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New neutral carbene complexes of gold(I) [Au(Im-Me)X] (X = Cl, Au1; X = Br, Au2; X = I, Au3) have been synthesized and fully characterized by different techniques, including NMR and UV-vis absorption spectroscopy and single crystal X-ray diffraction. The carbene ligand Im-Me is decorated with a glucoside fragment via a triazole linker, obtainable through a click chemistry reaction. The compounds retain the Au-NHC fragment in aqueous solvents, and an equilibrium between the neutral halo- and the cationic di-carbene form [Au(Im-Me)2]+ is observed, whose extent follows the trend Au1 < Au2 < Au3. Cytotoxicity studies on two cancer and two non-tumorigenic cell lines reflect the solution behavior, as a certain difference among the complexes was disclosed, with the iodo complex Au3 being more active and selective. The compounds interact with both DNA and protein model systems. The X-ray structure of the adduct formed upon the reaction of Au1 with bovine pancreatic ribonuclease (RNase A) reveals Au binding at the side chain of His105 of both protein molecules A and B of the asymmetric unit. The binding of gold atoms at both the nitrogen atoms of the imidazole ring of His15 and at the N-terminal tail has been found in the adduct formed with hen egg white lysozyme.

This study describes new platinum(II) cationic five-coordinate complexes (1-R,R’) of the formula [PtR(NHC)(dmphen)(ethene)]CF3SO3 (dmphen = 2,9-dimethyl-1,10-phenanthroline), containing in their axial positions an alkyl group R (methyl or octyl) and an imidazole-based NHC-carbene ligand with a substituent R’ of variable length (methyl or octyl) on one nitrogen atom. The Pt–carbene bond is stable both in DMSO and in aqueous solvents. In DMSO, a gradual substitution of dmphen and ethene is observed, with the formation of a square planar solvated species. Octanol/water partitioning studies have revealed the order of hydrophobicity of the complexes (1-Oct,Me > 1-Oct,Oct > 1-Me,Oct > 1-Me,Me). Their biological activity was investigated against two pairs of cancer and non-cancer cell lines. The tested drugs were internalized in cancer cells and able to activate the apoptotic pathway. The reactivity of 1-Me,Me with DNA and protein model systems was also studied using UV–vis absorption spectroscopy, fluorescence, and X-ray crystallography. The compound binds DNA and interacts in various ways with the model protein lysozyme. Remarkably, structural data revealed that the complex can bind lysozyme via non-covalent interactions, retaining its five-coordinate geometry.

Hydrophobic molecules, in particular, carotenoids, have been directly extracted from Synechococcus bigranulatus ACUF680 by means of secondary amine switchable solvent N-ethylbutylamine (EBA) without any other pretreatment. EBA was able to extract hydrophobic molecules from both fresh and frozen biomass at the same extent of the conventional procedure (about 20% of dry biomass). In particular, selective extraction of a zeaxanthin-enriched fraction (green fraction, GF) and a β-carotene-enriched fraction (orange fraction, OF) was obtained. The ratio between zeaxanthin and β-carotene was 4.4 ± 1.5 for GF, 0.07 ± 0.06 for OF, and about 1 for conventional extraction. These fractions showed in vitro antioxidant activity (IC50 values of 0.056 ± 0.013 and 0.024 ± 0.008 mg mL-1 for GF and OF, respectively) and biocompatibility on immortalized cells. Moreover, OF and GF were able to protect cells from oxidative stress, both before and after thermal treatment. Results clearly indicate that EBA is a good candidate to specifically extract β-carotene and zeaxanthin from the wet biomass of S. bigranulatus without affecting their biological activity. Skipping energy-intensive operations to break the cells and using either fresh or frozen biomass may be the driving factors to use EBA switchable solvent on an industrial scale.

Here, an unprecedented biorefinery approach has been designed to recover high-added value bioproducts starting from the culture of Porphyridium cruentum. This unicellular marine red alga can secrete and accumulate high-value compounds that can find applications in a wide variety of industrial fields. 300 ± 67 mg/L of exopolysaccharides were obtained from cell culture medium; phycoerythrin was efficiently extracted (40% of total extract) and isolated by a single chromatography, with a purity grade that allowed the crystal structure determination at 1.85 Å; a 2-fold increase in β-carotene yield was obtained from the residual biomass; the final residual biomass was found to be enriched in saturated fatty acids. Thus, for the first time, a complete exploitation of P. cruentum culture was set-up.

