Mariateresa Maldini

Metabolic profiling of roots of liquorice (Glycyrrhiza glabra) from different geographical areas by ESI/MS/MS and determination of major metabolites by LC-ESI/MS and LC-ESI/MS/MS.

Liquid chromatography electrospray mass spectrometry (LC-ESI/MS) has been applied to the full characterization of saponins and phenolics in hydroalcoholic extracts of roots of liquorice (Glycyrrhiza glabra). Relative quantitative analyses of the samples with respect to the phenolic constituents and to a group of saponins related to glycyrrhizic acid were performed using LC-ESI/MS. For the saponin constituents, full scan LC-MS/MS fragmentation of the protonated (positive ion mode) or deprotonated (negative ion mode) molecular species generated diagnostic fragment ions that provided information concerning the triterpene skeleton and the number and nature of the substituents. On the basis of the specific fragmentation of glycyrrhizic acid, an LC-MS/MS method was developed in order to quantify the analyte in the liquorice root samples. Chinese G. glabra roots contained the highest levels of glycyrrhizic acid, followed by those from Italy (Calabria).

Metabolite fingerprinting of Camptotheca acuminata and the HPLC-ESI-MS/MS analysis of camptothecin and related alkaloids.

The major phytochemical constituents, namely, alkaloids, flavonoids and ellagic acid derivatives, of leaves of Camptotheca acuminata were identified using high performance liquid chromatography (HPLC) coupled with electrospray mass spectrometry (ESI-MS) in extracts of plants cultivated in Italy and collected at different growth stages. Alkaloids related to camptothecin were identified and quantified by HPLC coupled with ESI-tandem mass spectrometry (MS/MS) employing, respectively, an ion trap and a triple quadrupole mass analyser. The fragmentation patterns of alkaloids related to camptothecin were analysed and a specific Multiple Reaction Monitoring HPLC-MS/MS method was developed for the quantitative determination of these constituents. The described method provides high sensitivity and specificity for the characterisation and quantitative determination of the alkaloids in C. acuminata.

Strong antioxidant phenolics from Acacia nilotica: Profiling by ESI-MS and qualitative–quantitative determination by LC–ESI-MS

Acacia nilotica (L.) Del. syn is a species rich in polyphenolic constituents, in which catechins are hypothesized to possess antioxidant properties and to play a role in the anti-inflammatory activity of several plants. Due to the complexity of catechin derivatives, the investigation of this class of natural compounds has been limited by difficulties in their separation. In this paper, rationalization of the phenolics occurring in the 80% EtOH extract of Acacia nilotica pods, on the basis of ESI-MS and ESI-MS/MS profiles, has been proposed. Additionally, an LC-ESI-MS qualitative study has been performed by using a C18 polar endcapped stationary phase. The fragmentation pattern obtained evidenced the presence in A. nilotica pods of galloylated catechin- and gallocatechin derivatives along with galloylated glucose derivatives. The structures were confirmed by NMR, after isolation of the pure compounds. In addition, the radical scavenging activities of extracts and pure compounds were investigated, by using the TEAC assay. Furthermore quantitative analyses were performed by LC-ESI-MS/MS, confirming the interest of this species as a rich source of very strong antioxidant principles.

'Moringa oleifera: study of phenolics and glucosinolates by mass spectrometry' †

Moringa oleifera is a medicinal plant and an excellent dietary source of micronutrients (vitamins and minerals) and health-promoting phytochemicals (phenolic compounds, glucosinolates and isothiocyanates). Glucosinolates and isothiocyanates are known to possess anti-carcinogenic and antioxidant effects and have attracted great interest from both toxicological and pharmacological points of view, as they are able to induce phase 2 detoxification enzymes and to inhibit phase 1 activation enzymes. Phenolic compounds possess antioxidant properties and may exert a preventative effect in regards to the development of chronic degenerative diseases. The aim of this work was to assess the profile and the level of bioactive compounds in all parts of M. oleifera seedlings, by using different MS approaches. First, flow injection electrospray ionization mass spectrometry (FI-ESI-MS) fingerprinting techniques and chemometrics (PCA) were used to achieve the characterization of the different plants organs in terms of profile of phenolic compounds and glucosinolates. Second, LC-MS and LC-MS/MS qualitative and quantitative methods were used for the identification and/or determination of phenolics and glucosinolates in M. oleifera.

