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

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.

Simultaneously characterization of multiple constituents in Valeriana jatamansi Jones using an online supercritical fluid extraction-high-performance liquid chromatography/supercritical fluid chromatography-mass spectrometry system

Valeriana jatamansi Jones is a commonly used traditional Chinese medicine, boasting rich effective compositions with versatile chemical structures and wide polarity, including iridoids, chlorogenic acid, and flavonoids. Previous reports indicate that conventional high-performance liquid chromatography (HPLC) analytical methods have proven inefficient performance in comprehensively characterizing components in Valeriana jatamansi. In the present study, a hybrid online analytical platform combining supercritical fluid extraction with both conventional HPLC separation (reverse phase) and supercritical fluid chromatography (normal phase) has been established and validated. This system can provide online extraction with two different chromatographic separation modes to increase separation ability and has been connected to a mass spectrometer to acquire high-resolution mass spectrometry data. Then, the online platform was applied to screening components in Valeriana jatamansi. A total of 117 compounds were identified, including five lignans, 18 organic acids, six flavonoids, and 88 iridoids. Thirty-three compounds were reported from Valeriana jatamansi for the first time. These results enrich our understanding of the components of Valeriana jatamansi and prove that the developed online platform in this study is a robust approach for accelerating working efficiency in comprehensively analyzing complicated samples.

Quantitative Determination of Organophosphorus, Pyrethroid, and Dithiolane Pesticide Residues in Brown Rice Using Supercritical Fluid Extraction and Liquid Chromatography-Tandem Mass Spectrometry

BACKGROUND

Supercritical fluid extraction (SFE) is a fast, versatile, and solvent-efficient automatic extraction method. Despite its advantages, the results of our proficiency tests imply that the applicability assessments of SFE for pesticide residues were insufficient.

OBJECTIVE

In this study, as analytical method using SFE was optimized and validated by testing the incurred and fortified brown rice samples with organophosphorus (OP), pyrethroid (PYR), and dithiolane (DIT) pesticides.

METHOD

A validation study using the incurred sample with etofenprox, fenitrothion, and isoprothiolane was performed by comparing the analytical results obtained using the SFE and solid-liquid extraction with homogenization (SLE), which is a well-validated official multi-residue extraction method. The tests on the fortified samples were also performed for seven pesticide residues, chlorpyrifos, diazinon, O-ethyl O-4-nitrophenyl phenylphosphonothioate (EPN), etofenprox, fenitrothion, isoxathion, and isoprothiolane, at three fortification levels, 0.001, 0.01, and 0.1 mg/kg.

RESULTS

In the test on the incurred samples, optimized SFE-to-SLE analytical values (CSFE/CSLE) were 99.2-100.1%, with RSD lower than 3%. In contrast, the analytical-to-spiked concentrations in the tests on the fortified samples were 96.4-105.0%, with RSD lower than 8.8%.

CONCLUSIONS

These results indicate that the proposed SFE method, which is well validated with the incurred brown rice sample, is useful for determining OP, PYR, and DIT pesticide residues in brown rice.

HIGHLIGHTS

The proposed SFE method satisfies EU and Japanese maximum residue limits (MRLs). The consumption of solvent can be reduced to one-fourth of that of SLE using the proposed SFE method.

Sustainable valorization of pitaya (Hylocereus spp.) peel in a semi-continuous high-pressure hydrothermal process to recover value-added products

This study evaluated the use of a semi-continuous high-pressure hydrothermal process for the recovery of value-added products from pitaya peel. The process was carried out at 15 MPa, a water flow rate of 2 mL/min, a solvent-to-feed ratio of 60 g water/g pitaya peel, and temperatures ranging from 40 to 210 °C. The results show that extraction temperatures (between 40 and 80 °C) promoted the recovery of betacyanin (1.52 mg/g), malic acid (25.6 mg/g), and citric acid (25.98 mg/g). The major phenolic compounds obtained were p-coumaric acid (144.63 ± 0.42 µg/g), protocatechuic acid (91.43 ± 0.32 µg/g), and piperonylic acid (74.2 ± 0.31 µg/g). The hydrolysis temperatures (between 150 and 210 °C) could produce sugars (18.09 mg/g). However, the hydrolysis process at temperatures above 180 °C generated Maillard reaction products, which increased the total phenolic compounds and antioxidant activity of the hydrolysates. Finally, the use of semi-continuous high-pressure hydrothermal process can be a sustainable and promising approach for the recovery of value-added compounds from pitaya peel, advocating a circular economy approach in the agri-food industry.

