1,720,974 research outputs found
Lignin nanoparticles from hydrotropic fractionation of giant reed and eucalypt: Structural elucidation and antibacterial properties
No full text: A hydrotropic solution of maleic acid (MA) was exploited to fractionate giant reed (AD) and eucalypt (EUC). The pre-treatment was successful for AD, while it was unsatisfactory for EUC, likely due to unoptimized reaction conditions. Interestingly, lignin nanoparticles (LNP) were produced via spontaneous aggregation following spent liquor dilution. LNP were studied by a plethora of analytical techniques, such as thermogravimetry, electron microscopy, and Nuclear Magnetic Resonance spectroscopy (NMR). Notwithstanding LNP from both AD and EUC showed similar thermal behaviour and morphology, a greater content of aliphatic hydroxyl, carboxyl, guaiacyl and p-hydroxyphenyl moieties was reported for AD-LNP, whereas EUC-LNP had a larger amount of syringyl groups and a higher S/G ratio. Also, the 1H-DOSY NMR indicated the lower size of AD-LNP. Moreover, the LNP were found to negatively impact on the development of several human or plant pathogens, and their bioactivity was related to the occurrence of guaiacyl and p-hydroxyphenyl moieties and a lower the LNP size. We therefore found that MA delignification allows both to achieve high delignification efficiency and to obtain LNP with promising antibacterial effect. Such LNP may help counteracting the antibiotics resistance and sustain the quest for finding sustainable agrochemicals
Antibacterial and antioxidant properties of humic substances from composted agricultural biomasses
Get PDFBackground: Bioactive components isolated from composted agricultural biomasses have been receiving progressive attention, because they may improve the antibiotic susceptibility of drug resistant bacterial strains. Here, three different humic substances (HS) were isolated from composted artichoke (HS-CYN) and pepper (HS-PEP) wastes, and from coffee grounds (HS-COF), and characterized by infrared spectrometry, NMR spectroscopy, thermochemolysis–GC/MS, and high-performance size-exclusion chromatography. The antibacterial activity of HS was evaluated against some pathogenic bacterial strains, while their bioactivity was determined by a germination assay on basil (Red–Violet variety) seeds. Results: HS-CYN and HS-PEP exhibited the largest antioxidant activity and most significant antimicrobial capacity against some gram-positive bacterial strains, such as Staphylococcus aureus and Enterococcus faecalis. The same HS determined a significant increase of both root and epicotyls in seed germination experiments. The bioactivity of HS was related not only to their specific molecular composition but also to the conformational stability of their suprastructures. Specifically, the greatest bioactive and antimicrobial properties were related to the largest abundance of hydrophobic aromatic and phenolic components and to a more rigid conformational arrangement, that, in turn, appeared to be related to a small fragmentation degree of lignin structures. Conclusions: Our results showed that extraction of bioactive HS from green composts may be a sustainable and eco-compatible way to valorise agricultural byproducts. HS may be indeed exploited as substrates to produce novel materials not only to improve plant productivity but also for medical applications. Graphical Abstract: [Figure not available: see fulltext.
Antiflammatory activity and potential dermatological applications of characterized humic acids from a lignite and a green compost
No full textLong-term exposure to air pollution has been associated with the development of some inflammatory processes related to skin. The goal of modern medicine is the development of new products with antiflammatory action deriving from natural sources to improve environmental and economic sustainability. In this study, two different humic acids (HA) were isolated from from lignite (HA-LIG) and composted artichoke wastes (HA-CYN) and characterized by infrared spectrometry, NMR spectroscopy, thermochemolysis-GC/MS, and high-performance size-exclusion chromatography (HPSEC), while their antiflammatory activity was evaluated on HaCaT cells. Spectroscopic results showing the predominance of apolar aliphatic and aromatic components in HA-LIG, whereas HA-CYN revealed a presence of polysaccharides and polyphenolic lignin residues. The HA application on human keratinocyte pre-treated with Urban Dust revealed a general increase of viability suggesting a protective effect of humic matter due to the content of aromatic, phenolic and lignin components. Conversely, the gene expression of IL-6 and IL-1β cytokines indicated a significant decrease after application of HA-LIG, thus exhibiting a greater antiflammatory power than HA-CYN. The specific combination of HA protective hydrophobic components, viable conformational arrangements, and content of bioactive molecules, suggests an innovative applicability of humic matter in dermatology as skin protectors from environmental irritants and as antiflammatory agents
