Search Results (856)

Corrosion continues to be a major concern in industrial systems, causing material degradation and raising maintenance costs. In recent years, plant-derived corrosion inhibitors have gained interest as environmentally friendly alternatives to conventional chemical treatments. In this work, ethanolic extracts from the leaves of Citrus limon (L.) Osbeck and Eucalyptus globulus Labill. were evaluated as green corrosion inhibitors for C45 carbon steel in 1 M HCl solution. The extracts were prepared by continuous Soxhlet extraction and characterized through antioxidant activity measurements using the 2,2-diphenyl-1-picrylhydrazyl DPPH radical scavenging method, gravimetric (weight loss) tests, and electrochemical techniques including potentiodynamic polarization. In addition, the extraction parameters were optimized using a face-centered central composite design (CCD) within a response surface methodology (RSM) framework, and the resulting models were analyzed by analysis of variance (ANOVA). The effects of inhibitor concentration and temperature on corrosion inhibition performance were systematically examined. The antioxidant assay indicated that E. globulus extract reached a scavenging activity above 95% at 1000 mg/L, while C. limon extract showed moderate activity around 71%. Gravimetric tests revealed that both extracts reduced the corrosion rate, with optimal inhibition efficiencies of approximately 67% for C. limon (at 0.3 g/100 mL) and 82% for E. globulus (at 1.0 g/100 mL). Beyond these optimal concentrations, a decline in performance was observed, suggesting surface saturation. The statistical optimization showed that the C. limon response model was solvent-driven (R² = 92.05%), whereas the E. globulus model was curvature-driven (R² = 95.45%), with contrasting response surface topographies. Electrochemical measurements confirmed that both extracts acted as mixed-type inhibitors, shifting the corrosion potential toward less negative values and reducing the corrosion current density. Overall, E. globulus extract demonstrated superior performance across all methods, and both extracts represent promising candidates for sustainable corrosion protection in acidic industrial environments. Full article

Efficient recovery of phenolic compounds from citrus processing by-products requires optimized solvent systems and reliable frameworks for comparing emerging extraction technologies. In this study, a solvent system was first optimized to maximize phenolic recovery from lemon (Citrus limon (L.) Burm. f.) processing by-products, enabling a standardized comparison of ultrasound-assisted extraction (UAE) and hydrodynamic cavitation (HC). A preliminary solid–liquid extraction screening using different water:ethanol ratios (v/v) identified a 50:50 hydroalcoholic mixture as the optimal solvent system for recovering phenolic compounds. HPLC analysis confirmed the presence of major flavanones (eriocitrin and hesperidin) and hydroxycinnamic acids (caffeic, p-coumaric, sinapic, and ferulic acids). Antioxidant capacity was assessed using complementary assays (Folin–Ciocalteu, DPPH, and ORAC) to provide a comprehensive evaluation of antioxidant activity. Under optimized solvent conditions, UAE significantly improved the recovery of total flavanones (+25.9%), hydroxycinnamic acids (+10.3%), total polyphenols (+20.5%), DPPH activity (+6.0%), and ORAC values (+9.6%) compared with conventional extraction. HC further enhanced extraction performance, increasing flavanone recovery by 12.0%, hydroxycinnamic acids by 7.2%, total polyphenols by 5.2%, and antioxidant activity (DPPH and ORAC) by 11.4% and 2.0%, respectively, relative to UAE. Following ethanol removal and concentration, HC-derived extracts showed the highest phenolic content and antioxidant capacity. These results demonstrate that solvent optimization, combined with a standardized comparison of extraction technologies, enhances phenolic recovery from lemon processing by-products. The findings indicate that HC is a promising, scalable approach for the sustainable recovery of bioactive compounds from citrus side-streams. The novelty of this work lies in the integration of solvent optimization with a systematic and standardized comparison of UAE and HC, providing a reproducible framework for evaluating emerging extraction technologies and highlighting the enhanced performance and scalability potential of HC for phenolic recovery from citrus processing by-products. Full article

