Subcritical Water Extraction of Natural Products

Formation and aqueous phase leaching of organic compounds following thermal degradation of commercial drinking water plastic pipes

After a wildfire, drinking water quality may be impacted by the thermal degradation of polyethylene pipes in drinking water distribution systems. Volatile organic compounds (VOC) and semi-VOCs (SVOC) have been detected in at least fifteen water distribution systems following wildfires between 2017 and 2024. This study investigated if plastics could potentially contaminate water directly by submerging four commercially available plastic drinking water pipes (crosslinked polyethylene (PEX)-a, PEX-b, PEX-c, and high density polyethylene (HDPE)) and one HDPE resin in water and heating them to various temperatures (100-285°C) in a continuously stirred tank reactor (CSTR). After cooling, clean water was pumped through the CSTR to assess flushing's efficacy as a decontamination strategy. Each plastic leached up to 10 VOCs out of 36 VOC/SVOCs examined at the highest exposure temperature of 285°C, including various monoaromatic and phenolic compounds. Benzene, a carcinogen, leached from all plastics at temperatures of 150°C and above. PEX-a leached the greatest concentrations of most detected VOCs, where the number and magnitude of compounds leached increased with increasing exposure temperature. Flushing removed the compounds over time, but flushing was slower than expected for the more hydrophobic compounds and not so for the more hydrophilic ones, due to their continuous leaching from the plastics. Similar compounds (7 of the 12 total found) were extracted from exhumed materials from wildfire impacted water systems, including several polyaromatic hydrocarbons which were not detected in the laboratory experiments. Benzene was found to leach from all exhumed plastic pipes above maximum contaminant levels. Results confirm that plastics may be a source of contamination, flushing removes contaminants over time, and procedures must be optimized to ensure their complete removal from water distribution systems post-wildfire. SYNOPSIS: Wildfires have caused contamination of drinking water systems. This study found that the thermal degradation of plastic drinking water pipes may be one source of detected contaminants and evaluated the efficacy of flushing as a decontamination strategy.

Solvent screening and extraction conditions prediction of subcritical extraction based on improved model: Extraction of lycopene as a case

In recent years, subcritical extraction has developed rapidly due to its environmental friendliness and high efficiency. In the extraction of low-polar and non-polar active substances, the addition of green low-polar solvents to subcritical extraction solvents can increase the yield of active substances. However, solvent screening and extraction conditions prediction are still a challenge. In this study, we employed the Williams formula to incorporate temperature and pressure correction into the Hansen solubility parameter to screen solvent under subcritical conditions by energetic spatial distance Ra between the solvent and solute. Then, an improved model along with corresponding dissolution factor e was established which allowed the prediction of optimum extraction condition range under subcritical conditions. Eventually, we chose the thermosensitive and non-polar substance lycopene as experimental case. Results showed that an e of 0.71 under experimental optimum extraction condition was within the predicted high extraction range, indicating the accuracy of the model predictions.

Bioactive flavonoids metabolites in citrus species: their potential health benefits and medical potentials

Citrus flavonoids are naturally occurring phytochemicals widely present in the peels and pulps of citrus fruits. They exhibit a wide range of biological activities, including antioxidant, anti-inflammatory, hypoglycemic, lipid-lowering, antimicrobial, and gut-protective effects. These metabolites show great potential in improving metabolic syndromes such as diabetes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular diseases. Additionally, citrus flavonoids have demonstrated significant effects in inhibiting pancreatic lipase activity, regulating lipid metabolism, and enhancing intestinal barrier function. Advances in extraction and purification techniques have further promoted their applications in the fields of food, medicine, and functional materials. This review systematically summarizes the types, bioactivities, and mechanisms of action of citrus flavonoids, providing scientific evidence for their research and development.

Bioactive Enrichment and Sustainable Processing of Vegetable Oils: New Frontiers in Agri-Food Technology

Vegetable oils are highly valued for their nutritional and functional properties, driving scientific interest in developing innovative technologies to enhance production processes. These advancements aim to improve yield, nutritional profiles and organoleptic and functional characteristics. Additionally, vegetable oils have been recognised for their ability to incorporate phenolics as bioactive compounds through stabilisation methods, further enhancing their health benefits. This study conducts a systematic review addressing two main objectives: (i) advanced technologies intended to enhance extraction efficiency while improving the overall quality of vegetable oils and (ii) stabilisation strategies developed to enrich and fortify edible vegetable oils with special focus on phenolic compounds. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was applied to evaluate their applications in developing bioactive vegetable oil ingredients and foods. Extraction techniques were assessed based on efficiency in yield and their impact on nutritional, organoleptic and functional properties. Pulsed electric field technology emerged as the most promising approach, offering an optimal balance between oil yield and quality. Combining stirring or high-performance dispersion with ultrasound proved effective in forming stable emulsions for phenolic stabilisation. These strategies provide valuable insights for the agro-industrial sector to enhance production processes and develop healthier, bioactive vegetable oils.

Development of Subcritical Water Extraction for Areca Alkaloids and Its Influence on the Structure of Areca Nut Husk

The optimal process parameters of subcritical water extraction (SWE) for areca alkaloids in areca nut (AN) husk were described: extraction temperature of 110.87 °C, liquid-to-solid ratio of 18.98:1 and extraction time of 50.01 min. It was found that the factors influencing the process in order of significance were extraction time > extraction temperature > liquid-to-solid ratio. Considering practical conditions, the parameters were adjusted to the extraction temperature of 110 °C, the liquid-to-solid ratio of 19:1 and the extraction time of 50 min. The measured extraction rate was 81.7%, which is close to the predicted value, indicating that the extraction process optimized by Response Surface Methodology (RSM) is feasible. Meanwhile, preliminary results from XRD and FT-IR indicated that SWE had a significant influence on the structure of the AN husk, possibly by damaging some of the crystalline regions of cellulose in the AN husk or reducing the concentration of various functional groups. Overall, this study provided valuable insights in the SWE for areca alkaloids and its influence on the structure of areca nut husk, and further exploration for industrialization is still under development in our laboratory.

Optimized Extraction Protocols for Bioactive Antioxidants from Commercial Seaweeds in Portugal: A Comparative Study of Techniques

This study aimed to optimize the extraction conditions for a valuable source of antioxidants: seaweed. Therefore, ten seaweed samples were subjected to a solid-liquid extraction (SLE), where the extraction conditions (biomass (g): solvent (mL) ratio, temperature, and time) were optimized using response surface methodology (RSM). The seaweeds were also subjected to subcritical water extraction (SWE) (140 and 190 °C) and ultrasound-assisted extraction (UAE) (10 and 20 min). The antioxidant capacity of the extracts was determined through the ferric-reducing antioxidant power and the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid). The total phenolic content revealed the significance of temperature and biomass; solvent ratio parameters in the extraction process with higher conditions generally promoting the release of phenolic compounds. Furthermore, applying RSM allowed for the identification of optimal conditions and the establishment of predictive models that can be valuable in industrial-scale extraction processes. The antioxidant potency composite index (APCI) shows that SWE at 190 °C stands out, with E. bicyclis reaching an APCI score of 46.27%. The AGREEprep evaluation showed that UAE is the most sustainable method, achieving the highest score (0.69). The results of this study contribute to the development of efficient and standardized extraction protocols for each seaweed species, allowing for the maximum yield of antioxidants.

Promoting the Emerging Role of Pulse By-Products as Valuable Sources of Functional Compounds and Novel Food Ingredients

The growth of the human population worldwide has increased food demand, generating the massive production of foods and consequently causing enormous production of waste every year. The indiscriminate exploitation of the already limited natural resources has also generated serious environmental and economic crises. The use, or reuse, of waste or by-products represents a viable solution to constrain the problem by promoting alternative routes of exploitation with multiple food and biotechnological applications. This review focuses on the most recent advances in the valorization of food by-products, with specific reference to legume-derived by-products. The main technological solutions for reintroducing and/or valorizing food waste are reported together with a critical discussion of the main pros and cons of each alternative, supported by practical case studies whenever available. First, the possibility to exploit the by-products as valuable sources of functional compounds is presented by reviewing both conventional and innovative extraction techniques tailored to provide functional extracts with multiple food, pharmaceutical, and biotechnological applications. Second, the possibility to valorize the by-products as novel food ingredients by inclusion in different formulations, either as a whole or as hydrolyzed/fermented derivatives, is also presented and discussed. To the best of our knowledge, several of the technological solutions discussed have found only limited applications for waste or by-products derived from the legume production chain; therefore, great efforts are still required to gain the full advantages of the intrinsic potential of pulse by-products.

