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Type 2 Diabetes is a major public health threat, and its prevalence is increasing worldwide. The abnormal accumulation of islet amyloid polypeptide (IAPP) in pancreatic β-cells is associated with the onset of the disease. Therefore, the design of small molecules able to inhibit IAPP aggregation represents a promising strategy in the development of new therapies. Here we employ in vitro, biophysical, and computational methods to inspect the ability of Silybin A and Silybin B, two natural diastereoisomers extracted from milk thistle, to interfere with the toxic self-assembly of human IAPP (hIAPP). We show that Silybin B inhibits amyloid aggregation and protects INS-1 cells from hIAPP toxicity more than Silybin A. Molecular dynamics simulations revealed that the higher efficiency of Silybin B is ascribable to its interactions with precise hIAPP regions that are notoriously involved in hIAPP self-assembly i.e., the S20-S29 amyloidogenic core, H18, the N-terminal domain, and N35. These results highlight the importance of stereospecific ligand-peptide interactions in regulating amyloid aggregation and provide a blueprint for future studies aimed at designing Silybin derivatives with enhanced drug-like properties.

Sideritis species have been used in folk medicine for their antimicrobial, antiulcerogenic, digestive and anti-inflammatory properties. Over the years, the phytochemistry of the genus Sideritis has been studied, and various terpenoids, sterols, coumarins and especially flavonoid aglycones and glycosides have been identified. In particular, species from the Balkan Peninsula have been studied and were found to be rich in flavonoids, with valuable antioxidant activity. In the folk medicine of the Balkan countries, Sideritis raeseri is used as a herbal tea in the treatment of inflammation, gastrointestinal disorders and coughs, and also as a tonic, whereas extracts are used as a component of dietary supplements for anaemia. Its dried inflorescences are used to prepare a beverage called ‘mountain tea’. In light of the considerable interest generated in the chemistry, pharmacological properties and commercial value of S. raeseri Boiss. & Heldr., we review and summarise the available literature on these plants. The review details the chemical composition of the essential oil, its mineral and polyphenol contents, the naming of these plants and their physicochemical characterisation, and the nuclear magnetic resonance spectral data and biological properties associated with the plant extracts, with a focus on their potential chemotherapeutic applications.

PhD project is focused on the synthesis and biophysically and biologically characterization of a new mini-library of d(TGGGAG) oligomers as potential anti-HIV. It has been developed an efficient procedure to synthesize modified d(TGGGAG) oligomers carrying hydrophobic and aromatic groups at the 5'-end by a phosphodiester bond. In addition, aiming at improving the kinetic of G-quadruplex formation using d(TGGGAG) as a lead sequence, it have been synthesized bimolecular G-quadruplexes based on d(TGGGAG) sequence containing a HEG loop as a 3'-3' or 5'-5' inversion of polarity site. Kinetic studies of G-quadruplex formation based on the most active 5'-end modified d(TGGGAG) sequences are carried out using ESI-Mass Spectrometry. The interest in G-quadruplex structures has greatly expanded for their existence in vivo in several important oncogenes and in human telomeres. Many antitumor strategies have been developed on the inhibition of telomerase activity through the use of specific ligands. In this frame, it has been analysed the potentiality of a natural compound, namely silibinin. It has been performed an efficient HPLC preparative method to obtain the pure form of silibinin (silybin A and B), and it has been developed a base-catalyzed oxidation of silybin A and B by microwave (MW), which leads to biologically interesting product: the 2,3-dehydrosilybin A and B.

Gymnema sylvestre is a commonly used herb in Ayurvedic medicine. The demand for its extracts in the commercial and pharmaceutical fields has been steadily increasing in recent years. Its extracts are used to treat various ailments as well as for their antimicrobial properties. This study has evaluated the antimicrobial effects of different G. sylvestre extracts and of eight triterpenes isolated from the most active extract on six bacterial poultry pathogens i.e. Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterobacter aerogenes. In particular, it has been evaluated the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of all extracts and isolated triterpenes. Finally, the cytotoxicity activity of triterpenes was evaluated by MTT assay and their antioxidant activity in basal and oxidant conditions by DCFH-DA assay.

A reduced proteasome activity tiles excessive amyloid growth during the progress of protein conformational diseases (PCDs). Hence, the development of safe and effective proteasome enhancers represents an attractive target for the therapeutic treatment of these chronic disorders. Here we analyze two natural diastereoisomers belonging to the family of flavonolignans, Sil A and Sil B, by evaluating their capacity to increase proteasome activity. Enzyme assays carried out on yeast 20S (y20S) proteasome and in parallel on a permanently "open gate" mutant (α3ΔN) evidenced that Sil B is a more efficient 20S activator than Sil A. Conversely, in the case of human 20S proteasome (h20S) a higher affinity and more efficient activation is observed for Sil A. Driven by experimental data, computational studies further demonstrated that the taxifolin group of both diastereoisomers plays a crucial role in their anchoring to the α5/α6 groove of the outer α-ring. However, due to the different stereochemistry at C-7" and C-8" of ring D, only Sil A was able to reproduce the interactions responsible for h20S proteasome activation induced by their cognate regulatory particles. The provided silybins/h20S interaction models allowed us to rationalize their different ability to activate the peptidase activities of h20S and y20S. Our results provide structural details concerning the important role played by stereospecific interactions in driving Sil A and Sil B binding to the 20S proteasome and may support future rational design of proteasome enhancers.

Introduction: Artemisia annua is a small herbaceous plant belonging to the Asteraceae family declared therapeutic by the World Health Organisation, in particu- lar for its artemisinin content, an active ingredient at the base of most antimalarial treatments, used every year by over 300 million people. In the last years, owing to low artemisinin content, research of new ways to increase the yield of the plant matrix has led to the use of the total extract taking advantage from the synergic and stabilising effects of the other components. Objective: In this work we evaluated and compared the content of artemisinin and scopoletin in extracts of A. annua collected in the Campania Region (southern Italy), by two different extraction processes. Methodology: Artemisia annua plants were extracted by traditional maceration (TM) in hydroalcoholic solution as a mother tincture prepared according to the Euro- pean Pharmacopeia and by pressurised cyclic solid–liquid (PCSL) extraction, a new generation method using the Naviglio extractor. Results: The results showed that the PCSL extraction technique is more effective than traditional methods in extracting both phytochemicals, up to 15 times more, reducing the extraction times, without using solvents or having risks for the opera- tors, the environment and the users of the extracts. Conclusion: The Naviglio extractor provides extracts with an artemisinin and scopoletin content eight times higher than the daily therapeutic dose, which should be evaluated for its stability over time and biological properties for possible direct use for therapeutic purposes.

