Search Results (6,468)

Reductive catalytic fractionation (RCF) has emerged as a representative lignin-first biorefining strategy for converting native lignin into aromatic monomers while preserving a carbohydrate-rich pulp for subsequent valorization. Although previous reviews have summarized the effects of feedstocks, solvents, and catalysts on monomer production, a process-oriented synthesis that connects reaction chemistry with reactor configuration, solvent recycling, catalyst recovery, and scale-up remains limited. This review, therefore, reassesses recent advances in RCF from an integrated process perspective. The comparative analysis indicates that monomer yield cannot be predicted by lignin content alone but is governed by the combined effects of β-O-4 abundance, lignin condensation, S/G ratio, lignin-carbohydrate connectivity, tissue structure, and solvent accessibility. Solvent systems are further evaluated not only by their ability to promote lignin extraction and intermediate stabilization, but also by their influence on carbohydrate retention, solvent recovery, and process sustainability. Catalyst development is discussed in relation to metal–support interactions, hydrogen-transfer pathways, catalyst placement, deactivation resistance, and compatibility with recycled solvents. Particular emphasis is placed on the transition from batch screening to semi-continuous, flow-through, and continuous-flow RCF, where spatial separation of lignin extraction and catalytic stabilization can improve residence-time control, mass transfer, catalyst recovery, and process scalability. The analysis further indicates that high-pressure batch reactors remain useful for laboratory screening, but their direct industrial implementation is restricted by equipment cost, safety requirements, energy input, high solvent-to-biomass ratios, and solvent recovery burden. Flow-through and continuous-flow configurations, coupled with solvent-loop optimization and catalyst recovery, are, therefore, more promising for scalable RCF. Finally, techno-economic analysis, life-cycle assessment, solvent-loop design, lignin-oil upgrading, and standardized reporting requirements are discussed as essential criteria for industrial implementation. Overall, this review highlights that scalable RCF should not be regarded simply as an optimized depolymerization reaction, but as a reactor- and recycle-aware lignin-first process architecture that integrates feedstock selection, solvent-catalyst chemistry, separation strategy, catalyst lifetime, solvent recovery, and downstream utilization. Full article

Citrus fruits are a significant source of flavonoids. Of all the citrus fruits, Citrus paradisi (grapefruit) presents the highest concentration of the flavonoid naringin, a compound offering a variety of human health benefits and applications in the pharmaceutical, food, and cosmetic industries. Commonly, when a citrus fruit is consumed, the peel and seeds are discarded, resulting in approximately 50% waste, making the potential use of citrus waste in order to reduce environmental impact a research priority. The present study used fresh grapefruit albedo to extract naringin via eco-friendly methods, such as ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE), which were compared against the conventional reflux extraction procedure. Furthermore, the presence of naringin was confirmed by nuclear magnetic resonance (NMR) spectroscopy, while naringin content was determined via HPLC-DAD analysis. The results obtained show that the pink grapefruit variety was the optimal source for extracting the flavonoid of interest, producing the highest content (3.41 g/kg), followed by the red (2.47 g/kg) and white (1.70 g/kg) varieties. The UAE method was observed to reduce the extraction time significantly, to only 10 min, which is up to 30-and -fold times less than the extraction times obtained using conventional (5 h) and MAE (40 min) methods, respectively. These results prove the usefulness of UAE as a simple, fast, efficient, and eco-friendly method for extracting naringin from fresh grapefruit albedo, via the use of a green solvent such as ethanol. In addition, the present study is the first to conduct a comparative analysis of naringin content in the three main grapefruit varieties grown in Mexico. Full article