Towards a Greener Future: Sustainable Innovations in the Extraction of Lavender (Lavandula spp.) Essential Oil

Lavender is one of the most appreciated aromatic plants, with high economic value in food, cosmetics, perfumery, and pharmaceutical industries. Lavender essential oil (LEO) is known to have demonstrative antimicrobial, antioxidant, therapeutic, flavor and fragrance properties. Conventional extraction methods, e.g., steam distillation (SD) and hydro-distillation (HD), have been traditionally employed to extract LEO. However, the low yield, high energy consumption, and long extraction time of conventional methods have prompted the introduction of novel extraction technologies. Some of these innovative approaches, such as ohmic-assisted, microwave-assisted, supercritical fluid, and subcritical water extraction approaches, are used as substitutes to conventional extraction methods. While other methods, e.g., sonication, pulsed electric field, and cold plasma, can be used as a pre-treatment that is preceded by conventional or emerging extraction technologies. These innovative approaches have a great significance in reducing the energy consumption, shortening the extraction time, and increasing the extraction yield and the quality of EOs. Therefore, they can be considered as sustainable extraction technologies. However, the scale-up of emerging technologies to an industrial level should also be investigated from the techno-economic points of view in future studies.

Waste-to-resource: Extraction and transformation of aquatic biomaterials for regenerative medicine

The fisheries and aquaculture industry are known for generating substantial waste or by-products, often underutilized, or relegated to low-value purposes. However, this overlooked segment harbors a rich repository of valuable bioactive materials of which have a broad-spectrum of high-value applications. As the blue economy gains momentum and fisheries expand, sustainable exploitation of these aquatic resources is increasingly prioritized. In this review, we present a comprehensive overview of technology-enabled methods for extracting and transforming aquatic waste into valuable biomaterials and their recent advances in regenerative medicine applications, focusing on marine collagen, chitin/chitosan, calcium phosphate and bioactive-peptides. We discuss the inherent bioactive qualities of these "waste-to-resource" aquatic biomaterials and identify opportunities for their use in regenerative medicine to advance healthcare while achieving the Sustainable Development Goals.

Advances in understanding dietary fiber: Classification, structural characterization, modification, and gut microbiome interactions

Gut microbiota and their metabolites profoundly impact host physiology. Targeted modulation of gut microbiota has been a long-term interest in the scientific community. Numerous studies have investigated the feasibility of utilizing dietary fibers (DFs) to modulate gut microbiota and promote the production of health-beneficial bacterial metabolites. However, the complexity of fiber structures, microbiota composition, and their dynamic interactions have hindered the precise prediction of the impact of DF on the gut microbiome. We address this issue with a new perspective, focusing on the inherent chemical and structural complexity of DFs and their interaction with gut microbiota. The chemical and structural complexity of fibers was thoroughly elaborated, encompassing the fibers' molecular composition, polymorphism, mesoscopic structures, porosity, and particle size. Advanced characterization techniques to investigate fiber structural properties were discussed. Additionally, we examined the interactions between DFs and gut microbiota. Finally, we summarized processing techniques to modify fiber structures for improving the fermentability of DF by gut microbiota. The structure of fibers, such as their crystallinity, porosity, degree of branching, and pore wettability, significantly impacts their interactions with gut microbiota. These structural differences also substantially affect fiber's fermentability and capability to modulate the composition of gut microbiota. Conventional approaches are not capable of investigating complex fiber properties and their influences on the gut microbiome; therefore, it is of the essence to involve advanced material characterization techniques and artificial intelligence to unveil more comprehensive information on this topic.

Isolation, structures, bioactivities, and applications of the polysaccharides from Boletus spp.: A review

Boletus spp., the edible mushrooms distributed in Europe, Asia, and North America, have been widely used as food and medicinal ingredients worldwide. Bioactive polysaccharides are highly abundant in Boletus spp., as demonstrated by modern phytochemical studies. The isolation, chemical properties, and bioactivities of polysaccharides from Boletus spp. have long been attracted by academics worldwide. However, there is still a lack of systematic tracking of research progress on Boletus polysaccharides (BPs), which is essential for researchers to understand their potential and gain a deeper insight into their functional mechanisms. In this review, we summarized the recent development of BPs, including the extraction and purification methods, physiochemical and structural features, bioactivities and functional mechanisms, the structure-activity relationship, and the potential applications. This review aims to provide researchers with a comprehensive understanding of the current progress and potential of BPs to assist their further investigations.

Quaternity method for integrated screening, separation, extraction optimization, and bioactivity evaluation of acetylcholinesterase inhibitors from Sophora flavescens Aiton

INTRODUCTION

Sophora flavescens Aiton (Fabaceae), a ubiquitous plant species in Asia, contains a wide range of pharmacologically active compounds, such as flavonoids, with potential anti-Alzheimer's disease (anti-AD) effects.

OBJECTIVES

The objective of the study is to develop a quaternity method for the screening, isolation, extraction optimization, and activity evaluation of acetylcholinesterase (AChE)-inhibiting compounds from S. flavescens to realize high-throughput screening of active substances in traditional Chinese medicine and to provide experimental data for the development of anti-AD drugs.

METHODS

With AChE as the target molecule, affinity ultrafiltration and liquid chromatography-mass spectrometry were applied to screen for potential inhibitors of the enzyme in S. flavescens. Orthogonal array experiments combined with the multi-objective Non-Dominated Sorting Genetic Algorithm III was used for the first time to optimize the process for extracting the active substances. Enzyme inhibition kinetics and molecular docking studies were performed to verify the potential anti-AD effects of the active compounds.

RESULTS

Five AChE-inhibiting compounds were identified: kushenol I, kurarinone, sophoraflavanone G, isokurarinone, and kushenol E. These were successfully separated at purities of 72.88%, 98.55%, 96.86%, 96.74%, and 95.84%, respectively, using the n-hexane/ethyl acetate/methanol/water (4.0/5.0/4.0/5.0, v/v/v/v), n-hexane/ethyl acetate/methanol/water (5.0/5.0/6.0/4.0, v/v/v/v), and n-hexane/ethyl acetate/methanol/water (4.9/5.1/5.7/4.3, v/v/v/v) mobile phase systems. Enzyme inhibition kinetics revealed that kushenol E had the best inhibitory effect.

CONCLUSION

This study elucidates the mechanism of action of five active AChE inhibitors in S. flavescens and provides a theoretical basis for the screening and development of anti-AD and other therapeutic drugs.

Comparative Analysis of Sustainable Extraction Methods and Green Solvents for Olive Leaf Extracts with Antioxidant and Antihyperglycemic Activities

Olive leaves are agro-industrial waste that pose an environmental management problem. However, they contain polyphenolic compounds with important bioactive properties beneficial to human. This study aimed to evaluate the effectiveness of two extraction technologies (pressurized liquid extraction and ultrasound-assisted extraction) combined with green solvents (pure water, 15% ethanol, and 15% glycerol) at 50 °C and 70 °C. The goal was to obtain extracts with both antioxidant capacity and antihyperglycemic properties from olive leaves. Pressurized liquid extraction with 15% glycerol at 70 °C was the most effective method for obtaining extracts rich in total polyphenols (19.46 mg GAE/g dw), with an antioxidant capacity of 4.11 mg/mL (inhibition capacity: IC50) and 500.26 µmol TE/g dw. For both extraction methods at 70 °C, glycerol was more effective at recovering phenolic acids, stilbenes and secoiridoid; while ethanol was more effective for recovering flavonols and phenylethanoids. Oleuropein was the most important polyphenol extracted from both pressurized liquid and ultrasound-assisted extractions, with concentrations of 171.48 µg/g dw and 246.70 µg/g dw, respectively. The extract obtained from pressurized liquid extraction with 15% ethanol at 70 °C exhibited significant inhibition (70%) of α-glucosidase enzymes, similar to the reference drug acarbose. In contrast, these extracts showed low inhibitory activity against the α-amylase enzyme. These findings can be applied to the development of functional foods and nutraceutical supplements aimed at managing postprandial glycemic response, offering a natural alternative for supporting type 2 diabetes management.

