HIV-1 Integrase Inhibition Activity by Spiroketals Derived from Plagius flosculosus, an Endemic Plant of Sardinia (Italy) and Corsica (France).

In this work we investigated, for the first time, the effect of Plagius flosculosus (L.) Alavi & Heywood, a Sardinian-Corsican endemic plant, on HIV-1 integrase (IN) activity. The phytochemical analysis of the leaves chloroform extract led us to isolate and characterize three compounds (SPK1, SPK2, and SPK3) belonging to the spiroketals, a group of naturally occurring metabolites of phytochemical relevance with interesting biological properties. Due to their structural diversity, these cyclic ketals have attracted the interest of chemists and biologists. SPK1, SPK2, and SPK3 were evaluated here for their ability to inhibit HIV-1 integrase activity in biochemical assays. The results showed that all the compounds inhibited HIV-1 IN activity. In particular, the most active one was SPK3, which interfered in a low molecular range (IC50 of 1.46 ± 0.16 µM) with HIV-1 IN activity in the presence/absence of the LEDGF cellular cofactor. To investigate the mechanism of action, the three spiroketals were also tested on HIV-1 RT-associated Ribonuclease H (RNase H) activity, proving to be active in inhibiting this function. Although SPK3 was unable to inhibit viral replication in cell culture, it promoted the IN multimerization. We hypothesize that SPK3 inhibited HIV-1 IN through an allosteric mechanism of action.

Phytochemical Investigation of Myrcianthes cisplatensis: Structural Characterization of New p-Coumaroyl Alkylphloroglucinols and Antimicrobial Evaluation against Staphylococcus aureus.

Species of Myrtaceae Juss., the ninth largest family of flowering plants, are a valuable source of bioactive specialized metabolites. A leading position belongs to phloroglucinol derivatives, thanks to their unusual structural features and biological and pharmacological properties. Myrcianthes cisplatensis (Cambess.) O. Berg, a common tree on the banks of rivers and streams of Uruguay, southern Brazil, and northern Argentina, with aromatic leaves, is known as a diuretic, febrifuge, tonic, and good remedy for lung and bronchial diseases. Despite knowledge about traditional use, few data on its phytochemical properties have been reported in the literature. The methanol extract of M. cisplatensis, grown in Arizona, USA, was first partitioned between dichloromethane and water and then with ethyl acetate. The enriched fractions were evaluated using a broth microdilution assay against Staphylococcus aureus ATCC 29213 and 43300 (methicillin-resistant S. aureus (MRSA)). The potential antimicrobial activity seemed to increase in the dichloromethane extract, with a MIC value of 16 µg/mL against both strains. Following a bio-guided approach, chromatographic techniques allowed for isolating three coumarin derivatives, namely endoperoxide G3, catechin, and quercitrin, and four new p-coumaroyl alkylphloroglucinol glucosides, named p-coumaroylmyrciacommulone A-D. Their structures were characterized through spectroscopic techniques: 2D-NMR experiments (HSQC, HMBC, and HSQC-TOCSY) and spectrometric analyses (HR-MS). The antimicrobial assessment of pure compounds against S. aureus ATCC 29213 and ATCC 43300 demonstrated the best activity for p-coumaroylmyrciacommulone C and D with the growth inhibition of 50% at 32 µg/mL against both strains of S. aureus.

Gallomyrtucommulones G and H, New Phloroglucinol Glycosides, from Bioactive Fractions of Myrtus communis against Staphylococcus Species.

