. The structure of 1 was deduced from one- and two-dimensional NMR spectroscopic experiments. Compounds 1– 7 were used successfully as chemical markers for the comparison of the four species of Gentiana used as Radix gentianae. Additionally, differentiation of Gentiana species mentioned and those used as adulterants was evaluated. The close similarity of chemical composition among the four genuine Gentiana species explain their popular usage as R. gentianae in Chinese medicine. We have also shown that the variation of chemical composition in R. gentianae and related adulterants agree well with their botanical phylogeny.

Gastroprotective effects of bitter principles isolated from Gentian root and Swertia herb on experimentally-induced gastric lesions in rats

Gentianae Radix, the dried root and rhizoma of Gentiana lutea L. (Gentianaceae), has long been used as a remedy for liver and stomach inflammation, eye troubles, etc. In this paper, the gastroprotective effects of the methanol extract of Gentian root (GM) were studied using different gastric lesion models. In pylorus-ligated rats, administration of GM in the duodenum suppressed gastric juice secretion and total acid output in a dose-dependent manner. Oral or duodenum administration of GM showed significant protection against acute gastric ulcer induced by aspirin plus pylorus ligation, water-immersion restraint stress-induced ulcers, and gastric mucosal injury induced by ethanol. Furthermore, four secoiridoid glycosides, amarogentin (A1), gentiopicroside (A2), amaroswerin (A3), and swertiamarin (A4), were obtained from Gentian root or Swertia herb, and their protective effects against stress-induced ulcers and ethanol-induced gastric mucosal injury were evaluated. The doses required for 50% inhibition (ID50) of A1, A3, and A4 on stress-induced ulcers were calculated to be 5.76, 2.58, and 167 mg/kg respectively. The protective effect of A2 at 250 mg/kg was 26.5%. On ethanol-induced gastritis, 5.0 mg/kg of A1 and A3 showed remarkable suppressive effects (33.7 and 45.4%, respectively), and 20 mg/kg of A4 exhibited a suppressive effect (30.8%). The effects of A1, A3, and A4 on ethanol-induced gastric lesions were canceled by 5.0 mg/kg indomethacin pretreatment. These results suggest that the therapeutic effects of Gentian root on gastric lesions are associated with enhanced mucosal defensive factors via the prostaglandin pathway in the cell membrane, and that secoiridoid glycosides contribute to this activity.

Secoiridoid Glycosides from Gentiana scabra

Six new secoiridoid glycosides, gentiascabraside A (1), 6beta-hydroxyswertiajaposide A (2), 1-O-beta-d-glucopyranosyl-4-epiamplexine (3), and scabrans G3 (4), G4 (5), and G5 (6), have been isolated from the rhizomes and roots of Gentiana scabra together with a known compound, swertiajaposide A (7). The structures of the new compounds were determined by spectroscopic (NMR, MS) and chemical means.

Studies on the Constituents of Swertia japonica MAKINO II. On the Structures of New Glycosides

Two new secoiridoid glycosides, swertiajaposide A (1) and swertiajaposide B (2), a new unsaturated alco-hol glycoside, 3-butenyl 6'-O-alpha-L-arabinopyranosyl-beta-D-glucopyranoside (3), and a new lignan glycoside, 7R,7'R,8S,8'S-(+)-neo-olivil-4-O-beta-D-glucopyranoside (4), were isolated together with six known compounds from the whole plants of Swertia japonica Makino. The structures of the new compounds were elucidated on the basis of chemical and spectroscopic evidence.

Identification and Antioxidant Potential of Flavonoids and Low Molecular Weight Phenols in Olive Cultivar Chemlali Growing in Tunisia

Increasing interest in phenolic compounds in olives is due to their antioxidant and health-enhancing properties. In this study the phenolics in fruits of the Tunisian olive cultivar Chemlali were extracted by methanol-water and fractionated using Sephadex LH-20 column chromatography. The identification of phenolic monomers and flavonoids was based on separation by high-performance liquid chromatography equipped with a diode array detector followed by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry analysis. Oleuropein, a secoiridoid glycoside esterified with a phenolic acid, was the major compound. Eight phenolic monomers and 12 flavonoids were also identified in Chemlali olives. Five flavonoids were isolated and purified using Sephadex LH-20 column chromatography and preparative paper chromatography. The antioxidant activity of the extract and the purified compounds was evaluated by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl and by using the beta-carotene-linoleate model assay. Acid hydrolysis of the extract enhanced its antioxidant activity. Hydroxytyrosol and quercetin showed antioxidant activities similar to that of 2,6-di-tert-butyl-4-methylphenol. A hydroxyl group at the ortho position at 3' on the B ring of the flavonoid nucleus could contribute to the antioxidant activity of the flavonoids.