Optimization of subcritical water extraction for pectin extraction from cocoa pod husks using the response surface methodology

This study optimized subcritical water extraction (SWE) conditions to maximize pectin yield from cocoa pod husk (CPH) and compared the characteristics of CPH pectin extracted through SWE with those of CPH pectin obtained through conventional extraction (CE) with citric acid. The Box-Behnken experimental design was employed to optimize SWE and examine the influence of process parameters, including temperature (100 °C-120 °C), extraction time (10-30 min), and solid:liquid ratio (SLR) (1:30-2:30 g/mL), on pectin yield. The maximum pectin yield of 6.58% was obtained under the optimal extraction conditions of 120 °C for 10 min with 1:15 g/mL SLR and closely corresponded with the predicted value of 7.29%. Compared with CE, SWE generated a higher yield and resulted in a higher degree of esterification, methoxyl content, and anhydrouronic acid value but a lower equivalent weight. The extracted pectin was pure, had low-methoxyl content, and similar melting and degradation temperatures.

Fractionation of Winemaking Grape Stalks by Subcritical Water Extraction to Obtain Added-Value Products

Grape stalks (GSs) from winemaking were submitted to a green process to valorise its lignocellulosic biomass that applied subcritical water extraction (SWE) at 170 °C and 180 °C to obtain active extracts and cellulose-enriched fractions. The sum of the total phenolic content of the soluble extract and the solid residue fractions from the SWE exceeded that of the GS, which suggests the generation of compounds with antioxidant properties through SWE. All SWE fractions showed high antioxidant power. The increased temperature promoted the extraction of polyphenolic compounds, enhancing the antioxidant power of both extracts and solid residues. These solid residue fractions were bleached with alkaline hydrogen peroxide solutions (4 and 8% v/v) to purify cellulose. After two bleaching cycles, no notable delignification progress was observed, as the bleaching yield or whiteness index did not significantly change in the further cycles. The first bleaching cycle led to a significant reduction in the lignin content at both SWE temperatures. The cellulose purity was higher in the samples obtained at 170 °C and bleached with 4% alkaline hydrogen peroxide. SWE at 180 °C led to greater cellulose oxidation during the bleaching step regardless of the hydrogen peroxide concentration.

Ultrasonic-Assisted Biphasic Aqueous Extraction of Polyphenols from Vaccinium Dunalianum Leaves: Optimization, Antioxidant, and Tyrosinase Inhibition Activities

To optimize the ultrasonic-assisted biphasic aqueous extraction conditions for polyphenolic compounds from Vaccinium dunalianum Wight leaves and investigate their antioxidant and tyrosinase inhibition activities, single-factor experiments were conducted to investigate the effects of ethanol volume fraction (%), ammonium sulfate mass fraction (%), solid-liquid ratio (g/mL), ultrasonic temperature (°C), and ultrasonic time (min) on polyphenolic content during extraction. Based on these experiments, three key factors influencing extraction were selected for response surface methodology (RSM) optimization. The results indicated that under conditions of 26 % ethanol, 20 % ammonium sulfate, a solid-liquid ratio of 1 : 30, and extraction for 35 minutes at 50 °C, the polyphenol content reached 61.62 mg/g. The relative contents of 6'-O-caffeoylarbutin, β-arbutin, and chlorogenic acid were 34.45 %, 4.56 %, and 31.06 %, respectively. The DPPH⋅ and ABTS+⋅ scavenging rates were above 95 % and 96 %, respectively, and the ferric reducing ability exhibited a significant dose-effect relationship. The inhibition rates of monophenolase and diphenolase activities of tyrosinase were 43.84 % and 35.73 %, respectively. The optimized process for ultrasonic-assisted biphasic aqueous extraction of polyphenols from Vaccinium dunalianum Wight leaves demonstrated significant antioxidant and tyrosinase inhibition activities.

Research on the Cell Wall Breaking and Subcritical Extraction of Astaxanthin from Phaffia rhodozyma

This study focused on developing an effective cell wall-breaking method for Phaffia rhodozyma, followed by utilizing subcritical fluid extraction to isolate, extract, and concentrate astaxanthin from the complex fermentation products of P. rhodozyma. A comprehensive comparison of seven distinct methods for disrupting cell walls, including dimethyl sulfoxide treatment, lactic acid treatment, sodium hydroxide treatment, β-glucanase enzymatic digestion, β-mannanase enzymatic digestion, and a combined enzymatic treatment involving both β-mannanase and β-glucanase was conducted. The results identified the lactic acid method as the most effective in disrupting the cell walls of P. rhodozyma. The software, Design Expert, was used in the process of extracting astaxanthin from cell lysates using a subcritical extraction method. Through fitting analysis and response surface optimization analysis by Design Expert, the optimal extraction conditions were determined as follows: an extraction temperature of 41 °C, extraction frequency of two times, and extraction time of 46 min. These parameters facilitated the efficient extraction, concentration, and enrichment of astaxanthin from P. rhodozyma, resulting in an astaxanthin concentration of 540.00 mg/L. This result can establish the foundation for its high-value applications.

Antitumor activity of Polygonatum sibiricum polysaccharides

Cancer is a global public health problem. Natural polysaccharides have been shown to enhance the effectiveness of cancer treatments. Polygonatum sibiricum (PS) has been used for millennia to treat diverse diseases. PS comprises numerous active constituents, including saponins, peptides, volatile oils, polysaccharides, and lectins. Many studies have highlighted the crucial role of polysaccharides in PS. Modern studies have shown that Polygonatum sibiricum polysaccharide (PSP) exhibits diverse pharmacological activities, including immunomodulatory, antitumor, antioxidant, and anti-aging effects. However, further study of the antitumor mechanisms is difficult because the activities of PSP are closely associated with its complex structural features and the different molecular weights of its components. Therefore, this review focuses on the research background and the extraction and purification of PSP. Studies related to the mechanism of the antitumor effects of PSP constituents of different molecular weights are also summarized, and perspectives on PSP research are presented.

Cocoa by-products: A comprehensive review on potential uses, waste management, and emerging green technologies for cocoa pod husk utilization

Cocoa is considered to be one of the most significant agricultural commodities globally, alongside Palm Oil and Rubber. Cocoa is the primary ingredient in the manufacturing of chocolate, a globally popular food product. Approximately 30 % of cocoa, specifically cocoa nibs, are used as the primary constituent in chocolate production., while the other portion is either discarded in landfills as compost or repurposed as animal feed. Cocoa by-products consist of cocoa pod husk (CPH), cocoa shell, and pulp, of which about 70 % of the fruit is composed of CPH. CPH is a renewable resource rich in dietary fiber, lignin, and bioactive antioxidants like polyphenols that are being underutilized. CPH has the potential to be used as a source of pectin, dietary fibre, antibacterial properties, encapsulation material, xylitol as a sugar substitute, a fragrance compound, and in skin care applications. Several methods can be used to manage CPH waste using green technology and then transformed into valuable commodities, including pectin sources. Innovations in extraction procedures for the production of functional compounds can be utilized to increase yields and enhance existing uses. This review focuses on the physicochemical of CPH, its potential use, waste management, and green technology of cocoa by-products, particularly CPH pectin, in order to provide information for its development.