The setup of an economic and sustainable method to increase the production and commercialization of products from microalgae, beyond niche markets, is a challenge. Here, a cascade approach has been designed to optimize the recovery of high valuable bioproducts starting from the wet biomass of Galdieria phlegrea. This unicellular thermo-acidophilic red alga can accumulate high-value compounds and can live under conditions considered hostile to most other species. Extractions were performed in two sequential steps: a conventional high-pressure procedure to recover phycocyanins and a solvent extraction to obtain fatty acids. Phycocyanins were purified to the highest purification grade reported so far and were active as antioxidants on a cell-based model. Fatty acids isolated from the residual biomass contained high amount of PUFAs, more than those recovered from the raw biomass. Thus, a simple, economic, and high effective procedure was set up to isolate phycocyanin at high purity levels and PUFAs.

The subsurface drip irrigation (SDI) system is a micro-irrigation technique applied below the soil surface through drip lines buried at a depth depending on the characteristics of the soil and on the plants to be irrigated. SDI distributes precise amounts of water directly to the root area, with the possibility of leaving the soil surface dry and less subject to weeds. This system reduces the use of water, herbicides, and environmental pollution. Furthermore, SDI allows the use of urban wastewater, advantageous from the environmentalpoint of view since it reduces the consumption of ground water and energy costs required for its pumping. In addition, it reduces the use of chemical fertilizers through the enhancement of organic fertilizer content in the waste. However, there are issues related to the use of SDI systems, such as the elimination or reduction of roots that wrap the dripper thus blocking the water flow. It has been hypothesized that it would be useful to add a pure or blended phytotoxic mixture to plastic during the production of drippers, whose herbicidal action dissolves gradually with the passage of water. Five species of plants have been selected in this study: Vetch villosa, Brassica juncea, Secale cereale, Juncus effusus, and Vallisneria natans. The phytotoxicity has been tested in vivo on Lactuca sativa, Lycopersicon esculentum, and Allium cepa. The plants showed the same behavior but the aerial biomass of V. natans resulted the most active ones. The phytotoxicity of the hydroalcoholic extract of each plant was evaluated on the same test organisms, with peak inhibitions up to 60, 70, and 80% at concentrations ranging from 10−4 to 10−7 M. In general, the most active hydroalcoholic infusion was that of V. villosa. Finally, after some chromatographic steps and LC/GC-MS analyses, the most abundant metabolites of the hydroalcoholic extracts were identified.

Gymnema sylvestre has been used in Asian traditional medicine for its anti-microbial, anti-hypercholesterolemic, hepatoprotective and sweet suppressing properties and activities. G. sylvestre has also been used extensively in chewing gum, as a health food for preventing obesity and diabetes, and as a tea. This study has evaluated the total phenolic content and antioxidant activity of the aqueous and organic G. sylvestre extracts and their sub-fractions for the initial characterization of the biological properties of the isolated compounds. An in vivo cell model was used to calculate the concentration inhibiting cell growth by 50% and the ability to exert antioxidant activity. All compounds inhibit cell growth in a dose-dependent manner, with an IC 50 value ranging between 29 and 1462 μM. The effects on intracellular ROS levels are extremely variable, but it is of interest that some of the compounds appear to display an antioxidant effect.

Phenylpropanoids are secondary metabolites widely distributed in plants. They are believed to protect human cells against oxidative stress and in turn, to prevent various diseases associated with it, such as cancer, cardiovascular, and neurodegenerative disorders as well [2,3]. Recently, many natural phenylpropanoids have emerged as a particularly promising class of small molecules able to inhibit β-amyloid aggregation and disrupt preformed amyloid fibrils that represent important targets in the development of pharmacological treatments of Alzheimer’s disease (AD) [4]. Unfortunately, natural phenylpropanoids often have poor pharmacokinetic properties and low bioavailability. In this frame an interesting approach in the design of new bioactive compounds could be the combination of two or more polyphenolic "fragments". This "natural-fragment-based drug-discovery" approach would allow the assembly, also in a combinatorial manner, of libraries based on complex polyphenols in a few steps. This strategy provides us with the possibility of easily modifying both scaffold and decorations and modulating pharmacodynamic and pharmacokinetic properties [5]. Therefore, we planned to join two "tyrosol-fragments" by a phosphodiester bridge to obtain a new class of phosphate-linked compounds [6], which are potentially more bioactive than the corresponding precursors. We report here the general synthetic strategy to obtain new phosphate-linked tyrosol dimers in good yield and their full characterization. Since oxidative stress, as well as metal ion dyshomeostasis, are known to play important roles in AD pathogenesis, preliminary studies are focused on the evaluation of their antioxidant activity, metal chelating ability and their ability to inhibit β-amyloid aggregation.

Outer membrane vesicles (OMVs) are nanostructures of 20– 200 nm diameter deriving from the surface of several Gram- negative bacteria. OMVs are emerging as shuttles involved in several mechanisms of communication and environmental adaptation. In this work, OMVs were isolated and charac- terized from Novosphingobium sp. PP1Y, a Gram-negative non-pathogenic microorganism lacking LPS on the outer membrane surface and whose genome was sequenced and annotated. Scanning electron microscopy performed on sam- ples obtained from a culture in minimal medium highlighted the presence of PP1Y cells embedded in an extracellular ma- trix rich in vesicular structures. OMVs were collected from the exhausted growth medium during the mid-exponential phase, and purified by ultracentrifugation on a sucrose gra- dient. Atomic force microscopy, dynamic light scattering and nanoparticle tracking analysis showed that purified PP1Y OMVs had a spherical morphology with a diameter of ca. 150 nm and were homogenous in size and shape. Moreover, pro- teomic and fatty acid analysis of purified OMVs revealed a specific biochemical “fingerprint”, suggesting interesting de- tails concerning their biogenesis and physiological role. More- over, these extracellular nanostructures do not appear to be cytotoxic on HaCaT cell line, thus paving the way to their future use as novel drug delivery systems.

