Publications

Abstract The human normal breast cell line MCF-10A is being widely used as a model in toxicity studies due to its structural similarity to the normal human mammary epithelium. Over the years, application of carbon dots (C-dots) in biomedicine has been increasing due to their photoluminescence properties, biocompatibility, biosafety and possible applications in bioimaging and as drug carriers. In this work we prepared three different C-dots from the same set of carbon and nitrogen precursors (citric acid and urea, respectively) via three distinct bottom-up synthetic routes and their safety was tested against the normal breast cell line MCF-10A. The characterization results demonstrated a similar size range and composition for all the C-dots. The MCF-10A cells were treated with different concentrations of C-dots for 24, 48 and 72 h to evaluate the cell viability over time. For the 24 h incubation, there were no significant decreases in the viability of the MCF-10A cells. For the 48 h treatment, there was a significant decrease in the viability of the cells treated with calcination-based C-dots, but without significant cellular viability changes for microwave and hydrothermal-based C-dots. For 72 h, cells treated with hydrothermal-based C-dots have the most promising viability profile. Also, compared with paclitaxel, these C-dots have a safety profile very close to that of an antineoplastic in non-tumor cells. Our results suggest that these new C-dots have potential as imaging candidates or biosensing tools as well as drug carriers, and further investigation in animal models is needed for future application in medicine.

Abstract In-vitro imaging by swept-source optical coherence tomography (OCT) represents a class of advanced tomography that provides comprehensive and accurate clinical diagnostics. Here colloidal NaGdF4:Er3+/Yb3+ particles having an average size of 32 nm were successfully synthesized by a facial thermal decomposition method and then used as a contrast agent in OCT imaging. Prepared phosphor has shown bright green upconversion emission under 976 nm diode laser. The phosphor particles had increased the scattering of OCT scanning radiation, and thus higher image contrast was observed. The results indicate that upconversion phosphors may work as suitable contrast agents for OCT imaging.

Abstract Research on mitochondria-targeted active molecules became a hot topic in the past decade. Development of mitochondria permeability transition pore (mPTP)-targeting agents with clinical applications is needed not only because of the importance of the target in several diseases but also due to the fact that the current developed molecules have shown poor clinical success. In fact, only a reduced percentage reach mitochondria, effectively preventing pathological mPTP opening. The mitochondrial-targeting strategies should be a promising solution to increase the selectivity of compounds to the mPTP, reducing also their potential side effects. Chemical conjugation of bioactive molecules with a lipophilic cation such as the triphenylphosphonium (TPP+) has been established as a robust strategy to specifically target mitochondria. Phytochemicals such as hydroxybenzoic acids are normal constituents of the human diet. These molecules display beneficial healthy effects, ranging from antioxidant action through diverse mechanisms to modulation of mitochondrial-related apoptotic system, although their therapeutic application is limited due to pharmacokinetic drawbacks. Accordingly, the development of a new antioxidant based on the dietary benzoic acid—gallic acid—is described as well as the demonstration of its mitochondriotropic characteristics. © 2021, Springer Science+Business Media, LLC, part of Springer Nature.