Waste to Wealth Approach: Improved Antimicrobial Properties in Bioactive Hydrogels through Humic Substance-Gelatin Chemical Conjugation
Get PDF: Exploring opportunities for biowaste valorization, herein, humic substances (HS) were combined with gelatin, a hydrophilic biocompatible and bioavailable polymer, to obtain 3D hydrogels. Hybrid gels (Gel HS) were prepared at different HS contents, exploiting physical or chemical cross-linking, through 1-ethyl-(3-3-dimethylaminopropyl)carbodiimide (EDC) chemistry, between HS and gelatin. Physicochemical features were assessed through rheological measurements, X-ray diffraction, attenuated total reflectance (ATR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy (SEM). ATR and NMR spectroscopies suggested the formation of an amide bond between HS and Gel via EDC chemistry. In addition, antioxidant and antimicrobial features toward both Gram(-) and Gram(+) strains were evaluated. HS confers great antioxidant and widespread antibiotic performance to the whole gel. Furthermore, the chemical cross-linking affects the viscoelastic behavior, crystalline structures, water uptake, and functional performance and produces a marked improvement of biocide action
Valorization of organic biomass through the production of active biopolymer film based on sodium caseinate, guar gum, and beeswax
No full textPossible Molecular Mechanisms Underlying the Decrease in the Antibacterial Activity of Protamine-like Proteins after Exposure of Mytilus galloprovincialis to Chromium and Mercury
Get PDFNatural bioactive compounds represent a new frontier of antimicrobial molecules, and the marine ecosystem represents a new challenge in this regard. In the present work, we evaluated the possibility of changes in the antibacterial activity of protamine-like (PL) proteins, the major nuclear basic protein components of Mytilus galloprovincialis sperm chromatin, after the exposure of mussels to subtoxic doses of chromium (VI) (1, 10, and 100 nM) and mercury (1, 10, and 100 pM) HgCl2, since these metals affect some properties of PL. After exposure, we analyzed the electrophoretic pattern of PLs by both acetic acid-urea polyacrylamide gel electrophoresis (AU-PAGE) and SDS-PAGE and determined the MIC and MBC of these proteins on different gram+ and gram- bacteria. PLs, particularly after mussels were exposed to the highest doses of chromium and mercury, showed significantly reduced antibacterial activity. Just at the highest doses of exposure to the two metals, changes were found in the electrophoretic pattern of PLs, suggesting that there were conformational changes in these proteins, which were confirmed by the fluorescence measurements of PLs. These results provide the first evidence of a reduction in the antibacterial activity of these proteins following the exposure of mussels to these metals. Based on the results, hypothetical molecular mechanisms that could explain the decrease in the antibacterial activity of PLs are discussed
Humic substances from composted fennel residues control the inflammation induced by Helicobacter pylori infection in AGS cells.
No full textHelicobacter pylori (H. pylori) is a common human pathogen causing inflammation. Recent studies have suggested a sophisticated interplay between mitochondria, innate immunity and inflammatory response, thus proposing mitochondrial disfunction as the hallmark of severe inflammatory disorders. In this study, humic substances isolated from composted fennel residues (HS-FEN) were tested as potential therapeutical strategy to restore the mitochondrial physiology and control the inflammation associated with H. pylori infection. The molecular features of HS-FEN were characterized by infrared spectrometry, thermochemolysis-GC/MS, NMR spectroscopy, and high-performance size-exclusion chromatography (HPSEC), which revealed the presence of aromatic polyphenolic components arranged in a rather stable conformation. In vitro results showed antioxidant and anti-inflammatory properties of HS-FEN, that was found to increase the expression level of OPA-1 and SOD-2 genes and in AGS cells stimulated with H. pylori culture filtrate (Hpcf) and concomitantly decrease the expression level of Drp-1 gene and IL-12, IL-17 and G-CSF proteins. The hydrophobic features of HS, their conformational arrangement and large content of bioactive molecules may explain the beneficial effects of HS-FEN, that may potentially become an interesting source of anti-inflammatory agents capable to counteract or prevent the H. pylori-related inflammatory disorders
Innovative nutraceutical and antibacterial proprieties of Humic extracts from composted vegetable wastes.