Polyphenols are active compounds from medicinal plants widely distributed in nature. Many reports suggest that the mechanisms by which plant polyphenols exert their protective actions against various diseases are in part due to their redox properties [1]. Silibinin, belonging to flavonolignan class, is the major component of Silymarin complex extracted from the fruits of milk thistle (Silybum marianum) [2]. Silibinin is a diastereoisomeric mixture of two flavonolignans, Silybin A and Silybin B, in a ratio of approximately 1:1; this metabolite has long been studied for its large variety of pharmacological properties ranging from the antioxidant to neuroprotective [3] and antiviral activities. Unfortunately, many drug candidates including Silibinin, even if have been reported to possess a strong therapeutic potential in vitro, fail in vivo because of their poor bioavailability, often connected to a low water solubility. The design and synthesis of water-soluble pro-drugs are a powerful approach in order to overcome these limits and to improve the pharmacological potentialities of these compounds [4]. In this regard, here, we report the synthesis and characterization of new phosphodiester Silibinin conjugates by the insertion of a phosphate group at the 9” position. This, besides improving the Silibinin water solubility, allows conjugation of different molecules (Figure) able to recognize cell targets and to improve Silibinin pharmaceutical properties [5-8]. The new derivatives have been tested in different radical scavenging assays. A antiviral and neuroprotective activities have also been explored.

Silibinin is the major component of an extract, known as Silymarin, obtained from the seeds of the milk thistle (Silybum marianum). Structurally, Silibinin is diastereoisomeric equimolar mixture of two flavonolignans (Silybin A and Silybin B). As extensively reported in literature, Silibinin displays multiple biological activities, most of them related to its radical scavenging activity. In the past two decades, in addition to hepatoprotective effects, Silibinin has demonstrated remarkable anti-cancer as well as cancer chemopreventive efficacy in pre-clinical cell culture and animal models of several epithelial cancers, including skin, bladder, colon, prostate, and lung [2]. Oral administration of chemotherapeutic agents is the mainstay for the treatment of disease. Sustained release formulations have been crucial for the safe and effective dosing of orally administered drugs [3]. In this frame, the synthesis of phosphodiester derivatives can improve the oral bioavailability of poorly water-soluble metabolites maintaining their pharmacologic activity [4,5]. Here, we reported the synthesis of new Silibinin conjugates with 3'-ribonucleotide units. The phosphodiester junction is typically used in pro-drug strategies, in which the phosphate group is susceptible to hydrolysis by endogenous phosphatases, allowing the release of the active compound. The new conjugates were prepared in few steps and in good yields, starting from the suitable Silibinin or Silybin building blocks and nucleotide phosphoramidites. All compounds were full characterized by NMR and Maldi-TOF and their serum stability was evaluated by HPLC analyses.

The synthesis of (1'S,2'S,4'R) and (1'S,2'R,4'R) stereoisomers of 2'-fluoro-3'-thiacytidine [(2' S)-F-3TC and (2' R)-F-3TC], the earliest examples of oxathiolanyl nucleosides with a fluorine atom in the 'sugar' backbone, is herein reported. From of a variety of synthetic routes devised for their preparation, the Pummerer rearrangement of protected lamivudine sulfoxides was successfully exploited for fluorine atom introduction. Despite the presence of three potentially labile stereocenters in such a small molecule, the (2'R)-isomer of F-3TC exhibited good chemical stability after protective group cleavage. Conversely, the (2'S)-epimer suffered from weak stability, owing to the formation of an undesired cyclization product. Based on the remarkable antiviral efficacy of the parent drugs, the access to 2'-fluorinated oxathiolanyl nucleosides (and more generally, 2'-fluorinated heterocyclic nucleosides) may provide a new source of candidates with antiviral potential.

During the lipidomic analysis of red blood cell membranes, the distribution and percentage ratios of the fatty acids are measured. Since fatty acids are the key constituents of cell membranes, by evaluating their quantities it possible to understand the general health of the cells and to obtain health indicators of the whole organism. However, because the analysis is precise, it is necessary to ensure that the blood does not undergo significant variations between the point of collection and analysis. The composition of the blood may vary dramatically weeks after collection, hence, here an attempt is made to stabilize these complex matrixes using antioxidants deposited on the paper cards on which the blood itself is deposited.

The biological relevance of tetramolecular G-quadruplexes especially as anti-HIV agents has been extensively reported in the literature over the last years. In the light of our recent results regarding the slow G-quadruplex folding kinetics of ODNs based on d(TGGGAG) sequence, here we report a systematic anti-HIV screening to investigate the impact of the G-quadruplex folding on their anti-HIV activity. In particular, varying the single stranded concentrations of ODNs, it has been tested a pool of ODN sample solutions with different G-quadruplex concentrations. The anti-HIV assays have been designed favouring the limited kinetics involved in the tetramolecular G4-association based on the d(TGGGAG) sequence. Aiming to determine the stoichiometry of G-quadruplex structures in the same experimental conditions of the anti-HIV assays, a native gel electrophoresis was performed. The gel confirmed the G-quadruplex formation for almost all sample solutions while showing the formation of high order G4 structures for the more concentrated ODNs solutions. The most significant result is the discovery of a potent anti-HIV activity of the G-quadruplex formed by the natural d(TGGGAG) sequence (IC50 = 14 nM) that, until now, has been reported to be completely inactive against HIV infection.

In the last decade, a large number of evidences points to the misfolding, aggregation and accumulation of structurally abnormal proteins, termed amyloid, as a common pathogenic mechanism of a range of increasingly common human disorders, including Alzheimer`s Disease (AD) and type II diabetes mellitus (T2DM). In particular, AD and T2DM are characterized by the accumulation of the amyloid-β (Aβ) peptide in neuronal tissues and islet amyloid polypeptide (IAPP) in pancreatic cells, respectively (1), implicitly suggesting that targeting protein misfolding and self-assembly would cure the diseases. However, the failure of all clinical trials focusing on anti-aggregating drugs has clearly demonstrated that a deeper understanding of the phenomena involved in proteome maintenance is needed. It is widely known that cells express an integrated array of proteolytic machineries that control protein homeostasis (proteostasis). As a matter of fact, the latest studies suggest that pathological conditions occur when the equilibrium between the production and the clearance of the involved protein results unbalanced. The ubiquitin–proteasome system (UPS) is the major quality control pathway responsible for cellular homeostasis; it is the primary proteolytic route for misfolded proteins and ubiquitination is utilized as a degradation signal (2). Many researchers have screened a number of molecules using the whole UPS as target (proteasome activators, inhibitors of deubiquitinating enzymes DUBs or ubistatins); however, very few molecules, if any, selected by using this strategy have shown to have the potential to be pipelined to clinical trials. But, due to the multifactorial nature of protein diseases, it may be difficult to find an effective drug by screening molecules on a single target. This study evaluates the ability of silybins A and B, components of the natural product silymarin, to rescue the proteostatic balance of the amyloidogenic peptides Aβ and IAPP against several targets: proteasome, polyubiquitination, membrane protection, amyloid aggregation and oxidative stress. The obtained results evidence the important role of the stereochemistry, demonstrating the high potential of these natural compounds in anti-AD therapeutics. Our multi-target strategy to rescue proteostasis opens the door to a new approach to face these important pathologies.