Application of an integrative system (2D PLE×HPLC-PDA) for bioactive compound extraction and online quantification: Advantages, validation, and considerations

Analyzing compounds such as polyphenols in solid samples frequently uses a solid-liquid extraction step. The solid-liquid extraction and analysis integration in a single equipment is not commercially available since several challenges are inherent to this hybridization. In the context of developing more sustainable analytical procedures, innovative techniques are demanded. Given that, this work proposes a new integrative system (2D PLE × HPLC-PDA) and presents its validation for bioactive compound extraction and online quantification, discussing the main advantages and cares that need to be taken. Two food byproducts - passion fruit bagasse and coffee husks - were chosen as solid model samples. The system was configured to perform pressurized liquid extraction (PLE) with periodical automated extract injection in the HPLC, consequently obtaining the online quantification of target compounds from the solid samples. In parallel with the online injections, extract fractions were collected and submitted to offline analysis in which the extraction yield of piceatannol and chlorogenic acid and caffeine were evaluated, respectively, for passion fruit bagasse and coffee husks. The extraction yields obtained by online and offline injections were compared and were significantly equal (p > 0.05). Thus, the 2D PLE × HPLC-PDA system represents a feasible tool to integrate solid sample preparation and chemical analysis of biocompounds in a single and online step.

Antioxidant and Antimicrobial Properties and GC-MS Chemical Compositions of Makwaen Pepper (Zanthoxylum myriacanthum) Extracted Using Supercritical Carbon Dioxide

This research aimed to optimize pressure (10-20 MPa) and temperature (45-60 °C) conditions for supercritical fluid extraction (SFE) of Makwaen pepper (Zanthoxylum myriacanthum) extract (ME) in comparison to conventional hydro-distillation extraction. Various quality parameters, including yield, total phenolic compounds, antioxidants, and antimicrobial activities of the extracts, were assessed and optimized using a central composite design. The optimal SFE conditions were found to be 20 MPa at 60 °C, which resulted in the highest yield (19%) and a total phenolic compound content of 31.54 mg GAE/mL extract. IC₅₀ values for DPPH and ABTS assays were determined to be 26.06 and 19.90 μg/mL extract, respectively. Overall, the ME obtained through SFE exhibited significantly better physicochemical and antioxidant properties compared to ME obtained through hydro-distillation extraction. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that beta-pinene was the major component in the ME obtained through SFE (23.10%), followed by d-limonene, alpha-pinene, and terpinen-4-ol at concentrations of 16.08, 7.47, and 6.34%, respectively. On the other hand, the hydro-distillation-extracted ME showed stronger antimicrobial properties than the SFE-extracted ME. These findings suggest that both SFE and hydro-distillation have the potential for extracting Makwaen pepper, depending on the intended purpose of use.

Phospholipids molecular species, proteins secondary structure, and emulsion microstructure of egg yolk with reduced polar and/or nonpolar lipids

This study investigated the phospholipids (PLs) molecular species (PLs-MS), protein secondary structure (PSS), and emulsion microstructure of the egg yolk (EY) treated with supercritical-CO₂ (T1), hexane (T2), and ethanol {at room temperature (T3) and 65 °C (T4)}. PLs-MS, PSS, and microstructure of EY emulsion were investigated with UPLC-Q-TOF-MS, Fourier-transforms infrared and Raman spectroscopy, and confocal laser scanning microscope, respectively. Predominant PLs molecular fractions were C18:0-C20:4, C18:0-C20:4, C16:0-C18:2, C16:0, C18:0-C18:2, and d18:1/16:0, for phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, lysophosphatidylcholine, sphingomyelin, and phosphatidylserine, respectively. All the PLs-MS were highest for T1 and many of them (C14:0-C16:0, C18:0-C18:1, C18:0-C20:3) were absent in T2, T3, and T4. PSS components (α-helices, β-sheets, β-turn, and random coil) were highest for T4, followed by T3, T2, T1, and control (non-treated EY). However, T1-added o/w emulsion showed excellent stability (95.64 %) with smaller and denser oil droplets due to better ionic interactions by synergistic effect of PLs-MS and PSS components.

