Supercritical fluid extraction and hydrodistillation for the recovery of bioactive compounds from Lavandula viridis L’Hér

The chemical profiles of bioactive essential oil and extracts obtained by hydrodistillation (HD) and supercritical fluid extraction (SFE), respectively, from Lavandula viridis were compared. The SFE was performed at 40 °C and at extraction pressures of 12 or 18 MPa in two different separators. Evaluation of the essential oil and SFE extracts by GC–FID and GC–IT–MS revealed that oxygen-containing monoterpenes were the major constituents in both cases, but there were important differences between the chemical profiles produced by the different extraction techniques. More compounds were isolated by HD but higher yields were achieved by SFE. Camphor was the main component identified in the essential oil (31.59 ± 1.32%), and in extracts from the first (1.61 ± 0.34%) and second SFE separators (22.48 ± 1.49%) at 12 MPa. In contrast, the first separator SFE extract at 18 MPa (heavy compounds) was dominated by myrtenol (5.38 ± 2.04%) and camphor (4.81 ± 1.93%), whereas the second separator SFE extract (volatiles) was dominated by verbenone (13.97 ± 5.27%). The essential oil and heavy compound extracts from the first separator possessed antioxidant and anti-cholinesterase activities. Our data show that phytochemicals from the aerial parts of L. viridis could be developed as natural antioxidant and anti-cholinesterase drugs, with particular applications in the symptomatic treatment of Alzheimer’s disease.     

Liquid-phase Dehydration of d-xylose over Microporous and Mesoporous Niobium Silicates

Microporous AM-11 crystalline niobium silicates were studied as solid acid catalysts for the dehydration of xylose in a water-toluene solvent mixture at 140–180 °C. After 6 h at 160 °C, xylose conversions of up to 90% and furfural yields of up to 50% were achieved, and the catalysts could be reused without loss of activity or selectivity. The calcined AM-11 catalysts gave higher furfural yields than HY zeolite and mordenite, under identical reaction conditions. Ordered mesoporous MCM-41-type niobium silicates with Si/Nb molar ratios of either 25 or 50 were also found to be recyclable catalysts for xylose dehydration, and gave furfural yields consistently in the range of 34–39% (after 6 h reaction at 160 °C).     

Silk‐based microcarriers: current developments and future perspectives

Cell‐seeded microcarriers (MCs) are currently one of the most promising topics in biotechnology. These systems are supportive structures for cell growth and expansion that allow efficient nutrient and gas transfer between the media and the attached cells. Silk proteins have been increasingly used for this purpose in the past few years due to their biocompatibility, biodegradability and non‐toxicity. To date, several silk fibroin spherical MCs in combination with alginate, gelatin and calcium phosphates have been reported with very interesting outcomes. In addition, other silk‐based three‐dimensional structures such as microparticles with chitosan and collagen, as well as organoids, have been increasingly studied. In this study, the physicochemical and biological properties of these biomaterials, as well as the recent methodologies for their processing and for cell culture, are discussed. The potential biomedical applications are also addressed. In addition, an analysis of the future perspectives is presented, where the potential of innovative silk‐based MCs processing technologies is highlighted.Inspec keywords: biodegradable materials, proteins, calcium compounds, gelatin, biomedical materials, cellular biophysics, molecular biophysicsOther keywords: supportive structures, cell growth, gas transfer, attached cells, silk proteins, biodegradability, nontoxicity, silk fibroin spherical MCs, gelatin, calcium phosphates, silk‐based three‐dimensional structures, chitosan, collagen, physicochemical properties, biological properties, cell culture, silk‐based microcarriers, cell‐seeded microcarriers, biotechnology, efficient nutrient transfer, biocompatibility, alginate, biomedical applications     

Hazel (Corylus avellana L.) leaves as source of antimicrobial and antioxidative compounds

Aqueous extracts of leaves of different hazel (Corylus avellana L.) cultivars (Cv. M. Bollwiller, Fertille de Coutard and Daviana), were analysed by reversed-phase HPLC/DAD for the definition of their phenolic composition. Antioxidant potential was assessed by the reducing power assay, and the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and β-carotene linoleate model system. Their antimicrobial capacity was also tested against Gram positive (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus) and Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae) and fungi (Candida albicans, Cryptococcus neoformans). Eight phenolic compounds were identified: 3-, 4- and 5-caffeoylquinic acids, caffeoyltartaric acid, p-coumaroyltartaric acid, myricetin-rhamnoside, quercetin 3-rhamnoside and kaempferol 3-rhamnoside. A p-coumaric acid, three myricetin and one quercetin derivatives were also detected. The hazel leaves extract presented high antioxidant activity in a concentration-dependent way, in general with similar behaviour of all cultivars. Gram positive bacteria revealed to be very sensitive to hazel leaf extract (MIC 0.1 mg/ml for B. cereus and S. aureus and 1 mg/ml for B. subtilis). However, Gram negative and the fungi displayed much lower sensitivity, being P. aeruginosa and C. albicans resistant at 100 mg/ml. Cv. M. Bollwiller exhibited the most potent antimicrobial activity.     