Myrtaceae family is a continuous source of antimicrobial agents. In the search for novel antimicrobial agents against Staphylococcus species, bioactive fractions of Myrtus communis L., growing in the Sardinia island (Italy) have been investigated. Their phytochemical analysis led us to isolate and characterize four alkylphloroglucinol glycosides (1-4), three of them gallomyrtucommulones G-H (1,2), and myrtucommulonoside (4) isolated and characterized for the first time. The structures of the new and known compounds, endopreroxide G3 (5), myricetin-3-O-glycosides (6,7) were determined based on the spectroscopic evidence including 1D-/2D-NMR and HR-MS spectrometry. Enriched fractions as well as pure compounds were tested for their antimicrobial activity by broth micro-dilution assay against Staphylococcus epidermidis and S. aureus. Results reported herein demonstrated that gallomyrtucommulone G (1) showed a selective antimicrobial activity against both S. aureus strains (ATCC 29213 and 43300) until 16 µg/mL while gallomyrtucommulone D (3) showed the best growth inhibition value at 64 µg/mL.

Biological Insights and NMR Metabolic Profiling of Different Extracts of Spermacoce verticillata (L.) G. Mey.

Spermacoce verticillata (L.) G. Mey. is commonly used in the folk medicine by various cultures to manage common diseases. Herein, the chemical and biological profiles of S. verticillata were studied in order to provide a comprehensive characterization of bioactive compounds and also to highlight the therapeutic properties. The in vitro antioxidant activity using free-radical scavenging, phosphomolybdenum, ferrous-ion chelating and reducing power assays, and the inhibitory activity against key enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase of S. verticillata extracts (dichloromethane, ethyl acetate, methanol and water) were investigated. The highest total phenolic and flavonoid content were observed in the methanolic and aqueous extracts. Exhaustive 2DNMR investigation has revealed the presence of rutin, ursolic and oleanoic acids. The methanolic extract, followed by aqueous extract have showed remarkable free radical quenching and reducing ability, while the dichloromethane extract was the best source of metal chelators. The tested extracts showed notable inhibitory activity against cholinesterases (AChE: 1.63-4.99 mg GALAE/g extract and BChE: 12.40-15.48 mg GALAE/g extract) and tyrosinase (60.85-159.64 mg KAE/g extract). No inhibitory activity was displayed by ethyl acetate and aqueous extracts against BChE and tyrosinase, respectively. All the tested extracts showed modest α-amylase inhibitory activity, while only the ethyl acetate and aqueous extracts were potent against α-glycosidase. This study further validates the use of S. verticillata in the traditional medicine, while advocating for further investigation for phytomedicine development.

Chemical Characterization and Anti-HIV-1 Activity Assessment of Iridoids and Flavonols from Scrophularia trifoliata.

Plants are the everlasting source of a wide spectrum of specialized metabolites, characterized by wide variability in term of chemical structures and different biological properties such antiviral activity. In the search for novel antiviral agents against Human Immunodeficiency Virus type 1 (HIV-1) from plants, the phytochemical investigation of Scrophularia trifoliata L. led us to isolate and characterize four flavonols glycosides along with nine iridoid glycosides, two of them, 5 and 13, described for the first time. In the present study, we investigated, for the first time, the contents of a methanol extract of S. trifoliata leaves, in order to explore the potential antiviral activity against HIV-1. The antiviral activity was evaluated in biochemical assays for the inhibition of HIV-1Reverse Transcriptase (RT)-associated Ribonuclease H (RNase H) activity and HIV-1 Integrase (IN). Three isolated flavonoids, rutin, kaempferol-7-O-rhamnosyl-3-O-glucopyranoside, and kaempferol-3-O-glucopyranoside, 8-10, inhibited specifically the HIV-1 IN activity at submicromolar concentration, with the latter being the most potent, showing an IC50 value of 24 nM.

Phytochemical Characterization of Olea europaea L. Cultivars of Cilento National Park (South Italy) through NMR-Based Metabolomics.