Microalgae started receiving attention as producers of third generation of biofuel, but they are rich in many bioactive compounds. Indeed, they produce many molecules endowed with benefic effects on human health which are highly requested in the market. Thus, it would be important to fractionate algal biomass into its several high-value compounds: this represents the basis of the microalgal biorefinery approach. Usually, conventional extraction methods have been used to extract a single class of molecules, with many side effects on the environment and on human health. The development of a green downstream platform could help in obtaining different class of molecules with high purity along with low environmental impact. This review is focused on technical advances that have been performed, from classic methods to the newest and green ones. Indeed, it is fundamental to set up new procedures that do not affect the biological activity of the extracted molecules. A comparative analysis has been performed among the conventional methods and the new extraction techniques, i.e., switchable solvents and microwave-assisted and compressed fluid extractions.

Amyloidoses are characterized by the accumulation and aggregation of misfolded proteins into fibrils in different organs, leading to cell death and consequent organ dysfunction. The specific substitution of Leu 75 for Pro in Apolipoprotein A-I protein sequence (ApoA-I; L75P-ApoA-I) results in late onset amyloidosis, where deposition of extracellular protein aggregates damages the normal functions of the liver. In this work, we describe that the autophagic process is inhibited in the presence of the L75P-ApoA-I amyloidogenic variant in stably transfected human hepatocyte carcinoma cells. The L75P-ApoA-I amyloidogenic variant alters the redox status of the cells, resulting into excessive mitochondrial stress and consequent cell death. Moreover, L75P-ApoA-I induces an impairment of the autophagic flux. Pharmacological induction of autophagy or transfection-enforced overexpression of the pro-autophagic transcription factor EB (TFEB) restores proficient proteostasis and reduces oxidative stress in these experimental settings, suggesting that pharmacological stimulation of autophagy could be a promising target to alleviate ApoA-I amyloidosis.

The demand for natural antioxidants to be used in food industry is increasing, as synthetic antioxidants are toxic and have high production costs. Specifically, food processing and preservation require antioxidants resistant to thermal sterilization processes. In this study, twenty-five strains among microalgae and cyanobacteria were screened as antioxidants producers. The species Enallax sp., Synechococcus bigranulatus and Galdieria sulphuraria showed the highest content of chlorophyll a and total carotenoids. In vitro stability and antioxidant activity of the ethanolic extracts were performed. The results revealed that pigments present in the extracts, obtained from the previously mentioned species, were stable at room temperature and exhibited in vitro free radical scavenging potential with IC50 values of 0.099 ± 0.001, 0.048 ± 0.001 and 0.13 ± 0.02 mg mL-1, respectively. Biocompatibility assay showed that the extracts were not toxic on immortalized cell lines. The antioxidant activity was also tested on a cell-based model by measuring intracellular ROS levels after sodium arsenite treatment. Noteworthy, extracts were able to exert the same protective effect, before and after the pasteurization process. Results clearly indicate the feasibility of obtaining biologically active and thermostable antioxidants from microalgae. Green solvents can be used to obtain thermo-resistant antioxidants from cyanobacteria and microalgae which can be used in the food industry. Thus, the substitution of synthetic pigments with natural ones is now practicable. Graphical abstract: [Figure not available: see fulltext.].

Auranofin (AF), a gold(I) compound that is currently used for the treatment of rheumatoid arthritis and is in clinical trials for its promising anticancer activity, was encapsulated within the human H-chain and the horse spleen ferritin nanocages using the alkaline disassembly/reassembly protocol. The aim of the work was to highlight possible differences in their drug loading capacity and efficacy. The drug-loaded ferritins were characterized via UV-vis absorption spectroscopy and inductively coupled plasma-atomic emission spectroscopy to assess AF encapsulation and to define the exact amount of gold atoms trapped in the Ft cavity. The crystal structures allowed us to define the nature of AF interaction with both ferritins and to identify the gold binding sites. Moreover, the biological characterization let us to obtain preliminary information on the cytotoxic effect of AF when bound to the human H-chain.

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.