Research trends in functionalized Fe3O4 composites based on affinity recognition systems for targeted extraction of natural products

In recent years, target-specific affinity recognition systems based on Fe3O4-based composites have proven to be an effective method for screening natural products. Herbal medicines contain a wide range of natural products and are considered to be a major source for the development of novel drugs. However, the process of isolating and obtaining these bioactive components for the production of novel drugs is complex. Meanwhile, the complexity and diversity of herbal constituents have posed a great challenge to the screening studies of herbal active ingredients. Currently, traditional extraction and screening studies of active ingredients in herbal medicine include extraction and chromatographic separation technology development, serum medicinal chemistry, metabolomics and computerized virtual screening. In order to achieve integrated targeting of Fe3O4 for extraction and separation of natural products from herbs, various Fe3O4-based composites need to be synthesized so that the composites can be further functionalized and modified. Composites such as Fe3O4@SiO2, Fe3O4-based magnetic graphene oxide and Fe3O4-based magnetic carbon nanotubes were used to achieve targeted extraction and isolation of natural products from herbal medicines. The main extraction techniques involved based on these Fe3O4-based composites are molecularly imprinted techniques, immobilized ligand fishing techniques, and cell membrane-coated bionanotechnology methods. This article will present recent advances in the synthesis and modification of Fe3O4 composites and their applications for the extraction of natural products in conjunction with molecular imprinting, immobilization-targeted fishing, and cell-membrane-coated biomimetic techniques, as well as the future goals and challenges of functionalized modification of Fe3O4 composites for the targeted extraction of natural products, like protein overexpression modification, doping of fluorescent substances and genetic engineering development. A deeper understanding of the multi-level, multidisciplinary, and applied studies in materials science and phytochemistry will be provided by this article.

The volatile organic compounds generated from the Maillard reaction between l-ascorbic acid and l-cysteine in hot compressed water

BACKGROUND

Hot compressed water (HCW), also known as subcritical water (SCW), refers to high-temperature compressed water in a special physical and chemical state. It is an emerging technology for natural product extraction. The volatile organic compounds (VOCs) generated from the Maillard reaction between l-ascorbic acid (ASA) and l-cysteine (Cys) have attracted significant interest in the flavor and fragrance industry. This study aimed to explore the formation mechanism of VOCs from ASA and Cys and examine the effects of reaction parameters such as temperature, time, and pH in HCW.

RESULTS

The identified VOCs were predominantly thiophene derivatives, polysulfides, and pyrazine derivatives in HCW. The findings indicated that thiophene derivatives were formed under various pH conditions, with polysulfide formation favored under acidic conditions and pyrazine derivative formation preferred under weak alkaline conditions, specifically at pH 8.0.

CONCLUSION

The Maillard reaction between ASA and Cys mainly produced thiophene derivatives, polysulfides, and pyrazine derivatives in HCW. The generation mechanism was significantly dependent on the surrounding pH conditions. © 2024 Society of Chemical Industry.

Polyphenols: Secondary Metabolites with a Biological Impression

Polyphenols are natural compounds which are plant-based bioactive molecules, and have been the subject of growing interest in recent years. Characterized by multiple varieties, polyphenols are mostly found in fruits and vegetables. Currently, many diseases are waiting for a cure or a solution to reduce their symptoms. However, drug or other chemical strategies have limitations for using a treatment agent or still detection tool of many diseases, and thus researchers still need to investigate preventive or improving treatment. Therefore, it is of interest to elucidate polyphenols, their bioactivity effects, supplementation, and consumption. The disadvantage of polyphenols is that they have a limited bioavailability, although they have multiple beneficial outcomes with their bioactive roles. In this context, several different strategies have been developed to improve bioavailability, particularly liposomal and nanoparticles. As nutrition is one of the most important factors in improving health, the inclusion of plant-based molecules in the daily diet is significant and continues to be enthusiastically researched. Nutrition, which is important for individuals of all ages, is the key to the bioactivity of polyphenols.

Environmental remediation of emerging contaminants using subcritical water: A review

The continuous rise of emerging contaminants (ECs) in the environment has been a growing concern due to their potentially harmful effects on humans, animals, plants, and aquatic life, even at low concentrations. ECs include human and veterinary pharmaceuticals, hormones, personal care products, pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organic dyes, heavy metals (HMs), and others. The world's growing population contributes to the release of many kinds of chemicals into the environment, which is estimated to be more than 200 billion metric tons annually and results in over 9 million deaths. The removal of these contaminants using conventional physical, chemical, and biological treatments has proven to be ineffective, highlighting the need for simple, effective, inexpesive, practical, and eco-friendly alternatives. Thus, this article discusses the utilization of subcritical water oxidation (SBWO) and subcritical water extraction (SBWE) techniques to remove ECS from the environment. Subcritical water (water below the critical temperature of 374.15 °C and critical pressure of 22.1 Mpa) has emerged as one of the most promising methods for remediation of ECs from the environment due to its non-toxic properties, simplicity and efficiency of application. Furthermore, the impact of temperature, pressure, treatment time, and utilization of chelating agents, organic modifiers, and oxidizing agents in the static and dynamic modes was investigated to establish the best conditions for high ECs removal efficiencies.

Obtaining Cellulose Fibers from Almond Shell by Combining Subcritical Water Extraction and Bleaching with Hydrogen Peroxide

Almond shell (AS) represents about 33% of the almond fruit, being a cellulose-rich by-product. The use of greener methods for separating cellulose would contribute to better exploitation of this biomass. Subcritical water extraction (SWE) at 160 and 180 °C has been used as a previous treatment to purify cellulose of AS, followed by a bleaching step with hydrogen peroxide (8%) at pH 12. For comparison purposes, bleaching with sodium chlorite of the extraction residues was also studied. The highest extraction temperature promoted the removal of hemicellulose and the subsequent delignification during the bleaching step. After bleaching with hydrogen peroxide, the AS particles had a cellulose content of 71 and 78%, with crystallinity index of 50 and 62%, respectively, for those treated at 160 and 180 °C. The use of sodium chlorite as bleaching agent improved the cellulose purification and crystallinity index. Nevertheless, cellulose obtained by both bleaching treatments could be useful for different applications. Therefore, SWE represents a promising green technique to improve the bleaching sensitivity of lignocellulosic residues, such as AS, allowing for a great reduction in chemicals in the cellulose purification processes.

Characterization of temperature-dependent subcritical water hydrolysis pattern of strong and floury rice cultivars and potential utilizations of their hydrolysates

This study investigated the effects of subcritical water (SW) temperatures on the hydrolysis pattern and characteristics of hydrolysates prepared with strong rice (SR) and floury rice (FR). The characteristics of the hydrolysates were generally dependent on the rice cultivar in the SW temperature range of 150-250 °C, while the cultivar dependence was diminished at temperatures greater than 300 °C. Based on brix and reducing sugar content, an optimal production of rice hydrolysates was obtained at a SW temperature range of 200-250 °C. However, thermal conversion of sugar into acids, 5-hydroxymethylfurfural (HMF) and furfural was manifested at 250 °C. The rice hydrolysates prepared at 250 ∼ 300 °C had the highest antioxidant activity with strong umami intensity, but they suppressed the growth of prebiotics. Therefore, the present study demonstrated that controlling the SW temperature is crucial to improve rice hydrolysis efficiency and to regulate the physiological activity of the hydrolysates.

Effects of Defatting Pretreatment on Polysaccharide Extraction from Rambutan Seeds Using Subcritical Water: Optimization Using the Desirability Approach

Rambutan seeds are by-products generated from fruit-processing factories; the leftover seeds are buried in landfills, generating methane emissions. This work aimed to extract polysaccharides (POLS) from rambutan seeds by using subcritical water extraction (SWE). The effects of defatting pretreatment and operating parameters in SWE were investigated using a Box-Behnken design. The results show that defatting pretreatment significantly enriched the POLS yield, while it had no significant effect on the total sugar content. Using the desirability approach, the suitable feedstock for SWE was defatted rambutan seeds. The maximum desirability of 0.86 was found at a temperature range of 145-150 °C, an extraction time of 15 min, and a liquid-solid ratio of 10:1. The POLS yield and total sugar content were in the range of 52.33-55.63 g/100 g feedstock and 83.37-87.45 g/100 g POLS, respectively. The extracted POLS had an equivalent molecular weight of 413.70 kDa that could be used as an extender in plant-based products. In conclusion, the defatting pretreatment of rambutan seeds not only improved the POLS yield obtained via SWE but also generated additional lipids that could be utilized as an unconventional source of specialty fat.

