Water as a green solvent for sustainable sample preparation: single drop microextraction of N-nitrosamines from losartan tablets.

Water, renowned for its sustainability and minimal toxicity, is an ideal candidate for environmentally friendly solvent-based microextraction. However, its potential as an extractant solvent in miniaturized sample preparation remains largely unexplored. This paper pioneers using water as the extraction solvent in headspace single-drop microextraction (HS-SDME) for N-nitrosamines from losartan tablets. Autonomous HS-SDME is executed by an Arduino-controlled, lab-made Cartesian robot, using water for the online preconcentration of enriched extracts through direct injection into a column-switching system. Critical experimental parameters influencing HS-SDME performance are systematically explored through univariate and multivariate experiments. While most previously reported methods for determining N-nitrosamines in pharmaceutical formulations rely on highly selective mass spectrometry detection techniques to handle the strong matrix effects typical of pharmaceutical samples, the water-based HS-SDME method efficiently eliminates the interfering effects of a large amount of the pharmaceutical active ingredient and tablet excipients, allowing straightforward analysis using high-performance liquid chromatography with ultraviolet detection (HPLC-UV-Vis). Under optimized conditions, the developed method exhibits linear responses from 100 to 2400 ng g-1, demonstrating appropriate detectability, precision, and accuracy for the proposed application. Additionally, the environmental sustainability of the method is assessed using the AGREEprep methodology, positioning it as an outstanding green alternative for determining hazardous contaminants in pharmaceutical products.

Insights into using green and unconventional technologies to recover natural astaxanthin from microbial biomass.

Microorganisms such as bacteria, microalgae and fungi, are natural and rich sources of several valuable bioactive antioxidant's compounds, including carotenoids. Among the carotenoids with antioxidant properties, astaxanthin can be highlighted due to its pharmaceutical, feed, food, cosmetic and biotechnological applications. The best-known producers of astaxanthin are yeast and microalgae cells that biosynthesize this pigment intracellularly, requiring efficient and sustainable downstream procedures for its recovery. Conventional multi-step procedures usually involve the consumption of large amounts of volatile organic compounds (VOCs), which are regarded as toxic and hazardous chemicals. Considering these environmental issues, this review is focused on revealing the potential of unconventional extraction procedures [viz., Supercritical Fluid Extraction (SFE), Ultrasound-Assisted Extraction (UAE), Microwave-Assisted Extraction (MAE), High-Pressure Homogenization (HPH)] combined with alternative green solvents (biosolvents, eutectic solvents and ionic liquids) for the recovery of microbial-based astaxanthin from microalgae (such as Haematococcus pluvialis) and yeast (such as Phaffia rhodozyma) cells. The principal advances in the area, process bottlenecks, solvent selection and strategies to improve the recovery of microbial astaxanthin are emphasized. The promising recovery yields using these environmentally friendly procedures in lab-scale are good indications and directions for their effective use in biotechnological processes for the production of commercial feed and food ingredients like astaxanthin.

Scavenging Capacity of Extracts of Arrabidaea chica Leaves from the Amazonia against ROS and RNS of Physiological and Food Relevance.

Arrabidaea chica, a medicinal plant found in the Amazon rainforest, is a promising source of bioactive compounds which can be used to inhibit oxidative damage in both food and biological systems. In this study, the in vitro scavenging capacity of characterized extracts of A. chica leaves, obtained with green solvents of different polarities [water, ethanol, and ethanol/water (1:1, v/v)] through ultrasound-assisted extraction, was investigated against reactive oxygen (ROS) and nitrogen (RNS) species, namely superoxide anion radicals (O2•-), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), and peroxynitrite anion (ONOO-). The extract obtained with ethanol-water presented about three times more phenolic compound contents (11.8 mg/g) than ethanol and water extracts (3.8 and 3.6 mg/g, respectively), with scutellarein being the major compound (6.76 mg/g). All extracts showed high scavenging efficiency against the tested ROS and RNS, in a concentration-dependent manner with low IC50 values, and the ethanol-water extract was the most effective one. In addition, all the extracts were five times more efficient against ROO• than Trolox. Therefore, the extracts from A. chica leaves exhibited high promising antioxidant potential to be used against oxidative damage in food and physiological systems.