Pompe disease is a metabolic myopathy due to acid alpha‐glucosidase deficiency. In addition to glycogen storage, secondary dysregulation of cellular functions, such as autophagy and oxidative stress, contributes to the disease pathophysiology. We have tested whether oxidative stress impacts on enzyme replacement therapy with recombinant human alpha‐glucosidase (rhGAA), currently the standard of care for Pompe disease patients, and whether correction of oxidative stress may be beneficial for rhGAA therapy. We found elevated oxidative stress levels in tissues from the Pompe disease murine model and in patients’ cells. In cells, stress levels inversely correlated with the ability of rhGAA to correct the enzymatic deficiency. Antioxidants (N‐acetylcysteine, idebenone, resveratrol, edaravone) improved alpha‐glucosidase activity in rhGAA‐treated cells, enhanced enzyme processing, and improved mannose‐6‐phosphate receptor localization. When co‐administered with rhGAA, antioxidants improved alpha‐glucosidase activity in tissues from the Pompe disease mouse model. These results indicate that oxidative stress impacts on the efficacy of enzyme replacement therapy in Pompe disease and that manipulation of secondary abnormalities may represent a strategy to improve the efficacy of therapies for this disorder., Enzyme replacement therapy (ERT) with recombinant human alpha‐glucosidase (rhGAA) is currently the standard of care for the treatment of Pompe disease. However, this approach shows important limitations. We have tested whether modulation of oxidative stress may improve the efficacy of ERT.

The synthesis of a novel water-soluble Pt(0) complex [Pt(1-gluAc)(dmf)] containing a glucoconjugated 2-iminopyridine ligand and dimethylfumarate is reported. Highly diastereoselectivity leads to the prevalent formation of only one of the possible diasteroisomers, which has been characterized by mono- and bi-dimensional NMR techniques. The anticancer activity of the complex was evaluated against two couples of cell lines, and the IC50 values reveal that it is more cytotoxic than cisplatin but no selective toward cancer cells.

Several plant extracts are acquiring increasing value because of their antioxidant activity and hypolipidemic properties. Among them, great interest has been recently paid to a&ccedil, ai fruit as a functional food. The aim of this study was to test the ability of a&ccedil, ai extract in reducing oxidative stress and modulating lipid metabolism in vitro using different cell models and different types of stress. In fact, lipid peroxidation as evaluated in a HepG2 model was reduced five-fold when using 0.25 &micro, g/mL of extract, and it was further reduced (20-fold) with the concentration increase up to 2.5 &micro, g/mL. With the non alcoholic fatty liver disease (NAFLD)in vitro model, all concentrations tested showed at least a two-fold reduced fat deposit. In addition, primary adipocytes challenged with TNF-&alpha, under hypoxic conditions to mimic the persistent subcutaneous fat, treated with a&ccedil, ai extract showed an approximately 40% reduction of fat deposit. Overall, our results show that a&ccedil, ai is able to counteract oxidative states in all the cell models analysed and to prevent the accumulation of lipid droplets. No toxic effects and high stability overtime were highlighted at the concentrations tested. Therefore, a&ccedil, ai can be considered a suitable support in the prevention of different alterations of lipid and oxidative metabolism responsible for fat deposition and metabolic pathological conditions.

The plants from genus Salvia, as one of the largest genus in Lamiaceae family, are frequently in use for various purposes, as foods, in cosmetic industry, or in traditional and official medicine. Salvia verticillata L. (liliac sage) is one of sidelined sage species with potential bioactivity, reported in traditional medicine. The aim of this study was to acquire a phytochemical profile of the methanol extract obtained from S. verticillata aerial parts and to evaluate its antioxidant, antimicrobial, and biocompatibility potential. Characteristic compounds of the genus Salvia, such as rosmarinic and caffeic acids, along with their derivatives (e.g. salvianolic and yunnaneic acids isomers) and flavonoids, have been identified by ultrahigh-performance Orbitrap metabolomic fingerprinting as the main phenolic metabolites in S. verticillata. The extract displayed moderate antimicrobial properties and significant antioxidant potential, with the half maximal inhibitory concentration values (IC50) ranging from 33 to 73 μg/mL. Importantly, full biocompatibility of the extract with eukaryotic cell lines was observed up to 72 h. The obtained results revealed the presence of polyphenolic bioactive compounds in S. verticillata extract with promising antioxidant potential and significant biocompatibility. In this regard, S. verticillata can find new perspectives of application as a food ingredient, in cosmetic and pharmaceutical industries, as it represents a valuable source of compounds with prominent health properties, with a special focus on rosmarinic acid.