Exploring Phenolic Compounds Extraction from Saffron (C. sativus) Floral By-Products Using Ultrasound-Assisted Extraction, Deep Eutectic Solvent Extraction, and Subcritical Water Extraction

Saffron (Crocus sativus) floral by-products are a source of phenolic compounds that can be recovered and used in the nutraceutical, pharmaceutical, or cosmetic industries. This study aimed to evaluate the phenolic compounds' extraction using green extraction techniques (GETs) in saffron floral by-products and to explore the influence of selected extraction techniques on the phytochemical composition of the extracts. Specifically, ultrasound-assisted extraction (UAE), subcritical water extraction (SWE), and deep eutectic solvents extraction (DESE) were used. Phenolic compounds were identified with (HR) LC-ESI-QTOF MS/MS analysis, and the quantitative analysis was performed with HPLC-PDA. Concerning the extraction techniques, UAE showed the highest amount for both anthocyanins and flavonoids with 50:50% v/v ethanol/water as solvent (93.43 ± 4.67 mg/g of dry plant, dp). Among SWE, extraction with 96% ethanol and t = 125 °C gave the best quantitative results. The 16 different solvent mixtures used for the DESE showed the highest amount of flavonoids (110.95 ± 5.55-73.25 ± 3.66 mg/g dp), while anthocyanins were better extracted with choline chloride:butane-1,4-diol (16.0 ± 0.80 mg/g dp). Consequently, GETs can be employed to extract the bioactive compounds from saffron floral by-products, implementing recycling and reduction of waste and fitting into the broader circular economy discussion.

Unveiling the Chemistry of Citrus Peel: Insights into Nutraceutical Potential and Therapeutic Applications

The recent millennium has witnessed a notable shift in consumer focus towards natural products for addressing lifestyle-related disorders, driven by their safety and cost-effectiveness. Nutraceuticals and functional foods play an imperative role by meeting nutritional needs and offering medicinal benefits. With increased scientific knowledge and awareness, the significance of a healthy lifestyle, including diet, in reducing disease risk is widely acknowledged, facilitating access to a diverse and safer diet for longevity. Plant-based foods rich in phytochemicals are increasingly popular and effectively utilized in disease management. Agricultural waste from plant-based foods is being recognized as a valuable source of nutraceuticals for dietary interventions. Citrus peels, known for their diverse flavonoids, are emerging as a promising health-promoting ingredient. Globally, citrus production yields approximately 15 million tons of by-products annually, highlighting the substantial potential for utilizing citrus waste in phyto-therapeutic and nutraceutical applications. Citrus peels are a rich source of flavonoids, with concentrations ranging from 2.5 to 5.5 g/100 g dry weight, depending on the citrus variety. The most abundant flavonoids in citrus peel include hesperidin and naringin, as well as essential oils rich in monoterpenes like limonene. The peel extracts exhibit high antioxidant capacity, with DPPH radical scavenging activities ranging from 70 to 90%, comparable to synthetic antioxidants like BHA and BHT. Additionally, the flavonoids present in citrus peel have been found to have antioxidant properties, which can help reduce oxidative stress by 30% and cardiovascular disease by 25%. Potent anti-inflammatory effects have also been demonstrated, reducing inflammatory markers such as IL-6 and TNF-α by up to 40% in cell culture studies. These findings highlight the potential of citrus peel as a valuable source of nutraceuticals in diet-based therapies.

Potential Role and Mechanism of Mulberry Extract in Immune Modulation: Focus on Chemical Compositions, Mechanistic Insights, and Extraction Techniques

Mulberry is a rapidly growing plant that thrives in diverse climatic, topographical, and soil types, spanning temperature and temperate countries. Mulberry plants are valued as functional foods for their abundant chemical composition, serving as a significant reservoir of bioactive compounds like proteins, polysaccharides, phenolics, and flavonoids. Moreover, these compounds displayed potent antioxidant activity by scavenging free radicals, inhibiting reactive oxygen species generation, and restoring elevated nitric oxide production induced by LPS stimulation through the downregulation of inducible NO synthase expression. Active components like oxyresveratrol found in Morus demonstrated anti-inflammatory effects by inhibiting leukocyte migration through the MEK/ERK signaling pathway. Gallic and chlorogenic acids in mulberry leaves (ML) powder-modulated TNF, IL-6, and IRS1 proteins, improving various inflammatory conditions by immune system modulation. As we delve deeper into understanding its anti-inflammatory potential and how it works therapeutically, it is crucial to refine the extraction process to enhance the effectiveness of its bioactive elements. Recent advancements in extraction techniques, such as solid-liquid extraction, pressurized liquid extraction, superficial fluid extraction, microwave-assisted extraction, and ultrasonic-assisted extraction, are being explored. Among the extraction methods tested, including Soxhlet extraction, maceration, and ultrasound-assisted extraction (UAE), UAE demonstrated superior efficiency in extracting bioactive compounds from mulberry leaves. Overall, this comprehensive review sheds light on the potential of mulberry as a natural immunomodulatory agent and provides insights into its mechanisms of action for future research and therapeutic applications.

Research Progress on Taxus Extraction and Formulation Preparation Technologies

Taxus, as a globally prevalent evergreen tree, contains a wealth of bioactive components that play a crucial role in the pharmaceutical field. Taxus extracts, defined as a collection of one or more bioactive compounds extracted from the genus Taxus spp., have become a significant focus of modern cancer treatment research. This review article aims to delve into the scientific background of Taxus extracts and their considerable value in pharmaceutical research. It meticulously sifts through and compares various advanced extraction techniques such as supercritical extraction, ultrasound extraction, microwave-assisted extraction, solid-phase extraction, high-pressure pulsed electric field extraction, and enzymatic extraction, assessing each technology's advantages and limitations across dimensions such as extraction efficiency, extraction purity, economic cost, operational time, and environmental impact, with comprehensive analysis results presented in table form. In the area of drug formulation design, this paper systematically discusses the development strategies for solid, liquid, and semi-solid dosage forms based on the unique physicochemical properties of Taxus extracts, their intended medical uses, and specific release characteristics, delving deeply into the selection of excipients and the critical technical issues in the drug preparation process. Moreover, the article looks forward to the potential directions of Taxus extracts in future research and medical applications, emphasizing the urgency and importance of continuously optimizing extraction methods and formulation design to enhance treatment efficacy, reduce production costs, and decrease environmental burdens. It provides a comprehensive set of preparation techniques and formulation optimization schemes for researchers in cancer treatment and other medical fields, promoting the application and development of Taxus extracts in pharmaceutical sciences.

Exploring the green frontier: Subcritical water chromatography for sustainable analytical practices

Water in the subcritical state is characterized by properties significantly different from water under standard conditions. These include low viscosity, low surface tension, and a much lower dielectric constant, increasing the solubility of nonpolar substances. For this reason, it can provide an alternative solvent and be used in chromatographic techniques-subcritical water chromatography (SBWC). SBWC appears to be one of the greenest analytical techniques until we unravel chromatography with pure water at room temperature. The versatility of SBWC is explored through its applications in the separation and analysis of a wide range of compounds, including pharmaceuticals, natural products, etc. The use of subcritical water as a mobile phase requires suitable stable stationary phases and special apparatus. Still, it makes it possible to conduct analyses without using organic solvents. When using this technique, it is important to remember that it suits the analysis of thermally stable substances. The following work is a critical review of developments in SBWC.

