Biomedical subjects
Publications and source records attributed to I Calis.
Two new aromatic monoterpenoid glycosides, cruciaside A (2,5-O-beta-D-diglucopyranosyl-3-hydroxy-p-cymene) (1) and cruciaside B (5-O-beta-D-glucopyranosyl-2,3-dihydroxy-p-cymene) (2), were isolated from aerial parts of Cruciata taurica. The structures of the new compounds were determined by spectral and chemical methods. The new compounds seem to be promising as taxonomic markers for C. taurica.
From the aerial parts of Putoria calabrica, two new flavonol triglycosides were isolated and their structures were elucidated as quercetin-3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside]-7-O-beta-D-glucopyranoside (1, calabricoside A) and quercetin-3-O-[4' "-O-caffeoyl-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside]-7-O-beta-D-glucopyranoside (2, calabricoside B). Additionally, seven iridoid and three lignan glycosides were isolated and characterized. Radical scavenging activities of all compounds were determined by quantifying their effects on luminol-enhanced chemiluminescence in formyl-methionyl-leucyl-phenylalanine (FMLP) stimulated human polymorphonuclear neutrophils (PMNs). Calabricoside A and B showed strong radical scavenging activity with IC(50) values of 0.25 and 0.3 microM, respectively.
Four new phenolic glycosides, beta-apiofuranosyl-(1-->2)-beta-glucopyranosides (1-4), along with the cycloartane triterpenes 20(R),25-epoxy-3beta,6alpha,16beta,24alpha-tetrahydroxycycloartane (5) and 20(R),24(S)-epoxy-3beta,6alpha,25-trihydroxycycloartan-16-one (6) were isolated from roots of Astragalus zahlbruckneri. The structure elucidation of all compounds was based on their (1)H and (13)C NMR spectral data including 1D-TOCSY, DQF-COSY, HSQC, and HMBC experiments.
Three new cycloartane-type triterpene glycosides have been isolated from the aerial parts of Astragalus trojanus. The structures were established mainly by a combination of one- and two-dimensional NMR techniques [1H-1H-correlation spectroscopy (COSY), 1H-13C-heteronuclear multiple quantum correlation spectroscopy (HMQC), and 1H-13C-heteronuclear multiple-bond correlation spectroscopy (HMBC)] and high resolution electrospray ionization mass spectrometry (HR-ESI-MS) as 3-O-beta-(2',3'-di-O-acetyl)-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-16-O- acetoxy-20(R),24(S)-epoxycycloartane-3beta,6alpha,16beta,25-tetrol, 3-0-[alpha-L-rhamnopyranosyl-(1-->2)-beta-(3',4'-di-O-acetyl)-D-xylopyranosyll-6-O-beta-D-xylopyranosyl-20(R),24(S)-epoxycycloartane-3p,6alpha,16beta,25-tetrol, 3-O-beta-D-xylopyranosyl-6,16-di-O-beta-D-glucopyranosyl-20(R)24(S)-epoxycycloartane-3beta,6alpha,16beta,25-tetrol.
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Four new bisanthraquinone glycosides, S-(+)-skyrin-6-O-beta-glucopyranoside (1), R-(-)-skyrin-6-O-beta-glucopyranoside (2), S-(+)-skyrin-6-O-beta-xylopyranoside (3) and S-(+)-skyrin-6-O-beta-alpha-arabinofuranoside (4), have been isolated from an ethanol-water (1:1, v/v) dry extract of the aerial parts of Hypericum perforatum L. The structures were elucidated by spectroscopic methods, mainly NMR and mass spectrometry. Circular dichroism was used to determine their axial stereochemistry revealing 1 and 2 to be atropisomers. 1 and 2 inhibited [125I]sauvagine binding to corticotropin releasing hormone (CRH-1) receptors.
Radical scavenger activities of 21 phenylethanoid glycosides, including 15 ester derivatives of caffeic, ferulic, vanillic and syringic acid as well as 6 deacyl derivatives were determined by quantifying their effects on the production of reactive oxygen species (ROS) in a luminol-enhanced chemiluminescence assay with formyl-methionyl-leucyl-phenylalanine (FMLP) stimulated human polymorphonuclear neutrophils (PMNs). All phenylethanoids acylated with phenolic acids showed strong antioxidant activity whereas the deacyl derivatives were more than 30-fold less active. Therefore, the antioxidant activity is mainly related to the number of aromatic methoxy and hydroxy groups and the structure of the acyl moiety (C6-C1 or C6-C3). In contrast, modification of the sugar chain or replacement of hydroxy groups by methoxy groups in the acyl or the phenylethanoid moiety is of minor importance. The position of the acyl moiety is without significance. Free caffeic, ferulic, vanillic and syringic acid are less active compared to the phenylethanoid derivatives. This points to the importance of dissociation and lipophilicity of these acids in a cellular test system.
