Publications

Retention and release kinetics of Cu on four acid Typic haplumbrepts developed on two different types of parent rock material (granite and amphibolite) were studied with a stirred‐flow chamber (SFC) method. The granitic soils were lower in organic material and lower in Fe and Al oxides than the soils formed in amphibolite. The kinetic parameters were assessed in four consecutive Cu retention–release cycles by alternately applying pulses of solutions with and without Cu. Granite soils showed lower total Cu retention (7–12 mmol kg −1 ) than amphibolite soils (16–21 mmol kg −1 ) after one single pulse application of 0.0787 mmol Cu L −1 at pH 5.5, which may be due to differences in their organic and oxides compositions. The amount of Cu retained diminished to 40 to 25% in the third retention cycle relative to the first, suggesting that the soils' Cu retention depends on the previous metal loading. Conversely, the released Cu was approximately 20% of that retained in the first cycle, but the amounts released were similar for all cycles and all soils. The results obtained were fitted using a first‐order equation for both retention and release of Cu. In the first cycle, first order rate coefficients of retention ranged from 0.084 to 0.56 min −1 , and increased by about a factor of two in the next cycle. Release rate coefficients were more than 10 times lower than those of retention, and less dependent on the previous metal loading. The process of retention and release of Cu was found to be hysteretic, which suggest that the desorption mechanism or path is not an exact opposite of the adsorption mechanism or path.

Among scaffolds used in tissue engineering, natural biomaterials such as plant-based materials show a crucial role in cellular function due to their biocompatibility and chemical indicators. Because of environmentally friendly behavior and safety, green methods are so important in designing scaffolds. A key bioactive flavonoid of the Epimedium plant, Icariin (ICRN), has a broad range of applications in improving scaffolds as a constant and non-immunogenic material, and in stimulating the cell growth, differentiation of chondrocytes as well as differentiation of embryonic stem cells towards cardiomyocytes. Moreover, fusion of ICRN into the hydrogel scaffolds or chemical crosslinking can enhance the secretion of the collagen matrix and proteoglycan in bone and cartilage tissue engineering. To scrutinize, in various types of cancer cells, ICRN plays a decisive role through increasing cytochrome c secretion, Bax/Bcl2 ratio, poly (ADP-ribose) polymerase as well as caspase stimulations. Surprisingly, ICRN can induce apoptosis, reduce viability and inhibit proliferation of cancer cells, and repress tumorigenesis as well as metastasis. Moreover, cancer cells no longer grow by halting the cell cycle at two checkpoints, G0/G1 and G2/M, through the inhibition of NF-κB by ICRN. Besides, improving nephrotoxicity occurring due to cisplatin and inhibiting multidrug resistance are the other applications of this biomaterial.

Abstract We present here a simple procedure for the surface modification of plasmonic nanoparticles (NPs) with a cationic water‐soluble ammonium pillar[5]arene (AP[5]A) in order to create selective surface‐enhanced Raman scattering (SERS) spectroscopy based sensors. The strategy is based on a ligand exchange reaction between the AP[5]A and the stabilizing agent of the as‐prepared plasmonic NPs. The approach could be applied to plasmonic nanoparticles either negatively charged, stabilized by citrate ions (Au spheres) or positively charged, stabilized by cetyltrimethylammonium bromide (Au and Au@Ag nanorods). The SERS performance of all systems was studied as a function of NP size and excitation laser line by using an analyte with no affinity towards the metal surface such as pyrene. The analytical enhancement factor (AEF) for the different systems was estimated between 0.55×10 4 and 1.49×10 5 . Finally the synergistic effect of combining supramolecular chemistry and plasmonic NPs is demonstrated through SERS‐based detection, in aqueous media, of molecules with no affinity towards a bare plasmonic substrate such as the contaminant pyrene or the biomolecule pyocyanin with nanomolar limit of detection.

Drimia maritima (L.) Stearn (squill), belonging to the Asparagaceae family, is acknowledged as a medicinally valuable species from the Drimia genera. In this study, water, methanol, and ethyl acetate extracts of D. maritima aerial parts and bulbs were investigated for their polyphenols profile and evaluated for their antioxidant and enzyme inhibition properties. Phenolics were profiled through an untargeted metabolomics approach using an ultra-high pressure liquid chromatograph coupled to quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS). This analysis revealed an enrichment of low molecular weight phenolics and flavonoids in the aerial parts of D. maritima, while lignans mainly characterized bulb extracts. Antioxidant capacity was investigated by different assays, including phosphomolybdenum assays, radical scavenging (DPPH: 2,2-diphenyl-1-picrylhydrazyl; ABTS: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), as well as reducing ability (CUPRAC: cupric reducing antioxidant capacity; FRAP: ferric reducing antioxidant power), and metal chelating. In radical scavenging and reducing power assays, the water extract of aerial parts exhibited the strongest ability (DPPH: 36.99 mg trolox equivalent (TE)/g; ABTS: 85.96 mg TE/g; CUPRAC: 87.37 mg TE/g; FRAP: 55.43 mg TE/g). In general, the ethyl acetate extracts from aerial parts and bulbs provided the weakest antioxidant capacity. Concerning enzyme inhibitory activities, the water extracts of the bulb were poorly active, while the ethyl acetate extracts from both plant portions displayed the best α-amylase inhibitory abilities. The best acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) abilities were recorded by ethyl acetate extract of aerial parts (2.36 mg galantamine equivalent (GALAE)/g) and bulbs (5.10 mg GALAE/g), respectively. Overall, these results support the medicinal aptitude of D. maritima and its possible use as a natural source of antioxidants and enzyme inhibitors with functional potential.