Objectives: Aspidopterys obcordata has been traditionally used by the Dai people in Xishuangbanna, China, for the prevention and treatment of renal calculi. This study aimed to investigate the inhibitory effect of A. tomentosa extracts on calcium oxalate stone formation. Methods: The extracts of A. tomentosa (EA) were obtained via 95% ethanol reflux extraction, followed by multi-polar solvent extraction and elution. The HK-2 cell injury model induced by calcium oxalate and the renal calculus mouse model established by intraperitoneal injection of glyoxylic acid were established to assess drug efficacy. EA intervention was performed to evaluate its effects on calcium oxalate crystal deposition, renal tubular injury, cell apoptosis, and serum creatinine (Scr) and blood urea nitrogen (BUN) levels. Furthermore, the potential mechanism underlying, particularly the regulation of PERK/ATF4/CHOP signaling pathway and endoplasmic reticulum stress-mediated apoptosis, was investigated. Results: EA treatment significantly reduced renal calcium oxalate crystal deposition, alleviated renal tubular injury, inhibited cell apoptosis, and decreased Scr and BUN levels. Mechanistically, the protective effects of EA were mediated by the downregulation of the PERK/ATF4/CHOP signaling pathway and the suppression of endoplasmic reticulum stress-mediated apoptosis. Conclusions: These findings provide experimental evidence supporting that A. tomentosa can be developed as a promising agent for the prevention of nephrolithiasis. Full article

Medicinal plants are being investigated as a source of compounds with biological activities related to diabetes. The antidiabetic properties of the plant Carica papaya have been reported in experimental models. This study aimed to evaluate the phytochemical composition, antioxidant activity, and inhibitory activity of extracts from C. papaya leaves against α-glucosidase and pancreatic lipase. Plant material was collected in Tabasco, Mexico, and extracted by sequential maceration with solvents of increasing polarity: hexane, dichloromethane, methanol, and methanol:water. The extracts were fractionated by column chromatography, and the most active fractions were selected for further purification. The phytochemical identification of the active compounds was performed, and their structures were elucidated using spectroscopic and spectrometric techniques. The methanolic extract, rich in phenols and flavonoids, showed the highest antioxidant capacity (DPPH: 8.99 mmol TE/g; ABTS: 35.94 mmol RE/g; FRAP: 48.62 mmol Fe²⁺/g). The hydroalcoholic extract exhibited α-glucosidase inhibitory activity (38.44%), and bioassay-guided fractionation led to the identification of clitorin. The dichloromethane extract showed pancreatic lipase inhibition (52.2%), and the most active fraction contained loliolide. These findings demonstrate that C. papaya leaves contain bioactive compounds with antioxidants and digestive enzyme inhibitory activities, suggesting they could be candidates for further research in the management of diabetes. Full article

This review critically analyzes bioactive compounds derived from agro-industrial by-products, including polyphenols, natural pigments, dietary fiber, prebiotics, lipids, proteins, and bioactive peptides. The review examines their chemical characteristics, major agro-industrial sources, and recovery strategies, highlighting both conventional technologies and emerging green technologies, such as ultrasound-assisted extraction, supercritical fluids, and natural deep eutectic solvents (NADESs). Across compound classes, common patterns are identified, including the importance of external plant tissues as primary biological reservoirs, as well as a methodological convergence in extraction processes despite the wide chemical diversity of the molecules. Shared challenges related to compound stability, scalability, and process efficiency are also discussed. The results demonstrate that agro-industrial by-products should be understood as complex, integrated matrices rather than isolated sources of individual compounds, thereby supporting the development of unified biorefinery schemes. Unlike previous reviews focused on individual compound classes, this review integrates multiple classes of bioactive compounds, green extraction technologies, analytical characterization strategies, and industrial valorization approaches within a circular biorefinery framework. In conclusion, this review helps bridge the current fragmented understanding of waste valorization and highlights key opportunities for the sustainable development of high-value-added functional ingredients within the framework of the circular economy. Full article