During the last years, the widespread occurrence of personal care products, pesticides and stimulating drugs in water has gained much attention, especially for the evaluation of the environmental risk based on the calculation of the Predicted Environmental Concentrations (PEC) obtained from consumption data [1]. Data on the occurrence of these emerging pollutants were reported by Xing et al. (2018) in sewage treatment plant influents, effluents and sludge in many countries of the world, where they were found until to hundreds ng/L concentrations [2]. Often the products obtained by disinfection treatment could be more toxic than parent compounds especially using the chlorination process [3]. Moreover, the potential risk posed by these pollutants could be increased by their susceptibility to produce photo-transformation products [4]. Tramadol is a synthetic, centrally acting analgesic agent used for the relief of acute and chronic pain, which has been used in both human and veterinary medicine. Recent papers have reported a study on the increasing tramadol utilization associated to the mortality over the past 15 years in the UK, highlighting the high toxicity of this drug [5]. Our research is focused on the evaluation of the environmental effects of tramadol and its transformation products, mimicking the most common experimental conditions in wastewater treatment plants. After disinfection treatment, the main transformation products have been isolated and characterized by NMR and ESI-MS analyses. Furthermore, in order to evaluate the environmental eects of products, aquatic acute and chronic toxicity have been tested on Brachionus calyciorus and Ceriodaphnia dubia as well as their mutagenesis and genotoxicity tested on bacterial strains.

In the last years, G-rich oligonucleotides (GROs) able to form G-quadruplexes, have attracted considerable interest in biological and therapeutic fields. G-quadruplexes are among the most studied DNA structures because of the large variety of their biological properties ranging from anticancer to antiviral activities.(1) Recently, new findings on the anti-HIV-1 activity of ODNs forming G-quadruplex have been reported.(2) In this frame, here it is reported the synthesis of a mini-library of 5' and 3'-modified oligonucleotides with the Riboflavin (Vitamin B). The choice to insert the Riboflavin into lead sequence, has been inspired by the similarity with the hydrogen bond pattern of guanine, in addition to its excellent fluorescence properties that may be an useful tools for in vitro and in vivo studies. In order to allow the Riboflavin moiety similar to a nucleoside unit, the ribityl chain is rigidified by 2',4'-O-benzylidene group. The synthetic strategy is focused on the synthesis of two key intermidiates, the Riboflavin-Nucleoside phosphoramidite (I), useful for the synthesis of the 5'-end modified sequences and the CPG (Control Pore Glass) support anchoring the 5'-O-DMT-2',4'-O-benzyldene-riboflavin unit (II), fruitful for the synthesis of 3'-modified sequences. Using the phosphoramidite coupling automated protocol, the building block I was incorporated into oligonucleotides with a good yield. The new modified ODNs were assembled by standard automated DNA synthesis and after RP-HPLC purifications, they were analyzed by MALDI-TOF. Preliminary biophysical studies (CD, DSC and fluorescence studies) were carried out in order to evaluate the ability of modified ODNs to fold into G-quadruplex structures. Finally, their anti-HIV activity were evaluated.

Potatoes are a staple food for over a billion people worldwide, a primary dietary source of carbohydrates, and a vital crop to the agricultural economy of South America, Africa, East Asia and Central Asia. Potatoes occupy third place (after rice and wheat) on the list of foods on which the world depends for food security. In particular, glyco-alkaloids contents in potatoes are potentially toxic and secondary metabolites such as α-solanine and α-chaconine are reported to be dangerous to human health. This paper describes new methods for α-solanine and α-chaconine reduction in the potato cultivar known as Marabel. The potatoes were incubated at room temperature in the dark for 24 h and the optimal experimental condition was achieved with NaOH solution at pH 12. In the assayed samples, α-solanine and α-chaconine reduction was 43% and 27% respectively. The process proposed here allows to minimize the total content of glyco-alkaloids, with respect to mode of collection, storage and cleaning of Marabel potatoes.

New silibinin phosphodiester glyco-conjugates were synthesized by efficient phosphoramidite chemistry and were fully characterized by 2D-NMR. A wide-ranging study focused on the determination of their pKa and E° values as well as on their radical scavenging activities by different assays (DPPH, ABTS+ and HRSA) was conducted. The new glyco-conjugates are more water-soluble than silibinin, and their radical scavenging activities are higher than those of silibinin. The conjugation therefore improves both the water solubilities and antioxidant activities of the flavonolignan moieties. The serum stability was evaluated under physiological conditions, and the glyco-conjugates degraded with half-lives of 40-70 h, making them useful in pro-drug approaches. We started by treating androgen-dependent prostate cancer (PCa) LNCaP cells and then expanded our studies to androgen-independent PCa PC3 and DU145 cells. In most cases, the new derivatives significantly reduced both total and live cell numbers, albeit at different levels. Anti-HIV activities were evaluated and the glucosamine-phosphate silibinin derivative showed higher activity (IC50 = 73 μM) than silibinin.

International audience; By exploiting the regioselective protection of the hydroxyl groups of silibinin along with the well-known phosphoramidite chemistry, we have developed an efficient strategy for the synthesis of new silibinin-modified species, which we have named Phosphate-Linked Silibinin Dimers (PLSd), in which the monomer units are linked by phosphodiester bonds. The antioxidant abilities of the new PLSd were estimated on HepG2 cells using DPPH free radical scavenging and xanthine/xanthine oxidase assays. The new phosphate-metabolites showed a higher anti-oxidant activity than the silibinin, as well as very low toxicity. The ability to scavenge reactive oxygen species (ROS) such as singlet oxygen () and hydroxyl radical () reveals that the two dimers are able to scavenge about two times more effectively than silibinin. Finally, solubility studies have shown that the PLSd present good water solubility (more than 20 mg·L−1) under circumneutral pH values, whereas the silibinin was found to be very poorly soluble (less than 0.4 mg·L−1) and not stable under alkaline conditions. Together, the above promising results warrant further investigation of the future potential of the PLSd as anti-oxidant metabolites within the large synthetic polyphenols field.