In the course of our research on the oligoglycosidic constituents of Turkish Astragalus species, we have isolated a number of cycloartane-type triterpene glycosides. The current study examines the immunostimulatory effects of nineteen of these cycloartane-type compounds using a transcription-based bioassay for Nuclear Factor kappa B (NF-kappaB) activation in a human macrophage/monocyte cell line, THP-1. All compounds were inactive at 100 microg/ml except astragaloside I which increased NF-kappaB directed luciferase expression to levels about 65% as compared with maximal stimulation by E. coli lipopolysaccharide (LPS) at 10 microg/ml. None of the compounds were active at low dosage levels (0.1 microg/ml) in combination with 50 ng/ml LPS. Astragaloside I also increased mRNA expression of the inflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) as measured using reverse transcriptase-polymerase chain reaction (RT)-PCR. Based on these results it is clear that certain structural features are required for immunostimulation of cycloartane-type triterpene glycosides.
Macrophyllosaponin E, a novel cycloartane-type triterpene, has been isolated from the roots of Astragalus oleifolius. The structure elucidation of the compound was achieved by a combination of one- and two-dimensional NMR techniques [1H-1H-correlation spectroscopy (COSY), 1H-13C-heteronuclear multiple guantum correlation spectroscopy (HMQC), and 1H-13C-heteronuclear multiple-bond correlation spectroscopy (HMBC)l and high resolution electrospray ionization Fourier transformation mass spectrometry (HR-ESI-FT-MS).
A new flavonol glycoside, isorhamnetin 3-O-beta-D-apiofuranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-galactopyranoside, and the known diglycoside, isorhamnetin 3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-galactopyranoside were isolated from the aerial parts of Astragalus vulneraria. Characterization of the two compounds was done by spectroscopic methods (1D and 2D NMR, and FAB-MS).
Two new oleanene glycosides (1-2) possessing hederagenin as the aglycone were isolated from the methanolic extract of the aerial parts of Caltha polypetala together with four known glycosides. The saccharide portion linked to C-3 of the aglycone is made up of alpha-L-arabinopyranose, alpha-L-rhamnopyranose and galactopyranose in the new compounds; while compound 1 possesses linked to C-28 a trisaccharide moiety made up of two beta-D-glucopyranose and one alpha-L-rhamnopyranose unit, in compound 2 the 28-COOH group is free. The structures were elucidated by 1D and 2D NMR experiments including 1H-1H (DQF-COSY, 1D-TOCSY, 2D-ROESY) and 1H-13C (HSQC, HMBC) spectroscopy.
Two new iridoid glucosides, 6-O-acetylajugol (1) and 7, 8-epoxy-8-epi-loganic acid (2), together with five known iridoid glucosides, galiridoside (3), ajugoside (4), 10-deoxygeniposidic acid (5), 7-deoxy-8-epi-loganic acid (6), and 8-O-acetylharpagide (7), have been isolated from the aerial parts of Leonurus persicus. Leucosceptoside A (8), eugenyl beta-rutinoside (9), and kaempferol 3-O-glucoside (10) were also isolated. The structures of 1 and 2 were elucidated by extensive 1D- and 2D-NMR spectroscopy and molecular modeling. The structure of 3 was confirmed by single-crystal X-ray diffraction. Antimicrobial activity of compounds (1-10) was also evaluated against a panel of gram-positive and gram-negative bacteria and two strains of fungi.
Six novel cycloartane-type glycosides were isolated from the roots of Astragalus trojanus. Two of these, compounds 1 and 2, have (20R, 24S)-epoxy-3beta,6alpha,16beta,25-tetrahydroxycycloartane as the aglycon, while compounds 3-6 possess 3beta,6alpha,16beta,(24S), 25-pentahydroxycycloartane as the aglycon. The saccharide moieties linked to the C-3, C-6, and C-24 or C-25 positions of the aglycons in 1-6 contained either xylopyranose, glucopyranose, rhamnopyranose, or arabinopyranose units. Structure elucidation of compounds 1-6 was accomplished through the extensive use of 1D and 2D NMR techniques. In addition, a new oleanene glycoside (7) and a new tryptophan derivative (8) were also isolated and characterized.