Olea europaea germplasm is constituted by a huge number of cultivars, each one characterized by specific features. In this context, endemic cultivars evolved for a very long period in a precise local area, developing very specific traits. These characteristics include the production and accumulation of phytochemicals, many of which are also responsible for the nutraceutical value of the drupes and of the oils therefrom. With the aim of obtaining information on the phytochemical profile of drupes of autochthonous cultivars of Cilento, Vallo di Diano and Alburni National Park, a metabolomics-based study was carried out on 19 selected cultivars. Multivariate data analysis of 1H-NMR data and 2D NMR analyses allowed the rapid identification of metabolites that were qualitatively and/or quantitatively varying among the cultivars. This study allowed to identify the cultivars Racioppella, Guglia, Pizzulella, Oliva amara, and Racioppa as the richest in health-promoting phenolic compounds. Furthermore, it showed a significant variability among the different cultivars, suggesting the possibility of using metabolic fingerprinting approaches for cultivar differentiation, once that further studies aimed at assessing the influence of growing conditions and environmental factors on the chemical profiles of single cultivars are carried out.

Chemical Fractionation Joint to In-Mixture NMR Analysis for Avoiding the Hepatotoxicity of Teucrium chamaedrys L. subsp. chamaedrys.

Dietary supplements based on Teucrium chamaedrys L. subsp. chamaedrys aerial parts were banned, due to the hepatotoxicity of furan-containing neo-clerodane constituents. Indeed, the plant leaf content in phenolic compounds could be further exploited for their antioxidant capability. Accordingly, bio-guided fractionation strategies have been applied, obtaining seven partially purified extracts. These latter were chemically investigated through 1D and 2D NMR techniques and tested for their antiradical, reducing and cytotoxic capability. Data acquired highlighted that, through a simple phytochemical approach, a progressive neo-clerodane depletion occurred, while maximizing phenylethanoid glycosides in alcoholic fractions. Thus, although the plant cannot be used as a botanical remedy as such, it is suggested as a source of healthy compounds, pure or in mixture, to be handled in pharmaceutical, nutraceutical and/or cosmeceutical sectors.

NMR Profiling of Ononis diffusa Identifies Cytotoxic Compounds against Cetuximab-Resistant Colon Cancer Cell Lines.

In the search of new natural products to be explored as possible anticancer drugs, two plant species, namely Ononis diffusa and Ononis variegata, were screened against colorectal cancer cell lines. The cytotoxic activity of the crude extracts was tested on a panel of colon cancer cell models including cetuximab-sensitive (Caco-2, GEO, SW48), intrinsic (HT-29 and HCT-116), and acquired (GEO-CR, SW48-CR) cetuximab-resistant cell lines. Ononis diffusa showed remarkable cytotoxic activity, especially on the cetuximab-resistant cell lines. The active extract composition was determined by NMR analysis. Given its complexity, a partial purification was then carried out. The fractions obtained were again tested for their biological activity and their metabolite content was determined by 1D and 2D NMR analysis. The study led to the identification of a fraction enriched in oxylipins that showed a 92% growth inhibition of the HT-29 cell line at a concentration of 50 µg/mL.

Plant Derived Natural Products against Pseudomonas aeruginosa and Staphylococcus aureus: Antibiofilm Activity and Molecular Mechanisms.

Bacteria are social organisms able to build complex structures, such as biofilms, that are highly organized surface-associated communities of microorganisms, encased within a self- produced extracellular matrix. Biofilm is commonly associated with many health problems since its formation increases resistance to antibiotics and antimicrobial agents, as in the case of Pseudomonas aeruginosa and Staphylococcus aureus, two human pathogens causing major concern. P. aeruginosa is responsible for severe nosocomial infections, the most frequent of which is ventilator-associated pneumonia, while S. aureus causes several problems, like skin infections, septic arthritis, and endocarditis, to name just a few. Literature data suggest that natural products from plants, bacteria, fungi, and marine organisms have proven to be effective as anti-biofilm agents, inhibiting the formation of the polymer matrix, suppressing cell adhesion and attachment, and decreasing the virulence factors' production, thereby blocking the quorum sensing network. Here, we focus on plant derived chemicals, and provide an updated literature review on the anti-biofilm properties of terpenes, flavonoids, alkaloids, and phenolic compounds. Moreover, whenever information is available, we also report the mechanisms of action.

