Selection Of Extraction Solvent Research Articles

Hydrophobic deep eutectic solvent-based vortex-assisted dispersive liquid–liquid microextraction with UV–visible spectrophotometry for copper determination in waste printed circuit boards

ABSTRACT Nearly all electronic devices utilise Printed Circuit Boards (PCBs), which contribute significantly to the generation of electronic waste (e-waste). They are rich in metal content, with copper being present in higher percentages. In this work, a simple, efficient and environment-friendly pre-concentration technique was developed, using hydrophobic deep eutectic solvent as an extractant in vortex-assisted dispersive liquid–liquid microextraction. This pre-concentration technique is coupled with spectrophotometry for the determination of copper in PCBs. The complexing agent, sodium diethyl di-thiocarbamate (DDTC), and copper formed a complex in the 2–3 pH range. The Cu-DDTC complex was vortexed for 1 min at 2800 rpm to extract in hydrophobic DES. The sediment was analysed using a UV–Visible spectrophotometer at λ max 435 nm. The optimisation parameters, including pH, extraction solvent selection and its volume, concentration and volume of chelating agent, interference of forein ios, etc., have been assessed. Analytical figures of merit such as limit of detection (1.98 μg/L), limit of quantification (5.9 μg/L), relative standard deviation (3.4%) and enrichment factor (10) have been obtained under optimal experimental conditions. The method was validated by a certified copper solution and applied successfully to determine copper in waste PCBs of personal computers.

Qualitative and Quantitative Phytochemical profiling of Digera muricata (L.) Mart Leaves

Plants possess an extensive variety of therapeutic compounds that exhibit significant potential for application within the pharmaceutical industry. In order to identify the diverse phytochemical composition present in the plant, range of solvents including alcoholic, aqueous, hexane, petroleum ether and hydroalcoholic were employed these extracts were used and the preliminary qualitative analysis reveals the presence of phytochemicals in higher concentrations in the hydro ethanolic extract compared to other solvent. The powdered plant sample was further investigated for the quantification of phytochemicals which revealed the presence of high total phenolic content, total flavonoid content, saponin content, total tannin content and steroids content of 246.82 ± 17.27 GAE equivalents per gram, 193.18 ± 13.52 milligrams of quercetin equivalents per gram, 134.76 ± 9.43 milligrams of saponin equivalents per gram, of 61.80 ± 4.32 milligrams of Tannic acid equivalents per gram and 117.66 ± 8.23 milligrams of Cholesterol equivalents per gram respectively. The present study elucidates the potential for isolating specific compounds possessing economically valuable bioactive properties through the utilization of suitable plants and careful selection of an appropriate solvent for extraction.

Extraction solvent selection for Cannabis sativa L. by efficient exploration of cannabinoid selectivity and phytochemical diversity.

Cannabis sativa L. is attracting worldwide attention due to various health-promoting effects. Extraction solvent type is critical for the recovery of bioactive compounds from the plant, especially cannabinoids. However, the choice of solvent is varied and not adequately warranted elsewhere, causing confusion in involved fields. The present work aimed to investigate the effect of extraction solvent on C. sativa (hemp) with regard to cannabinoid recovery and phytochemical profile of the extracts, considering most of the related solvents. The majority of solvents reported for C. sativa (n = 14) were compared using a representative hemp pool. Quantitative results for major and minor cannabinoids were rapidly and reliably obtained using ultrahigh-performance liquid chromatography coupled with photodiode array detection (UPLC-PDA). In parallel, high-performance thin-layer chromatographic (HPTLC) fingerprinting was employed, involving less toxic mobile phase than in relevant reports. Various derivatisation schemes were applied for more comprehensive comparison of extracts. Differential selectivity towards cannabinoids was observed among solvents. MeOH was found particularly efficient for most cannabinoids, in addition to solvent systems such as n-Hex/EtOH 70:30 and ACN/EtOH 80:20, while EtOH was generally inferior. For tetrahydrocannabinol (THC)-type compounds, EtOAc and n-Hex/EtOAc 60:40 outperformed n-Hex, despite its use in the official EU method. Solvents that tend to extract more lipids or more polar compounds were revealed based on HPTLC results. Combining the observations from UPLC quantitation and HPTLC fingerprinting, this work allowed comprehensive evaluation of extraction solvents, in view of robust quality assessment and maximised utilisation of C. sativa.