One-step sustainable extraction of Silymarin compounds of wild Algerian milk thistle (Silybum marianum) seeds using Gas Expanded Liquids.

This work reports the application of Gas Expanded Liquid (GXL) extraction to concentrate the flavonolignan fraction (silymarin) and taxifolin from Silybum marianum seeds, which have proven to be highly valuable health-promoting compounds. GXL using green solvents was used to isolate silymarin with the objective of replacing conventional methods. In one hand, the effect of different compositions of solvents, aqueous ethanol (20%, 50% or 80% (v/v)) at different CO2/liquid (25, 50 and 75%) ratios, on the GXL extraction was investigated. The obtained extracts have been chemically and functionally characterized by means of UHPLC-ESI-MS/MS (triple quadrupole) and in-vitro assays such as anti-inflammatory, anti-cholinergic and antioxidant. Results revealed that the operating conditions influenced the extraction yield, the total phenolic content and the presence of the target compounds. The best obtained yield was 55.97% using a ternary mixture of solvents composed of CO2:EtOH:H2O (25:60:15) at 40 °C and 9 MPa in 160 min. Furthermore, the results showed that obtained extracts had significant antioxidant and anti-inflammatory activities (with best IC50 value of 8.80 µg/mL and 28.52 µg/mL, respectively) but a moderate anti-cholinesterase activity (with best IC50 value of 125.09 µg/mL). Otherwise, the concentration of silymarin compounds in extract can go up to 59.6% using the present one-step extraction method without further purification, being silybinA+B the predominant identified compound, achieving value of 545.73 (mg silymarin/g of extract). The obtained results demonstrate the exceptional potential of GXL to extract high-added values molecules under sustainable conditions from different matrices.

Extraction of Lipophilic Antioxidants from Native Tomato Using Green Technologies.

Research background: Tomato (Solanum lycopersicum L.) fruit is highly consumed worldwide and contains high amounts of carotenoids and tocopherols, two powerful antioxidants. Native tomato genotypes are rarely used in large-scale market but serve as a reservoir to diversify the species gene pool and can be employed to obtain functional compounds. Extraction methods are currently changing towards cleaner procedures that are more efficient and environmentally friendly, including avoiding toxic or polluting solvents. Experimental approach: In this study, factorial and fractional factorial designs were used to evaluate the efficiency of digestive enzymes, sonication and green solvents to obtain lipophilic antioxidant extracts from native tomato. To monitor the efficiency of the extraction process, spectrophotometric quantification of total carotenoids and antioxidant activity was carried out, and then individual quantification of carotenoids and tocopherols in the extracts was done by HPLC. Results and conclusions: Digestive enzymes and sonication increased the carotenoid content and the antioxidant activity of the obtained extracts when applied individually. However, when these treatments were applied together and in combination with isopropyl acetate, a green solvent, the obtained extracts had the highest carotenoid and tocopherol contents as well as the maximal antioxidant activity. A correlation analysis suggested that antioxidant activity resulted from synergistic effects rather than individual compounds. Tomato extracts were obtained through a rapid and environmentally friendly extraction method and their antioxidant activity was enhanced. Novelty and scientific contribution: Tomato fruits have been the subject of numerous studies; however, functional compound extraction through environmentally friendly methods remains an attractive use of native tomato fruit, enhancing its limited production and harnessing a large amount of tomato product industry. There are few reports where environmentally friendly extraction methods are combined; even rarer are those where green solvents are also used. In this work, the combination of different environmentally friendly extraction methods improved the extraction of carotenoids and tocopherols and allowed to establish a more efficient process. These results could stimulate the use of clean technologies and make the native tomato more attractive for industrial or compound extraction processes.

Defatted rice bran pretreated with deep eutectic solvents and sequential use as feedstock for subcritical water hydrolysis.