NMR-Based Plant Metabolomics in Nutraceutical Research: An Overview.

Few topics are able to channel the interest of researchers, the public, and industries, like nutraceuticals. The ever-increasing demand of new compounds or new sources of known active compounds, along with the need of a better knowledge about their effectiveness, mode of action, safety, etc., led to a significant effort towards the development of analytical approaches able to answer the many questions related to this topic. Therefore, the application of cutting edges approaches to this area has been observed. Among these approaches, metabolomics is a key player. Herewith, the applications of NMR-based metabolomics to nutraceutical research are discussed: after a brief overview of the analytical workflow, the use of NMR-based metabolomics to the search for new compounds or new sources of known nutraceuticals are reviewed. Then, possible applications for quality control and nutraceutical optimization are suggested. Finally, the use of NMR-based metabolomics to study the impact of nutraceuticals on human metabolism is discussed.

Lymphocytes exposed to vegetables grown in waters contaminated by anticancer drugs: metabolome alterations and genotoxic risks for human health.

Wastewater irrigation of crops may be effective to avoid depletion (about 70%) of freshwater resources. However, the use of reclaimed waters containing persistent microcontaminants such as antineoplastic drugs is of high environmental concern. These active compounds may affect human health with potentially severe adverse effects. To better understand the impact on human health following irrigation of crops with reused contaminated waters, we exposed four edible plants, Brassica rapa, Lactuca sativa, Raphanus sativus, and Triticum durum, to two commonly used antitumoral drugs: 5-fluorouracil (5-FU), and Cisplatin (CDDP), using metabolomics as a potential functional genomics tool to combine with genotoxicity experiments. The metabolome of the treated and untreated plants was analysed to detect biochemical alterations associated to the exposure, and the potential genotoxic damage related to human exposure to the treated plants was evaluated using the comet assay in human lymphocytes, which are characterized by high sensitivity to genotoxic substances. The edible species were able to assimilate 5-FU and CDDP during the treatment, affecting the biochemical pathways of these plants with subsequent metabolome modifications. These metabolic alterations differed according to the specific species used for the test. Furthermore, all vegetables treated with two concentrations of the selected drugs (10 and 100 µg/L) caused significant (p < 0.0001) genotoxic damage in the cells of the immune system at a higher level than in the lymphocytes directly exposed to single antineoplastic drugs.

NMR-based metabolomics and bioassays to study phytotoxic extracts and putative phytotoxins from Mediterranean plant species.

INTRODUCTION: Mediterranean plants are characterised by a high content of bioactive secondary metabolites that play important roles in plant-plant interactions as plant growth regulators and could be useful for the development of new eco-friendly herbicides. OBJECTIVE: An NMR-based metabolomics approach was reported to seek selective phytotoxic plant extracts and putative plant-derived active molecules. METHODS: Plant extracts derived from five Mediterranean donor species (Pistacia lentiscus, Bellis sylvestris, Phleum subulatum, Petrohrhagia saxifraga and Melilotus neapolitana) were used to treat the hydroponic cultures of three receiving plants (Triticum durum, Triticum ovatum and Avena fatua). Morphological analyses of the treated receiving plants were carried out. NMR-based metabolomics was applied both to characterise the donor plant extracts and to study the effects of the treatments on the receiving plants. RESULTS: This study allowed the identification of Melilotus neapolitana and Bellis sylvestris as phytotoxic plant and good candidates for further studies. Specifically, the NMR-based metabolomics investigation showed that these species affect a specific set of metabolites (such as sugars, amino and organic acids) and therefore metabolic pathways [i.e. tricarboxylic acid (TCA) cycle, amino acid metabolism, etc.] that are crucial for the plant growth and development. Moreover, it was possible to identify the metabolite(s) probably responsible for the phytotoxicity of the active extracts. CONCLUSION: The NMR-based metabolomics approach employed in this study led to the identification of two phytotoxic plant extracts and their putative active principles. These new insights will be of paramount importance in the future to find plant derived molecules endowed with phytotoxic activities.