Hansen Solubility Parameters Applied to the Extraction of Phytochemicals.

In many analytical chemical procedures, organic solvents are required to favour a better global yield upon the separation, extraction, or isolation of the target phytochemical analyte. The selection of extraction solvents is generally based on the solubility difference between target analytes and the undesired matrix components, as well as the overall extraction procedure cost and safety. Hansen Solubility Parameters are typically used for this purpose. They are based on the product of three coordinated forces (hydrogen bonds, dispersion, and dipolar forces) calculated for any substance to predict the miscibility of a compound in a pure solvent, in a mixture of solvents, or in non-solvent compounds, saving time and costs on method development based on a scientific understanding of chemical composition and intermolecular interactions. This review summarises how Hansen Solubility Parameters have been incorporated into the classical and emerging (or greener) extraction techniques of phytochemicals as an alternative to trial-and-error approaches, avoiding impractical experimental conditions and resulting in, for example, saving resources and avoiding unnecessary solvent wasting.

Ionic liquid-based dispersive liquid-liquid microextraction of anthelmintic drug residues in small-stock meat followed by LC-ESI-MS/MS detection.

An ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) of 20 anthelmintic drugs followed and detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed, optimized, and validated. The parameters affecting the anthelmintic extraction efficiencies such as selection of extraction solvent (ionic liquids), selection of disperser solvent, volume of extraction solvent, volume of disperser solvent, pH of the aqueous phase, extraction time, salt addition, and centrifugation time were optimized. Validation was conducted according to ISO/IEC 17025:2017 and Commission Implementing Regulation (EU) 2021/808 of 22 March 2021. Validation parameters such as calibration function, matrix effect, limit of detection (LOD), limit of quantification (LOQ), decision limit (CCα), accuracy, and precision were established. Coefficient of determination (R 2) values ranging from .99938 to .99995 were obtained using the matrix calibration curve spiked at 0, 0.25, 1.0, 1.5, and 2.0 times MRL. The LODs and LOQs were calculated using the standard deviation of the response and the slopes of the calibration curves ranged from 0.35 to 26.1 μg/kg and from 1.2 to 87.0 μg/kg, respectively, and were dependent on calibration range. The CCα values ranged from 23 to 1022.0 μg/kg and are also dependent on the MRL concentration levels. The coefficient of variation (CV) values calculated are within the reproducibility range of 16%-30% adapted from the Horwitz Equation CV = 2(1-0.5 log C) and ranged from 1.7% to 16.9%. The developed and validated and the standard QuEChERS method were compared. The IL-DLLME LC-MS/MS method was applied to 32 small stock (18 caprine [goat] and 14 ovine [sheep]) liver samples received from municipal abattoirs at Botswana National Veterinary Laboratory for the analysis of anthelmintic drug residues. The results obtained indicated that the anthelmintic drug residues were all below the detection capability, and therefore, the samples were passed as fit for human consumption.

A Review on Antioxidant Properties of Extracts Obtained from the Leaf, Stem, Bark and Flower of Calotropis Species

The extracts obtained from different parts of Calotropis plant have been utilized for various activities. In this review we have compiled different methods used for the extraction of phytoconstituents from various parts of Calotropis. We have compiled the antioxidant studies done on these extracts. This review gives an idea about selection of solvents for extraction of different phytochemicals from Calotropis plant along with the methodologies adopted for antioxidant study of these extracts. Numerous investigations have been carried out to investigate the active chemicals and potential biological activities of Calotropis gigantea. Isolated chemicals from various parts of the plant have been evaluated for their pharmacological effects such as analgesic anthelmintic anti-asthmatic anti-arthritis anti-bacterial anti-cancer anti-convulsive anti-diabetic anti-diarrhoeal anti-histaminic anti-inflammatory anti-pyretic anti-ulcer antihypertensive and antioxidant activity. The pharmacological effects and phytochemistry of Calotropis species are summarized in this review article. This potential herb could be investigated with additional research towards the development of effective medications for a range of therapies.