Polyphenols are active compounds of the medicinal plants widely distributed in nature. Despite the few and common biosynthetic origins, polyphenols encompass many subclasses of structurally different entities with a variety of pharmacological properties. Many studies suggest that the mechanisms by which plant polyphenols exert their protective actions against various diseases, are in part due to their redox properties.1Silibinin belongs to flavonolignan class, it is a major component of the Silymarin complex extracted from the milk thistle (Silybum marianum). Silibinin has long been studied for its large variety of pharmacological properties ranging from the antioxidant activity to neuroprotective and antiviral activities. In order to expand the repertoire of the modified Silibinins with high molecular diversity and good water solubility, here, we present a new and efficient method for the synthesis of dimers and trimers of the Silibinin, in which the monomer units are linked by phosphodiester bond Exploiting the selective protection of the Silibinin hydroxyl groups, we carried out a new synthetic approach using the well-established phosphoramidite chemistry. Aiming at the discovery of new pharmacological activities of these molecules, the water solubility, the radical scavenger activity by DPPH test, as well as, their ability to scavenge different reactive oxygen species (1O2 and HO●) have been studied. Additionally, the serum stability and cytoprotective behaviour (X/XO assay on HepG2 cells) of dimers have been evaluated. The combination of both striking antioxidant ability and high water solubility, makes these molecules, promising synthetic metabolites for future therapeutic applications.

Polyphenols are active compounds of the medicinal plants widely distributed in nature. Despite the few and common biosynthetic origins, polyphenols encompass many subclasses of structurally different entities with a variety of pharmacological properties. Many studies suggests that the mechanisms by which plant polyphenols exert their protective actions against various diseases, in part are due to their redox properties. Silibinin belongs to flavonolignan class and is a major component (approximately 30%) of the Silymarin complex extracted from milk thistle [Silybum marianum (L.) Gaertn. Carduus marianus L., Asteraceae]. Silibinin exists as a mixture of two diastereomers: Silybin A and Silybin B. Silibinin has long been studied for a large variety of pharmacological properties ranging from its antioxidant activity to neuroprotective and antiviral activities. Unfortunately, its in vivo applications are rather hampered by its very low bioavailability mainly due to low water solubility. In an attempt to improve its biological properties and facilitate the in vivo applications, we have developed an efficient strategy for the synthesis of Silibinin modified namely Phosphate-Linked Silibinin dimers (PLSd) in which the Silibinin monomer units are linked by phosphodiester bond (Figure). Exploiting the selective protection of Silibinin’s hydroxyl groups, we carried out a synthetic approach using the phosphoramidite chemistry. Water solubility of dimers, radical scavenger activity as well as their ability to react with reactive oxygen species (ROS) were determined. In particular, dimers reactivity with 1O2 and HO∙ was determined by use of Rose Bengal (RB) and hydrogen peroxide (H2O2) as respective ROS sources. For this purpose, laser flash photolysis (LFP) experiments were coupled with a kinetic competition approach. In addition to scavenging activity, the serum stability and cytoprotective (X/XO assay on HepG2 cells) behavior of dimers were evaluated.

The interaction of the porphyrin derivative H2TCPPSpm4, having four spermines in the meso positions, with the G-quadruplex (GQ) structure formed by the DNA aptamer TGGGAG, a sequence that show anti-HIV activity, has been investigated by means of UV, CD and PAGE studies. The results demonstrate that porphyrin substituted with positively charged side chains is capable of inducing the formation of different complexes with parallel GQs, including higherordered complexes, depending on the method used to achieve their relative stoichiometry (titration vs single addition). Indeed the CD melting experiments indicated different thermal stability fort the 1:1 H2TCPPSpm4:GQ and the 2:1 H2TCPPSpm4:GQ species obtained by titration. Interestingly also the 2:1 H2TCPPSpm4:GQ complexes obtained by titration or by direct mixing show different behavior.

Polyphenols are widely distributed in nature and and very often represent the active compounds of the medicinal plants from which they can be isolated. Many studies suggests that the mechanisms by which plant polyphenols exert their protective actions against cardiovascular and neurodegenerative diseases, as well as cancer and diabetes, are due to their redox properties and their ability to directly bind bio-targets (peptides, proteins, nucleic acids).[1] To this huge group of metabolites belongs Silibinin, [2] the major biologically active component of Silymarin extracted from the seeds of the milk thistle [Silybum marianum (L.) Gaertn.]. In the past decade Silibinin has received attention due to its anticancer and chemopreventive actions, [3] as well as hypocholesterolemic, [4] cardioprotective and neuroprotective [5] activities. Unfortunately, the bioavailability and therapeutic efficiency of Silibinin are rather limited by its low water-solubility, therefore new synthetic approaches for selectively modifying Silibinin are of high interest. Different approaches have been recently described in order to improve its bioavailability, including the synthesis of new derivatives, the complexation with β-cyclodextrins or phospholipids, liposomes and phytosomes. As part of our ongoing efforts towards the exploitation of a readily available natural product used as a scaffold for chemical diversification, we recently considered Silibinin as a versatile starting material. Exploiting the regioselective protection of its hydroxyl groups and the well-known phosphoramidite chemistry, we developed an efficient strategy for the synthesis of a variety of Silibinin and 2,3-dehydrosilybin modified, bearing different groups at position C-9" (amino, sulphate),[6] and also inserting a suitable conjugation by a phosphodiester bound.[7, 8] By combinatorial solution phase strategies, a large family of Silibinin derivatives was successfully realized in a short time and in very good yields. For the conjugation, we have selected some molecules known for their ability to act as molecular carriers (steroids, bile acids), and able to improve water solubility (polyether) and radical scavenging activity (nucleosides). The redox behaviour of new Silibinin derivatives were analysed by potentiometric and voltammetric studies; moreover the scavenging activity was evaluated both in vitro by radical scavenger test and on cells by X/XO assay.

The interaction of the porphyrin derivative H(2)TCPPSpm4, having spermine pendants in the four meso positions, with the G-quadruplex (GQ) structure formed by the DNA aptamer TGGGAG has been investigated by means of UV, electronic circular dichroism and PAGE studies. The results reported here demonstrate that the porphyrin derivative is capable of stabilizing or destabilizing the higher-ordered structures of parallel GQs, depending on the method used to reach their relative stoichiometry (titration vs. single addition). Noteworthily, when two equivalents of H(2)TCPPSpm4 were mixed directly with one equivalent of the (TGGGAG)(4) GQ to reach a 2 : 1 H(2)TCPPSpm4: GQ ratio T-1/2 higher than 80 degrees C was also observed confirming the presence of higher-ordered GQ structures.

New phosphorylating reagents 1 and 2 were prepared in three steps from 4-hydroxybenzaldehyde. They showed good efficiency in the solid phase synthesis of 5′-phosphate monoester nucleosides. End-phosphate DNA sequence synthesis demonstrated the efficiency of the new reagents ( 1 and 2 ) according to the general procedure of automated DNA synthesis. The oxidation of P(III) to P(V) and the removal of benzyl protecting groups were achieved in a single step by treatment with a 0.02 M I 2 /pyridine/H 2 O solution. Due to this one-pot treatment, it is possible to use the phosphorylating reagents ( 1 and 2 ) for the synthesis of base-sensitive ODNs. The reagents 1 and 2 are unique among phosphorylating reagents.