Microbiological contamination of surface water represents a critical public health concern, while conventional disinfectants face limitations such as the generation of toxic by-products and the emergence of microbial resistance. In this study, the application of an ethanolic peel extract of Citrus paradisi (grapefruit), obtained by sonication at 40 kHz for 90 min at 55 °C using a 1:4 (w/v) solvent-to-solid ratio, was evaluated as a natural alternative for bacterial reduction in contaminated waters. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extract were first determined against Staphylococcus aureus and Escherichia coli. The extract was then applied to samples of slightly contaminated surface water with bacterial loads between 10³–10⁴ CFU/mL and turbidity of 150 NTU, as well as to highly contaminated surface water with bacterial loads ≥10⁵ CFU/mL and turbidity of 250 NTU. Bacterial removal was assessed at 6, 12, and 24 h. FTIR and UV-Vis characterization of the extract confirmed the presence of flavonoids (naringin), terpenes (limonene), and phenolic compounds. Results showed MIC/MBC values of 2.5/5.0 mg/mL for S. aureus and 5.0/10.0 mg/mL for E. coli. In slightly contaminated water, the extract at 5.0 mg/mL achieved complete (100%) removal of both microorganisms after 12 h, whereas in highly contaminated water, removals ranged from 80–90% for Staphylococcus spp. and E. coli. Statistical analysis (ANOVA, Bonferroni) demonstrated significant differences (p < 0.05) between the extract and ethanol. These findings indicate that Citrus paradisi extract constitutes an effective, sustainable, and low-cost natural alternative for bacterial reduction in surface waters, contributing to the valorization of agro-industrial residues and to the achievement of Sustainable Development Goal (SDG) 6. Full article

Sample preparation is frequently a time-consuming process and can be a major bottleneck in many analytical techniques that involve some form of modification to a sample so that it can be analyzed without interference or to increase its sensitivity. As part of the movement towards “green analytical chemistry”, the reduction in organic solvent usage and toxicity via alternative solvents compared to those traditionally used in analytical chemistry has gained increasing interest. Although ionic liquids were thought to have limitations, deep eutectic solvents (DESs) are being looked at as alternatives to traditional organic solvents in analytical chemistry because of their ability to produce a “tunable” set of physico-chemical properties that enable the selective and efficient extraction of a wide variety of analytes from a very diverse array of matrices. Although deep eutectic solvents have attracted increasing attention in analytical extraction applications, a systematic comparison of their performance across various extraction techniques is still lacking. This review fills this gap by offering a comprehensive and integrated evaluation of DES-based extraction approaches, emphasizing the interdependence between solvent characteristics, extraction efficiency, selectivity, and sustainability. The insights presented herein are intended to support the rational selection of appropriate DES-based extraction strategies for diverse analytical purposes. Moreover, these findings are expected to contribute to the advancement of greener, more efficient sample preparation methodologies within the field of green analytical chemistry. In this review article, we describe several analytical chemistry techniques that utilize DESs, such as dispersive liquid–liquid microextraction, solid-phase extraction, ultrasound-assisted extraction, etc., and explain the basic principles and mechanisms behind each technique. Additionally, comparative evaluations are provided to identify the relative advantages and disadvantages of the techniques mentioned above in terms of extraction efficiency and selectivity, and speculation regarding future trends and challenges in DES-based extraction systems will also be included. By integrating recent advances and comparative performance assessments, this review serves as a reference for researchers and industry practitioners, fostering innovation and promoting the wider adoption of sustainable extraction technologies. Full article

Fermented foods and beverages based on plant-derived ingredients are of growing technological interest, especially when they are designed as alternatives to conventional dairy products. This study evaluated the effects of herbal extracts from Verbascum thapsus L., Cnicus benedictus L., and Fumaria officinalis L. on lactic acid bacteria growth, acidification kinetics, and viable cell counts during the fermentation of organic milk, coconut beverage, and soy beverage. The extracts were characterized for extraction yield, total phenolic content, and antioxidant activity before use in fermentation trials. Mixtures of organic solvents and water produced extracts with higher total phenolic content and antioxidant activity than water alone. The highest values were obtained for F. officinalis extracts prepared with water and methanol or water and acetone, while for C. benedictus, the most effective solvents were water and acetone or water and ethanol. The agar well-diffusion assay showed no relevant antibacterial activity against the tested LAB strains under the applied conditions. No biologically relevant inhibition zones were observed in any of the 84 extract-strain combinations under the tested conditions. The only borderline response was observed for Lactobacillus acidophilus La-14 exposed to the 70% ethanolic extract of C. benedictus. The clear halo did not exceed 1.50 mm outside the 5 mm well and was treated as a weak, strain-specific screening result. Fermentation kinetics depended mainly on the food matrix. The coconut beverage acidified most rapidly, reaching pH 4.38 to 4.79 after 6 h, whereas the soy beverage required 24 h to reach pH 4.31 to 4.56. Organic milk showed the slowest acidification, and selected C. benedictus extracts delayed pH reduction. All analyzed fermented samples contained more than 7 log CFU/mL of viable LAB. These results indicate that selected herbal extracts can be used in fermented milk and plant-based beverages without reducing LAB survival, but their suitability should be assessed separately for each strain and matrix. Full article