Abstract Lactarius sanguifluus is part of the diverse mycological heritage in the Koudiat Taifour forest (a site of biological and ecological interest in the northern region of Morocco), although this fungus is in danger of extinction in this forest. The main objective of the research reported here was to perform an advanced chemical analysis of a methanolic extract from L. sanguifluus and to investigate its biological activities. Spectrophotometric determination of the chemical compounds present in the extract showed that this fungus contains significant amounts of phenolics and flavonoids [18.71-18.81 mg GAE per g of dry methanolic extract (dme)], moderate quantities of ascorbic acid and tannins [3.50-3.86 mg/g of dry weight (dw)], and low levels of beta-carotene and lycopene (0.11-0.10 mg/g dme). The phenolic compounds were identified and quantified via LC-MS, and the results showed that p-hydroxybenzoic acid (134.10 mu g/g dw) and paraben acid (85.35 mu g/g dw) were the main phenolic compounds in the sample. GC-MS analysis of the methanol extract led to the identification of more than 77 chemical compounds in the sample, which were categorized into five main groups: sugars (48.15%), fatty acids (20.66%), amino acids (11.92%), organic acids (9.30%), and alcohols (8.42%). The antioxidant activity of the fungal methanol extract was demonstrated using three methods: the DPPH assay (IC50: 2.045 mg/ml), the beta-carotene bleaching test (IC50: 0.56 mg/ml), and the ferric reducing antioxidant power assay (FRAP; RC50: 0.85 mg/ml). The antimicrobial activity was evaluated using microdilution methods. Antifungal susceptibility tests indicated that the extract was able to inhibit the growth of five fungal pathogen species. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) ranged from 1 to 16 mg/ml for Epidermophyton floccosum, Trichophyton rubrum, and Microsporum canis, and from 21 to 64 mg/ml for Candida albicans and Aspergillus fumigatus. Likewise, antibacterial tests showed that the extract inhibited the growth of Escherichia coli and Staphylococcus aureus at concentrations ranging from 21 to 64 mg/ml for the MIC and at 64 mg/ml for the MFC. Considering their nutritional and nutraceutical value, fruiting bodies of L. sanguifluus and extracts from them could be used as nutritional supplements and as natural antioxidant and antimicrobial agents in food preservation and human health.

Abstract The present study aimed to investigate the chemical composition, bioactive compounds, and antioxidant activity of two wild edible mushrooms, the honey fungus (Armillaria mellea) and the parasol mushroom (Macrolepiota procera), collected from Northern Morocco (MA) and Portugal (PT). Those species were chosen due to their edibility, nutraceutical, and medicinal properties. Bioactive compounds (ascorbic acid, tannin, total phenolic, total flavonoid, beta-carotene, and lycopene) and their antioxidant activity were determined by spectrophotometric methods. Herein, the fruiting body of the samples revealed a significantly higher amount of bioactive compounds, and values varied between the Moroccan and the Portuguese ones. Methanolic extracts shown a strong antioxidant capacity: Using DPPH free radical-scavenging activity radicals (IC50 1.06-1.32 mg/mL); inhibition of beta-carotene bleaching radicals (IC50 0.09-0.53 mg/mL); and, reducing power radicals (IC50 0.52-1.11 mg/mL). The mushroom species with the highest antioxidant capacity was A. mellea from MA. Chemical composition was analyzed by GC-MS and LC-MS methodologies. GC-MS analysis showed that the most abundant biomolecules group was sugar compositions in the four samples (62.90%, 48.93%, 59.00%, and 53.71%) and the main components were galactitol 16.74%, petroselinic acid 19.83%, d-galactose 38.43%, and glycerol 24.43% in A. mellea (MA), A. mellea (PT), M. procera (MA), and M. procera (PT), respectively. LC-MS analysis of individual phenolic compounds revealed that vanillic acid (198.40 +/- 2.82 mu g/g dry weight (dw) and cinnamic acid (155.20 +/- 0.97 mu g/g dw) were the main compounds detected in A. mellea, while protocatechuic acid (92.52 +/- 0.45 and 125.50 +/- 0.89 mu g/g dw) was predominated in M. procera for MA and PT samples, respectively. In general, the results of this comparative study demonstrate that the geographic and climatic conditions of the collection site can influence biomolecule compounds and antioxidant properties of wild mushrooms. This study contributes to the elaboration of nutritional, nutraceutical, and pharmaceutical databases of the worldwide consumed mushrooms.

