Simona Piccolella

Influence of seasonal variation on Thymus longicaulis C. Presl chemical composition and its antioxidant and anti-inflammatory properties.

Thymus longicaulis C. Presl. (Lamiaceae) is a small aromatic perennial herb typical of the Illyric-Mediterranean flora, traditionally used as remedy for cold, flu, cough, nephritis and abdominal pain. In order to carry out a thorough chemical and biological screening of the plant and to explore phenophases influence on its polyphenol content, samples of the plant were collected at different phases during its life cycle (July/October 2012 and January/April 2013). Each sample, previously extracted using a hydroalcoholic solution, was phytochemically analyzed for its metabolic constitution applying LC-DAD-ESI-MS/MS techniques. Although identified metabolites were differently concentrated at the various collection times, T. longicaulis leaf extracts were mainly constituted by low molecular weight phenols, and flavonoids. Rosmarinic acid was found as the main metabolite in Oct12 sample. Chemopreventive efficacy of the investigated extracts, by means of their anti-inflammatory, cytotoxic and antioxidant activities, was assessed. To this purpose, each extract underwent an extensive screening towards five human cell lines: CCRF-CEM (leukemia); U251 (glioblastoma); MDA-MB-231 (breast cancer); HCT-116 (colon cancer) and MRC-5 (lung fibroblasts) through XTT [2,3bis(2-metoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H tetrazolium hydroxide] test. The ability of the extracts to counteract cyclooxygenase-2 (COX-2) expression was also evaluated by COX-2 expression assay in human THP-1 monocyte-derived macrophages. COX-2 inhibition could represent a valuable anticancer strategy as it is associated with carcinogenesis and over-expressed in a variety of human malignancies. Oct12 extract, which was particularly rich in rosmarinic acid and methylapigenin, exhibited a strong antioxidant and anti-inflammatory effectiveness.

Durum wheat seedling responses to simultaneous high light and salinity involve a fine reconfiguration of amino acids and carbohydrate metabolism

Durum wheat plants are extremely sensitive to drought and salinity during seedling and early development stages. Their responses to stresses have been extensively studied to provide new metabolic targets and improving the tolerance to adverse environments. Most of these studies have been performed in growth chambers under low light [300-350 µmol m-2 s-1 photosynthetically active radiation (PAR), LL]. However, in nature plants have to face frequent fluctuations of light intensities that often exceed their photosynthetic capacity (900-2000 µmol m-2 s-1 ). In this study we investigated the physiological and metabolic changes potentially involved in osmotic adjustment and antioxidant defense in durum wheat seedlings under high light (HL) and salinity. The combined application of the two stresses decreased the water potential and stomatal conductance without reducing the photosynthetic efficiency of the plants. Glycine betaine (GB) synthesis was inhibited, proline and glutamate content decreased, while γ-aminobutyric acid (GABA), amides and minor amino acids increased. The expression level and enzymatic activities of Δ1-pyrroline-5-carboxylate synthetase, asparagine synthetase and glutamate decarboxylase, as well as other enzymatic activities of nitrogen and carbon metabolism, were analyzed. Antioxidant enzymes and metabolites were also considered. The results showed that the complex interplay seen in durum wheat plants under salinity at LL was simplified: GB and antioxidants did not play a main role. On the contrary, the fine tuning of few specific primary metabolites (GABA, amides, minor amino acids and hexoses) remodeled metabolism and defense processes, playing a key role in the response to simultaneous stresses.

Silica/quercetin sol?gel hybrids as antioxidant dental implant materials

Abstract The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing the onset of peri-implant diseases. In this context, quercetin, a naturally occurring flavonoid, has been entrapped at different weight percentages in a silica-based inorganic material by a sol–gel route. The establishment of hydrogen bond interactions between the flavonol and the solid matrix was ascertained by Fourier transform infrared spectroscopy. This technique also evidenced changes in the stretching frequencies of the quercetin dienonic moiety, suggesting that the formation of a secondary product occurs. Scanning electron microscopy was applied to detect the morphology of the synthesized materials. Their bioactivity was shown by the formation of a hydroxyapatite layer on sample surface soaked in a fluid that simulates the composition of human blood plasma. When the potential release of flavonol was determined by liquid chromatography coupled with ultraviolet and electrospray ionization tandem mass spectrometry techniques, the eluates displayed a retention time that was 0.5 min less than quercetin. Collision-activated dissociation mass spectrometry and untraviolet-visible spectroscopy were in accordance with the release of a quercetin derivative. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods, whereas the 2,7-dichlorofluorescein diacetate assay highlighted their ability to inhibit the H2O2-induced intracellular production of reactive oxygen species in NIH-3T3 mouse fibroblast cells. Data obtained, along with data gathered from the MTT cytotoxicity test, revealed that the materials that entrapped the highest amount of quercetin showed notable antioxidant effectiveness.