Toward the antioxidant and chemical characterization of mycorrhizal mushrooms from northeast Portugal

Abstract: Mushrooms are widely appreciated all over the world for their nutritional properties and pharmacological value as sources of important bioactive compounds. Mycorrhizal macrofungi associate with plant roots constituting a symbiotic relationship. This symbiosis could influence the production of secondary metabolites, including bioactive compounds. We focused on the evaluation of antioxidant potential and chemical composition of mycorrhizal mushrooms species from Northeast Portugal: Amanita caesarea, Amanita muscaria, Amanita pantherina, Chroogomphus fulmineus, Cortinarius anomalus, Cortinarius collinitus, Cortinarius violaceus, Lactarius quietus, Lactarius volemus, Russula sardonia, Suillus luteus, and Tricholoma ustale. A similar profile of metabolites was observed in the studied species with the order sugars > fat > ascorbic acid > phenolic compounds > tocopherols. Nevertheless, the samples revealed different compositions: prevalence of sugars in L. volemus, fat and ascorbic acid in A. muscaria, phenolic compounds in C. anomalus and tocopherols, and antioxidant activity in S. luteus. Practical Application: Chemical characterization of 12 mycorrhizal mushrooms was achieved. They are sources of nutraceuticals, such as sugars and fatty acids, and contain bioactive compounds, such as vitamins and phenolic acids. Edible species can be incorporated in diets as sources of antioxidants, while nonedible species can be explored as sources of bioactive metabolites.     

Thymus lotocephalus wild plants and in vitro cultures produce different profiles of phenolic compounds with antioxidant activity

We compared the phenolic metabolites and antioxidant activities of Thymus lotocephalus G. López & R. Morales wild plants and in vitro cultures using different extraction solvents. HPLC-DAD analysis allowed the identification and quantification of phenolic (caffeic and rosmarinic) acids and flavones (luteolin and apigenin) in extracts from both sources. The in vitro cultures accumulated large amounts of rosmarinic acid. However, extracts from both sources were able to neutralise free radicals in different test systems (TEAC and ORAC assays), to form complexes with Fe(2+) and to protect mouse brains against Fe(2+)-induced lipid peroxidation. The solvent significantly influenced the phenolic content and antioxidant activity of the extracts, water/ethanol being the most efficient for the extraction of antioxidant phytochemicals. We conclude that in vitro cultures of T. lotocephalus represent a promising alternative for the production of valuable natural antioxidants and an efficient tool for the in vitro biosynthesis of rosmarinic acid, therefore avoiding the need to exploit populations of wild plants.     

Lupinus albus Protein Components Inhibit MMP-2 and MMP-9 Gelatinolytic Activity In Vitro and In Vivo

Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) are regarded as important clinical targets due to their nodal-point role in inflammatory and oncological diseases. Here, we aimed at isolating and characterizing am MMP-2 and-9 inhibitor (MMPI) from Lupinus albus and at assessing its efficacy in vitro and in vivo. The protein was isolated using chromatographic and 2-D electrophoretic procedures and sequenced by using MALDI-TOF TOF and MS/MS analysis. In vitro MMP-2 and 9 inhibitions were determined on colon adenocarcinoma (HT29) cells, as well as by measuring the expression levels of genes related to these enzymes. Inhibitory activities were also confirmed in vivo using a model of experimental TNBS-induced colitis in mice, with oral administrations of 15 mg·kg⁻¹. After chromatographic and electrophoretic isolation, the L. albus MMP-9 inhibitor was found to comprise a large fragment from δ-conglutin and, to a lower extent, small fragments of β-conglutin. In vitro studies showed that the MMPI successfully inhibited MMP-9 activity in a dose-dependent manner in colon cancer cells, with an IC50 of 10 µg·mL⁻¹ without impairing gene expression nor cell growth. In vivo studies showed that the MMPI maintained its bioactivities when administered orally and significantly reduced colitis symptoms, along with a very significant inhibition of MMP-2 and -9 activities. Overall, results reveal a novel type of MMPI in lupine that is edible, proteinaceous in nature and soluble in water, and effective in vivo, suggesting a high potential application as a nutraceutical or a functional food in pathologies related to abnormally high MMP-9 activity in the digestive system.