Dioctyl adipate (DOA) and dioctyl sebacate (DOS) are widely used cold-resistance plasticizers; however, their low molecular weight and weak polarity result in poor thermal stability and migration resistance. Here, we report the synthesis and performance of bio-based cold-resistance plasticizers derived from trans-aconitic acid with enhanced migration resistance. Tri-n-butyl trans-aconitate (TBTA), tri-n-hexyl trans-aconitate (THTA), and tri-n-octyl trans-aconitate (TOTA) were synthesized via one-step esterification with aliphatic alcohols and applied in poly(vinyl chloride) (PVC). Compared with commercial plasticizers di-(2-ethylhexyl) phthalate (DEHP), tributyl citrate (TBC) and DOA, the synthesized plasticizers demonstrated excellent thermal stability and cold-resistance. After freezing treatment, the $T_g$ values of TBTA/PVC (18.99 °C) and THTA/PVC (20.88 °C) were lower than those of DEHP/PVC (22.74 °C). The branched architecture was supposed to strengthen interactions between plasticizers and PVC, improving volatility resistance and solvent extraction resistance. Compared with DOA/PVC at 48 h, TBTA/PVC, THTA/PVC and TOTA/PVC displayed volatility mass loss reduction of ~1.5%, 4% and 7%, respectively. Their extraction mass loss in ethanol decreased by 5–6%, while in petroleum ether, TBTA/PVC and TOTA/PVC dropped by 11.95% and 2.63%, respectively. These bio-based plasticizers are promising alternatives to the poor migration resistance of conventional low-temperature plasticizers. Full article

The sustainable valorization of spontaneous flora biomass for the recovery of high value-added phytochemicals represents a key opportunity within the circular bioeconomy, yet it remains constrained by the environmental limitations of conventional extraction solvents and the lack of data-driven optimization frameworks. In this study, Natural Deep Eutectic Solvents (NADES) composed of betaine and 1,3-propanediol were designed and applied as bio-based extraction media for the recovery of bioactive metabolites from Artemisia annua L. spontaneous biomass in the context of green extraction and sustainable resource utilization. Two liquid–solid extraction techniques, namely vortex-assisted extraction and ultrasound-assisted extraction, were evaluated. The influence of key process parameters, including the eutectic component molar ratio, water content, solid-to-liquid (S/L) ratio, extraction temperature, and extraction time, was systematically investigated. Results demonstrated that extraction efficiency was strongly dependent on both solvent composition and process conditions, with distinct optimum parameters for different phytochemical classes. Maximum total polyphenol content (52.08 mg GAE/mL) was achieved via ultrasound-assisted extraction at 20 °C for 15 min, using a 1:3 NADES ratio with 40% water dilution and S/L = 1:5, while the highest flavonoid yield (17.34 mg QE/mL) was obtained by vortex-assisted extraction for 45 min using a 1:6 NADES ratio under the same dilution and S/L conditions. To identify extraction conditions associated with improved process efficiency, a hybrid modeling approach combining deep neural networks with the Success-History-based Adaptive Differential Evolution (SHADE) algorithm was employed, enabling high-accuracy prediction of extraction performance across a broad parameter space. The proposed framework demonstrates the feasibility of integrating green solvent design with machine learning-driven process modeling for the efficient valorization of underutilized plant biomass, contributing to the development of resource-efficient, sustainable extraction protocols, consistent with principles of process intensification and resource-efficient extraction strategies. Full article