Solvent selection for extraction of bioactive compound from bekasam with antioxidant and anticholesterol activities

Heart disease and hypertension are two of the main causes of human mortality worldwide. Both can be caused by the oxidation of cholesterol, causing plaque and narrow blood vessels. The purpose of this research was to determine the solvent for the extraction of antioxidant and anticholesterol bioactive compounds from bekasam extracts. Bekasam was extracted by polar solvents, i.e., aquabides, methyl alcohol (methanol), and ethyl alcohol (ethanol). The parameters observed in this research were the yield of crude extract, antioxidant assay, lovastatin assay, and peptide profile analysis (SDS-PAGE). The result of this study indicated that the yields of crude extract of bekasam using aquabides, methanol, and ethanol were 17.00%, 9.00%, and 2.83%, respectively. The antioxidant activities of bekasam extracts produced using methanol, ethanol, and aquabidest were 69.09%, 64.09%, and 53.43%, respectively. Lovastatin contents of bekasam extracts produced using ethanol, aquabides, and methanol were 442.53 ppm, 168.67 ppm, and 158.19 ppm, respectively. Peptides were detected on bekasam extract by aquabidest in the range of 5.60-29.26 kD but undetected when extracted using the other solvents.

Comparative investigation on the value-added products obtained from continuous and batch hydrothermal liquefaction of sewage sludge

Hydrothermal liquefaction (HTL) can be considered a promising route for the energy valorisation of waste sewage sludge (SS). However, not much information is available on continuous flow processing. In this study, the mixed SS was subjected to HTL at 350°C for 8 min in a continuous reactor with loadings of 10 wt% in the feed flow. The results show that the mass recovery reached 88%, with a biocrude yield of 30.8 wt% (3.9 wt% N content). The recovered biocrude yields are highly dependent on the selection of the recovery solvent for extraction, and dichloromethane can contribute an additional 3.1 wt% biocrude from aqueous phase, acetone can extract some pyrrole derivatives into the trapped phases. Comparable results were also achieved by performing batch reactions under the same conditions: a slightly higher biocrude yield (33.1 wt%) with an N content of 4.3 wt%. The higher N content observed in the biocrude from the batch process indicates that interactions and chelation between intermediates are enhanced during heating up and cooling period, which lead to more N-containing compounds.

Impact of winter savory extract (Satureja montana L.) on biochemical parameters in serum and oxidative status of liver with application of the principal component analysis in extraction solvent selection.

Satureja montana L. is traditionally used as spice and for treatment various diseases. Many studies have shown antioxidative effect of Satureja species. Our thorough study in an animal model was performed through measurement of biochemical parameters in the serum, histology analysis and determination of oxidative status of the liver, coupled with investigation of extraction solvent selection using principal component analysis (PCA). Winter savory dry extract (500 mg/kg) dispersion and saline solution were given to Wistar rats for 7 days after exposure to oxidative stress using toxic doses of paracetamol (600 mg/kg). Rats were sacrificed, after which a complete autopsy was performed, the blood obtained was used to determine biochemical parameters, and the liver was sliced for histological analysis and determination of oxidative stress enzymes. Indicators of hepatic and kidney functions, as well as the concentration of oxidative stress enzymes, were statistically significantly lower in animals treated with Satureja montana L. extract compared to the paracetamol group alone before the toxic dose of paracetamol. Liver enzymes were unaltered by pre-treatment with the extract, but the level of lipid peroxidase was decreased, and the level of catalase, glutathione reductase and superoxide dismutase increased proving in vivo antioxidant effect. In addition, the number of inflammatory cells is decreased coupled with activity of CYP2E1 enzymes proving hepatoprotective effect. Satureja montana L. extract in our research has shown hepatoprotective, anti-inflammatory and antioxidative effect. PCA analyses indicated that extraction mediums have a great impact on the antioxidative effect.