Spectroscopic Characterization and Cytotoxicity Assessment towards Human Colon Cancer Cell Lines of Acylated Cycloartane Glycosides from Astragalus boeticus L.

In several European countries, especially in Sweden, the seeds of the species Astragalus boeticus L. were widely used as coffee substitutes during the 19th century. Nonetheless, data regarding the phytochemistry and the pharmacological properties of this species are currently extremely limited. Conversely, other species belonging to the Astragalus genus have already been extensively investigated, as they were used for millennia for treating various diseases, including cancer. The current work was addressed to characterize cycloartane glycosides from A. boeticus, and to evaluate their cytotoxicity towards human colorectal cancer (CRC) cell lines. The isolation of the metabolites was performed by using different chromatographic techniques, while their chemical structures were elucidated by nuclear magnetic resonance (NMR) (1D and 2D techniques) and electrospray-ionization quadrupole time-of-flight (ESI-QTOF) mass spectrometry. The cytotoxic assessment was performed in vitro by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays in Caco-2, HT-29 and HCT-116 CRC cells. As a result, the targeted phytochemical study of A. boeticus enabled the isolation of three new cycloartane glycosides, 6-O-acetyl-3-O-(4-O-malonyl)-ß-d-xylopyranosylcycloastragenol (1), 3-O-(4-O-malonyl)-ß-d-xylopyranosylcycloastragenol (2), 6-O-acetyl-25-O-ß-d-glucopyranosyl-3-O-ß-d-xylopyranosylcycloastragenol (3) along with two known compounds, 6-O-acetyl-3-O-ß-d-xylopyranosylcycloastragenol (4) and 3-O-ß-d-xylopyranosylcycloastragenol (5). Importantly, this work demonstrated that the acetylated cycloartane glycosides 1 and 4 might preferentially inhibit cell growth in the CRC cell model resistant to epidermal growth factor receptor (EGFR) inhibitors.

Urtica dioica L. inhibits proliferation and enhances cisplatin cytotoxicity in NSCLC cells via Endoplasmic Reticulum-stress mediated apoptosis.

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and the ineffectiveness of the current therapies seriously limits the survival rate of NSCLC patients. In the search for new antitumor agents, nature has played a pivotal role providing a variety of molecules, which are likely to exert selective anti-tumour properties. Herein, we investigated the antiproliferative potential of Urtica dioica L. extract (UD) against NSCLC cell models with low sensitivity to cisplatin, a cytotoxic agent largely employed to cure NSCLCs. UD inhibited cell proliferation in the selected cells, while no toxic effects were observed in normal lung cells. Furthermore, the co-treatment of UD and cisplatin notably sensitised NSCLC cells to cisplatin. Mechanistically, we discovered that UD-promoted endoplasmic reticulum (ER) stress via activation of the growth arrest and DNA damage-inducible gene 153 (GADD153) triggering apoptosis. We also performed an extensive NMR analysis of UD, identifying rutin and oxylipins as the main secondary metabolites present in the mixture. Additionally, we discovered that an oxylipins' enriched fraction contributes to the antiproliferative activity of the plant extract. In the future, this study may provide new chemical scaffolds for the design of anti-cancer agents that target NSCLCs with low sensitivity to cisplatinum.

Antimicrobial and anti-biofilm properties of novel synthetic lignan-like compounds.

Antibiotic resistance and biofilm tolerance are among the principal factors involved in the persistence of chronic infections. The need for new antimicrobials is an ever-increasing challenge in clinical environments and in the control of global health. Arylfurans form a set of structures that have been identified in many natural products, e.g. lignans. Lignans are a sub-group of non-flavonoid polyphenols that play an active role in plants' defense against bacteria and fungi infections. The aim of this study was to identify novel synthetic arylfurans and lignan-like arylbenzylfurans exhibiting antimicrobial properties. The molecules synthetized were tested against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and S. epidermidis. We found that among tested compounds, arylbenzylfuran 11 was active against S. aureus and S. epidermidis with an MIC of 4 µg ml-1. Compound 11 was also active on methicillin-resistant S. aureus and S. epidermidis. By confocal laser scanning microscopy, we showed that 32 µg ml-1 of compound 11 was able to induce a significant reduction in S. aureus and S. epidermidis biofilms viability. Finally, we demonstrated that compound 11 was not cytotoxic on HaCat cells up to 128 µg ml-1. This work shows the antimicrobial and anti-biofilm potential of a synthetic lignan-like furan.