Sustainable Green Extraction of Carotenoid Pigments: Innovative Technologies and Bio-Based Solvents

Carotenoids are ubiquitous and versatile isoprenoid compounds. The intake of foods rich in these pigments is often associated with health benefits, attributable to the provitamin A activity of some of them and different mechanisms. The importance of carotenoids and their derivatives for the production of foods and health-promotion through the diet is beyond doubt. In the new circular economy paradigm, the recovery of carotenoids in the biorefinery process is highly desirable, for which greener processes and solvents are being advocated for, considering the many studies being conducted at the laboratory scale. This review summarizes information on different extraction technologies (ultrasound, microwaves, pulsed electric fields, pressurized liquid extraction, sub- and supercritical fluid extraction, and enzyme-assisted extraction) and green solvents (ethyl lactate, 2-methyltetrahydrofuran, natural deep eutectic solvents, and ionic liquids), which are potential substitutes for more toxic and less environmentally friendly solvents. Additionally, it discusses the results of the latest studies on the sustainable green extraction of carotenoids. The conclusions drawn from the review indicate that while laboratory results are often promising, the scalability to real industrial scenarios poses a significant challenge. Furthermore, incorporating life cycle assessment analyses is crucial for a comprehensive evaluation of the sustainability of innovative extraction processes compared to industry-standard methods.

Ultrasonic-assisted extraction of flavonoids from peanut leave and stem using deep eutectic solvents and its molecular mechanism

Natural bioactive compounds extracted from agricultural by-products have received considerable attentions. Twenty-two kinds of deep eutectic solvents (DESs) with ultrasonic were screened to extract flavonoids from peanut leave and stem. ChCl-acetic acid (ChCl-Aa) with 1:2 M ratio resulted in more effective extraction of flavonoids compared to other solvents The best extraction conditions were found to be at a 27% water content in DES/H2O, for 43 min with 31:1 g/mL liquid/solid ratio, giving 2.980 mg/g dw of flavonoids through the response surface method. SEM showed that ChCl-Aa had a certain dissociation impact on the sample matrix, while 1H NMR analysis revealed the formation of hydrogen bonds between daidzein and ChCl-Aa. Changes in the H-bond length and number were observed by the B3LYP/6-31G (d,p) level of theory to confirm the experimental spectra. This study reveals that DESs are efficient for obtaining value-added products and could applied to other natural products.

Exploring a Sustainable Process for Polyphenol Extraction from Olive Leaves

Olive leaves are residues from pruning and harvesting and are considered an environmental management problems. Interestingly, these residues contain high polyphenol concentrations, which can be used to treat chronic diseases. However, these compounds are a technological challenge due to their thermolability and reactivity during extraction. Thus, this study assessed the use of pressurized liquid extraction (PLE) with green solvents like water-ethanol and water-glycerol mixtures (0-15%) at 50 °C and 70 °C to yield polyphenol-rich antioxidant extracts with reduced glucose and fructose content. The use of 30% ethanol at 70°C presented the highest polyphenol content (15.29 mg gallic acid equivalent/g dry weight) and antioxidant capacity, which was expressed as IC50 (half maximal inhibitory concentration): 5.49 mg/mL and oxygen radical absorbance capacity (ORAC): 1259 μmol Trolox equivalent/g dry weight, as well as lower sugar content (glucose: 3.75 mg/g dry weight, fructose: 5.68 mg/g dry weight) compared to water-glycerol mixtures. Interestingly, ethanol exhibits a higher degree of effectiveness in recovering flavanols, stilbenes and secoiridoids, while glycerol improves the extraction of phenolic acids and flavonols. Therefore, to enhance the efficiency of polyphenol recovery during the PLE process, it is necessary to consider its solvent composition and chemical structure.

A Review: Subcritical Water Extraction of Organic Pollutants from Environmental Matrices

Most organic pollutants are serious environmental concerns globally due to their resistance to biological, chemical, and photolytic degradation. The vast array of uses of organic compounds in daily life causes a massive annual release of these substances into the air, water, and soil. Typical examples of these substances include pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Since they are persistent and hazardous in the environment, as well as bio-accumulative, sensitive and efficient extraction and detection techniques are required to estimate the level of pollution and assess the ecological consequences. A wide variety of extraction methods, including pressurized liquid extraction, microwave-assisted extraction, supercritical fluid extraction, and subcritical water extraction, have been recently used for the extraction of organic pollutants from the environment. However, subcritical water has proven to be the most effective approach for the extraction of a wide range of organic pollutants from the environment. In this review article, we provide a brief overview of the subcritical water extraction technique and its application to the extraction of PAHs, PCBs, pesticides, pharmaceuticals, and others form environmental matrices. Furthermore, we briefly discuss the influence of key extraction parameters, such as extraction time, pressure, and temperature, on extraction efficiency and recovery.

Recent Progress on Green New Phase Extraction and Preparation of Polyphenols in Edible Oil

With the proposal of replacing toxic solvents with non-toxic solvents in the concept of green chemistry, the development and utilization of new green extraction techniques have become a research hotspot. Phenolic compounds in edible oils have good antioxidant activity, but due to their low content and complex matrix, it is difficult to achieve a high extraction rate in a green and efficient way. This paper reviews the current research status of novel extraction materials in solid-phase extraction, including carbon nanotubes, graphene and metal-organic frameworks, as well as the application of green chemical materials in liquid-phase extraction, including deep eutectic solvents, ionic liquids, supercritical fluids and supramolecular solvents. The aim is to provide a more specific reference for realizing the green and efficient extraction of polyphenolic compounds from edible oils, as well as another possibility for the future research trend of green extraction technology.

Recent Advances in the Extraction of Pectin from Various Sources and Industrial Applications

Pectin is a structural polysaccharide present in plants that primarily consists of galacturonic acid units. This Review discusses the chemistry of pectin, including its composition and molecular weight. Pectin is conventionally extracted from agricultural waste (fruit and vegetable peels) using an acidic or basic aqueous medium at high temperatures. These processes are time- and energy-consuming and also result in severe environmental problems due to the production of acidic effluents and equipment corrosion. As pectin usage is increasing in food industries for developing different products and it is also used as an excipient in pharmaceutical products, better extraction procedures are required to maximize the yield and purity. The Review encompasses various alternate green approaches for the extraction of pectin, including traditional acid extraction and various emerging technologies such as deep eutectic solvent-based extraction, enzyme-assisted extraction, subcritical fluid extraction, ultrasound-assisted extraction, and microwave-based extraction, and evaluates the yield and physicochemical characteristics of the extracted pectin. This work aims to provide a platform for attracting more thorough research focused on the engineering of novel and more efficient green methods for the extraction of pectin and its utilization for various biotechnological purposes.

Steps to achieve carvone-rich spearmint (Mentha spicata L.) essential oil: a case study on the use of different distillation methods

Introduction

Spearmint essential oil is a valuable medical and food product. Spearmint essential oil is effective for the treatment of flatulence, indigestion, nausea, and colic along with Alzheimer, obesity, and fungal infections.

Methods

This study evaluated the quality and quantity of spearmint essential oil by examining some extraction strategies. The procedures were hydro-distillation, hydro-steam distillation, microwave-assisted hydro-distillation, and open hydro-distillation. The hydro-distillation had five pH levels (2, 4, 6, 8, and 10) and four NaCl concentrations (0.5, 1, 1.5, and 2%). microwave-assisted hydro-distillation at a power of 225 W was applied for 60, 90, and 120 minutes for process durations. The solvent extraction of herbal distillate obtained by an open hydro-distillation system was done using n-pentane and n-hexane to achieve a recovered essential oil by a rotary evaporator.

Results and discussion

The results showed that the lowest pH in the hydro-distillation process led to obtaining double yield compared to the control. Additionally, at 1 and 1.5% NaCl concentrations, the oil yield increased by 12.86 and 20.87%, respectively. Although the yield was reduced by microwave-assisted hydro-distillation, however within 120 minutes, carvone increased by 12.7% and limonene decreased by 42.3%. The best quality of spearmint oil belonged to solvent extraction followed by rotary evaporator.