A Rapid Method for the Isolation of Swertiamarin from Enicostemma littorale

We report a simple method for the isolation of swertiamarin, a secoiridoid glycoside, from the whole plant of Enicostemma littorale Blume. Methanol extract of defatted plant material when treated with diethyl ether gave a precipitate containing swertiamarin as one of the major components. Swertiamarin was separated from this precipitate by column chromatography over silica gel. The identity of the compound isolated was confirmed through infrared (IR), ultraviolet (UV), nuclear magnetic resonance (NMR), and mass spectra and melting point and co-chromatography with a reference standard on thin-layer chromatography (TLC). The purity of the compound was confirmed from the UV absorption spectrum, NMR, mass, high performance thin layer chromatography (HPTLC), and differential scanning calorimetry.

Secoiridoid glycoside and alkaloid constituents of Hydrangea chinensis.

A new secoiridoid glycoside, hydrachoside A (1), along with 14 known compounds, was isolated from the leaves of Hydrangea chinensis. The absolute stereochemistry of the side chain attached to C-15 on the secoiridoid glycoside hydrangenoside E (2) was determined by NMR spectral analysis. The structures of compounds 1 and 2 were elucidated on the basis of spectral data. The previously reported structure, hydrachine A (3), was revised as its epimer, (-)-neodichroine (4), a new compound.

Bioactivity of gentiopicroside from the aerial parts of Centaurium erythraea

Gentiopicroside ( 1), a secoiridoid glycoside isolated from the methanol extract of the aerial parts of Centaurium erythraea, has been assessed for antibacterial and free radical scavenging activities. General toxicity of 1 has also been determined by brine shrimp lethality bioassay.

Bioactivity of secoiridoid glycosides from Centaurium erythraea.

As part of our on-going search for bioactive compounds from Scottish plants, two secoiridoid glycosides, swertiamarin and sweroside, have been isolated from the aerial parts of Centaurium erythraea Rafn (Family: Gentianaceae) by reversed-phase preparative HPLC coupled with a photo-diode-array detector. The structures of these compounds were elucidated unambiguously by UV, FABMS and extensive 1D and 2D NMR spectroscopic analyses and also by comparing experimental data with literature data. Antibacterial, free radical scavenging activities and general toxicity of these glycosides have been assessed. Both compounds inhibited the growth of Bacillus cereus, Bacillus subtilis, Citrobacter freundii and Escherichia coli. While swertiamarin was also active against Proteus mirabilis and Serratia marcescens, sweroside inhibited the growth of Staphylococcus epidermidis. Swertiamarin and sweroside exhibited significant general toxicity in brine shrimp lethality bioassay and the LD50 values were 8.0 microg/ml and 34 microg/ml, respectively, whereas that of the positive control podophyllotoxin, a well known cytotoxic lignan, was 2.79 microg/ml. Chemotaxonomic implications of these compounds in the family Gentianaceae have also been discussed briefly.

Study on the change of coal water slurry particle size distribution before and after irradiation

Repetitive chromatography of the methanol extract of the roots of Gentiana tibetica afforded two new secoiridoid glycosides and a novel antifungal anthranilic acid derivative, together with β-sitosterol, daucosterol, oleanolic acid, loganic acid, gentiopicroside, sweroside, 2′-(2,3-dihydroxybenzoyl)sweroside, trifloroside, rindoside and macrophylloside A. The structures of the new products were determined mainly by spectroscopic methods as 8-hydroxy-10-hydrosweroside, isomacrophylloside and ethyl N-docosanoylanthranilate. Ethyl N-docosanoylanthranilate inhibited the growth of the human pathogenic fungi Candida albicans and Aspergillus flavus. The taxonomic significance of the constituent is discussed briefly.