Galdieria phlegrea is a polyextremophilic red alga belonging to Cyanidiophyceae. Galdieria phlegrea C-phycocyanin (GpPC), an abundant light-harvesting pigment with an important role in energy capture and transfer to photosystems, is the C-phycocyanin (C-PC) with the highest thermal stability described so far. GpPC also presents interesting antioxidant and anticancer activities. The X-ray structure of the protein was here solved. GpPC is a [(αβ)3]2 hexamer, with the phycocyanobilin chromophore attached to Cys84α, Cys82β and Cys153β. Details of geometry and interaction with solvent of the chromophores are reported. Comparison with the structure of a C-PC in the entire Porphyridium purpureum phycobilisome system reveals that linker polypeptides have a significant effect on the local structure of the chromophores environment. Comparative analyses with the structures of other purified C-PCs, which were carried out including re-refined models of G. sulphuraria C-PC, reveal that GpPC presents a significantly higher number of inter-trimer salt bridges. Notably, the higher number of salt bridges at the (αβ)3/(αβ)3 interface is not due to an increased number of charged residues in this region, but to subtle conformational variations of their side chains, which are the result of mutations of close polar and non-polar residues.

Octahedral Pt(IV) complexes (2Pt–R) containing a glycoconjugate carbene ligand were prepared and fully characterized. These complexes are structural analogues to the trigonal bipyramidal Pt(II) species (1Pt–R) recently described. Thus, an unprecedented direct comparison between the biological properties of Pt compounds with different oxidation states and almost indistinguishable structural features was performed. The stability profile of the novel Pt(IV) compounds in reference solvents was determined and compared to that of the analogous Pt(II) complexes. The uptake and antiproliferative activities of 2Pt–R and 1Pt–R were evaluated on the same panel of cell lines. DNA and protein binding properties were assessed using human serum albumin, the model protein hen egg white lysozyme, and double stranded DNA model systems by a variety of experimental techniques, including UV–vis absorption spectroscopy, fluorescence, circular dichroism, and electrospray ionization mass spectrometry. Although the compounds present similar structures, their in-solution stability, cellular uptake, and DNA binding properties are diverse. These differences may represent the basis of their different cytotoxicity and biological activity., An unprecedented direct comparison between the biological properties of Pt compounds with different oxidation states and almost indistinguishable structural features was performed. The reasons of the diverse activity and selectivity have been investigated through several techniques by evaluating structural and stability properties, cellular uptake, and the interaction with macromolecules.

A green cascade approach was used to recover phycocyanins, carotenoids and lipids from Galdiera phlegrea. Phycocyanin extraction was performed by high pressure homogenization and purified by ultrafiltration, whereas carotenoids were obtained by a pressurized liquid extraction and lipids by supercritical fluid extraction. The second step of this innovative, green, and cost-effective procedure is able to improve the recovery of zeaxanthin and β-carotene up to 40%, without affecting the quality of compounds and avoiding the use of organic solvents and the drying processes. The isolated carotenoids were active as antioxidants, as clearly shown by their protective activity on a cell-based model. The lipid yield was increased by 12% with respect to conventional methods., M.B. acknowledges MINECO for the “Juan de La Cierva-Formación” postdoctoral grant FJCI-2016-30902. This research was financed under projects ABACUS (Algae for a Biomass Applied to the produCtion of added value compounds—funded by the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 745668) and AGL2017-89417-R (MINECO, Spain).

Medicinal plants are considered to be a major source of biologically active compounds, which provides unlimited opportunities for their use either as medical treatments or as novel drug formulations. The focus of our study was on basic phytochemical analysis and in vitro examination of the biological activity of Alchemilla vulgaris L. Methanolic extracts of above ground parts and roots of A. vulgaris (AVA and AVR, respectively) were prepared by maceration for 72 h. Phytochemical profile of extracts was evaluated by spectrophotometric determinations of phenolic compounds and HPLC-PDA analysis. AVA and AVR were analysed for their antioxidant efficacy as total antioxidant capacity, metal chelation and reducing power ability, inhibition of lipid peroxidation as well as their potential to neutralise DPPH, ABTS, and OH radicals. Microdilution method was employed to investigate the antibacterial and antifungal activity of extracts against nine ATCC and isolates of bacteria and ten fungal strains from biological samples. Anti-inflammatory activity of the extracts was evaluated using cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) assays and the assay for determination of COX-2 gene expression, while biocompatibility of extracts was assessed by MTT assay. Our results revealed the high amount of phenolic compounds in both extracts; especially they were rich in condensed tannins. Ellagic acid and catechin were tentatively identified in AVA and AVR, respectively. Full biocompatibility as well as remarkable bioactivity were observed for both extracts in all employed assays, so our further investigations will be focused on the identification of active constituents in A. vulgaris and the molecular mechanisms of their action.