The exponential growth of the fruit-processing industry generates significant quantities of organic by-products, such as peels, seeds, and pomace, which represent a rich but underutilized source of bioactive polyphenols. Valorizing these residues is critical for the transition toward a circular bioeconomy, yet conventional extraction methods remain solvent-intensive and kinetically inefficient. This review provides a comprehensive analysis of emerging green extraction technologies, specifically Ultrasound-Assisted (UAE), Microwave-Assisted (MAE), Enzyme-Assisted (EAE), Pressurized Liquid (PLE), and Supercritical Fluid Extraction (SFE), and Pulsed Electric Field (PEF), applied to key industrial matrices including apple, citrus, grape, olive, and coffee. Comparative data demonstrate that intensification technologies significantly outperform conventional maceration, with UAE and MAE reducing processing times by up to 90% while enhancing polyphenol yields by 20–55% through mechanisms such as acoustic cavitation and dipole rotation. Furthermore, high-pressure methods exhibit tunable selectivity, enabling the specific recovery of heat-sensitive anthocyanins and bound phenolics without the use of toxic organic solvents. The study concludes that the future of industrial valorization lies in the adoption of hybrid technologies and sequential biorefinery strategies to achieve high-purity isolates with minimal environmental impact. Full article

Polyphenols are structurally diverse plant secondary metabolites with broad biological activities and growing applications across the food, health, and materials sectors. Conventional extraction based on organic solvents (e.g., methanol, ethanol) is often energy-intensive, inefficient, and environmentally burdensome. Ionic liquids (ILs) and deep eutectic solvents (DESs) have therefore emerged as greener alternatives for polyphenol extraction. This review evaluates recent advances in solvent design, extraction performance, and process sustainability. Imidazolium-based ILs frequently achieve high yields and selectivity, particularly when coupled with ultrasound or microwave-assisted extraction, but high cost, synthetic complexity, viscosity-related constraints, and potential toxicity hinder scaleup. By contrast, DESs—especially those derived from choline chloride or lactic acid—are easier to prepare, less costly, and more compatible with industrial implementation, with efficiency enhanced by tailoring hydrogen bond networks, water content, and process intensification. Critical downstream challenges persist for both solvent classes, notably in extract purification and solvent recovery due to low volatility; approaches such as resin adsorption, antisolvent precipitation, and direct formulation have been explored. Overall, ILs and DESs represent compelling alternatives to conventional solvents, and future progress will depend on integrated extraction–recovery strategies, systematic solvent selection, and validation under scalable, sustainable processing conditions. Full article

Nalca (Gunnera tinctoria Mol.) is traditionally consumed for its edible petioles and valued for medicinal properties associated with its bioactive compounds. In this study, natural deep eutectic solvents (NADESs) were synthesized and applied for the ultrasound-assisted extraction of phenolic compounds and alkaloids from Nalca leaves. NADES synthesis was confirmed using ¹H NMR, and their physicochemical properties were evaluated to assess their influence on extraction efficiency. The extracts showed total phenolic contents ranging from 6.8 to 142.6 mg GAE/g DW and total alkaloid contents ranging from 0.2 to 3.2 mg OXIE/g DW, depending on solvent composition. Antioxidant activity, evaluated using DPPH and FRAP assays, confirmed that most NADES extracts exhibited significant radical-scavenging and ferric-reducing capacities, generally correlating with phenolic content. The extraction yields obtained with specific NADES formulations were comparable or superior to those achieved with conventional solvents, demonstrating their efficiency. These results demonstrate that NADESs are effective and environmentally friendly alternatives to conventional solvents for extracting bioactive compounds from Nalca leaves. The physicochemical properties of NADESs enable the selective extraction of different metabolite classes, highlighting their potential for green extraction processes in food, nutraceutical, and pharmaceutical applications. Full article