Current Developments of Analytical Methodologies for Aflatoxins' Determination in Food during the Last Decade (2013-2022), with a Particular Focus on Nuts and Nut Products

This review aims to provide a clear overview of the most important analytical development in aflatoxins analysis during the last decade (2013-2022) with a particular focus on nuts and nuts-related products. Aflatoxins (AFs), a group of mycotoxins produced mainly by certain strains of the genus Aspergillus fungi, are known to impose a serious threat to human health. Indeed, AFs are considered carcinogenic to humans, group 1, by the International Agency for Research on Cancer (IARC). Since these toxins can be found in different food commodities, food control organizations worldwide impose maximum levels of AFs for commodities affected by this threat. Thus, they represent a cumbersome issue in terms of quality control, analytical result reliability, and economical losses. It is, therefore, mandatory for food industries to perform analysis on potentially contaminated commodities before the trade. A full perspective of the whole analytical workflow, considering each crucial step during AFs investigation, namely sampling, sample preparation, separation, and detection, will be presented to the reader, focusing on the main challenges related to the topic. A discussion will be primarily held regarding sample preparation methodologies such as partitioning, solid phase extraction (SPE), and immunoaffinity (IA) related methods. This will be followed by an overview of the leading analytical techniques for the detection of aflatoxins, in particular liquid chromatography (LC) coupled to a fluorescence detector (FLD) and/or mass spectrometry (MS). Moreover, the focus on the analytical procedure will not be specific only to traditional methodologies, such as LC, but also to new direct approaches based on imaging and the ability to detect AFs, reducing the need for sample preparation and separative techniques.

Green Extraction Processes for Complex Samples from Vegetable Matrices Coupled with On-Line Detection System: A Critical Review

The detection of analytes in complex organic matrices requires a series of analytical steps to obtain a reliable analysis. Sample preparation can be the most time-consuming, prolonged, and error-prone step, reducing the reliability of the investigation. This review aims to discuss the advantages and limitations of extracting bioactive compounds, sample preparation techniques, automation, and coupling with on-line detection. This review also evaluates all publications on this topic through a longitudinal bibliometric analysis, applying statistical and mathematical methods to analyze the trends, perspectives, and hot topics of this research area. Furthermore, state-of-the-art green extraction techniques for complex samples from vegetable matrices coupled with analysis systems are presented. Among the extraction techniques for liquid samples, solid-phase extraction was the most common for combined systems in the scientific literature. In contrast, for on-line extraction systems applied for solid samples, supercritical fluid extraction, ultrasound-assisted extraction, microwave-assisted extraction, and pressurized liquid extraction were the most frequent green extraction techniques.

Microscale supercritical fluid extraction combined with supercritical fluid chromatography and proton-transfer-reaction ionization time-of-flight mass spectrometry for a magnitude lower limit of quantitation of lipophilic compounds

The application of proton transfer ionization reaction mass spectrometry (PTR MS) combined with microscale supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) aiming to quantitate single-cell fatty acid analysis levels was investigated. Using a microscale extraction vessel, the obtained low limits of quantitation (LLOQs) of arachidonic acid and arachidic acid were 1.2 and 2.7 fmol, respectively, by using less than 1 µL of sample on stainless steel frit. A series of phthalate, vitamin K₁, and α-tocopherol were also tested, and the LLOQ was less than one femtomole for phthalate and 35 and 13 fmol for vitamin K₁ and α-tocopherol, respectively. A microliter portion of SFE extracts was introduced into the SFC column by split injection, improving the reproducibility of the chromatography and separation efficiency. The method in the present study has great potential to quantitate lipophilic molecules on the nanogram scale of a sample without complex preparation procedures.

A cartridge-based device for automated analyses of solid matrices by online sample prep-capillary LC-MS/MS

Sample preparation is an essential step focused on eliminating interfering compounds while pre-concentrating the analytes. However, its multiple steps are laborious, time-consuming, and a source of errors. Currently, automated approaches represent a promising alternative to overcome these drawbacks. Similarly, miniaturisation has been considered an ideal strategy for creating greener analytical workflows. The combination of these concepts is currently highly desired by analytical chemists. However, most automated and miniaturised sample preparation techniques are primarily concerned with liquid samples, while solids are frequently overlooked. We present an approach based on a cartridge packed with solids (soil samples) coupled with a capillary LC-MS, combining sample preparation and analytical steps into a unique platform. As a proof-of-concept, nine pesticides used in sugarcane crops were extracted and analysed by our proposed method. For optimisation, a fractional factorial design (2^5-1) was performed with the following variables: aqueous dilution of the sample (V₁), extraction strength (V₂), matrix washing time (V₃), extraction flow (V₄), and analytical flow (V₅). After, the most influential ones (V₁, V₂, and V₃) were taken into a central composite design (2³) to select their best values. Under optimised conditions, the method reported linear ranges between 10 and 125 ng g^-1 with R² > 0.985. Accuracy and precision were in accordance with the values established by the International Council for Harmonisation (Q2(R1)). Therefore, the proposed approach was effective in extracting and analysing selected pesticides in soil samples. Also, we carried out initial qualitative tests for pesticides in honeybees to see if there is the possibility to apply our method in other solids.