Five phenylethanoid glycosides, crenatoside (= oraposide) (1), verbascoside (= acteoside) (2), trichosanthoside A (3), rossicaside A (4), and trichosanthoside B (5), were isolated from the aerial parts of Globularia trichosantha. Compounds 3 and 5 are new natural compounds, and their structures were established as 3, 4-dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1-->4)-alpha -L- rhamnopyranosyl-(1-->3)-4-O-caffeoyl-beta-D-glucopyranoside and 3, 4-dihydroxy-beta-phenylethoxy-O-[beta-D-xylopyranosyl-(1-->4)-alph a-L -rhamnopyranosyl-(1-->3)]-[beta-D-xylopyranosyl-(1-->6)]-4-O-caffeoyl -beta-D-glucopyranoside, respectively. The structures of all compounds were established by spectral evidence. Compounds 1-5 also demonstrated scavenging properties toward the 2, 2-diphenyl-1-picrylhydrazyl radical in TLC autographic assays.
(3R)-O-beta-D-Glucopyranosyloxy-5-phenylvaleric acid (1), (3R)-O-beta-D-glucopyranosyloxy-5-phenylvaleric acid n-butyl ester (2), and a new dihydrochalcone diglycoside 4'-O-[beta-D-glucopyranosyl-(1-->6)-glucopyranosyl]oxy-2'-hydroxy-3', 6'-dimethoxydihydrochalcone (3), together with six known flavonoid glycosides [kaempferol-3-O-beta-D-glucopyranoside (= astragalin) (4), kaempferol-3-O-beta-D-galactopyranoside (5), quercetin-3-O-beta-D-glucopyranoside (= isoquercitrin) (6), quercetin-3-O-beta-D-galactopyranoside (= hyperoside) (7), quercetin-3-O-(2''-O-galloyl)-beta-D-glucopyranoside (8), and quercetin-3-O-beta-D-glucuronopyranoside (9)] were isolated from the aerial parts of Polygonum salicifolium. The structure elucidation of the isolated compounds was performed by spectroscopic (UV, IR, ESI-MS, 1D- and 2D-NMR), chemical (methylation, enzymatic hydrolysis, partial synthesis), and chromatographic methods (HPLC, Chiralcel OD). The flavonoid glycosides (4-9) demonstrated scavenging properties toward the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical in TLC autographic assays.
The stem bark of the Brazilian medicinal plant Zizyphus joazeiro C. Mart. was phytochemically investigated. Three known compounds (betulinic, ursolic and alphitolic acid) and three new derivatives of betulinic acid, 7 beta-(4-hydroxybenzoyloxy)-betulinic acid, 7 beta-(4-hydroxy-3'-methoxybenzoyloxy)-betulinic acid and 27-(4-hydroxy-3'-methoxybenzoyloxy)-betulinic acid which showed a considerable activity against Gram-positive bacteria were isolated from the dichloromethane extract. The structures were established on the basis of NMR spectroscopy and mass spectrometry.
Four new allose-containing triterpenoid saponosides, scabriosides A, B, C and D were isolated from the roots of Scabiosa rotata. Their structures were established as 3-O-beta-D-xylopyranosyl-28-O-[beta-D-allopyranosyl (1-->6)-beta-D-glucopyranosyl]-pomolic acid, 3-O-[alpha-L-rhamnopyranosyl (1-->2)-beta-D-xylopyranosyl]-28-O-[beta-D-allopyranosyl (1-->6)-beta-D-glucopyranosyl]-pomolic acid, 3-O-[alpha-L-rhamnopyranosyl (1-->2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-allopyranosyl (1-->6)-beta-D-glucopyranosyl]-pomolic acid, and 3-O-[beta-D-glucopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->2)-beta-D-xylopyranosyl]-28-O-[beta-D-allopyranosyl(1-->6) -beta-D-glucopyranosyl]-pomolic acid, respectively, by the help of spectral evidence (IR, 1D- and 2D-NMR, FAB-MS).
Three new cycloartane-type triterpene glycosides, brachyosides A (1), B (3), and C (2), from the roots of Astragalus brachypterus and one new glycoside, cyclocephaloside II (4), from the roots of Astragalusmicrocephalus have been isolated together with five known saponins, astragalosides I, II, and IV, cyclocanthoside E, and cycloastragenol. The structures of the new compounds were established as 3-O-[beta-D-xylopyranosyl(1-->3)-beta-D-xylopyranosyl-6-O-beta-D-gluc opyranosyl-3beta,6alpha,16beta,24(S),25-pentahydrox ycycloartane (1), 3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-24-O-beta-D-glucop yranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxyc ycloartane (2), 20(R),24(S)-epoxy-6-O-beta-D-glucopyranosyl-3beta,6alpha,16beta , 25-tetrahydroxycycloartane (3), and 20(R), 24(S)-epoxy-3-O-(4'-O-acetyl)-beta-D-xylopyranosyl-6-O-beta-D-glucopy ranosyl-3beta,6alpha,16beta,25-tetrahydroxycycloart ane (4). For the structure elucidations, 1D- and 2D-NMR experiments and FABMS were used.