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ABSTRACT: The allelopathic potential of oat (Avena sativa L., var. Argentina, Poaceae, Cyperales) was investigated under field and laboratory conditions. In field trials, oat plants
provided an effective control of weeds, showing a species-specific impact: the most abundant weed species, Picris echioides was reduced by 94% in number of individuals. Aerial parts of oat plants, harvested immediately before soil incorporation,
were utilized in a bioassay-guided isolation, which was aimed at identifying the phytotoxic compounds in a methanol/water
extract of the aerial parts of the plants. Further partitions of extract gave an active n-butanol portion composed of flavonoids and saponins. Phytotoxic activity was detected for the flavonoid fraction, whereas
no activity was found for the saponin mixture. Germination of an indicator species, lettuce (Lactuca sativa L.), was completely inhibited at flavonoid concentrations of 6.7, 10.0, and 20.0mg/mL, and conversely the number of abnormal
seedlings was greatly increased from 2% of control to over 96% at concentrations equal to 6.7 and 10.0mg/mL. Analysis of
the flavonoid fraction by ESI-MS techniques identified two components of the mixture as isoorientin 2-O-glucoside and isovitexin 2″-O-arabinoside. Saponins were characterized as avenacoside A, avenacoside B, 26-desglucoavenacoside A, and 26-desglucoavenacoside
B. Both flavone C-glycosides and saponins were isolated previously from oat.
Chemoecology 04/2012; 19(3):169-176. · 1.56 Impact Factor
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ABSTRACT: Six compounds, eudesm-11(13)-en-4beta,9beta-diol, 15R,16-dihydroxy-3-oxoisopimar-9(11)-ene, 15S,16-dihydroxy-3-oxoisopimar-9(11)-ene, 1alpha-hydroxy-7-oxo-iso-anhydrooplopanone, 10alpha-hydroxy-11,13-dihydro-5-epi-psilostachyin, and 4beta-hydroxypseudoguaian-12,6-olide 4-O-beta-d-glucopyranoside, together with 12 known sesquiterpenes, were isolated from the leaves of Ambrosia arborescens. Structures were elucidated by 1D and 2D NMR spectroscopy including 1D-TOCSY, DQF-COSY, 2D-ROESY, HSQC, and HMBC experiments, as well as by ESI mass spectrometry. The absolute configuration of the 15,16-diol moiety in 15R,16-dihydroxy-3-oxoisopimar-9(11)-ene and 15S,16-dihydroxy-3-oxoisopimar-9(11)-ene was determined using Snatzke's method. All compounds were evaluated for antiproliferative activity.
Phytochemistry 02/2010; 71(7):804-9. · 3.35 Impact Factor
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ABSTRACT: From the n-butanol extract of the aerial parts of Exellodendron coriaceum (Benth.) Prance the flavonoids quercetin-3-O-beta-D-galactopyranoside (1), quercetin-3-O-alpha-L-arabinopyranoside (2), quercetin-3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-rhamnopyranoside (3), and quercetin-3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-galactopyranoside (4) were isolated. Additionally from this extract three flavonoids were isolated and partially characterized as quercetin glycosides. All these compounds were tested for their hypoglycemic activity using the glucose-6-phosphatase microsomal hepatic system. The flavonoids inhibited the activity of the enzyme when intact microsomes were used, the highest percentage of inhibition being 65%. To the best of our knowledge, this is the first report of chemical and biological activity of E. coriaceum.
Natural product communications 12/2009; 4(12):1657-9. · 1.24 Impact Factor
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ABSTRACT: Tramadol is a centrally acting analgesic drug that has been used clinically for the last two decades to treat pain in humans. The clinical response of tramadol is strictly correlated to its metabolism, because of the different analgesic activity of its metabolites. O-Desmethyltramadol (M1), its major active metabolite, is 200 times more potent at the micro-receptor than the parent drug. In recent years tramadol has been widely introduced in veterinary medicine but its use has been questioned in some species. The aim of the present study was to develop a new sensible method to detect the whole metabolic profile of the drug in horses, through plasma analyses by high-performance liquid chromatography (HPLC) coupled with fluorimetric (FL) and photodiode array electrospray ionization mass spectrometric (PDA-ESI-MS) detection, after its sustained release by oral administration (5 mg/kg). In HPLC/FL experiments the comparison of the horse plasma chromatogram profile with that of a standard mixture suggested the identification of the major peaks as tramadol and its metabolites M1 and N,O-desmethyltramadol (M5). LC/PDA-ESI-MS/MS analysis confirmed the results obtained by HPLC/FL and also provided the identification of two more metabolites, N-desmethyltramadol (M2), and N,N-didesmethyltramadol (M3). Another metabolite, M6, was also detected and identified. The present findings demonstrate the usefulness and the advantage of LC/ESI-MS/MS techniques in a search for tramadol metabolites in horse plasma samples.