Deffated rice bran has potential to processing into ethanol due to its lignocellulosic composition and agricultural productivity. The composition of the pretreated deffated rice bran with Deep Eutectic Solvent was investigated aiming the production of sugars and bioproducts using subcritical water hydrolysis. Changes in the deffated rice bran composition at different pretreatment times and mixtures of deep eutectic solvent were evaluated by the derivative of thermogravimetric analysis. The pretreated deffated rice bran presented an enrichment in the content of hemicelluloses (281.0%) and delignification (59.3 %). Under the same condition of subcritical water hydrolysis (230 °C/R-100) the yield of fermentable sugars increased 2.20 times in the same study time interval (20 min) when comparing pretreated and untreated deffated rice bran.

Microwave hydrodiffusion and gravity model with a unique hydration strategy for exhaustive extraction of anthocyanins from strawberries and raspberries.

This study aimed to verify if microwave hydrodiffusion and gravity (MHG) could efficiently extract anthocyanins from strawberries and raspberries with low environmental impact and costs. Our findings revealed that it was possible to extract 69 and 64% anthocyanins from the strawberries and raspberries in a single extraction step, respectively. When the co-product (product remaining after extracting in natura fruits) was hydrated with green solvents and subjected to re-extraction, it was possible to exhaustively extract the anthocyanins from both fruits. Using the Green Analytical Procedure Index (GAPI), the MHG proved to cause low environmental impact due to the solvents used, enabling the reuse of the co-product for food and pharmaceutical products application. Moreover, the MHG was economically viable, and the sample pretreated with distilled water was the most indicated re-extraction method. The MHG process proved to be exhaustive for strawberry and raspberry anthocyanins, thus demonstrating to be an excellent alternative for sustainable extraction.

Multivariate optimization results in an edible extract from Ilex paraguariensis unexplored residues with a high amount of phenolic compounds.

Ilex paraguariensis A. St. Hil. plants are used for the preparation of food and drinks which are widely consumed worldwide. During the harvest season of these plants, 2-5 ton hec-1 of agricultural residue is generated, which remains underutilized. Therefore, this study aimed to obtain an edible extract with high content of bioactive compounds and antimicrobial properties from the agricultural residue of I. paraguariensis for industrial use in food applications. The extraction conditions were optimized through a multivariate experimental design using ethanol:water. The extracted compounds were characterized by HPLC-ESY-QTOF-MS. In the optimal extraction conditions, 55 compounds were extracted, including 8 compounds that were not previously reported in I. paraguariensis. The method proved to be simple, fast, economical and environmentally friendly, with the use of green solvents. This optimization allowed for the extraction of 15.07 g of phenolic compounds per 100 g of residue. The extract showed high antioxidant activity and the capacity to inhibit Staphylococcus aureus. Results indicate that it is possible to obtain an edible extract with a high content of bioactive compounds, particularly phenolic compounds, from the I. paraguariensis residue, which has high prospects for the valorization of unexplored natural resources.

Chitosan as a Valuable Biomolecule from Seafood Industry Waste in the Design of Green Food Packaging.

Chitosan is a versatile biomolecule with a broad range of applications in food and pharmaceutical products. It can be obtained by the alkaline deacetylation of chitin. This biomolecule can be extracted using conventional or green methods from seafood industry residues, e.g., shrimp shells. Chitin has limited applications because of its low solubility in organic solvents. Chitosan is soluble in acidified solutions allowing its application in the food industry. Furthermore, biological properties, such as antioxidant, antimicrobial, as well as its biodegradability, biocompatibility and nontoxicity have contributed to its increasing application as active food packaging. Nevertheless, some physical and mechanical features have limited a broader range of applications of chitosan-based films. Green approaches may be used to address these limitations, leading to well-designed chitosan-based food packaging, by employing principles of a circular and sustainable economy. In this review, we summarize the properties of chitosan and present a novel green technology as an alternative to conventional chitin extraction and to design environmentally friendly food packaging based on chitosan.

Latest Insights on Novel Deep Eutectic Solvents (DES) for Sustainable Extraction of Phenolic Compounds from Natural Sources.