Total Flavonoids in Artemisia absinthium L. and Evaluation of Its Anticancer Activity

To overcome the shortcomings of traditional extraction methods, such as long extraction time and low efficiency, and considering the low content and high complexity of total flavonoids in Artemisia absinthium L., in this experiment, we adopted ultrasound-assisted enzymatic hydrolysis to improve the yield of total flavonoids, and combined this with molecular docking and network pharmacology to predict its core constituent targets, so as to evaluate its antitumor activity. The content of total flavonoids in Artemisia absinthium L. reached 3.80 ± 0.13%, and the main components included Astragalin, Cynaroside, Ononin, Rutin, Kaempferol-3-O-rutinoside, Diosmetin, Isorhamnetin, and Luteolin. Cynaroside and Astragalin exert their cervical cancer inhibitory functions by regulating several signaling proteins (e.g., EGFR, STAT3, CCND1, IGFIR, ESR1). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the anticancer activity of both compounds was associated with the ErbB signaling pathway and FoxO signaling pathway. MTT results showed that total flavonoids of Artemisia absinthium L. and its active components (Cynaroside and Astragalin) significantly inhibited the growth of HeLa cells in a concentration-dependent manner with IC50 of 396.0 ± 54.2 μg/mL and 449.0 ± 54.8 μg/mL, respectively. Furthermore, its active components can mediate apoptosis by inducing the accumulation of ROS.

Subcritical Water Extraction to Valorize Grape Biomass-A Step Closer to Circular Economy

With the increase in the world population, the overexploitation of the planet's natural resources is becoming a worldwide concern. Changes in the way humankind thinks about production and consumption must be undertaken to protect our planet and our way of living. For this change to occur, sustainable development together with a circular economic approach and responsible consumption are key points. Agriculture activities are responsible for more than 10% of the greenhouse gas emissions; moreover, by 2050, it is expected that food production will increase by 60%. The valorization of food waste is therefore of high importance to decrease the environmental footprint of agricultural activities. Fruits and vegetables are wildly consumed worldwide, and grapes are one of the main producers of greenhouse gases. Grape biomass is rich in bioactive compounds that can be used for the food, pharmaceutical and cosmetic industries, and their extraction from this food residue has been the target of several studies. Among the extraction techniques used for the recovery of bioactive compounds from food waste, subcritical water extraction (SWE) has been the least explored. SWE has several advantages over other extraction techniques such as microwave and ultrasound extraction, allowing high yields with the use of only water as the solvent. Therefore, it can be considered a green extraction method following two of the principles of green chemistry: the use of less hazardous synthesis (principle number 3) and the use of safer solvents and auxiliaries (principle number 5). In addition, two of the green extraction principles for natural products are also followed: the use of alternative solvents or water (principle number 2) and the use of a reduced, robust, controlled and safe unit operation (principle number 5). This review is an overview of the extraction process using the SWE of grape biomass in a perspective of the circular economy through valorization of the bioactive compounds extracted. Future perspectives applied to the SWE are also discussed, as well as its ability to be a green extraction technique.

Pressurized Hot Water Extraction of Mangosteen Pericarp and Its Associated Molecular Signatures in Endothelial Cells

The mangosteen (Garcinia mangostana L.) pericarp is known to be rich in potent bioactive phytochemical compounds such as xanthones, which possess pharmacologically important antioxidant activity and beneficial cardiometabolic properties. Mangosteen pericarp is typically classified as unavoidable food waste and discarded, despite being rich in bioactive phytochemical compounds that therefore present an exciting opportunity for valorization. Thus, this study aims to extract phytochemical compounds from mangosteen pericarp using pressurized hot water extraction (PHWE) and determine its biological effects in endothelial cells using RNA sequencing. Liquid chromatography with MS/MS (LC/MSMS) and UV detection (LC/UV) was subsequently used to identify three key phytochemical compounds extracted from the mangosteen pericarp: α-Mangostin, γ-Mangostin, and Gartanin. Within the tested range of extraction temperatures by PHWE, our results demonstrated that an extraction temperature of 120 °C yielded the highest concentrations of α-Mangostin, γ-Mangostin, and Gartanin with a concomitant improvement in antioxidant capacity compared to other extraction temperatures. Using global transcriptomic profiling and bioinformatic analysis, the treatment of endothelial cells with mangosteen pericarp extracts (120 °C PHWE) for 48 h caused 408 genes to be differentially expressed. Furthermore, our results demonstrated that key biological processes related to "steroid biosynthesis and metabolism", likely involving the activation of the AMPK signaling pathway, were upregulated by mangosteen pericarp extract treatment. In conclusion, our study suggests a green extraction method to valorize phytochemical compounds from mangosteen pericarp as a natural product with potential beneficial effects on cardiometabolic health.

Total Triterpenes, Polyphenols, Flavonoids, and Antioxidant Activity of Bioactive Phytochemicals of Centella asiatica by Different Extraction Techniques

Obtaining phytochemical-rich plant extracts from natural products where the active ingredients are present in comparatively low levels in the tissue matrix is the critical initial step of any chemical analysis or bioactivity testing. The plant C. asiatica is rich in various phytochemicals, the major constituents being triterpenes and flavonoids, as well as other polyphenols, leading to a number of bioactivities. In this study, an attempt was made to achieve several green technology principles, while optimizing the extraction method for the efficient extraction of bioactive compounds from C. asiatica. Soxhlet extraction (SE), ultrasound-assisted extraction (UAE) with low-frequency sonication, microwave-assisted extraction (MAE) using a closed-vessel microwave digestion system, and subcritical water extraction (SWE) in a high-pressure reactor were employed to extract the bioactive compounds. The solvent system, extraction time, and solid-to-solvent ratio were varied to optimize the extraction. UAE gave the best extraction yield, while MAE gave similar results, with a solid-to-liquid ratio of 1:25, a binary solvent system of 9:1 methanol to water (v/v), and a 20 min extraction time for the extraction of triterpenes, including madecassoside, asiaticoside, madicassic acid, and asiatic acid. Investigation of different solvent systems based on water and methanol also revealed information on the extraction behavior of total triterpene content (TTC), total polyphenolic content (TPC), total flavonoid content (TFC), and the variations in the antioxidant capacity of the extracts. In this study, it was evident that UAE and MAE offer more efficient and effective extraction of bioactive compounds in terms of extraction yield, time, and minimal solvent and energy use. Furthermore, the results showed that the different solvent ratios in the extraction mixture will affect the extraction of bioactive compounds, and a binary solvent system with a combination of methanol and water was the most efficient for the studied compounds in Centella asiatica.

Ursolic acid: biological functions and application in animal husbandry

Ursolic acid (UA) is a plant-derived pentacyclic triterpenoid with 30 carbon atoms. UA has anti-inflammatory, antioxidative, antimicrobial, hepato-protective, anticancer, and other biological activities. Most studies on the biological functions of UA have been performed in mammalian cell (in vitro) and rodent (in vivo) models. UA is used in animal husbandry as an anti-inflammatory and antiviral agent, as well as for enhancing the integrity of the intestinal barrier. Although UA has been shown to have significant in vitro bacteriostatic effects, it is rarely used in animal nutrition. The use of UA as a substitute for oral antibiotics or as a novel feed additive in animal husbandry should be considered. This review summarizes the available data on the biological functions of UA and its applications in animal husbandry.

Subcritical Water Extraction for Valorisation of Almond Skin from Almond Industrial Processing

Almond skin (AS) is an agro-industrial residue from almond processing that has a high potential for valorisation. In this study, subcritical water extraction (SWE) was applied at two temperatures (160 and 180 °C) to obtain phenolic-rich extracts (water-soluble fraction) and cellulose fibres (insoluble fraction) from AS. The extraction conditions affected the composition and properties of both valorised fractions. The dry extracts obtained at 180 °C were richer in phenolics (161 vs. 101 mg GAE. g-1 defatted almond skin (DAS)), with greater antioxidant potential (1.063 vs. 1.490 mg DAS.mg-1 DPPH) and showed greater antibacterial effect (lower MIC values) against L. innocua (34 vs. 90 mg·mL-1) and E. coli (48 vs. 90 mg·mL-1) than those obtained at 160 °C, despite the lower total solid yield (21 vs. 29%) obtained in the SWE process. The purification of cellulose from the SWE residues, using hydrogen peroxide (H2O2), revealed that AS is not a good source of cellulose material since the bleached fractions showed low yields (20-21%) and low cellulose purity (40-50%), even after four bleaching cycles (1 h) at pH 12 and 8% H2O2. Nevertheless, the application of a green, scalable, and toxic solvent-free SWE process was highly useful for obtaining AS bioactive extracts for different food, cosmetic, or pharmaceutical applications.