Kaempferol glycosides from Lobularia maritima and their potential role in plant interactions.

Six kaempferol glycosides, four of them characterized for the first time, were isolated from the leaf extract of Lobularia maritima. The structural elucidation was performed by a combined approach using Electrospray-Ionization Triple-Quadrupole Mass-Spectrometric (ESI/TQ/MS) techniques, and 1D- and 2D-NMR experiments (1H, 13C, DEPT, DQ-COSY, TOCSY, ROESY, NOESY, HSQC, HMBC, and HSQC-TOCSY). The isolated kaempferol derivatives have different disaccharide substituents at C(3) and four of them have a rhamnose unit at C(7). To evaluate their potential allelopathic role within the herbaceous plant community, the compounds, as well as the aglycone obtained from enzymatic hydrolysis, have been tested in vitro on three coexisting plant species, Dactylis hispanica, Petrorhagia velutina, and Phleum subulatum. The results obtained allow us to hypothesize that the type of the sugar modulates the biological response. The bioassay data, analyzed by a multivariate approach, and grouping the compounds on the basis of the number of sugar units and the nature of carbohydrates present in the disaccharide moiety, indicate a structure-activity relationship.

Influence of harvest season on chemical composition and bioactivity of wild rue plant hydroalcoholic extracts.

The rue (Ruta graveolens) copiousness in rural areas of the Campania Region based a thorough chemical and biological investigation aimed at exploring the seasonal variability of phenol constituents in rue leaves and its influence on their antioxidant, cytotoxic and anti-inflammatory capabilities. To this purpose, hydroalcoholic extracts were prepared from plant samples seasonally collected. LC-ESI-MS/MS techniques were employed to analyze qualitatively and quantitatively the seasonal rue phenol content, whereas different chemical antioxidant assays (by DPPH, ABTS, Fe(3+) RP, ORAC, and FCR methods) and XTT redox metabolic activity assay were performed to screen the seasonal phenol complex-related antioxidant and cytotoxic power. The ability of the rue leaf extracts to counteract cyclooxygenase-2 (COX-2) expression was also evaluated. Data obtained highlighted that the adopted extraction procedure markedly pauperized the furanocoumarin content in all the prepared rue extracts. Flavonol glycosides, along with the flavone acacetin and two sinapic acid derivatives were the main constituents of the spring harvest-derived extract, which exerted the highest antioxidant capability in cell-free systems and was capable to inhibit COX-2 synthesis by 44% comparably to dexamethasone, used as positive control. Data provide new insights for developing a proper management of rue plants for new safe industrial purposes in herbal medicine field.

LC-MS/MS Profiling of a Mastic Leaf Phenol Enriched Extract and Its Effects on H2O2 and Aβ(25–35) Oxidative Injury in SK-B-NE(C)-2 Cells

The development of polyphenol neuroprotective nutraceuticals useful for functional foods could be a valuable strategy for counteracting oxidative stress relative diseases as Alzheimers Disease (AD). Oxidative stress is one of the AD earliest event and seems to play a central role in Aβ generation, neuroinflammation, and neuronal apoptosis. In order to counteract AD neurodegeneration, the inhibition of the vicious cycle of Aβ generation and oxidation is an attractive therapeutic strategy, and antiamyloidogenic and antioxidant plant drugs could represent an alternative and valid approach. In this context, an alcoholic extract (Pl-M) from deterpenated Pistacia lentiscus L. leaves was investigated for its phenol composition through LC-ESI-MS/MS analysis. Besides the identified metabolites, ten compounds were reported for the first time as constituents of Pistacia lentiscus leaves. Through DPPH, ABTS, and ORAC methods, the antioxidant potential of the extract was initially investigated. In order to evaluate the preparation of a safe and no toxic extract, MTT, SRB, and LDH assays toward SH-5YSY, and SK-N-BE(2)-C human neuronal cell lines, as well as on C6 mouse glial cell line, were performed. Evaluating the protective effects from oxidant injury in SK-N-BE(2)-C cells cotreated with the plant complex and H2O2, or Aβ(25-35) fragment, it was observed that Pl-M extract exerted a significant cytoprotective response in both the oxidized cell systems. In particular, Pl-M extract was able to reduce by nearly 50% the Aβ(25-35) induced toxicity at 25.0 μg/mL dose level, whereas it counteracted almost completely the cytotoxic action at 100.0 μg/mL. Data obtained allow us to hypothesize the use of Pistacia lentiscus leaves, a broadly available and renewable source, as an alternative strategy for the enrichment of food matrices with polyphenol bioactives. The present study put the basis for bioavailability and preclinical studies, able to define Pl-M extract safety and efficacy.