Radical scavenging activity and LC-MS metabolic profiling of petals, stamens, and flowers of Crocus sativus L.

UNLABELLED Radical scavenging activities of Crocus sativus petals, stamens and entire flowers, which are waste products in the production of the spice saffron, by employing ABTS radical scavenging method, were determined. At the same time, the metabolic profiles of different extract (obtained by petals, stamens and flowers) were obtained by LC-ESI-IT MS (liquid chromatography coupled with electrospray mass spectrometry equipped with Ion Trap analyser). LC-ESI-MS is a techniques largely used nowadays for qualitative fingerprint of herbal extracts and particularly for phenolic compounds. To compare the different extracts under an analytical point of view a specific method for qualitative LC-MS analysis was developed. The high variety of glycosylated flavonoids found in the metabolic profiles could give value to C. sativus petals, stamens and entire flowers. PRACTICAL APPLICATION Waste products obtained during saffron production, could represent an interesting source of phenolic compounds, with respect to the high variety of compounds and their free radical scavenging activity.

Variability of chemical composition and antioxidant activity of essential oils between Myrtus communis var. Leucocarpa DC and var. Melanocarpa DC

Essential oils (EOs) from several individuals of Myrtus communis L. (M. communis) growing in different habitats in Sardinia have been studied. The analyses were focused on four groups of samples, namely cultivated and wild M. communis var. melanocarpa DC, characterized by red/purple berries, and cultivated and wild M. communis var. leucocarpa DC, characterized by white berries. Qualitative and quantitative analyses demonstrated different EO fingerprints among the studied samples: cultivated and wild leucocarpa variety differs mainly from the melanocarpa variety by a high amount of myrtenyl acetate (>200 mg/mL and 0.4 mg/mL in leucocarpa and melanocarpa varieties respectively). Conversely, the wild group is characterized by a higher amount, compared with the cultivated species, of linalool (about 110 mg/mL and 20 mg/mL respectively), linalyl acetate (about 24 mg/mL and about 6 mg/mL respectively) whereas EOs of the cultivated plants were rich in pinocarveol-cis compared with wild plants (about 2 mg/mL and about 0.5 mg/mL respectively). Principal component analysis applied to the chromatographic data confirm a differentiation and classification of EOs from the four groups of M. communis plants. Finally, antioxidant activity of the studied EOs shows differences between the various categories of samples.

Phenolic compounds from Byrsonima crassifolia L. bark: Phytochemical investigation and quantitative analysis by LC-ESI MS/MS

Phytochemical investigation of the methanolic extract of Byrsonima crassifolias bark led to the isolation of 8 known phenolic compounds 5-O-galloylquinic acid, 3-O-galloylquinic acid, 3,4-di-O-galloylquinic acid, 3,5-di-O-galloylquinic acid, 3,4,5-tri-O-galloylquinic acid, (+)-epicatechin-3-gallate along with (+)-catechin and (+)-epicatechin. Due to their biological value, in the present study, a high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, working in multiple reaction monitoring (MRM) mode, has been developed to quantify these compounds. B. crassifolia bark resulted in a rich source of phenolic compounds and particularly of galloyl derivates. The proposed analytical method is promising to be applied to other galloyl derivatives to quantify these bioactive compounds in raw material and final products.

Improvement of the nutraceutical quality of broccoli sprouts by elicitation.