Rapid Communications in Mass Spectrometry 12/2008; 23(2):228-36. · 2.79 Impact Factor
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ABSTRACT: Five new oleanane saponins (1-5) together with four know flavonol glycosides were isolated from the aerial parts of Stylosanthes erecta. Their structures were elucidated by 1D and 2D NMR experiments including 1D-TOCSY, DQF-COSY, ROESY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis. The aglycone moieties of 1-4 were assigned as new oleanane derivatives.
Journal of Natural Products 07/2007; 70(6):979-83. · 3.13 Impact Factor
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ABSTRACT: Glycoconjugates are a class of complex molecules that are widely distributed in the plant kingdom and in some marine organisms. This class of compounds has a wide range of biological activities such as anti-inflammatory, antimicrobial, antifungal, anticancer, antiulcer, and immunoenhancing actions.1-3 Some of them also show various toxic activities such as cytotoxic, hemolytic, cardiotoxic, and teratogenic. Among these compounds, steroidal and triterpenoid saponins have long been known as components of widely used herbal drugs and pharmaceutical preparations; ginseng, Tribulus terrestris, Quillaja saponaria, and Digitalis ssp. are just a few examples. Thus, identification of saponins in herbal drugs used worldwide is of significance in phytochemical and toxicological quality control studies, and for the production of safe health products. Therefore, there is continuing demand for methods to rapidly identify and characterize these natural products.
Rapid Communications in Mass Spectrometry 02/2007; 21(3):286-96. · 2.79 Impact Factor
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ABSTRACT: Arbutus unedo L., the strawberry tree (Ericaceae family), is an evergreen shrub or small tree, typical of the Mediterranean fringe and climate. The aim of the present study was to evaluate the profile of the phenolic constituents of A. unedo fruits. Seven compounds were purified by Sephadex LH-20 column chromatography of the MeOH extract followed by HPLC and were characterized as arbutin, beta-D-glucogalline, gallic acid 4-O-beta-D-glucopyranoside, 3-O-galloylquinic acid, 5-O-galloylquinic acid, 3-O-galloylshikimic acid, and 5-O-galloylshikimic acid, by means of NMR and ESI-MS analyses. Moreover, LC-PDA-MS analysis of the red pigment of A. unedo fruits revealed the presence of three anthocyanins recognized as cyanidin 3-O-beta-D-galactopyranoside, delphinidin 3-O-beta-D-glucopyranoside, and cyanidin 3-O-beta-D-arabinopyranoside. These pigments were also quantified.
Journal of Agricultural and Food Chemistry 01/2007; 54(26):10234-8. · 2.82 Impact Factor
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ABSTRACT: Thirteen oleanane saponins (1-13), four of which were new compounds (1-4), were isolated from Pteleopsis suberosa Engl. et Diels stem bark (Combretaceae). Their structures were determined by 1D and 2D NMR spectroscopy and ESI-MS spectrometry. The compounds were identified as 2alpha,3beta,19alpha,23,24-pentahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (1), 2alpha,3beta,19beta,23,24-pentahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (2), 2alpha,3beta,19alpha,23-tetrahydroxy-11-oxo-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester (3), and 2alpha,3beta,6beta,19alpha,24-pentahydroxy-11-oxo-olean-12- en-28-oic acid 28-O-beta-D-glucopyranosyl ester (4). The presence of alpha,beta-unsaturated carbonyl function was not common in the oleanane class and the aglycons of these compounds were not found previously in the literature. Moreover, the isolated compounds were tested against Helicobacter pylori standard and vacA, and cagA clinical virulence genotypes. Results showed that compound 6 has an anti-H. pylori activity against three metronidazole-resistant strains (Ci 1 cagA, Ci 2 vacA, and Ci 3).
Phytochemistry 01/2007; 67(24):2623-9. · 3.35 Impact Factor
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ABSTRACT: In this work we describe the chemical composition of Pteleopsis suberosa (Combretaceae) leaf extract and its biological activity against androgen-insensitive human prostate cancer cells (DU-145). The methanol extract of the plant leaves exhibited activity against tumor cell growth. Fractionation of this active extract led to the isolation and identification of sixteen flavonoids, including gallocatechin and flavonols having kaempferol, quercetin, and myricetin as aglycones. Among the myricetin derivatives, myricetin 3-O-(3''-acetyl)-alpha-L-arabinopyranoside (1) and myricetin 3-O-(4''-acetyl)-alpha- L-arabinopyranoside (2) are now reported for the first time. Six compounds, myricetin 3-O-alpha- L-rhamnopyranoside (4), myricetin 3-O-beta-D-galactopyranoside (7), myricetin 3-O-(6''-galloyl)-beta-D-galactopyranoside (9), myricetin 3-O-beta-D-xylopyranoside (10), myricetin 3-O-alpha-L-arabinofuranoside (12), and gallocatechin (14), exhibited significant activity, reducing cell vitality and inducing apoptosis via the caspase-dependent pathway in DU-145 cells that can be, in part, correlated to modulation of redox-sensitive mechanisms.