This study explores an innovative approach based on deep eutectic solvent (DES)-synergistic ultrasonic-assisted extraction (UAE) of anthocyanins from blueberry pomace (BP). Choline chloride–lactic acid (ChCl-LA, 1:2) was identified as the most efficient DES and provided the highest anthocyanin recovery. The optimal conditions for ChCl-LA-synergistic UAE (ChCl-LA-UAE) were obtained as follows: ultrasonic power of 270 W, extraction time of 30 min, liquid-to-solid ratio of 35:1, and water content in ChCl-LA of 40%, achieving a total anthocyanin content (TAC) of 3.5168 mg/g, with R² = 0.9860. This value was significantly higher than those obtained with 70% ethanol (3.1962 mg/g) and pure water (1.9137 mg/g). SEM images revealed that ChCl-LA-UAE disrupted the surface structure of the samples, thereby promoting anthocyanin release. COSMO-RS simulations confirmed that ChCl-LA significantly enhanced the interaction between the solvent and the representative anthocyanin (cyanidin-3-O-glucoside, C3G), resulting in higher extraction efficiency. In vitro antioxidant assays further demonstrated that the synergistic system exhibited stronger antioxidant activity. Overall, ultrasonic-synergistic DES extraction could be an eco-friendly method for recovering high-value compounds from blueberry and its byproducts. Full article

Microalgal lipid extraction, particularly the subsequent solvent recovery phase, constitutes the primary energy bottleneck in algal-based biodiesel biorefineries. Recently, switchable polarity solvents (SPS), such as the tertiary amine N,N-dimethylcyclohexylamine (DMCHA), have emerged as promising ‘green’ alternatives capable of extracting lipids directly from wet biomass, theoretically bypassing energy-intensive drying and solvent recovery distillation stages. This study presents a rigorous techno-energetic and thermodynamic evaluation combined with supporting experiments for qualitative conclusions to scrutinize the actual viability of DMCHA-mediated extraction against conventional hexane benchmarks, across three process configurations using different biomass types: algal liquor, wet paste, and dried biomass. Contrary to widespread assumptions in the literature, fundamental thermodynamic calculations reveal that the energy required for amine regeneration via protonation/deprotonation mechanisms equals or exceeds that of conventional distillation. Furthermore, mitigating biomass drying inadvertently escalates overall downstream energy and economic penalties due to the excessive solvent volumes demanded by dilute aqueous matrices. Direct extraction from algal liquor displays a cost and energy consumption countably higher than the other scenario; precisely, a cost of 232 €/kg of lipids and energy consumption of 454 kWh/kg of lipids. Extraction from wet paste exhibits, indeed, a slightly lower energy consumption compared to the hexane process (respectively 51 kWh/h versus 72 kWh/kg), but, due to the CO₂ requirements, the cost is double (19 €/kg of lipids versus 8 €/kg of lipids). Ultimately, while switchable polarity chemistry offers a marginal reduction in process water footprints, it introduces substantial operational complexity, elevated carbon dioxide payloads, and severe solvent degradation risks, challenging its current readiness for industrial upscaling. Full article