Application of gas flow headspace liquid phase micro extraction coupled with gas chromatography-mass spectrometry for determination of 4-methylimidazole in food samples employing experimental design optimization.

Background4-Methylimidazole (4-MeI) or 4-methyl-1H-imidazole, a slightly yellowish solid with molecular formula C4H6N2, is a heterocyclic compound which supposedly does not exist as a natural product and is formed when carbohydrates are heating with ammonium compounds. This compound is used in pharmaceuticals, agriculture and photography chemicals, dyes and pigments, and rubber manufacturing. In the present study, a simple and efficient sample preparation method designated gas flow headspace liquid phase microextraction (GF-HS-SDME) was employed for the extraction and preconcentration of 4-methylimidazole (4-MeI) from food and beverage samples, before its determination by gas chromatography-mass spectrometry.ResultTo investigate the optimal conditions for the extraction process in GF-HS-SDME method, factors affecting extraction, including selection of extraction solvent, vial volume, extraction solvent ratio, position of extracting solvent, drop volume, sample volume, stirring speed, temperature, extraction time, sample pH, ionic strength of the sample solution and gas flow rate were optimized by utilizing both one-variable-at-a-time method and Plackett–Burman design. The investigation of protocol was carried out by using a standard solution containing 100.0 μg L−1 of 4-MeI in deionized water.ConclusionIn this study, a simple and green analytical method based on GF-HS-SDME was proposed for the extraction and preconcentration of 4-MeI from foodstuffs, followed by GC–MS determination. The main advantage of this method is its high preconcentration factor and fastness due to the application of an inert gas stream during microextraction.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13065-022-00823-z.

Expansion of the composition library for chemodiversity of hardwood extractives at molecular level by ultrahigh-resolution mass spectrometry.

To enhance the characterization of wood extractives at molecular level, a detailed ultrahigh-resolution mass spectrometry (UHRMS)-based analytical methodology was developed in this work. The analytical strategies, including selection of compatible solvent for extraction, evaluation of ionization solvent for effective electrospray ionization, and multi-dimensional data analysis, were established to ensure a comprehensive characterization of complex compositions in wood extractives. Extraction capability of seven solvents with varied polarities was examined by a standard reference material of hardwood biomass and evaluated based on thousands of compounds which were much more than those discovered before. With a variety of data-processing approaches, including compound type distribution, double bond equivalent versus carbon number plot, and van Krevelen diagram, the chemodiversity of the extractives was fully explored from different perspectives. This work greatly expanded the compound library of wood extractives and could also provide guidance for the integrated composition analysis of other biomass materials.

Application of multivariate linear regression models for selection of deep eutectic solvent for extraction of apigenin and luteolin from Chrysanthemum indicum L.

Among a variety of compounds presented in chrysanthemum, apigenin and luteolin are the two main components that play a major role in numerous biological activities of this herb. We aimed to obtain linear models showing the dependence of the yield of extraction of apigenin and luteolin on the composition of deep eutectic solvent and investigate the extraction of these two ingredients from Chrysanthemum indicum L. Two models showing the dependence of luteolin and apigenin concentrations on the composition of the solvent were established using a multilinear regression algorithm and were applied to screen 119 different solvents. After that, the extraction process was optimized using response surface methodology and an artificial neural network. Apigenin and luteolin were recovered from the extract by the combination of distillation and addition of water. The screening results on 119 solvents revealed that choline chloride-acetic acid (1:4) was the most suitable deep eutectic solvent. It was showed that both response surface methodology and the artificial neural network could accurately determine the optimal conditions of extraction of apigenin and luteolin from C. indicum L., including time of extraction (65 minutes), temperature of extraction (90°C) and water content (20%). By the combination of distillation and addition of water, apigenin and luteolin could be effectively recovered from the deep eutectic solvent extract with a recovery rate of over 80%. Deep eutectic solvent could be used as an effective green alternative to the conventional solvents for the extraction of bioactive compounds from plants.