Mild Heat Treatment and Biopreservatives for Artisanal Raw Milk Cheeses: Reducing Microbial Spoilage and Extending Shelf-Life through Thermisation, Plant Extracts and Lactic Acid Bacteria

The microbial quality of raw milk artisanal cheeses is not always guaranteed due to the possible presence of pathogens in raw milk that can survive during manufacture and maturation. In this work, an overview of the existing information concerning lactic acid bacteria and plant extracts as antimicrobial agents is provided, as well as thermisation as a strategy to avoid pasteurisation and its negative impact on the sensory characteristics of artisanal cheeses. The mechanisms of antimicrobial action, advantages, limitations and, when applicable, relevant commercial applications are discussed. Plant extracts and lactic acid bacteria appear to be effective approaches to reduce microbial contamination in artisanal raw milk cheeses as a result of their constituents (for example, phenolic compounds in plant extracts), production of antimicrobial substances (such as organic acids and bacteriocins, in the case of lactic acid bacteria), or other mechanisms and their combinations. Thermisation was also confirmed as an effective heat inactivation strategy, causing the impairment of cellular structures and functions. This review also provides insight into the potential constraints of each of the approaches, hence pointing towards the direction of future research.

Functional and Nutritional Characteristics of Natural or Modified Wheat Bran Non-Starch Polysaccharides: A Literature Review

Wheat bran (WB) consists mainly of different histological cell layers (pericarp, testa, hyaline layer and aleurone). WB contains large quantities of non-starch polysaccharides (NSP), including arabinoxylans (AX) and β-glucans. These dietary fibres have long been studied for their health effects on management and prevention of cardiovascular diseases, cholesterol, obesity, type-2 diabetes, and cancer. NSP benefits depend on their dose and molecular characteristics, including concentration, viscosity, molecular weight, and linked-polyphenols bioavailability. Given the positive health effects of WB, its incorporation in different food products is steadily increasing. However, the rheological, organoleptic and other problems associated with WB integration are numerous. Biological, physical, chemical and combined methods have been developed to optimise and modify NSP molecular characteristics. Most of these techniques aimed to potentially improve food processing, nutritional and health benefits. In this review, the physicochemical, molecular and functional properties of modified and unmodified WB are highlighted and explored. Up-to-date research findings from the clinical trials on mechanisms that WB have and their effects on health markers are critically reviewed. The review points out the lack of research using WB or purified WB fibre components in randomized, controlled clinical trials.

Subcritical Water Extraction of Phenolic Compounds from Vaccinium Dunalianum Wight Leaves and Their Antioxidant and Tyrosinase Inhibitory Activities in Vitro

Subcritical water extraction was used to extract bioactive phenolic compounds from Vaccinium dunalianum Wight leaves. The optimal extraction conditions were determined as an extraction temperature of 150 °C, an extraction time of 40 min, and a liquid-solid ratio of 35 : 1 mL/g. The total phenolic content reached 21.35 mg gallic acid /g, which was 16 % higher than that by hot water extraction. The subcritical water extraction extract exhibited strong scavenging activity of DPPH free radical and ABTS⁺ free radical, as well as significant tyrosinase inhibitory activity. The study suggests that subcritical water extraction can alter the composition of the extracts, leading to the production of various phenolic compounds, effective antioxidants, and tyrosinase inhibitors from Vaccinium dulciana Wight leaves. These findings confirm the potential of Vaccinium dunalianum Wight as a natural antioxidant molecule source for the medicine and food industries, and for the therapy of skin pigmentation disorders.

Subcritical low temperature extraction of bioactive ingredients from foods and food by-products and its applications in the agro-food industry

Bioactive ingredients are part of the food chain and are responsible for numerous health benefits. Subcritical low temperature extraction has been employed to acquire bioactive ingredients because of its excellent properties, such as energy conservation, low temperature, elimination of residual solvent, and high extraction yield and quality. This review aims to provide a clear picture of the basics of subcritical-temperature extraction, its bioactive ingredient extraction efficiency, and possible applications in the agro-food industry. This review suggested that the extraction temperature, time, co-solvents, solid-fluid ratio, and pressure impacted the extraction efficiency of bioactive ingredients from foods and food by-products. Subcritical solvents are appropriate for extracting low polar ingredients, while the inclusion of co-solvents could extract medium and high polar substances. Bioactive ingredients from foods and food by-products can be used as antioxidants, colorants, and nutritional supplements. Additionally, this technology could remove pesticide residues in tea, concentrate edible proteins, and reduce cigarette tar. A new trend toward using subcritical low temperature extraction in extracting bioactive ingredients will acquire momentum.

Subcritical Water Extraction of Rosmarinic Acid from Lemon Balm (Melissa officinalis L.) and Its Effect on Plant Cell Wall Constituents

Rosmarinic acid (RA), an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid, is a potent radical scavenger, a chelator of prooxidant ions, and an inhibitor of lipid peroxidation. RA-containing extracts are widely used natural antioxidants in food products, and many herbal preparations and food supplements, containing RA, are marketed with claims of beneficial health effects. The current study investigated the effectiveness of subcritical water extraction (SWE) for the recovery of RA from lemon balm (Melissa officinalis), as a "green" alternative to conventional hydro-alcoholic extraction. Different durations (10 min and 20 min) and extraction temperatures (100 °C and 150 °C) were applied. Subcritical water applied at a temperature of 100 °C was equally efficient as 50% ethanol in extracting RA. However, the further elevation of temperature to 150 °C decreased RA content by up to 20% due to thermal degradation. The content of RA in dried extracts was between 2.36% and 5.55% and the higher temperature of SWE increased extract yield by up to 41%. The higher extraction yield resulted from the degradation of plant material by subcritical water as evidenced by the increased extraction and degradation of proteins, pectin, and cellulose. These results reveal that SWE is an efficient technology for the extraction of RA and other antioxidants from lemon balm at reduced extraction time and without the use of toxic organic solvents. Furthermore, by modification of SWE conditions, dry extracts with different purity and content of RA are obtained. These extracts could be used in the food industry as food antioxidants, or in the development of food supplements and functional foods.

Extraction of Humic Acids from Lignite and Its Use as a Biochar Activator

Current research focuses on extracting humic acid (HA) compounds from low-rank coals to obtain high value-added products. In this study, HAs with high purity and low heavy metal content were obtained from lignite by combining acid pretreatment with hydrothermal treatment. Scanning electron microscopy, elemental analysis (EA), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, and inductively coupled plasma optical emission spectrometry (ICP-OES) were used to analyze raw lignite and HAs. The effects of acid and hydrothermal treatments on the inorganic elements, functional groups, and yield of HAs were examined. The results showed that acid treatment reduced the ash content of lignite from 20 to 9%, and hydrothermal treatment increased the yield of HAs from 36 to 68%. The chemical properties of HAs exhibited an increase in molecular weight and improved aromaticity after acid and hydrothermal treatments. The results of ICP-OES analysis suggested that the combined method of acid and hydrothermal treatments resulted in a significant reduction of heavy metal elements in HAs. FTIR analysis confirmed the results and demonstrated that the extracted HA from nitric acid pretreated and hydrothermal generation of lignite PHA was rich in carboxyl and phenolic functional groups. PHA was applied to biochar as an activator for the adsorption of heavy metal ions. The experimental results showed that PHA was successfully loaded onto biochar and introduced a large number of functional groups, and the adsorption capacity of the modified biochar for Pb²⁺ was effectively improved.