Supercritical fluid extraction-supercritical fluid chromatography of saliva: Single-quadrupole mass spectrometry monitoring of caffeine for gastric emptying studies†

Saliva is an attractive sampling matrix for measuring various endogenous and exogeneous substances but requires sample treatment prior to chromatographic analysis. Exploiting supercritical CO₂ for both extraction and chromatography simplifies sample preparation, reduces organic solvent consumption, and minimizes exposure to potentially infectious samples, but has not yet been applied to oral fluid. Here, we demonstrate the feasibility and benefits of online supercritical fluid extraction coupled to supercritical fluid chromatography and single-quadrupole mass spectrometry for monitoring the model salivary tracer caffeine. A comparison of ¹³ C- and ³² S-labeled internal standards with external standard calibration confirmed the superiority of stable isotope-labeled caffeine over nonanalogous internal standards. As proof of concept, the validated method was applied to saliva from a magnetic resonance imaging study of gastric emptying. After administration of 35 mg caffeine via ice capsule, salivary levels correlated with magnetic resonance imaging data, corroborating caffeine's usefulness as tracer of gastric emptying (R²  = 0.945). In contrast to off-line methods, online quantification required only minute amounts of organic solvents and a single manual operation prior to online bioanalysis of saliva, thus demonstrating the usefulness of CO₂ -based extraction and separation techniques for potentially infective biomatrices.

Metabolomics-Guided Elucidation of Plant Abiotic Stress Responses in the 4IR Era: An Overview

Plants are constantly challenged by changing environmental conditions that include abiotic stresses. These are limiting their development and productivity and are subsequently threatening our food security, especially when considering the pressure of the increasing global population. Thus, there is an urgent need for the next generation of crops with high productivity and resilience to climate change. The dawn of a new era characterized by the emergence of fourth industrial revolution (4IR) technologies has redefined the ideological boundaries of research and applications in plant sciences. Recent technological advances and machine learning (ML)-based computational tools and omics data analysis approaches are allowing scientists to derive comprehensive metabolic descriptions and models for the target plant species under specific conditions. Such accurate metabolic descriptions are imperatively essential for devising a roadmap for the next generation of crops that are resilient to environmental deterioration. By synthesizing the recent literature and collating data on metabolomics studies on plant responses to abiotic stresses, in the context of the 4IR era, we point out the opportunities and challenges offered by omics science, analytical intelligence, computational tools and big data analytics. Specifically, we highlight technological advancements in (plant) metabolomics workflows and the use of machine learning and computational tools to decipher the dynamics in the chemical space that define plant responses to abiotic stress conditions.

Metabolomics as a Tool to Study Underused Soy Parts: In Search of Bioactive Compounds

The valorization of agri-food by-products is essential from both economic and sustainability perspectives. The large quantity of such materials causes problems for the environment; however, they can also generate new valuable ingredients and products which promote beneficial effects on human health. It is estimated that soybean production, the major oilseed crop worldwide, will leave about 597 million metric tons of branches, leaves, pods, and roots on the ground post-harvesting in 2020/21. An alternative for the use of soy-related by-products arises from the several bioactive compounds found in this plant. Metabolomics studies have already identified isoflavonoids, saponins, and organic and fatty acids, among other metabolites, in all soy organs. The present review aims to show the application of metabolomics for identifying high-added-value compounds in underused parts of the soy plant, listing the main bioactive metabolites identified up to now, as well as the factors affecting their production.