Epidemiological studies show an inverse association between Brassica consumption and chronic diseases. Phytochemicals are thought to be beneficial for human health and therefore responsible for this protective effect. Increasing their levels into Brassica food is considered an expedient nutritional strategy that can be achieved through the manipulation of growth conditions by elicitors. In this work we systematically evaluated the influence of treatment with different elicitors (sucrose, mannitol, NaCl, 1-aminocyclopropane-L-carboxylic acid, salicylic acid and methyl jasmonate) on the phytochemical composition of broccoli sprouts. The content of total and single glucosinolates, total phenolic compounds, total flavonoids, total anthocyanins, vitamin C and E and β-carotene was assessed. The exposure to different elicitors produced concentration- and elicitor-dependent specific changes in the content of all the phytochemicals considered. Sucrose, identified as the most effective elicitor by principal component analysis, induced a significant increase of total and specific glucosinolates, vitamin C, total anthocyanins and polyphenols. Sucrose is likely to represent an effective tool to increase the nutritional value of broccoli sprouts.

Saponin Inventory from Argania spinosa Kernel Cakes by Liquid Chromatography and Mass Spectrometry

INTRODUCTION Argania spinosa kernel cakes, obtained from argan oil extraction process, are known to contain large amounts of saponins. Only a few have been characterised previously, due to the use of pure ethanol as extracting solvent. The use of aqueous 50% ethanol improved the extraction of more polar saponins. OBJECTIVE Identification of polar saponins in kernel cakes of Argania spinosa by liquid chromatography-mass spectrometry and NMR techniques. METHODS Defatted kernel cakes were first extracted with ethanol and then twice with 50% aqueous ethanol. Individual crude extracts were analysed with an ion-trap mass spectrometer in negative mode electrospray MS and MS/MS modes. NMR experiments were run under standard conditions at 300 K on a Bruker DRX-600 spectrometer. RESULTS The LC-MS base peak chromatogram of saponins from pure ethanol extract was dominated by 11 large and several small peaks but the UV chromatogram showed only two peaks, corresponding to the main neutral saponins found previously in Argania: arganine A and B. In 50% aqueous ethanol extracts, numerous other saponins were detected. Many of them were glucuronide oleanane-type triterpene carboxylic acid 3,28-O-bidesmosides (GOTCAB saponins). The assignments of (1) H- and (13) C-NMR spectra of the four most abundant GOTCAB saponins confirmed the MS results. CONCLUSION Four GOTCAB saponins were structurally identified by NMR analysis in the 50% aqueous ethanol extract. Furthermore, LC-MS analyses showed the presence of at least 19 additional polar saponins in these kernel cakes.

Flavanocoumarins from Guazuma ulmifolia bark and evaluation of their affinity for STAT1.

From the bark of Guazuma ulmifolia, a plant used as anti-inflammatory remedy, the flavanocoumarin epiphyllocoumarin (1) along with epiphyllocoumarin-[4β→8]-(-)-epicatechin (2) and epiphyllocoumarin-[4β→8]-(-)-epicatechin-[4β→8]-(-)-epicatechin (3), never reported before, have been isolated. The structures of the proantocyanidins 2-3 have been elucidated by extensive NMR and ESI-MS analysis. On the basis of the flavane nature of the isolated compounds and considering the strong anti-STAT1 activity reported for epigallocatechin 3-O-gallate (EGCG), the affinity of compounds 1-3 for STAT1 has been evaluated by Surface Plasmon Resonance. Compounds 1-2 showed affinity for STAT1 comparable to that exerted by EGCG. In order to confirm this result, molecular docking studies to evaluate the interactions of compounds 1-3, phyllocoumarin (4), the reference compound EGCG (5), and its related compound (+)-gallocatechin 3-O-gallate (6) with STAT1 have been carried out. Furthermore the ability of compounds 1-3 to inhibit STAT1 activation has been evaluated using a nuclear extract obtained from the human monocytic leukemia cell line TPH-1. Flavanocoumarins 1-2 inhibited STAT1-DNA binding.