Phenolic compounds have long been of great importance in the pharmaceutical, food, and cosmetic industries. Unfortunately, conventional extraction procedures have a high cost and are time consuming, and the solvents used can represent a safety risk for operators, consumers, and the environment. Deep eutectic solvents (DESs) are green alternatives for extraction processes, given their low or non-toxicity, biodegradability, and reusability. This review discusses the latest research (in the last two years) employing DESs for phenolic extraction, solvent components, extraction yields, extraction method characteristics, and reviewing the phenolic sources (natural products, by-products, wastes, etc.). This work also analyzes and discusses the most relevant DES-based studies for phenolic extraction from natural sources, their extraction strategies using DESs, their molecular mechanisms, and potential applications.

Isolation of Polyphenols from Soursop Annona muricata L Leaves Using Green Chemistry Techniques and their Anticancer Effect

HIGHLIGHTS Isolate, fractionate and characterize extracts obtained from soursop leaves. Use of emerging green technologies such as microwave-ultrasound hybridization. The extracts contain kaempferol, procyanidins, catechin, and quercetin. The total ethanolic extract demonstrates cytotoxic effect on HeLa cells.

Abstract Cervical cancer is classified as the fourth most common malignancy in women. Natural compounds are a therapeutic alternative in cancer therapy. The aim of the study is to isolate, fractionate, and characterize extracts obtained from soursop leaves (Annona muricata L.) and determine their cytotoxic effect against HeLa cervical cancer cells and non-carcinogenic fibroblast 3T3 cells. The phytochemicals of soursop leaves were extracted through emerging green technologies such as the novel use of microwave-ultrasound hybridization and the use of environmentally friendly solvents (water and ethanol), in addition to the purification of extracts enriched in polyphenols by liquid chromatography with Amberlite XAD-16. Total aqueous and ethanolic extract were purified, as well as the fraction one of each extract. The extracts recovered from soursop leaves contained kaempferol and its isomers, procyanidins, catechin, and quercetin. The viability of the cells was determined with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. HeLa and 3T3 cells were exposed to concentrations of 25, 50, 75, 100, 150, 200, and 250 ppm of a solution of soursop leaf extract powder. The MTT assay showed that soursop leaf extracts were toxic to both cell lines in general, however, the ethanolic extract at 25 and 50 ppm demonstrated inhibition in cell viability against the HeLa cancer line and low cytotoxicity for 3T3 fibroblast cells. In conclusion, the novel microwave-ultrasound hybridization technology allows the extraction of polyphenols that may have a potential cytotoxic effect on cancer cells.

Synthesis of 2-Organylchalcogenopheno[2,3-b]pyridines from Elemental Chalcogen and NaBH4 /PEG-400 as a Reducing System: Antioxidant and Antinociceptive Properties.

An alternative method to prepare 2-organylchalcogenopheno[2,3-b]pyridines was developed by the insertion of chalcogen species (selenium, sulfur or tellurium), generated in situ, into 2-chloro-3-(organylethynyl)pyridines by using the NaBH4 /PEG-400 reducing system, followed by an intramolecular cyclization. It was possible to obtain a series of compounds with up to 93 % yield in short reaction times. Among the synthesized products, 2-organyltelluropheno[2,3-b]pyridines have not been described in the literature so far. Moreover, the compounds 2-phenylthieno[2,3-b]pyridine (3 b) and 2-phenyltelluropheno[2,3-b]pyridine (3 c) exhibited significant antioxidant potential in different in vitro assays. Further studies demonstrated that compound 3 b exerted an antinociceptive effect in acute inflammatory and non-inflammatory pain models, thus indicating the involvement of the central and peripheral nervous systems on its pharmacological action. More specifically, our results suggest that the intrinsic antioxidant property of compound 3 b might contribute to attenuating the nociception and inflammatory process on local injury induced by complete Freund's adjuvant (CFA).

Recent applications of on-line supercritical fluid extraction coupled to advanced analytical techniques for compounds extraction and identification.