Planta Medica 07/2006; 72(7):604-10. · 2.15 Impact Factor
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ABSTRACT: Twenty-seven new pregnane glycosides were isolated from the whole plant of Caralluma dalzielii, and their structures elucidated from extensive 2D NMR analysis as well as ESI-MS experiments. All isolated compounds were tested for their antiproliferative activity on J774.A1, HEK-293, and WEHI-164 cell lines. Moderate to high potency of cytotoxicities were found in almost all tested compounds, confirming the significant cytotoxic activity of pregnane glycosides.
Steroids 09/2005; 70(9):573-85. · 2.83 Impact Factor
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ABSTRACT: The pyrrolizidine alkaloid (PA) content of flowers, leaves, and roots of Anchusa strigosa (Boraginaceae) was analysed by ESI-LC-MS. Six PAs, including two new natural compounds, were detected, characterized by NMR spectroscopy, and quantified in each plant organ. The results indicated that the highest total concentration of PAs was in the leaves (23.63 mg/g of dried part), followed by the flowers (19.77 mg/g), and finally by the roots (1.80 mg/g). All PAs isolated were subjected to Spodoptera exigua and Pieris brassicae larvae. Feeding activity by both herbivore species using a bioassay was inhibited up to circa 75% depending on PA and applied concentration.
Phytochemistry 08/2005; 66(13):1593-600. · 3.35 Impact Factor
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ABSTRACT: Pregnane glycosides are a class of naturally occurring substances characterized by some interesting biological activities and widely distributed in the plant kingdom and in some marine organisms. Their toxicity and use in herbal drugs and folk medicines has generated great interest in the chemical characterization of these molecules. In the study reported here the potential of electrospray ionization mass spectrometry (ESI-MS) in the identification and structural characterization of pregnane glycosides was examined. ESI-MS/MS and ESI-MS(n) analyses were performed on 27 different compounds employing two mass spectrometers equipped with a triple-quadrupole or an ion-trap analyzer. The data illustrate the ability of the ESI techniques in the identification of pregnane glycosides, including the nature of the pregnane core, the kind of ester substituents, the types of sugar residues (hexose, deoxyhexose, dideoxyhexose, O-methyldeoxyhexose and O-methyldideoxyhexose), and the primary structure of the saccharide chain. From these data, a generalized fragmentation pathway was proposed by comparing the spectra acquired for all the compounds. Interestingly, similar results were obtained from the two instruments, thus demonstrating that detailed analyses of product ion spectra obtained using a triple-quadrupole mass spectrometer led to structural information comparable to those obtainable in MSn experiments using an ion trap. Different and complementary information was deduced by fragmenting the [M+H]+ or the [M+Na]+ ions, or the protonated aglycone [Agl+H]+ generated by in-source fragmentation. The present evidence clearly suggests that, in order to obtain a complete characterization of pregnane glycosides by MS, all three of these species should be accurately analyzed.
Rapid Communications in Mass Spectrometry 02/2005; 19(8):1041-52. · 2.79 Impact Factor
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ABSTRACT: Three new phenolic compounds, 1-galloyl-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside (1), 2-methoxy-5-(1 '2 3'-trihydroxypropyl)-phenyl- 1-0-(6"-galloyl)-beta-D-glucopyranoside (2),and 2-methoxy-5-hydroxymethyl-phenyl-1-O-(6"-galloyl)-beta-D-glucopyranoside (3), together with the known compounds benzyl 6'-O-galloyl-beta-D-glucopyranoside (4), 1,6-di-O-galloyl-beta-D-glucopyranose (5), myrciaphenone B (6), kaempferol 3-0-(6"-galloyl)-beta-D-glucopyranoside (7), quercetin 3-0-(6"-galloyl)-beta-D-glucopyranoside (8), vomifoliol 9-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside, 2,3-dihydrobenzofuran-2-(4'-hydroxy-3'-methoxyphenyl)-3-alpha-L-rhamnopyranosyloxymethyl-7-methoxy-5-propanol, and benzyl-O-alpha-L-rhamnopyranosyl-(1-->6)-Beta-D-glucopyranoside were isolated from the leaves of Baseonema acuminatum P. Choux (Asclepiadaceae). Their structures were determined by 1D- and 2D-NMR spectroscopy and by ESI-MS analysis. The antimicrobial activity of all compounds was evaluated in vitro against bacteria (Staphylococcus aureus two strains, Bacillus cereus, Bacillus subtilis, Escherichia coli, Salmonella thyphimurium) and three strains of Candida albicans. The new compounds 2 and 3, together with the known compound 4, showed antifungal activity against two clinically isolated Candida albicans strains and against C. albicans ATCC 2091; MIC values were in the range of 25-100 microg/mL. Compound 5 was active against the two clinically isolated strains of C. albicans with MICs of 12.5 microg/mL and 25 microg/mL. Compounds 1, 6, 7, and 8 inhibited only one strain of C albicans at the maximum concentration used. None of the phenolic compounds tested was active against the bacteria studied.
Planta Medica 10/2004; 70(9):841-6. · 2.15 Impact Factor