Exploring the halophyte Cistanche phelypaea (L.) Cout as a source of health promoting products: In vitro antioxidant and enzyme inhibitory properties, metabolomic profile and computational studies.

In this study, ethyl acetate, acetone, ethanol and water extracts from flowers, stems and roots of Cistanche phelypaea (L.) Cout were appraised for radical scavenging activity (RSA) towards 1,1-diphenyl-2-picrylhydrazyl,2,2-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) and superoxide free radicals, and for metal chelating activities on iron and copper ions. The water extracts had the highest antioxidant activity, especially those from roots and flowers, and were further appraised for in vitro inhibition of enzymes implicated on the onset of human ailments, namely acetyl- (AChE) and butyrylcholinesterase (BuChE) for Alzheimer's disease, α-glucosidase and α-amylase for diabetes, and tyrosinase for skin hyperpigmentation disorders. The extracts had a higher activity towards BuChE, and the roots extract had the highest capacity to inhibit tyrosinase. Samples showed a low capacity to inhibit carbohydrate hydrolysing enzymes, except for the root extract with a good inhibition on glucosidase. Samples were then characterized by NMR (1D and 2D): the main metabolites identified in the flowers extract were iridoid glycosides, in particular gluroside and bartsioside. In stems, phenylehanoid glycosides (PhGs) and iridoids were detected, especially acteoside. In roots were detected essentially PhGs, mainly echinacoside and tubuloside A. Docking studies were performed on the identified compounds. A favorable binding energy of tubuloside A to tyrosinase was calculated, and indicated this compound as a possible competitive inhibitor of α-glucosidase and tyrosinase. Our results suggest that C. phelypeae is a promising source of biologically-active compounds with health promoting properties for pharmaceutical and biomedical applications.

Metabolomic approach for a rapid identification of natural products with cytotoxic activity against human colorectal cancer cells.

The discovery of bioactive compounds from natural sources entails an extremely lengthy process due to the timescale and complexity of traditional methodologies. In our study, we used a rapid NMR based metabolomic approach as tool to identify secondary metabolites with anti-proliferative activity against a panel of human colorectal cancer cell lines with different mutation profiles. For this purpose, fourteen Fabaceae species of Mediterranean vegetation were investigated using a double screening method: 1H NMR profiling enabled the identification of the main compounds present in the mixtures, whilst parallel biological assays allowed the selection of two plant extracts based on their strong anti-proliferative properties. Using high-resolution 2D NMR spectroscopy, putative active constituents were identified in the mixture and isolated by performing a bio-guided fractionation of the selected plant extracts. As a result, we found two active principles: a cycloartane glycoside and protodioscin derivative. Interestingly, these metabolites displayed a preferential anti-proliferative effect on colon cancer cell lines with an intrinsic resistance to anti-EGFR therapies. Our work provides an NMR-based metabolomic approach as a powerful and efficient tool to discover natural products with anticancer activities circumventing time-consuming procedures.

Physiological characterization and quantitative proteomic analyses of metabolically engineered E. coli K4 strains with improved pathways for capsular polysaccharide biosynthesis.