Many drug candidates have been reported to possess a strong therapeutic potential in vitro but they have failed in vivo because of their poor pharmacokinetic behaviour, very often due to the low water solubility. There are many formulations and drug design strategies that can be used to overcome solubility issues. The design and synthesis of soluble pro-drugs is one of the most common approach used. In this frame, the phosphate group is a useful tool for the enhancement of aqueous solubility of phenolic and other metabolites, in addition it displayed excellent chemical stability and rapid bioconversion in vivo to the parent drug by phosphatases. On the other hand, also the conjugation of specific molecules recognized by a receptor on the target cell could be a successful strategy. In our studies, we have combined both aspects through the synthesis of new phosphodiester modified Silibinin with a good water solubility, as well as, attractive antioxidant properties. In the past decade, Silibinin has received more attention due to its large variety of activities ranging from anticancer and chemopreventive actions to hypocholesterolemic, cardioprotective and neuroprotective activities. Unfortunately, the bioavailability and the therapeutic efficiency of Silibinin are rather limited by its low water-solubility. In this work, we present the synthesis of a new library of modified Silibinins and related studies of their redox behaviour. Exploiting the selective protection of the hydroxyl groups of the Silibinin, we developed an efficient strategy for the synthesis of Silibinin phosphate-based flavonolignans consisting of phosphodiester glycoconjugates and dimers of Silibinin. The water solubility, the radical scavenger efficiency and the ability to scavenge different reactive oxygen species (ROS) have been evaluated for the new phosphodiester modified Silibinins in comparison to Silibinin. Moreover, the serum stability, and their cytoprotective (X/XO assay on HepG2 cells) behaviours have been studied. The remarkable antioxidant activity and the high water solubility (compared to Silibinin) make Silibinin phosphatebased flavonolignans promising molecules for future studies.

In the last years, G-rich oligonucleotides (GROs) able to form G-quadruplexes, have attracted considerable interest in biological and therapeutic fields. G-quadruplex are among the most studied DNA structures because they are thought to be involved in important biological processes such as the modulation of gene expression; in addition they present a large variety of biological properties ranging from anticancer to antiviral activities. In all cases, the G-quadruplex formation is a crucial prerequisite for the biological effects. Recently, we reported the synthesis and full characterization of a mini-library of G quadruplex ODNs carrying aryl groups at the 5’-end through a phosphodiester bond and endowed with prominent anti-HIV activity. In this frame, we report here, the synthesis of new Riboflavin-Nucleoside (RF, Vitamin B) building block in which the ribityl chain is rigidified by 2',4' benzylidene group, the 5'-OH function is protected with DMT group and the 3’ position is functionalized with phosphoramidite. The new Riboflavin building block is incorporated into different ODN sequences able to form Gquadruplex structures using the well known phosphoramidite chemistry. This research project has been encouraged by recent studies on the use of RF as useful tool for both in vivo and in vitro studies: the Riboflavin is internalized through RF transporters and is one of the most efficient natural photosensitizers. Several modified ODN sequences have been synthesized with a solid phase synthetic approach in good yields; their biophysical and biological characterization has been carried out in order to evaluate the effect of RF-nucleotide insertion into G-quadruplex arrangements and their anti-HIV activity.

Because plants are estimated to produce over 200,000 metabolites, research into new natural substances that can be used in the pharmaceutical, agrochemical and agro-industrial production of drugs, biopesticides and food additives has grown in recent years. The global market for plant-derived drugs over the last decade has been estimated to be approximately 30.69 billion USD. A relevant specific example of a plant that is very interesting for its numerous pharmacological properties, which include antidiabetic, anticarcinogenic, and neuroprotective effects is Gymnema sylvestre, used as a medicinal plant in Asia for thousands of years. Its properties are attributed to triterpenoidic saponins. In light of the considerable interest generated in the chemistry and pharmacological properties of G. sylvestre triterpenes and their analogues, we have undertaken this review in an effort to summarise the available literature on these promising bioactive natural products. The review will detail studies on the isolation, chemistry and bioactivity of the triterpenoids, which are presented in the tables. In particular the triterpenoids oxidised at C-23; their isolation, distribution in different parts of the plant, and their NMR spectral data; their names and physico-chemical characterisation; and the biological properties associated with these compounds, with a focus on their potential chemotherapeutic applications.

The pharmacological relevance of ODNs forming G-quadruplexes as anti-HIV agents has been extensively reported in the literature over the last few years. Recent detailed studies have elucidated the peculiar arrangement adopted by many G-quadruplex-based aptamers and provided insight into their mechanism of action. In this review, we have reported the history of a strong anti-HIV agent: the 6-mer d(TGGGAG) sequence, commonly called “Hotoda’s sequence„. In particular, all findings reported on this sequence and its modified sequences have been discussed considering the following research phases: (i) discovery of the first 5′-modified active d(TGGGAG) sequences; (ii) synthesis of a variety of end-modified d(TGGGAG) sequences; (iii) biophysical and NMR investigations of natural and modified Hotoda’s sequences; (iv); kinetic studies on the most active 5′-modified d(TGGGAG) sequences; and (v) extensive anti-HIV screening of G-quadruplexes formed by d(TGGGAG) sequences. This review aims to clarify all results obtained over the years on Hotoda’s sequence, revealing its potentiality as a strong anti-HIV agent (EC50 = 14 nM).

In recent years, many studies have highlighted the consistent finding of tramadol (TRA) in the effluents from wastewater treatment plants (WTPs) and also in some rivers and lakes in both Europe and North America, suggesting that TRA is removed by no more than 36% by specific disinfection treatments. The extensive use of this drug has led to environmental pollution of both water and soil, up to its detection in growing plants. In order to expand the knowledge about TRA toxicity as well as the nature of its disinfection by-products (DBPs), a simulation of the waste treatment chlorination step has been reported herein. In particular, we found seven new by-products, that together with TRA, have been assayed on different living organisms (Aliivibrio fischeri, Raphidocelis subcapitata and Daphnia magna), to test their acute and chronic toxicity. The results reported that TRA may be classified as a harmful compound to some aquatic organisms whereas its chlorinated product mixture showed no effects on any of the organisms tested. All data suggest however that TRA chlorination treatment produces a variety of DBPs which can be more harmful than TRA and a risk for the aquatic environment and human health.