Sequential extraction of carnosic acid, rosmarinic acid and pigments (carotenoids and chlorophylls) from Rosemary by online supercritical fluid extraction-supercritical fluid chromatography

A high degree of selectivity is required during the plant extraction process in order to obtain extracts enriched in specific compounds or to avoid the extraction of unwanted ones. Rosemary is well known for its antioxidant compounds (carnosic acid, carnosol and rosmarinic acid). The plant also contains pigments (i.e. carotenoids, chlorophylls) which may cause a colour problem during the use of the extract in cosmetic formulations, for example. Supercritical fluid extraction is considered as a selective technique for plant extraction. Due to the physico-chemical properties of supercritical fluids, related to pressure, temperature and modifier addition, it is possible to carry out sequential extraction with successive conditions to collect different fractions that are rich either in pigments or in bioactive compounds. The aim of this study was to selectively extract bioactive compounds (i.e. carnosic acid and rosmarinic acid) and pigments (carotenoids and chlorophylls) from rosemary using supercritical fluid extraction. The optimisation of the extraction method was carried out using supercritical fluid extraction online coupled with a supercritical fluid chromatography (SFE-SFC) system. Two columns of different polarities were coupled to achieve the separation of the targeted compounds every five minutes during the extraction. Four fractions were obtained: a first one rich in carotenoids obtained with pure CO2 (25°C and 20 MPa), a second rich in carnosic acid obtained with 3% polar modifier (EtOH:water 50/50 v/v), a third fraction rich in rosmarinic acid using 10% of the same modifier and a fourth fraction rich in chlorophylls with 30% of ethanol as modifier. These four samples were then analysed by UHPLC-DAD-ESI-QTOF-HRMS in order to identify other extracted compounds and to study how the selected conditions impacted their extraction.

Microbiological and Antioxidant Activity of Phenolic Compounds in Olive Leaf Extract

According to many reports, phenolic compounds isolated from olive leaves have very good biological activities, especially antimicrobial. Presently, the resistance of microorganisms to antibiotics is greater than ever. Therefore, there are numerous recent papers about alternative solutions for inhibiting their influence on human health. Olive leaf is studied as an important source of antimicrobials with low cost and used in medicine. Numerous publications on involving green technologies for isolation of active compounds from olive leaves have appeared over the past few decades. The present review reports on current knowledge of the most isolated phenolic compounds from olive leaf extract as well as methods for their isolation and characterization. This paper uses recent research findings with a wide range of study models to describe the antimicrobial potential of phenolic compounds. It also describes the vast range of information about methods for determination of antimicrobial potential focusing on effects on different microbes. Additionally, it serves to highlight the role of olive leaf extract as an antioxidants and presents methods for determination of antioxidant potential. Furthermore, it provides an overview of presence of enzymes. The significance of olive leaves as industrial and agricultural waste is emphasized by means of explaining their availability, therapeutic and nutritional effects, and research conducted on this field.

Modern technologies for extraction of aroma compounds from fruit peels: a review

Fruit peel is an agricultural by-product and potential source to extract natural aroma compounds with low cost. In the past few decades, the extraction of plant aroma volatiles experienced a transition from traditional to modern technologies. This review summarizes the main aroma compounds in different fruit peels, evaluates modern extraction techniques applicable for these aroma compounds in terms of mechanism, procedure, merits and demerits, and practice. Additionally, the applications of fruit peel aroma extract in food, pharmaceutical and cosmetic industries are also discussed. This review provides comprehensive information for extraction and application of aroma compounds from fruit peels, which could facilitate the valorization of the agricultural by-products and reduce environmental impacts.

Quality control of the traditional herbs and herbal products: a review

Background

Herbal medicinal material and product need is increasing, and with this increase in the need, it is very much an essential requirement to maintain the quality of them.

Main body

The quality of the herbals is altered by various physical, chemical, and geographical aspects which contribute to the quality of these materials. Apart from that, adulteration is also an increasing concern when it comes to herbal material quality. Various chemical and phytochemical test, analytical techniques, and hyphenated analytical techniques are used for determining the quality aspects of the herbal materials in the herbal pharmaceuticals.

Conclusion

These techniques can be used as quality control tool in assessing the quality of herbal materials and herbal pharmaceuticals.

In vitro estimation of superfluid critical extracts of some plants for their antimicrobial potential, phytochemistry, and GC-MS analyses

BACKGROUND

Along with swift economic evolution and continuous amelioration of lifestyle, people at present are paying more attention to health issues. Synthetic drugs will be compensated with other natural ones that belong to natural origin. Plants have always been considered as sources of several compounds that are used in many fields, especially human and animal health, starting from boosting immunity to the treatment of infectious diseases caused by some pathogenic microbes such as bacteria, fungi as well as viruses. This study aimed to incorporate some types of plants within the antimicrobial portfolio through the examination of different six plants which were Cichorium intybus, Cinnamomum camphora, Commiphora myrrha, Foeniculum vulgare, Nerium oleander, and Spartium junceum. As well, attempting to identify the active constituents of their extracts using GC-MS.