Among capsulated bacteria, some produce polysaccharides with unique properties that have been shown to possess relevant industrial applications and commercial value. The capsular polysaccharide (CPS) produced by Escherichia coli K4 is similar to chondroitin sulphate, and recent efforts focused on the development of genetic and fermentation strategies to increase its production titers up to technologically attractive levels. However, the control of the metabolic pathways leading to CPS synthesis together with the effect of varying the concentration of pathway intermediates on CPS final titers, is still quite unexplored, and not fully understood. In the present study four genes involved in the biosynthesis of UDP-sugar CPS precursors, namely kfoA, kfoF, pgm, and galU, were overexpressed in different combinations, and diversely affected the biosynthetic machinery. At the physiological level, results revealed a central role for kfoF, coding for UDP-glucose dehydrogenase, that increased CPS production mostly. In the attempt to unravel the molecular mechanisms regulating CPS biosynthesis, an in depth analysis of the proteome of the recombinant strains overexpressing respectively pgm and galU, and pgm, galU, and kfoF was performed and compared to the wild-type. Although, interestingly, in both strains the impact of the genetic manipulation seemed rather limited at the proteome level, results obtained from the triple mutant indicated a crosstalk between the two pathways leading to UDP-sugar precursors biosynthesis, and also an unexpected link with the purine biosynthetic pathway. Overall our results present new insights into the role of metabolic intermediates for the formation of capsular polysaccharides, utilizing a systematic approach of metabolic engineering, combined with state-of-the-art quantitative proteomic approaches, as well as genetic and physiological information.

Evaluation of the antioxidant properties of carexanes in AGS cells transfected with the Helicobacter pylori's protein HspB.

Naturally derived compounds represent a potential source of pharmacologically active drugs able to contrast different diseases, including gastric cancer, a multifactorial disease, in which the important role played by H. pylori infection has been demonstrated. Carexanes, stilbene derivatives, isolated from plants of the Carex distachya Desf., are unusual secondary metabolites with a tetracyclic skeleton arising from a cyclization of prenylstilbenoid precursors. In this study we firstly showed the ability of three purified carexanes CxB, CxG, and CxI to enhance the antioxidant response of AGS cells and to contrast the effect of the H. pylori's protein HspB. Among them CxI was the molecule that best modified the expression of genes involved in the antioxidant response. In particular, CxI was able to reduce Keap-1 gene expression and induce NQO1 gene expression, both at 4 and 24 h in AGS cells, as showed by real time PCR. Nrf2 induction was evident only at 24 h. Interestingly, the effect of CxI was stronger in HspB-transfected AGS cells, where Keap-1 gene expression was nearly abrogated. Finally, we demonstrated that CxI was able to reduce also COX-2 gene expression in HspB-transfected AGS cells, compared with untreated HspB-transfected cells, both at 4 and 24 h. This study first report that carexanes might represent candidate molecules able to contrast the deleterious effect of HspB protein but also to reduce the inflammatory process induced by H. pylori infection.

Highlighting the effects of coumarin on adult plants of Arabidopsis thaliana (L.) Heynh. by an integrated -omic approach.

In this study, the effects of the allelochemical coumarin through a metabolomic, proteomic and morpho-physiological approach in Arabidopsis adult plants (25days old) were investigated. Metabolomic analysis evidenced an increment of amino acids and a high accumulation of soluble sugars, after 6days of coumarin treatment. This effect was accompanied by a strong decrease on plant fresh and dry weights, as well as on total protein content. On the contrary, coumarin did not affect leaf number but caused a reduction in leaf area. An alteration of water status was confirmed by a reduction of relative water content and an increase in leaf osmotic potential. Moreover, coumarin impaired plant bio-membranes through an increase of lipid peroxidation and H2O2 content suggesting that coumarin treatment might induce oxidative stress. Coumarin reduced the effective quantum yield of the photosystem II, the energy dissipation in the form of heat, the maximum PSII efficiency, the coefficient of the photochemical quenching and the estimated electron transport rate, while it significantly stimulated the fluorescence emission and the coefficient of the non photochemical quenching. Finally, the proteomic characterization of coumarin-treated plants revealed a down-regulation of the ROS detoxifying proteins, responsible of oxidative damage and consequently of physiological cascade effects.