Depletion of reserves of rich copper–porphyry ore deposits necessitates the development of highly efficient methods for Mo (VI) extraction from complex, corrosive hydro-metallurgical media. The present study undertakes a comprehensive assessment of sorptive concentration of Mo (VI) from strongly acidic sulfate solutions (120 g/L H₂SO₄) by employing a spectrum of commercially available strong- and weak-base anion-exchange resins. It has been established that the macroporous weak-base anion exchanger Purolite A-100 demonstrates decisive superiority over gel-type analogs (Lewatit M-800, AB-17), facilitating unimpeded intra-gel diffusion of bulky molybdenyl sulfato-complexes anions, thereby circumventing the obstructive “sieve effect.” Thermodynamic and kinetic investigations revealed that the sorption process exhibits pronounced concentration- and pH-dependent characteristics. Peak extraction efficiency (up to 95.91%) is achieved at pH ≈ 1, a finding that correlates with the region of maximal protonation of tertiary amino groups within the resin matrix. Kinetic acceleration of mass transfer upon heating to 80 °C has been experimentally confirmed, yielding 94.6% extraction within 60 min. The obtained results corroborate the prospective integration of macroporous weak-base anion exchangers into operational hydro-metallurgical schemes as an environmentally benign and efficacious alternative to conventional solvent extraction of molybdenum. Full article

Natural deep eutectic solvents (NADESs) have emerged as promising green alternatives to conventional solvents for the extraction of bioactive compounds from plant materials. In this study, eight natural deep eutectic solvents were synthesized and evaluated for their efficiency in extracting betulin from birch bark. Extraction yield was assessed using high-performance liquid chromatography with ultraviolet detection. Among the tested systems, N3 (choline chloride and urea in a 1:1 molar) and N4 (choline chloride and fructose in a 1:1 molar) were the most effective, yielding 101.26 ± 0.03 and 243.32 ± 0.26 mg betulin per gram of dry extract, respectively. Fourier transform infrared spectroscopy analysis confirmed the structural similarity of the N4 extract to pure betulin. In addition to increased extraction performance, the N4 extract demonstrated the greatest antioxidant activity (DPPH (1,1-diphenyl-2-picrylhydrazyl): 63% and ABTS (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)): 97% inhibition) and total phenolic content (12.12 mg GAE/g extract), and betulin yield was strongly correlated with total phenolic content (TPC) and antioxidant activity (FRAP (ferric ion reducing antioxidant power), DPPH, and ABTS), indicating the preservation of bioactivity. These findings underscore the potential of NADESs as sustainable solvents for the extraction of bioactive compounds from birch bark, supporting greener extraction technologies for biomass valorization and natural product processing. Full article

Spent coffee grounds (SCG) are the main by-product generated by the coffee industry, with an estimated annual production of approximately 7 million tons. Although commonly treated as waste, SCG constitute a valuable source of phenolic compounds, particularly chlorogenic acid, which has been associated with antimicrobial, antioxidant, antimutagenic, anti-inflammatory, and cardioprotective properties. These bioactive compounds are of interest as functional ingredients for food, cosmetic, and pharmaceutical applications. However, their recovery by conventional extraction methods often depends on volatile, flammable, or toxic organic solvents. In this context, hydrophobic eutectic solvents (HES) have emerged as a greener and more sustainable alternative. In the present study, phenolic compounds were extracted from SCG using HES combined with microwave-assisted extraction (MAE). Sixteen terpene-based HES formulated with fatty acids and fatty alcohols were evaluated. Among them, camphor:dodecanoic acid and borneol:dodecanoic acid gave the highest total phenolic contents. Process optimization showed that the borneol:dodecanoic acid system, under 12% water content, a 1:10 solid-to-liquid ratio, 57 °C, and 120 min, reached 80.94 ± 4.44 mg GAE g⁻¹ by MAE. HPLC analysis revealed chlorogenic, caffeic, and ferulic acids as the main phenolic compounds, while the extracts also displayed high antioxidant activity. Overall, these findings demonstrate that HES-MAE is a promising and sustainable strategy for the recovery of value-added phenolics from SCG. Full article