In this work, a new analytical approach based on the trapping of Se and Hg vapours using silver nanoparticles (Ag NPs) immobilized on quartz reflectors, prior to their determination by total reflection X-ray fluorescence (TXRF), is proposed. Ag NPs were synthesized by reduction of the metal precursor with a reducing agent in aqueous solution. Silanization with 3-mercaptopropyltrimethoxysilane (MPTMS) was used in order to modify the quartz reflectors and immobilize Ag NPs by interaction between the organosilane compound and Ag NPs. A comprehensive characterization of synthesized Ag NPs was carried out by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). SeH2 and Hg(0) vapours were generated by means of a continuous flow vapour generation system and trapped onto the quartz reflector containing immobilized Ag NPs. Different parameters involved in both the Ag NP synthesis and the continuous flow system for vapour generation and preconcentration were optimized in order to obtain the best results. Detection limits were 0.18 and 0.55 μg L−1 for selenium and mercury, respectively. Enrichment factors of 265 and 175 were obtained for Se and Hg, respectively. The new method was successfully validated against three biological certified reference materials and applied to several seafood samples. Recoveries carried out on three certified reference materials were in the range 94–106% with a relative standard deviation of 5% (N = 5).

In fish processing, a great amount of side streams, including skin, bones, heads and viscera, is wasted or downgraded as feed on a daily basis. These side streams are rich sources of bioactive nitrogenous compounds and protein, which can be converted into peptides through enzymatic hydrolysis as well as bacterial fermentation. Peptides are short or long chains of amino acids differing in structure and molecular weight. They can be considered as biologically active as they can contribute to physiological functions in organisms with applications in the food and pharmaceutical industries. In the food industry, such bioactive peptides can be used as preservatives or antioxidants to prevent food spoilage. Furthermore, peptides contain several functional qualities that can be exploited as tools in modifying food ingredient solubility, water-holding and fat-binding capacity and gel formation. In the pharmaceutical industry, peptides can be used as antioxidants, but also as antihypertensive, anticoagulant and immunomodulatory compounds, amongst other functions. On the basis of their properties, peptides can thus be used in the development of functional foods and nutraceuticals. This review focuses on the bioactive peptides derived from seafood side streams and discusses their technological properties, biological activities and applications.

The consumption of macroalgae has increased in occidental countries, favored by the excellent nutritional properties of their food products and the bioactive properties attributed to them. The present work aims to analyze the nutritional values, the composition in fatty acids, organic acids and carotenoids of several macroalgae species: Codium tomentosum; Himanthalia elongata; Laminaria ochroleuca.; Saccharina latissima; Undaria pinnatifida; Porphyra sp. and Palmaria palmata. Furthermore, the antioxidant and antimicrobial properties were assessed. Regarding the composition of the macroalgae, the levels of proteins (which ranged between 6 and 30 g/100 g of dry weight (DW)) and the low levels of lipids (below 1 g/100 g DW for all the species) stand out. In the case of carotenoids, lycopene and chlorophyll a were detected in all samples. Regarding antioxidant activity, OxHLIA assay was employed. EC50 values varied between 1.7 and 650 µg/mL for L. ochroleuca and P. palmata. H. elongata presented the greatest antibacterial potential (0.5–2 mg/mL) while L. ochroleuca showed the best antifungal effects (2–4 mg/mL). These species have good nutritional values and present interesting bioactivities. Thus, the incorporation of this macroalgae into the daily diet could provide nutritional and health benefits to the consumers. In addition, they could be used as a source of compounds for the nutraceutical, cosmetic and pharmaceutical industries.

Summary The aim of this study was to investigate the inhibitory mechanism of oenothein B (OeB), a unique oligomer ellagitannin with a rigid structure, on porcine trypsin using fluorescence spectroscopy, isothermal titration calorimetry ( ITC ), circular dichroism ( CD ) and molecular docking. Trypsin activity was strongly inhibited by OeB in a competitive way. Fluorescence quenching of trypsin by OeB was a static quenching. The CD spectra showed that binding of OeB to trypsin altered trypsin's conformation. The ITC and docking studies revealed that the inhibitory mechanism of OeB occurred via binding to the interior hydrophobic groups of trypsin and the formation of hydrogen bonds with trypsin through binding to the amino acid residues Asn97, His573, Ser195 and Gln192. This study provides a theoretical and computational basis for the precise control of trypsin in food industry. Based on the results, OeB may be used in food technology research as novel bioactive trypsin inhibitor.