The methanol extracts of the aerial part of four ethnomedicinal plants of Mediterranean region, two non-seed vascular plants, Equisetum hyemale L. and Phyllitis scolopendrium (L.) Newman, and two Spermatophyta, Juniperus communis L. (J. communis) and Cotinus coggygria Scop. (C. coggygria), were screened against four human cells lines (A549, MCF7, TK6 and U937). Only the extracts of J. communis and C. coggygria showed marked cytotoxic effects, affecting both cell morphology and growth. A dose-dependent effect of these two extracts was also observed on the cell cycle distribution. Incubation of all the cell lines in a medium containing J. communis extract determined a remarkable accumulation of cells in the G2/M phase, whereas the C. coggygria extract induced a significant increase in the percentage of G1 cells. The novelty of our findings stands on the observation that the two extracts, consistently, elicited coherent effects on the cell cycle in four cell lines, independently from their phenotype, as two of them have epithelial origin and grow adherent and two are lymphoblastoid and grow in suspension. Even the expression profiles of several proteins regulating cell cycle progression and cell death were affected by both extracts. LC-MS investigation of methanol extract of C. coggygria led to the identification of twelve flavonoids (compounds 1-11, 19) and eight polyphenols derivatives (12-18, 20), while in J. communis extract, eight flavonoids (21-28), a alpha-ionone glycoside (29) and a lignin (30) were found. Although many of these compounds have interesting individual biological activities, their natural blends seem to exert specific effects on the proliferation of cell lines either growing adherent or in suspension, suggesting potential use in fighting cancer.

In ‘90s, Hotoda et al. identified a variety of tetramolecular G-quadruplexes based on the sequence d(TGGGAG) and modified at the 5’-end with aromatic groups, targeting the glycoprotein of HIV-1, gp120. In 2011 Di Fabio et al. reported the synthesis and characterization of a new mini-library of d(TGGGAG) ODNs carrying aryl groups at the 5’-end through a phosphodiester bond and endowed with prominent anti-HIV activity[2]. In order to have more information on the G-quadruplex folding depending on the modifications at 5’-end of d(TGGGAG), we have explored the kinetic aspects involved into G-quadruplex folding using electrospray mass spectrometry (ESI-MS). The studies are conducted on more active 5’-end modified ODNs in comparison with unmodified sequence d(TGGGAG). By ESI-MS experiments, we could obtain information about the number of strands, and the inner cations for each complex, moreover it is possible to detect all possible intermediate complexes and to determine their equilibrium binding constants. We followed the kinetics of G-quadruplex formation during 14 days in the presence of an internal reference (dT6), selecting some time points after addition of different buffers (150mM NH4OAc and 150mM TMAA/1mM KCl). Overall data, have reported a rapid conversion of the single strand into dimer and trimer, and slower conversion in a tetramer and into an unexpected G4-supramolecular structure: the octamer complex. The formation of octamer is confirmed also in solution by native PAGE.

To investigate what properties make tetramolecular G-quadruplex ODNs good anti-HIV aptamers, we studied the stoichiometry and the self-assembly kinetics of the highly active 5'-end modified G-quadruplexes based on the d(TGGGAG) sequence. Our results demonstrate that the 5'-end conjugation does not necessarily increase the folding rate of the G-quadruplex; indeed, it ascribes anti-HIV activity. Unexpectedly, the G4-folding kinetics of the inactive G4 is similar to that of the 5'-end modified sequences. ESI-MS studies also revealed the formation of higher order G4 structures identified as octameric complexes along with tetramolecular G-quadruplexes.

Introduction: Recently, we reported the synthesis and characterization of a new mini-library of tetramolecular G quadruplexes based on the d(TGGGAG) sequence, which was previously shown to target the HIV-1 glycoprotein gp120. Oligodeoxynucleotides (ODNs) carrying aryl groups at the 5’-end through a phosphodiester bond were endowed with prominent anti-HIV activity. Biophysical studies on these aptamers demonstrated that there is no relationship between thermal stability of G4 structures and their anti-HIV activity. To identify the properties that make these tetramolecular G-quadruplexes good anti-HIV aptamers, we studied by ESI-MS the stoichiometry and the self-assembly kinetics of G-quadruplex structures based on the most active 5’-end modified d(TGGGAG) aptamers [5]. ESI-MS results showed that the conjugation of d(TGGGAG) at the 5’-end does not necessarily increase the folding rate of the G-quadruplex structure. Unexpectedly, the folding kinetics of the inactive G4 (unmodified sequence) was similar to that of the 5’-end modified sequences. In addition to the slow G4-kinetics revealed by ESI-MS studies, PAGE experiments on the modified d(TGGGAG) highlighted the strong effect of ODN concentration (single stranded) on the G4-folding kinetics. Results and Discussion: In order to clarify the role of G-quadruplex structures in the anti-HIV activity on the basis of the above kinetic studies, we investigated the anti-HIV activity of ODNs at different concentrations of G-quadruplex structure. All ODNs, as well as the unmodified sequence, were evaluated against a variety of HIV-1 viruses and resistant strains. SPR experiments were also carried out to evaluate their binding to the HIV envelope gp120 and gp41 proteins. Almost all compounds showed a good anti-HIV activity, suggesting the absence of a straight correlation between the amount of available G-quadruplex and anti-HIV activity of ODNs. Surprisingly, we found a strong anti-HIV activity of the unmodified sequence d(TGGGAG), in contrast to what has been extensively reported by Hotoda and others, who showed a lack of anti-HIV activity of the d(TGGGAG) sequence without 5’-end modifications. Also, by SPR experiments no straight correlation between gp120 binding and anti HIV activity was observed. Conclusions: The anti-HIV activity results highlight the absence of a straight correlation between the formation of G-quadruplex structures and the antiviral potential of ODNs, suggesting instead that the G4 is not the specie providing anti-HIV activity. In addition, anti-HIV data do not strictly correlate with the SPR results, suggesting that gp120 and gp41 is not the primary target of these aptamers.

Potato (Solanum tuberosum), which belongs to the family Solanaceae, is a native of South America and was introduced in Europe in the sixteenth century by the Spanish at first as a botanical curiosity and subsequently as a food plant. Potato cultivation has spread worldwide, with a high concentration of cropland in Europe. For many people, it serves as a staple food in place of bread. Potatoes are used in the food industry to produce starch, dextrin, and glucose; it is also used in distillation and in animal feed. The market also requires appropriate potato product for canning and for the production of French fries. Potato leaves and fruits can be poisonous because they are rich in alpha-solanine and alpha-chaconine, toxic alkaloids that can cause serious damages if consumed in large quantities. There are many varieties of potatoes, which differ in the shape of the tuber and the color of the flesh and skin. This study measures the content of the two toxic alkaloids in 15 different varieties of potatoes considered important for a commercial use; measurements were taken immediately following the collection and after 20 days. The data show that after 20 days the alpha-solanine content decreases (with the exception of only four varieties), whereas the alpha-chaconine content increases to alarming levels.

