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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.

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.

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.

Alzheimer's disease (AD) is a multifactorial pathology that requires multifaceted agents able to address its peculiar nature. Increasing evidence has shown that aggregation of amyloid β (Aβ) and oxidative stress are strictly interconnected, and their modulation might have a positive and synergic effect in contrasting AD-related impairments. Herein, a new and efficient fragment-based approach towards tyrosol phosphodiester derivatives (TPDs) has been developed starting from suitable tyrosol building blocks and exploiting the well-established phosphoramidite chemistry. The antioxidant activity of new TPDs has been tested as well as their ability to inhibit Aβ protein aggregation. In addition, their metal chelating ability has been evaluated as a possible strategy to develop new natural-based entities for the prevention or therapy of AD. Interestingly, TPDs containing a catechol moiety have demonstrated highly promising activity in inhibiting the aggregation of Aβ40 and a strong ability to chelate biometals such as CuII and ZnII .

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.

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.

Curcumin is a bioactive natural compound with a wide range of pharmacological properties, including antitumor activity; however, its clinical application has been limited because of its low solubility, stability, and bioavailability. In this study, a solid phase approach was proposed for the combinatorial synthesis of a mini library of the mimics of curcumin in good purity and yield. The non-effective findings in pancreatic cancer cells switched to strong growth inhibition and cell death efficacy for PC3 prostate cancer cells, and mimic 9, in which tyrosol (TYR) and homovanillyl alcohol (HVA) units were linked by a phosphodiester bond, was quite effective not only in cell growth inhibition but also in causing strong cell death under the study conditions and treatments that were not effective in PANC1 cells. The results got more exciting when we also consider the findings in SW480 human colorectal carcinoma cell line, where the growth inhibitor effects were more in line with that of the PC3 cells, but the lack of cell death effect was more in line with the PANC1 cells.

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.

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.