MATERIALS AND METHODS

All selected plants were analyzed to determine their phytochemical composition such as phenolics, alkaloids, flavonoids, terpenoids, and so on. The extraction step was done by sophisticated equipment called supercritical fluid extractor SFE through adjustment of specific conditions include temperature, time, flow rate and pressure to change the behavior of CO2. Testing the antimicrobial activity of each plant extract via agar well diffusion method through the formation of clear zones against a wide range of test microorganisms including both Gram-positive and Gram-negative bacteria as well as yeasts. Finally, attempting to primarily identify the constituents of each plant extract using GC-MS.

RESULTS AND DISCUSSION

The crude extract of F. vulgare showed the highest potency against C. albicans, E. faecalis and S. typhimurium, it contains some unique compounds such as squalene, eugenol and isoeugenol while, Extract of C. intybus showed a moderate activity especially against C. lipolytica and MRSA and it includes Vitamin A like compound which indicates antioxidant property.

CONCLUSION

Conclusively, fennel gave a promising result as a good wide spectrum antimicrobial agent because it contains some compounds act as antimicrobial agents such as eugenol which was used as food preservatives in addition to squalene which acts as an antioxidant and antimycotic agent so, it will be useful especially while it was used in highly purified form excluding all undesirable subcomponents.

Advances in various techniques for isolation and purification of sterols

Plants consist of triterpenoids such as phytosterols (PT) (C₂₉H₅₀O) with steroidal nuclei, including sitosterol, stigmasterol, brassicasterol and campesterol. They are hydrophobic but soluble in alcohol and other organic solvents and are isolated from industrial waste deodorizer distillates of various edible oil industries. They exist as free PT or their ester derivatives in soybean, rice, wheat, oat, cottonseed and corn fiber, and other cereals and grains. Conventional isolation techniques such as solvent extraction, distillation, evaporative fractionation, saponification and chemical esterification are employed for isolation and purification of PT. The present article reviews the various advanced separation techniques like solvent crystallization, supercritical fluid extraction, high speed counter-current chromatography and enzymatic process as strategic methods to isolate and purify sterols.

Potential Hepatoprotective Activity of Super Critical Carbon Dioxide Olive Leaf Extracts against CCl4-Induced Liver Damage

Virgin olive oil has demonstrated its effective activity against oxidative stress. However, data on the bioactive effect of olive leaves or their major constituents on the liver are scarce. The present research work was conducted to evaluate the hepatoprotective effects of supercritical carbon dioxide (SC-CO₂) extracts from fresh and dried olive leaves on hepatotoxicity caused by carbon tetrachloride (CCl₄) in rat models. For this purpose, healthy albino rats of 180–250 g weight were used. The assessment of biochemical markers was carried out on blood and liver tissue. Then, a histopathological study was carried out on liver tissue. The obtained results showed that fresh and dried olive leaf extracts ameliorate the perturbed biochemical parameters caused by CCl₄ treatment. Furthermore, the results registered for the histopathological study are in accordance with the biochemical parameters and the protective capacity of SC-CO₂ extracts against DNA damage, indicating that olive leaf extracts helped to improve liver fibrosis caused by CCl₄ treatment.

On the Enhanced Accuracy of Kinetic Curve Building in Supercritical Fluid Extraction from Aroma Plants Using a New 3D-Printed Extract Collection Device

Accurate collection of extracted material represents a technical problem in supercritical fluid extraction because trapping should be performed in severe conditions of rapidly moving and freezing expanded fluid. We have developed a simple device for effective sample collection in analytical-scale supercritical fluid extraction. The device consists of a cyclone separator equipped with a spray trap and a heated check valve. The cyclone separator and spray trap are manufactured from a light polymer via 3D printing and are quick-detachable, which encourages its use in applications where mass yield measurements are required. The device was compared to a standard tubing-and-vial approach in the task of building kinetic curves for the extraction from two aroma plants, namely, laurel and rosemary. The new device showed almost two-fold increase in extraction trapping, most probably due to better collection of volatile compounds. A curious effect of the number of mass measurement points per curve on apparent yield was observed. An increase in the number of points led to an increase in yield, probably due to the effect of the static-dynamic extract regime posed by the manner in which the device is used.

