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Cataldi TR Rubino A Lelario F Bufo SA 《Rapid communications in mass spectrometry : RCM》2007,21(14):2374-2388
A method for the comprehensive profiling of intact glucosinolates (GLSs), major and minor, occurring in leaves and seeds of rocket salad (Eruca sativa L.) is presented using optimized reversed-phase liquid chromatography (RP-LC) with electrospray ionization (ESI) ion trap mass spectrometry (ITMS). ESI-ITMS in the negative mode was confirmed to be very suitable to analyze these compounds in crude extracts. After extraction from the plant material with methanol/water (70:30 v/v) at 70 degrees C, the analytes of interest were separated on a C18 column using an eluent acidified with formic acid (0.1%) and modified with acetonitrile. All the GLSs found in leaves of rocket salad gave good signals corresponding to the deprotonated precursor ion, [M-H]-. Although the mass spectra also exhibited an analytically important non-covalent adduct ion at [2M-H]-, the structures of glucosinolates were confirmed by extensive sequential MS analysis, thereby substantially improving the identification of unknown compounds. The results obtained not only revealed in leaves of E. sativa at least twelve species of GLSs including seven aliphatic compounds (glucoraphanin with [M-H]- at m/z ratio of 436, glucoerucin at m/z 420, 4-mercaptobutyl-GLS at m/z 406, progoitrin/epiprogoitrin at m/z 388, sinigrin at m/z 358, 4-methylpentyl- and n-hexyl-GLS at m/z 402) and three indole glucosinolates (i.e., three N-heterocyclic compounds: 4-hydroxyglucobrassicin and 5-hydroxyglucobrassicin at m/z 463, and 4-methoxy-glucobrassicin at m/z 477), but also two structurally related compounds containing one intermolecular disulfide linkage (4-(beta-D-glucopyranosyldisulfanyl)butyl-GLS at m/z 600 and a dimeric 4-mercaptobutyl-GLS at m/z 811). This latter symmetric disulfide was previously considered as an artefact formed during extraction of GLSs from vegetative tissues. Glucosinolates were detected in the leaves with a wide range of contents (10-200 micromol/g) and a great variation in the composition. Only three GLSs were identified in seeds of rocket salad, namely glucoraphanin, glucoerucin and 4-methoxyglucobrassicin. As expected, the most abundant GLS in seeds is glucoerucin. The feasibility of the strategy was also demonstrated using a rapeseed extract of certified reference material (BCR367R). The results indicated the usefulness of this method for a rapid, sensitive and comprehensive profiling of the GLS family naturally occurring in extracts of crude plant matter. 相似文献
203.
Dal Piaz F De Leo M Braca A De Simone F De Tommasi N 《Rapid communications in mass spectrometry : RCM》2007,21(3):286-296
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. 相似文献
204.
Tarozzi A Marchesi A Hrelia S Angeloni C Andrisano V Fiori J Cantelli-Forti G Hrelia P 《Photochemistry and photobiology》2005,81(3):623-629
Ultraviolet-A (UVA) radiation causes significant oxidative stress because it leads to the generation of reactive oxygen species (ROS), leading to extensive cellular damage and eventual cell death either by apoptosis or necrosis. We evaluated the protective effects of cyanidin-3-O-beta-glucopyranoside (C-3-G) against UVA-induced apoptosis and DNA fragmentation in a human keratinocyte cell line (HaCaT). Treatment of HaCaT cells with C-3-G before UVA irradiation inhibited the formation of apoptotic cells (61%) and DNA fragmentation (54%). We also investigated antioxidant properties of C-3-G in HaCaT cells against ROS formation at apoptotic doses of UVA; C-3-G inhibited hydrogen peroxide (H2O2) release (an indicator of cellular ROS formation) after UVA irradiation. Further confirmation of the potential of C-3-G to counteract UVA-induced ROS formation comes from our demonstration of its ability to enhance the resistance of HaCaT cells to the apoptotic effects of both H2O2 and the superoxide anion (O2*-), two ROS involved in UVA-oxidative stress. Furthermore, in terms of Trolox Equivalent Antioxidant Activity, C-3-G treatment led to a greater increase in antioxidant activity in the membrane-enriched fraction than in the cytosol (55% vs 19%). The protective effects against UVA-induced ROS formation can be attributed to the higher membrane levels of C-3-G incorporation. These encouraging in vitro results support further research into C-3-G (and other anthocyanins) as novel agents for skin photoprotection. 相似文献
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In this work the separation of eighteen flavonoids was attempted using reduced-flow micellar elektrokinetic chromatography (RF-MEKC) electrolytes modified by selected solvents with differing properties: methanol (MeOH), acetonitrile (ACN) and tetrahydrofuran (THF). Structural aspects such as unsaturation of the C ring, number and position of OH groups, methylation and glycosylation as well as solvent effects and their impact on the electrophoretic behavior of flavonoids were addressed. By evaluating the electropherograms obtained from mixture-designed electrolytes and searching for changes in the critical pairs, a favorable separation condition was achieved using 20 mmol/L phosphate buffer at pH 2.5 containing 50 mmol/L sodium dodecyl sulfate (SDS), 15% ACN and 5% THF (one critical pair) in less than 12 min with 1.5% coefficient of variation (CV) for retention factor and 3% CV for peak area (n = 5). The applicability of the proposed separation condition was demonstrated by the inspection of flavonoids in herbal extracts of Neem. 相似文献
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