Development of green and efficient technologies for valorizing crayfish shell waste is crucial for enhancing industrial value. This study presents an integrated strategy for the extraction and structural engineering of chitin using a novel alkaline deep eutectic solvent (DES) system composed of lysine and monoethanolamine (LysMEA), which enables the simultaneous deproteinization and architectural modification of chitin. Following mild demineralization, the optimized process yielded chitin with 97.1% purity and a high molecular weight of 209.3 kDa. DES demonstrated considerable reusability and decolorization capability. Structural characterization revealed that the LysMEA system effectively engineered the chitin architecture, resulting in lower crystallinity and a larger surface area compared to conventional methods. This engineered structure rendered the chitin highly accessible to enzymes. Consequently, the chitin extracted by LysMEA exhibited superior reactivity, achieving a deacetylation degree of 63.7% when catalyzed by Bacillus aryabhattai chitin deacetylase, significantly outperforming chitin obtained via acid-alkali or acidic DES methods. Molecular dynamics simulations elucidated the mechanism, showing that lysine and monoethanolamine molecules penetrated the chitin fiber bundles at high temperatures, weakening interchain hydrogen bonds and partially separating the chains. This work provides a green route for producing enzymatically reactive chitin, demonstrating the potential of solvent-based structural engineering in biocatalytic valorization. Full article

Industrial processing of apple to obtain products like juice or cider generates a significant amount of pomace, which represents 25–30% of the fresh fruit mass. Different technologies are needed to valorize apple pomace (AP), considering its significant amount of high-value compounds, such as fiber, vitamins, and polyphenols. Hot-air convection (CA) and infrared (IR) drying are widely used methods for preserving polyphenols from by-products, such as apple pomace (AP), while also extending their shelf life. This study aimed to evaluate the influence of CA and IR drying on drying kinetics, color parameters, and the preservation of polyphenolic compounds, as well as to identify a sustainable extraction approach. Both drying methods significantly affected the color characteristics and content of polyphenols with high antioxidant activity. A significant impact was noticed at higher temperatures, which may be associated with the partial inactivation of browning enzymes. IR drying resulted in a shorter drying time and lower specific energy consumption compared to CA. Furthermore, the assessment of solvent efficiency in ultrasound-assisted extraction (UAE) indicated that the natural deep eutectic solvent (NaDES) composed of choline chloride and glycerol (1:1 molar ratio) provided superior recovery of phenolic compounds with high antioxidant activity compared to conventional solvents and the other NaDES analyzed. Optimization of UAE conditions using this polyol-based NaDES allowed for achieving an extract characterized by a polyphenolic profile dominated by flavan-3-ols (catechin and epigallocatechin), followed by phenolic acids, mainly chlorogenic acid. These results confirm the potential of AP as a valuable source of bioactive compounds and of polyol-based NaDESs as a sustainable and efficient alternative for their recovery. Full article

Spent coffee grounds (SCGs) are an abundant agro-industrial residue with high potential as a source of phenolic compounds and proteins. This study evaluated the extraction of these value-added fractions using hydrophilic and hydrophobic eutectic solvents, applied either alone or combined with enzyme-assisted extraction. A total of 31 hydrophobic eutectic solvents (HESs), nine hydrophilic deep eutectic solvents (DESs), and five conventional solvents were screened for phenolic recovery. Extraction performance was strongly formulation-dependent, with hydrophobic systems showing the highest phenolic yields. HES 4 (camphor:oleic acid) was the best-performing solvent, reaching 1279.49 ± 2.31 mg GAE L⁻¹, followed by borneol:oleic acid (1133.92 ± 5.29 mg GAE L⁻¹). Enzyme addition did not enhance phenolic extraction; the highest values under enzymatic conditions were 896.12 ± 4.80 mg GAE L⁻¹ for HES 4 + Cellic^® CTec2 and 819.84 ± 2.66 mg GAE L⁻¹ for HES 4 + Viscozyme^®. In contrast, protein extraction increased remarkably with enzyme supplementation, particularly with Cellic^® CTec2. The highest protein recovery was obtained with HES 4 + Cellic^® CTec2 (1608.74 ± 3.32 mg·L⁻¹), compared with 506.37 ± 5.20 mg·L⁻¹ for neat HES 4. In general, neat HESs were more suitable for phenolic recovery, whereas HESs combined with Cellic^® CTec2 were more effective for protein extraction. Full article