Evaluation of supercritical fluid extraction for the determination of neonicotinoid pesticides in green onion

A supercritical fluid extraction (SFE) method was presented for the determination of neonicotinoid pesticides in green onion. We optimized the SFE parameters, namely the pressure, temperature, type and concentration of the modifier solvent, and extraction time, by testing on the incurred green onion applied with four commercial neonicotinoid formulations at the harvesting stage. The analytical values of the four neonicotinoids, obtained by 5 min dynamic SFE with a 25% (v/v) methanol/supercritical carbon dioxide mixture at 80 °C and 25 MPa, were in good agreement with those obtained by solid-liquid extraction using a homogenizer. This latter homogenization method is employed as a Japanese official method for the analysis of pesticide residues in food. The SFE-to-homogenization analytical value ratios were in the range 98.8-100.0%. Spike-and-recovery testing with spiked green onion was also performed by optimized SFE. The ratios of the analytical-to-spiked concentrations for six neonicotinoids obtained by the SFE method were 96.1-102.1% for 0.4 mg/kg and 93.9-104.1% for 4.0 mg/kg spiking levels. These values satisfied the Japanese validation guidelines for the testing method of pesticides in food. These results indicate that SFE is applicable for the analysis of neonicotinoids in green onion and enables automatic extraction with a small amount of solvent.

Determination of lipid mediators in breast cancer cells using lyophilization-supercritical fluid extraction online coupled with supercritical fluid chromatography-quadrupole tandem mass spectrometry

A lyophilization-supercritical fluid extraction coupled with supercritical fluid chromatography-quadrupole tandem mass spectrometry online method was developed for the determination of lipid mediators in breast cancer cells. Supercritical fluid extraction was applied to the cell samples for the first time due to the use of lyophilization. The conditions of supercritical fluid extraction and supercritical fluid chromatography-quadrupole tandem mass spectrometry were investigated systematically. Under the optimized conditions, all the calibration curves for the lipid mediators showed good linearity (correlation coefficient > 0.99). The limits of detection and the limits of quantification were in the range of 0.190-5.36 pg and 0.560-16.2 pg, respectively. The recoveries were in the range of 70.3-125%. The relative standard deviations of the precision ranged from 1.49-18.7% and the accuracies were higher than 84%. Compared with liquid-liquid extraction coupled with liquid chromatography and tandem mass spectrometry method, the present approach reduced the manual labor and obtained higher sensitivity as well as higher extraction recoveries for all 15 lipid mediators. Finally, the online method was applied to the quantification of lipid mediators in breast cancer cells and normal mammary epithelial cells. On the basis of the results, this lyophilization-supercritical fluid extraction online coupled with supercritical fluid chromatography-quadrupole tandem mass spectrometry method showed great promise in the analysis of lipid mediators in complex biological samples.

Distribution of sapogenins in morphological Medicago sativa L. parts: Comparison of various extraction techniques

Saponins in plant extracts were indirectly determined by estimation of the content of sapogenins. The first step of determination is extraction with high efficiency. One conventional extraction technique (maceration) and two modern ones (accelerated solvent extraction and supercritical fluid extraction) were compared. Methanol and ethanol were used as solvents or co-solvents. The results were supported by statistical analysis. Saponins were extracted from leaves, roots, and sprouts of Medicago sativa. Acid hydrolysis, purification, and determination by high-performance liquid chromatography with evaporative light scattering detector were used. The content of sapogenins was the highest in the roots. Smaller amounts of sapogenins were found in sprouts and the smallest ones in leaves. The main ingredient was medicagenic acid with mean concentration of 621.8 µg/g in roots, 456.7 µg/g in sprouts, and 471.3 µg/g in leaf extract. The highest content of sapogenins in extract was obtained after maceration with methanol; however, this method is nonselective in relation to biologically active compounds. Due to the possibility of using the obtained extracts with sapogenins in the cosmetic or pharmaceutical industry, the selection of extraction techniques and solvents is a very important aspect. Additionally, the chosen technique should be considered eco-friendly and consistent with the assumptions of "green chemistry."