This study was conducted to test five phenolic and cyanogenic glycoside compounds for growth regulating activity on the germination and seedling growth of Portulaca oleracea L., Amaranthus retroflexus L., and Lactuca sativa L. at different concentrations. Overall, the tested compounds revealed growth-regulating activity in species-specific and concentration dependent manner. The most powerful effects were much pronounced on seedling growth rather than on germination. In fact, the compounds 1 (amygdalin) and 2 (salicylic acid) were the most phytotoxic on root growth of P. oleracea , and they caused, respectively, an inhibition of 55% and 85% at 10 -6 M and 10 -4 M. On the other hand, the lettuce seedling growth was more sensitive than weeds growth to the compounds 4 (3,4,5-trihydroxybenzoic acid) and 5 (7-hydroxycoumarin), which exhibited a moderate inhibition at the highest concentration. This selectivity and specificity of these active allelopathic compounds could be very useful for the development of new application of natural substances to control the aggressive weeds. Thus, our findings suggest that the integration of these compounds may maintain irrigation system and reduce the massive use of agrochemicals in agro-ecosystems.

Gymnema sylvestre R. Br. is one of the most important medicinal plants that grows in tropical forests in India and South East Asia. Its active ingredients and extracts of leaves and roots are used in traditional medicine to treat various ailments and they are present in the market for pharmaceutical and parapharmaceutical products. Commercial products based on substances of plant origin that are generally connoted as natural have to be subjected to monitoring and evaluation by health authorities for their potential impacts on public health. The monitoring and evaluation of these products are critical because the boundary between a therapeutic action and a functional or healthy activity has not yet been defined in a clear and unambiguous way. Therefore, these products are considered borderline products, and they require careful and rigorous studies, in order to use them as complement and/or even replacement of synthetic drugs that are characterized by side effects and high economic costs. This review explores the traditional uses, chemical composition and biological activity of G. sylvestre extracts, providing a general framework on the most interesting extracts and what are the necessary studies for a complete definition of the range of activities.

Le patate sono un alimento base per oltre un miliardo di persone in tutto il mondo, una fonte alimentare primaria di carboidrati e una coltura vitale per l'economia agricola del Sud America, Africa, Asia orientale e centrale. Le patate occupano il terzo posto (dopo il riso e il grano) nella lista degli alimenti da cui dipende il mondo per la sicurezza alimentare. In particolare, il contenuto di glicoalcaloidi nelle patate è potenzialmente tossico e metaboliti secondari come α-solanina e α-caconina sono considerati pericolosi per la salute umana. Questo brevetto descrive nuovi metodi perla riduzione dell’ α-solanina e dell’ α-caconina nella cultivar di patate nota come Marabel. Durante il trattamento, le patate sono state incubate a temperatura ambiente al buio per 24 ore, la condizione sperimentale ottimale è stata raggiunta lavando le patate con una soluzione basica. Nei campioni analizzati, la riduzione di α-solanina e α-caconina è rispettivamente del 43% e del 27%. Il processo qui proposto consente di ridurre al minimo il contenuto totale di glicoalcaloidi tenendo conto delle modalità di raccolta, conservazione e pulizia delle patate Marabel.

We describe the facile syntheses of new modified oligonucleotides based on d(TG3AG) that form bimolecular G-quadruplexes and possess a HEG loop as an inversion of polarity site 3'-3' or 5'-5' and aromatic residues conjugated to the 5'-end through phosphodiester bonds. The conjugated hairpin G-quadruplexes exhibited parallel orientation, high thermal stability, elevated resistance in human serum and high or moderate anti-HIV-1 activity with low cytotoxicity. Further, these molecules showed significant binding to HIV envelope glycoproteins gp120, gp41 and HSA, as revealed by SPR assays. As a result, these conjugated hairpins represent the first active anti-HIV-1 bimolecular G-quadruplexes based on the d(TG3AG) sequence. publisher: Elsevier articletitle: Hairpin oligonucleotides forming G-quadruplexes: New aptamers with anti-HIV activity journaltitle: European Journal of Medicinal Chemistry articlelink: http://dx.doi.org/10.1016/j.ejmech.2014.10.030 content_type: article copyright: Copyright © 2014 Elsevier Masson SAS. All rights reserved. ispartof: European Journal of Medicinal Chemistry vol:89 pages:51-8 ispartof: location:France status: published

b ) Tecno-Bios srl, Piazza San G. Moscati, I-82030 Apollosa (BN) c ) Dipartimento di Farmacia - via D. Montesano 49, I-80131, Napoli d ) AIPRAS Onlus-Associazione Italiana per la Promozione delle Ricerche sullAmbiente e la Salute umana-Via Nazionale 50, I-82030 Dugenta (BN) Silibinin, the major flavonolignan of silymarin, displays a broad spectrum of biological features that are generally ascribed to its antioxidant properties. Silibinin occurs in two diastereoisomeric forms, i.e., silybins A and B, in a ratio of ca. 1 : 1. With a simple and robust purification method, it is now possible to obtain silybins A and B in pure forms, in g-scale amounts, and within a short period of time. Herein, we describe an efficient synthesis strategy to obtain a variety of new and more H2O-soluble derivatives from the single silybins in which the 9''-OH group was converted to a sulfate, N3, phosphodiester, or NH2 group via a solution-phase approach. Thus, eight new compounds have been synthesized, purified by HPLC analysis, and characterized by NMR and MS analyses. To conduct experiments to clarify the many biological properties of pure silibinin diastereoisomers and their derivatives, the synthetic compounds were tested by using the DPPH assay to evaluate their antioxidant activities. The results, even if only for a small number of derivatives, revealed that some of these compounds are much more active than their parent compounds. It is also interesting to consider the synergetic effects.

New silibinin glyco-conjugates have been synthesized by efficient method and in short time. Exploiting our solution phase strategy, several structurally diverse silibinin glyco-conjugates (gluco, manno, galacto, and lacto-) were successfully realized in very good yields and in short time. In preliminary study to evaluate their antioxidant and neuroprotective activities new derivatives were subjected to DPPH free radical scavenging assay and the Xanthine oxidase (XO) inhibition models assay. Irrespective of the sugar moiety examined, new glyco-conjugates are more than 50 times water-soluble of silibinin. In the other hand they exhibit a radical scavenging activities slightly higher than to silibinin and XO inhibition at least as silibinin. (C) 2014 Elsevier Ltd. All rights reserved.