Get PDFCompost is commonly used as an organic fertilizer to recover and preserve the chemical and physical properties of agricultural soils. Effectively, the use of recycled biomasses, residues and by-products, such as compost, is an effective way to improve the environmental and economic sustainability of agroecosystems and agri-food value chains. The use of green compost is increasingly acknowledged in the EU policies as one of the most sustainable approaches to implement the circular economy in agricultural sector due to an economic and environmental re-evaluation of agricultural biomass. Following the raising attention on compost as valuable organic resource for crop productivity, in the recent years the research activity was addressed on the innovative utilization of specific compost fractions such as humic substances and compost teas for crop biostimulation, acting as bio-effectors on biochemical activities, physiological processes and plant microbial interactions The research described in this thesis, is focused on the application of compost as renewable resource for the production of these potential bioactive materials such as humic substances (HS) and compost teas (CTs) as biostimulant to promote the biosynthesis of nutraceutical products in aromatic crop represented by common basil plant. These organic materials were obtained from different composted agricultural biomasses: artichoke, coffee and pepper. Compost teas and humic substances isolated from the different on-farm composts were characterized in details for their chemical properties and molecular composition. Experiments using HS and CTs obtained from artichoke, coffee and pepper composted biomasses highlighted a relationship with the capacity to increase the development of Basil plants with positive effects on phenological parameters such as fresh and dry biomasses and chlorophyll content. Moreover, the plant treatments with compost extracts promoted the synthesis of metabolites with antioxidant proprieties and antibacterial activity against some common human pathogens. In line with the most advanced research approaches, the results indicated the occurrence of structural-activity relationships based on a combination of physical and chemical features of applied organic fractions as triggering factors for biostimulant properties. The data of molecular characterization suggested the prevalent role of hydrophobic conformation and aromatic components, lignin derivatives and peptidic cluster in the modulation of analysed metabolic pathways. The application of metabolomics and lipidomic approaches have shown an increase in the biosynthesis of secondary metabolites with nutraceutical properties such as hydroxycinnamic acids (caffeic, ferulic, trans-cinnamic and p-cumaric) naringenin, resveratrol and coenzyme Q-10, thus confirming the effect of compost derivatives on plant metabolism. The organic materials influenced the production of primary metabolic intermediates such as erythrosis-4-phosphate and phosphoenolpyruvate that activate the production of metabolites involved in the biochemical pathway of schikimic acid. Moreover, the treatment of Basil plants with humic materials such as HS-artichoke improved the yield, antimicrobial and antioxidant properties of Essential oils (EOs) extracted from Basil leaves by steam distillation with a clear dose-response effect on the production of most bioactive chemical components like eucalyptol, methyl-chavicol, eugenol, methyl-Eugenol, trans-α-Bergamotene, geranyl acetate. Finally, medical applications of the HS and CTs extracted from different composted biomasses were carried out using in vitro assays on epithelial adenocarcinoma epithelial colon cancer cells (CaCo-2) and immortalized cells of cervical tumor (HeLa). The results of the determination of cytotoxic activity showed the significant inhibition in the proliferation of these tumorigenic cell lines, thus further supporting the reliable utilization and exploitation of natural compost extracts in pharmaceutical, nutraceutical and cosmetic field
Combination of humic biostimulants with a microbial inoculum improves lettuce productivity, nutrient uptake, and primary and secondary metabolism
Get PDFBiostimulants of natural origin represent a growing ecological strategy to increase crops productivity, especially when applied in combination with microbial bioeffectors. We studied the effect of biostimulants such as Potassium Humates (KH) from Leonardite and Compost Tea (CT) from green compost on both productivity and nutritional status of lettuce plants, as well as on the primary and secondary metabolism of treated plants, when amended either alone or in combination with a commercial microbial inoculum (M+), mainly based on arbuscular mycorrhizal fungi (Micosat TabPlus)
From waste to resource: Hydrogen generation and antimicrobial activity of Ag-based photocatalysts recovered from biomedical waste
Get PDFElectrocardiogram (ECG) disposable electrodes contain a substantial amount of silver (Ag), which can be extracted and recycled. Most current methods for recovering Ag from waste are expensive and environmentally harmful. This study investigated a sustainable chemical process for extracting Ag from discarded medical electrodes using a simple Cu(II) solution under moderately acidic conditions. Using response surface methodology (RSM) based on a three-level, full-factorial design, the optimized extraction conditions were determined as pH = 4.78, T = 80°C, [Cu(II)]0 = 8.0 × 10−3 M, and [NaCl]0 = 3.72 M. Under these conditions, a process efficiency approaching 100 % was achieved. Moreover, the recovery of metallic silver exceeded 85 %, even when using real matrices. (i.e., discarded ECG electrodes). As a result, the Ag-containing leachate solutions were utilized to synthesize silver-based materials with varying Ag content. These materials demonstrated (i) excellent photocatalytic activity for hydrogen production in aqueous solutions containing organic compounds and (ii) significant antipathogenic properties. In summary, effective Ag/TiO2 photocatalytic materials with high efficiency for hydrogen production and antimicrobial activity were successfully prepared through a novel, sustainable, and cost-effective chemical recovery process of silver from discarded ECG electrodes
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