Opuntia ficus-indica L. is known for its beneficial effects on human health, but still little is known on cladodes as a potent source of antioxidants. Here, a direct, economic and safe method was set up to obtain water extracts from Opuntia ficus-indica cladodes rich in antioxidant compounds. When human keratinocytes were pre-treated with the extract before being exposed to UVA radiations, a clear protective effect against UVA-induced stress was evidenced, as indicated by the inhibition of stress-induced processes, such as free radicals production, lipid peroxidation and GSH depletion. Moreover, a clear protective effect against apoptosis in pre-treated irradiated cells was evidenced. We found that eucomic and piscidic acids were responsible for the anti-oxidative stress action of cladode extract. In conclusion, a bioactive, safe, low-cost and high value-added extract from Opuntia cladodes was obtained to be used for skin health/protection.

Staphylococcus epidermidis, a harmless human skin colonizer, is a significant nosocomial pathogen in predisposed hosts because of its capability to form a biofilm on indwelling medical devices. In a recent paper, the purification and identification of the pentadecanal produced by the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125, able to impair S. epidermidis biofilm formation, were reported. Here the authors report on the chemical synthesis of pentadecanal derivatives, their anti-biofilm activity on S. epidermidis, and their action in combination with antibiotics. The results clearly indicate that the pentadecanal derivatives were able to prevent, to a different extent, biofilm formation and that pentadecanoic acid positively modulated the antimicrobial activity of the vancomycin. The cytotoxicity of these new anti-biofilm molecules was tested on two different immortalized eukaryotic cell lines in view of their potential applications.

Arsenoplatin-1 (AP-1), the prototype of a novel class of metallodrugs containing a PtAs(OH)2 core, was encapsulated within the apoferritin (AFt) nanocage. UV-Vis absorption spectroscopy and inductively coupled plasma-atomic emission spectroscopy measurements confirmed metallodrug encapsulation and allowed us to determine the average amount of AP-1 trapped inside the cage. The X-ray structure of AP-1-encapsulated AFt was solved at 1.50 Å. Diffraction data revealed that an AP-1 fragment coordinates the side chain of a His residue. The biological activity of AP-1-loaded AFt was comparatively tested on a few representative cancer and non-cancer cell lines. Even though the presence of the cage reduces the overall cytotoxicity of AP-1, it improves its selectivity towards cancer cells.

Blackstonia perfoliata (L.) Huds. is known as a highly bitter secoiridoid glycosides-containing plant and as a possible substitute for some Gentianaceae plants in herbal preparations. Nevertheless, its bioactive properties are still unknown. The present study aimed to characterize both, secoiridoid glycosides and phenolic constituents, and to investigate antioxidant, antimicrobial, anti-inflammatory, and cytotoxic activities of B. perfoliata methanolic extract. The secoiridoid glycosides swertiamarin, gentiopicrin, and sweroside were found to be the dominant compounds of the extract, while 23 phenolic compounds were identified in much lower concentrations. Among phenolics, flavanols were the most abundant, which represents a unique feature among Gentianaceae species. The extract showed moderate to weak antioxidant activity with better performance in inhibition of lipid peroxidation than in free radical scavenging activities. The extract showed generally better antifungal properties compared with its antibacterial potential. Also, B. perfoliata demonstrated in vitro anti-inflammatory activity, the extract (50 μg/mL) showed inhibition of cyclooxigenases, COX-1 and COX-2, activities (19.65 and 48.02%, respectively). It also displayed biocompatibility on the immortalized and cancer cells, as no cytotoxic effect was observed. For the first time, the bioactive potential of this species was demonstrated, justifying its usage in pharmaceutical and food products as an alternative for some overexploited and endangered species from the Gentianaceae family.