In a previous review (Sánchez-Camargo et al., J. Sep. Sci. 40 (2017) 213-227), we discussed the application of on-line supercritical fluid extraction coupled to chromatographic techniques. This review includes an update of the most recent publications (from January 2016 till June 2018) on this topic, which employs advanced analytical techniques for extracting and identifying valuable analytes. Supercritical fluid extraction has been widely recognized as a green sample preparation technique, because it is efficient, environmentally friendly, powerful, and faster, offering the possibility of direct coupling to analytical instrumental techniques. Among those techniques, supercritical fluid chromatography has experienced an innovative progression in the last 10 years, and the most recent applications of supercritical fluid extraction are coupled to this advanced analytical tool. The general principles, both methodological and instrumental of on-line supercritical fluid extraction coupled to supercritical fluid chromatography are described here. Besides, applications of the mentioned coupling for analysing biological fluids, food, soil, and botanical samples are also presented and discussed. Finally, a brief description about the very recent on-line coupling of supercritical fluid extraction to ion mobility spectrometry is presented, as well as concluding remarks about the importance of using these coupled techniques in the near future.

Using natural deep eutectic solvents for the extraction of metabolites in Byrsonima intermedia leaves.

Natural deep eutectic solvents have been used as an alternative to organic solvents for the extraction of plants metabolites, allowing for the extraction of compounds of different polarities, while being inexpensive, non-toxic, and easy to prepare. This work presents the comparison of the chromatographic profiles by high-performance liquid chromatography with diode-array detection obtained from Byrsonima intermedia (Malpighiaceae) using five choline chloride-based natural deep eutectic solvents, in addition to the most used traditional extraction solvents, methanol/water 7:3 and ethanol/water 7:3 v/v. A reference extract was used to tentatively identify compounds by high-performance liquid chromatography with tandem mass spectrometry. The water content appeared to be important for the extraction efficiency and the mixture choline chloride/glycerol was shown to be the best candidate for efficiently extracting this matrix when compared with the traditional extraction media in addition to being far greener as shown by the environmental analysis tool. Seven phenolic compounds (digalloyl quinic acid, proanthocyanidin dimer, galloylproanthocyanidin dimer, quercetin-O-hexoside, galloyl quercetin hexoside, quercetin-O-pentoside, and galloyl quercetin pentoside) were tentatively identified in all extracts. Moreover, the influence of these solvents on the antioxidant activity of the extracts was studied and the results for choline chloride/glycerol extracts were very similar to that of the traditional extraction solvents.

Coupled monolithic columns as an alternative for the use of viscous ethanol-water mobile phases on chromatographic fingerprinting complex samples

ABSTRACT Concepts of sustainability have received attention from people involved in investigation of nature-derived matrices. The effects of concomitant pollutant activities are cumulative and harmful to the environment from which these matrices are obtained. High performance liquid chromatography analyses generate millions of litters of chemical waste worldwide every year. Reduction of organic solvent consumption during the analyses and replacement of harmful solvents with greener options are the main approaches to mitigate this problem. This work explored the strategy of employing monolithic columns when the problematic acetonitrile is intended to be replaced with the greener but more viscous ethanol in fingerprinting a leaf extract of Lippia sidoides Cham., Verbenaceae, by high performance liquid chromatography. Two monolithic columns were coupled in series to test a more critical backpressure condition while doubling the number of theoretical plates, which can be useful to separate the hundreds of compounds present in plant extracts. All work was conducted by employing design of experiments. A mathematical model indicated an optimum point in which ethanol was the only organic solvent of the mobile phase. However, the use of a proper metric, which considered environmental parameters together with separation parameters, evidenced that an experimental condition of the original central composite design should be preferred over the former even if containing 20% acetonitrile in the organic modifier mixture. Flow rates of up to 3 ml/min were accommodated with two coupled monolithic columns without exceeding 250 bar. These findings reinforced that no state-of-the-art instruments are needed to shift from traditional harmful solvents to greener ones, but only require a shift in researchers' approach toward sustainability.