Structure determination of chamaedryosides A-C, three novel nor-neo-clerodane glucosides from Teucrium chamaedrys, by NMR spectroscopy.

Three new nor‐neo‐clerodane diterpenes, named chamaedryoside A (1), B (2) and C (3), have been isolated from the organic extracts of Teucrium chamaedrys (L.) and their structural characterization has been accomplished by 1H and 13C‐NMR spectra, and DEPT, by COSY, TOCSY, HSQC, HSQC‐TOSCY and HMBC experiments, as well as by ESI‐MS/MS techniques. The stereostructures have been elucidated by NOESY and computational calculations. Copyright

Entrapping quercetin in silica/polyethylene glycol hybrid materials: Chemical characterization and biocompatibility

Sol-gel synthesis was exploited to entrap quercetin, a natural occurring antioxidant polyphenol, in silica-based hybrid materials, which differed in their polyethylene glycol (PEG) content (6, 12, 24 and 50wt%). The materials obtained, whose nano-composite nature was ascertained by Scanning Electron Microscopy (SEM), were chemically characterized by Fourier Transform InfraRed (FT-IR) and UV-Vis spectroscopies. The results prove that a reaction between the polymer and the drug occurred. Bioactivity tests showed their ability to induce hydroxyapatite nucleation on the sample surfaces. The direct contact method was applied to screen the cytotoxicity of the synthetized materials towards fibroblast NIH 3T3 cells, commonly used for in vitro biocompatibility studies, and three nervous system cell lines (neuroblastoma SH-SY5Y, glioma U251, and pheochromocytoma PC12 cell lines), adopted as models in oxidative stress related studies. Using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay NIH 3T3 proliferation was assessed and the morphology was not compromised by direct exposure to the materials. Analogously, PC-12, and U-251 cell lines were not affected by new materials. SH-SY5Y appeared to be the most sensitive cell line with cytotoxic effects of 20-35%.

The Mechanism of 2-Furaldehyde Formation from d -Xylose Dehydration in the Gas Phase. A Tandem Mass Spectrometric Study

AbstractThe mechanism of reactions occurring in solution can be investigated also in the gas phase by suited mass spectrometric techniques, which allow to highlight fundamental mechanistic features independent of the influence of the medium and to clarifying controversial hypotheses proposed in solution studies. In this work, we report a gas-phase study performed by electrospray triple stage quadrupole mass spectrometry (ESI-TSQ/MS) on the dehydration of d-xylose, leading mainly to the formation of 2-furaldehyde (2-FA). It is generally known in carbohydrate chemistry that the thermal acid catalyzed dehydration of pentoses leads to the formation of 2-FA, but several aspects on the solution-phase mechanism are controversial. Here, gaseous reactant ions corresponding to protonated xylose molecules obtained from ESI of a solution containing d-xylose and ammonium acetate as protonating reagent were allowed to undergo collisionally activated decomposition (CAD) into the triple stage quadrupole analyzer. The product ion mass spectra of protonated xylose are characterized by the presence of ionic intermediates arising from xylose dehydration, which were structurally characterized by their fragmentation patterns. As expected, the xylose triple dehydration leads to the formation of the ion at m/z 97, corresponding to protonated 2-FA. On the basis of mass spectrometric evidences, we demonstrated that in the gas phase, the formation of 2-FA involves protonation at the OH group bound to the C1 atom of the sugar, the first ionic intermediate being characterized by a cyclic structure. Finally, energy resolved product ion mass spectra allowed to obtain information on the energetic features of the d-xylose→2-FA conversion. Figureᅟ

Plant-Derived Polyphenols: A Chemopreventive and Chemoprotectant Worth-Exploring Resource in Toxicology

Abstract Cancer is a devastating disease affecting millions of people worldwide. Scientific research validly counteracts the onset of cancer and its resistances with a multiplicity of treatments. Healthy lifestyles and avoidance of exposure to potential carcinogens are highly recommended cancer preventive measures. Antioxidant and anti-inflammatory plant-derived polyphenols, peculiarly rich in plant dietary products, are thoroughly investigated as capable of hindering carcinogenesis in its various stages. Furthermore, a growing toxicological research, mostly based on cell and animal models, is identifying polyphenols or their formulations, properly obtained from plant sources, as promising anticancer agents with chemotherapeutic and chemopreventive effectiveness. Thus, polyphenols could also be employed as protectant agents, useful in overcoming the failures of the most common anticancer treatments. This chapter provides an update of the current scientific knowledge of plant polyphenols and all their anticancer-linked properties that make them a resource in toxicology worth exploring.