Natural deep eutectic solvents (NADES) offer sustainable alternatives to conventional solvents for plant extraction, yet their influence on extract composition and bioactivity preservation requires further study. Here, choline chloride-based NADES with lactic acid or propylene glycol were evaluated for ultrasound-assisted extraction (60 °C, 30 min, 1:20 w/v) of polyphenol-rich fractions from Sanguisorba officinalis and Symphytum officinale. Spectrophotometric analysis yielded total phenolic contents of 6.49–9.67 mg GAE g⁻¹ and total flavonoids of 0.08–0.52 mg g⁻¹, with values dependent on the plant matrix and the NADES formulation. Targeted HPLC-MS/MS enabled identification of representative phenolic acids (chlorogenic, caffeic, ferulic, rosmarinic) and flavonoid markers (rutin, quercetin derivatives), showing qualitative differences in the detected marker profiles between solvents and matrices. Functional assays demonstrated pronounced antioxidant-related effects, including DPPH radical scavenging at 0.5–25 µg mL⁻¹ (polyphenols), inhibition of lipid peroxidation in rat erythrocytes at 0.25–1.20 µg mL⁻¹, and modulation of mitochondrial respiration and permeability transition in isolated rat liver mitochondria. Overall, the results indicate that choline chloride-based NADES can be used to obtain polyphenol-rich plant extracts compatible with the applied analytical workflow while preserving redox-active fractions, supporting their utility in green analytical sample preparation. Full article

Cancer is an alarming health concern and economic burden in both developed and developing countries. Recently, there has been a growing demand for new alternative medications with more effectiveness and fewer harmful effects. During the past decades, a set of chemotherapeutic agents has been developed to fight against a large spectrum of cancer types. Unfortunately, their use is associated with a high level of toxicity; they are expensive, also, and their deployment is restricted by the emergence of cellular resistance. Plant-based components are garnering attention due to their low toxicity, selectivity, efficiency, and ease of accessibility. Alkaloids are one of these targeted compounds. Indeed, they are a highly diverse group with basic heterocyclic nitrogen-containing alkaloids that exhibit potent anticancer effects against a large panel of solid and liquid tumors, such as lung, breast, leukemia, liver, and colon cancer. The main molecular mechanisms involved in alkaloids’ anticancer effect are the induction of apoptosis via the extrinsic and intrinsic pathways, DNA damage, and the inhibition of cell cycle progression. Amazingly, these auspicious compounds exhibited strenuous inhibitory effects against a whole range of key enzymes involved in cancer progression and metastasis, such as Cytochrome P450 (CYP450), Cyclooxygenase-2 (Cox-2), Lysine-Specific Demethylase 1 (LSD1), Poly [ADP-ribose] polymerase (PARP), and topoisomerase, mainly through two action modes, namely irreversible and reversible inhibition. Furthermore, several conventional extraction methods have been developed to extract bioactive compounds from natural matrices, such as Soxhlet and hot water extraction. However, these techniques have many drawbacks, as they require a large amount of organic solvents, which not only affect human health but also generate severe environmental issues. To overcome these limitations, multiple eco-extraction techniques have emerged as potential alternatives to traditional extraction methods such as ultrasonic extraction, microwave-assisted extraction, and supercritical fluid extraction. In fact, they are considered eco-friendly and efficient technologies with less time and solvent consumption. Overall, this review aims to provide an updated overview of the most prominent anticancer alkaloids that have not been well reviewed already, as well as the main green extraction techniques relevant to the extraction of antineoplastic alkaloids. Full article