This study investigates subcritical water extraction (SWE) as an alternative to hydroalcoholic extraction for the production of Echinacea purpurea root extracts standardized to hydroxycinnamic acids (cichoric and caftaric acids). Extractions were performed at 100 °C, 125 °C, 150 °C, and 170 °C for 10–30 min. The recovery of cichoric and caftaric acids was significantly (p < 0.05) influenced by extraction temperature, with the highest values obtained within the range of 100–125 °C. Further experiments identified 110 °C for 10 min as the optimal condition, yielding the highest cumulative recovery of cichoric and caftaric acids (1.87 ± 0.10% of dry material). In the resulting dry extracts, SWE at 100–125 °C produced hydroxycinnamic acid contents of 5.5–7.1%, whereas the total dry extract yield in-creased from 24–28% at 100 °C to 40–41% at 150–170 °C (p < 0.05). Higher temperatures, however, reduced cichoric and caftaric acid cumulative content to 0.6–1.7% (p < 0.05), indicating a degradation of the target compounds. In contrast, total polyphenol recovery in-creased continuously with temperature, reaching 4.86% at 170 °C for 30 min. This was accompanied by marked increases in rutin, gallic and caffeic acid, reaching 458.5 mg/100 g dry weight (DW), 175.5 mg/100 g DW and 945.7 mg/100 g DW (p < 0.05), respectively, suggesting the release of bound phenolics following partial disruption of plant cell wall structures. SWE also enhanced the extraction of carbohydrates, uronic acids, fructans, proteins and organic acids, demonstrating an extensive temperature-dependent modification of the root matrix. 5-HMF was not detected in extracts obtained below 125 °C, but increased progressively at higher temperatures, reaching 200 mg/100 g (p < 0.05) at 170 °C. Biological evaluation in the human colorectal adenocarcinoma cell line (HT29) showed favorable cytocompatibility of SWE extracts, confirmed by cell viability, morphological assessment and low DNA damage in the Comet Assay. Overall, SWE enables the production of cichoric and caftaric acid-standardized E. purpurea extracts without organic solvents, supporting its application in pharmaceutical, nutraceutical, food and cosmeceutical products. Full article

ZnO nanopowders were synthesized via a solvent-mediated green route using Mitragyna speciosa Korth. leaf extract as reducing and stabilizing agents. Deionized water and methanol were employed to tailor the phytochemical composition of the extracts. The influence of extract concentration (5–20 mL) and solvent polarity on structural, morphological, and functional properties was systematically investigated. Structural analyses confirmed the formation of Zn-O bonds and a phase-pure hexagonal wurtzite ZnO without secondary phases. Surface morphology revealed solvent-dependent morphological evolution toward spherical shapes and reduced aggregation in the methanol-derived system. For antibacterial activity, green ZnO nanopowders demonstrated enhanced biocidal effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, comparable to that of commercial ZnO nanoparticles. Enhanced piezo-photocatalytic degradation of rhodamine B was achieved under combined light and ultrasonic irradiation, with superior performance observed for methanol-derived ZnO. This enhancement is attributed to the synergistic interplay of solvent-induced defect states, reduced particle size, and piezoelectric field-driven charge separation. Scavenger analysis confirmed that superoxide radicals (${·\mathrm{O}}_2^{-}$) dominate the degradation pathway by green-synthesized ZnO nanopowders prepared from different solvent extracts. Thus, a correlation between solvent-mediated phytochemical environments and piezo-photocatalytic activity provides new insights for the design of sustainable, high-performance ZnO-based catalysts. Full article

Hydrodynamic cavitation is assessed as a conditional process-intensification platform for the sustainable recovery and transformation of bioactive and functional fractions from agri-food residues, food-processing by-products, and plant-derived matrices. The analysis focuses on fractions enriched in polyphenols, flavonoids, pectins, carotenoids, proteins, pigments, essential oils, and other value-added compounds with potential relevance for food, nutraceutical, formulation-oriented, and related high-value applications. Rather than being considered an inherently green or universally superior technology, hydrodynamic cavitation is evaluated according to the specific process functions it can provide, including matrix disruption, mass-transfer enhancement, solvent-use reduction, recovery of pectin-associated fractions, protein extraction, macromolecular restructuring, dispersion, and process integration. Quantitative and scale-relevant indicators are considered where available, including recovery yield, target-compound content, solvent use, operating conditions, treated volume, energy input, fraction quality, and reporting limits. Comparison with ultrasound-assisted extraction, microwave-assisted extraction, pulsed electric fields, subcritical water extraction, natural deep eutectic solvents, and enzyme-assisted extraction indicates that its advantage is most defensible when hydrodynamic effects address a clearly identified matrix or process limitation. The available evidence supports substantial potential for wet matrices, plant by-products, aqueous suspensions, and liquid food systems. However, critical gaps remain in energy reporting, selectivity, recovered-fraction stability, scale-up, downstream processing, and application-oriented validation. Recovered fractions should therefore be regarded as candidate ingredients or functional intermediates, rather than as direct evidence of efficacy in final products. Full article