Abstract In the present contribution is shown the application of the recently developed functional alignment of pure vectors (FAPV) as a proper algorithm to align second-order chromatographic data with severe retention time shifts in peak position and shape. FAPV decomposed a three-way chromatographic data array in their three modes (sample, spectral and elution time vectors), using a basis function to pre-process the non-linear mode (elution time) and then it aligns the functionalized pure vectors and reshapes the transformed vectors into matrices, restoring the trilinearity of second-order chromatographic data. The well-aligned three-way chromatographic data array is then successfully decomposed by advanced chemometric models such as parallel factor analysis (PARAFAC) and multivariate curve resolution - alternating least-squares (MCR-ALS) with the trilinearity constraint. The performance of this innovative analytical strategy based on PARAFAC and MCR-ALS with previous synchronization of data through FAPV algorithm is properly evaluated using real second-order chromatographic data with multiple artifacts, i.e., shifts in peak position and shape for the simultaneous quantification of amoxicillin and potassium clavulanate in commercial medicinal drugs. The present contribution compares some analytical results achieved by: (1) the usual MCR-ALS as a bilinear model applied in augmented data matrix without previous synchronization and with interval correlation optimized shifting (ICOSHIFT) and FAPV and (2) trilinear models using PARAFAC with ICOSHIFT and FAPV and trilinearity constraint in MCR-ALS with FAPV. Available results suggest that these strongly shifted and warped elution time profiles cause for the loss of trilinearity, which can be adequately restored by FAPV algorithm. PARAFAC performed a successful trilinear decomposition of three-way chromatographic data array with law values of relative prediction error (REP) in the order of 1.34-1.42% in both analytes.

Abstract <jats:p>Engineered nanomaterials are purposely manufactured particles with sizes typically between 1 and 100 nm, which can be either organic, inorganic, or organometallic in nature [...]</jats:p>

Abstract Phenol red (X-PR) and malachite green carbinol (MGC) are two textile finishing dyes, which are present in aquatic environments through industrial effluents. Due to the toxic nature of both dyes, they are harmful to human health. In the present study, two materials, barley seeds and the biochar of barley (Hordeum vulgare L.), were used to remove the dyes in an aqueous solution. The materials used are characterized by AFM, FTIR, SEM, XRD and EDX techniques. In this study, the parameters studied are the adsorbent dose, pH, initial adsorbate concentration and contact time. The maximum equilibrium time was found to be 90 min for all dyes. Kinetic studies revealed that the adsorption of X-PR and MGC on barley seeds (BS-HVL) and the biochar of barley (BC-HVL) followed pseudo-second-order kinetics and that both porous and intraparticle diffusion mechanisms were involved. The adsorption equilibrium data were well fitted to the Langmuir and Freundlich isotherm model for both materials, and the maximum adsorption capacity of monolayer and multilayers for X-PR and MGC were 71.642 mg g(-1) and 50 mg g(-1) on BS-HVL, and 44.843 mg g(-1) and 121.95 mg g(-1) on BC-HVL, respectively. The thermodynamic results reveal that the dye removal on barley was endothermic and spontaneous in nature.

Abstract <jats:p>Brown carbon is a type of carbonaceous aerosol with strong light absorption in the ultraviolet and visible wavelengths that leads to radiative forcing. However, it is difficult to correlate the chemical composition of brown carbon with its atmospheric light absorption properties, which translates into significant uncertainty. Thus, a time-dependent density functional theory (TD-DFT) approach was used to model the real-world absorption properties of 14 polycyclic aromatic hydrocarbons (PAHs) over three regions of the Basque Country (Spain): Bilbao, Urretxu, and Azpeitia. The data were corrected for atmospheric concentration. The results show that the absorption spectra over each region are qualitatively identical, with the absorption intensities being significantly higher over Bilbao than over Azpeitia and Urretxu. Furthermore, it was found that the light absorption by PAHs should be more relevant for radiative forcing when it occurs at UVA and (sub)visible wavelengths. Finally, among the 14 studied PAHs, benzo[b]fluoranthene, pyrene, fluoranthene, benzo[a]pyrene, and benzo[k]fluoranthene and benzoperylene were identified as the molecules with larger contributions to radiative forcing.</jats:p>