As a new class of green functional liquids, deep eutectic solvents (DESs) have attracted increasing attention as alternatives to conventional solvents, such as mineral acids, organic solvents and ionic liquids (ILs), in nuclear chemistry. Owing to their low cost, easy preparation, structural tunability, and adjustable physicochemical properties, DESs provide unique solvation and coordination environments that enable various applications. This review summarizes recent research advances in the application of DESs for the chemical processes of the nuclear fuel cycle. Particular emphasis is focused on dissolution, extraction and separation, electrochemical deposition and redox processes, radionuclide capture, decontamination and detection. This review highlights the fundamental advantages and current limitations of DES-based systems and outlines future trends. Full article

Ethnopharmacological relevance. Withania somnifera (L.) Dunal, widely used in traditional medical systems such as Ayurveda, Unani, and Middle Eastern folk medicine, is valued for its adaptogenic, anti-inflammatory, neuroprotective, antimicrobial, and anticancer properties. These activities are primarily attributed to withanolides, with Withaferin A recognized as one of the most bioactive constituents. Although traditional preparations often rely on the root, leaf use provides a more sustainable alternative and may yield significant quantities of active metabolites. Identifying efficient, modern extraction technologies that can enhance the recovery of bioactive compounds from leaves is essential for developing effective, standardized ethnopharmacological formulations. Materials and methods. Plants of W. somnifera grown from seeds were subjected to different environmental conditions (control, drought, cold, yeast extract treatment). Leaves were extracted using Pressurized Cyclic Solid–Liquid Extraction (PCSLE) with hydroalcoholic solvents and compared with conventional infusion of dried leaves. Extracts were fractionated with solvents of varying polarity and analyzed by TLC, HPLC, and NMR for quantification of Withaferin A. Expression levels of key withanolide-biosynthetic genes (CAS, SMT1, DWARF1, CYP71, CYP76) were assessed using qRT-PCR. Antimicrobial activity of pure Withaferin A, aqueous extract, and hydroalcoholic PCSLE extract was evaluated through MIC and MBC assays against Gram-positive and Gram-negative strains. Cytotoxic activity was measured via MTT assays in six human cancer cell lines after 3, 6, and 24 h of treatment. Results. PCSLE yielded substantially higher levels of Withaferin A than traditional infusion, especially in medium-polarity fractions (chloroform and ethyl acetate), with concentrations reaching 0.70% in fresh leaf mass (4.8% dry weight), compared to 0.11% obtained by infusion. Gene expression analysis revealed that 24-week-old plants exhibited the highest transcription of withanolide-biosynthetic genes, and drought stress significantly upregulated CAS, SMT1, DWARF1, CYP71, and CYP716, indicating enhanced metabolic flux toward withanolide production. Hydroalcoholic PCSLE extracts showed broad-spectrum antimicrobial activity, with MIC and MBC values comparable to pure Withaferin A and demonstrating bactericidal effects against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes. The aqueous extract showed activity only against Gram-positive strains. Cytotoxicity assays demonstrated an optimistic, dose-dependent reduction in cell viability across all tumour cell lines treated with the hydroalcoholic PCSLE extract, closely mirroring the activity of pure Withaferin A and consistently exceeding the effect of the aqueous extract. IC50 values confirmed the high bioactive content of PCSLE extracts and suggested mechanisms like those known for Withaferin A. Conclusions. PCSLE proved to be a highly efficient extraction technology for obtaining leaf extracts rich in Withaferin A, outperforming conventional extraction methods while exploiting sustainable plant tissue. Developmental stage and drought stress significantly modulated the expression of genes involved in withanolide biosynthesis, highlighting agronomic strategies capable of enhancing metabolite production. Hydroalcoholic PCSLE extracts exhibited antimicrobial and cytotoxic activities comparable to pure Withaferin A, supporting their relevance as promising therapeutic candidates. These findings advocate for the use of W. somnifera leaves as a sustainable source of bioactive compounds and demonstrate that advanced extraction technologies can contribute to the development of innovative ethnopharmacological preparations for antimicrobial and anticancer applications. Full article