Understanding glycaemic control and current approaches for screening antidiabetic natural products from evidence-based medicinal plants

Type 2 Diabetes Mellitus has reached epidemic proportions as a result of over-nutrition and increasingly sedentary lifestyles. Current therapies, although effective, are not without limitations. These limitations, the alarming increase in the prevalence of diabetes, and the soaring cost of managing diabetes and its complications underscores an urgent need for safer, more efficient and affordable alternative treatments. Over 1200 plant species are reported in ethnomedicine for treating diabetes and these represents an important and promising source for the identification of novel antidiabetic compounds. Evaluating medicinal plants for desirable bioactivity goes hand-in-hand with methods in analytical biochemistry for separating and identifying lead compounds. This review aims to provide a comprehensive summary of current methods used in antidiabetic plant research to form a useful resource for researchers beginning in the field. The review summarises the current understanding of blood glucose regulation and the general mechanisms of action of current antidiabetic medications, and combines knowledge on common experimental approaches for screening plant extracts for antidiabetic activity and currently available analytical methods and technologies for the separation and identification of bioactive natural products. Common in vivo animal models, in vitro models, in silico methods and biochemical assays used for testing the antidiabetic effects of plants are discussed with a particular emphasis on in vitro methods such as cell-based bioassays for screening insulin secretagogues and insulinomimetics. Enzyme inhibition assays and molecular docking are also highlighted. The role of metabolomics, metabolite profiling, and dereplication of data for the high-throughput discovery of novel antidiabetic agents is reviewed. Finally, this review also summarises sample preparation techniques such as liquid-liquid extraction, solid phase extraction, and supercritical fluid extraction, and the critical function of nuclear magnetic resonance and high resolution liquid chromatography-mass spectrometry for the dereplication, putative identification and structure elucidation of natural compounds from evidence-based medicinal plants.

Rapid Solid-Liquid Dynamic Extraction (RSLDE): A Powerful and Greener Alternative to the Latest Solid-Liquid Extraction Techniques

Traditionally, solid-liquid extractions are performed using organic and/or inorganic liquids and their mixtures as extractant solvents in contact with an insoluble solid matrix (e.g., the Soxhlet method) or using sequential atmospheric pressure systems that require long procedures, such as maceration or percolation. The objective of this procedure is the extraction of any compounds that can be carried out from the inner solid material to the outlet, resulting in a solution containing colorants, bioactive compounds, odorous substances, etc. Over the years, in the extraction techniques sector, there have been many important changes from the points of view of production, quality, and human and environmental safety due to improvements in technology. In more recent times, the interest of the scientific community has been aimed at the study of sustainable processes for the valorization of extracts from vegetables and food by-products, through the use of non-conventional (innovative) technologies that represent a valid alternative to conventional methods, generally through saving time and energy and the formation of fewer by-products. Therefore, with the development of principles based on the prevention of pollution, on a lower risk for human health, and on a low environmental impact, new systems have been implemented to reduce extraction times and solvent consumption, to improve efficiency, and to increase the productivity of the extracts. From this point of view, rapid solid-liquid dynamic extraction (RSLDE), performed using the Naviglio extractor, compared to traditional applications, is a technique that is able to reduce extraction times, generally leads to higher yields, does not require heating of the system, allows one to extract the active ingredients, and avoids their degradation. This technique is based on a new solid-liquid extraction principle named Naviglio’s principle. In this review, after reviewing the latest extraction techniques, an overview of RSLDE applications in various research and production sectors over the past two decades is provided.

Comparison of Retention Behavior between Supercritical Fluid Chromatography and Normal-Phase High-Performance Liquid Chromatography with Various Stationary Phases

The retention behavior of a wide variety of stationary phases was compared in supercritical fluid chromatography (SFC) and normal-phase high-performance liquid chromatography (NP-HPLC). We also attempted to elucidate the retention behavior in SFC by investigating the selectivity of the different stationary phases. SFC separation conditions with polar stationary phases, such as silica gel (SL) and diol (Diol) phases, operate via adsorptions that include hydrophilic and ionic interactions similar to those in NP-HPLC. Moreover, non-polar stationary phases, such as pentabromophenyl (PBr), pyrenylethyl (PYE), and octadecyl (C₁₈), could be used despite the non-polar mobile phase conditions, because the dispersion and π-π interactions were stronger in SFC than in HPLC. These results reflect the selectivity of the stationary phase and its retention factor, thus providing useful information for the selection of appropriate stationary phases for particular analytes.

Online supercritical fluid extraction mass spectrometry (SFE-LC-FTMS) for sensitive characterization of soil organic matter

We report a novel technical approach for subcritical fluid extraction (SFE) for organic matter characterization in complex matrices such as soil.