Selection of extraction solvents for edible oils from microalgae and improvement of the oxidative stability

Microalgae are natural, green raw material and could be used for the development of edible oil for its abundant polyunsaturated fatty acids, with fast growth rate. The wet mud and dry powder of Scenedesmus dimorphus were applied to compare the extraction effects of different organic solvent systems in this study. The results displayed that, by using the ethanol/n-hexane (3:2, v/v) mixed solvent, the oil extraction rate from wetalgal mud was 68.31 %, with 71.65 % of neutral lipid, and 1.87 % of vitamin E; the retention rates of protein, chlorophyll, and carbohydrates in the algal residue after oil extraction were 60.56 %, 53.27 %, and 80.20 %, respectively. Through the single solvent n-hexane, the oil extraction rate from dried algal powder was 71.52 %, with 75.86 % of neutral lipids, and 1.63 % of vitamin E. The retention rates of protein, chlorophyll, and carbohydrate were 55.92 %, 61.33 % and 78.35 %, respectively, suggesting the high rate of nutrient retention. In addition, the orthogonal experiments indicated that the compound of low concentration natural antioxidants with 0.010 % of tea polyphenols, 0.005 % of vitamin E, and 0.015 % of rosemary extract had the best effects on improvement of oxidative stability.

PHYTOCHEMICAL SCREENING AND CHARACTERIZATION OF VOLATILE COMPOUNDS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY FROM “NEPHROLEPIS EXALTATA”

Objective: Plants contain various types of phytochemicals with different solvent as per solvation properties, depending on their polarity. The goal of this analysis is to compare the effects of different solvents on the phytochemical profile and the characterization of different volatile bioactive compounds of Nephrolepis exaltata, a typical fern belonging to pteridophyte species.
 Methods: For the screening of phytochemical, a sequential extraction was carried out using different solvent systems namely methanol (MeOH), chloroform, carbon tetrachloride, hexane, and ethyl acetate (EtAc). A varied range of phytochemicals was found in the extracts. The volatile components were analyzed using the hyphenated technique gas chromatography-mass spectrometry (GC-MS).
 Results: All the extracts were found to be rich in alkaloids, whereas phenols and Phytosterols were extracted only in MeOH. The MeOH extract of the fern presented positive results for six phytochemical tests and the n-Hexane (nH) extract presented positive results for seven phytochemical tests. The present investigation on the plant N. exaltata aimed to prove that pteridophytes should have various kinds of bioactive phytochemicals and the selection of solvent for extraction of phytochemicals should be based on the target compounds.
 Conclusion: From the % yield of different extract, it can be concluded that some the bioactive phytochemicals are more soluble in more polar solvents such as MeOH, some are soluble in moderate solvents like EtAc and mostly non-polar organic molecules can be extracted using non-polar solvents like nH. The GC-MS characterization indicates the presence of different fatty compounds and sterols in the plant extract.

Haematococcus pluvialis로부터 아스타잔틴 추출을 위한 추출공정 조건 최적화

In this study, the selection of extraction solvent and optimization of extraction condition were carried out to increase the extraction of astaxanthin, an antioxidant material produced from Haematococcus pluvialis. For increasing the extraction of astaxanthin through more effective cell disruption, the concentration of acetone, rotation speed of homogenizer, extraction temperature, and extraction time were sequentially optimized. When acetone (50% v/v) was used as an extract solvent, the extraction concentration of astaxanthin was found to be the highest (1.41 ㎍/mL), and the extraction concentration increased 3.3 times compared to ethanol extraction. As the concentration of acetone increased to 99.5% (v/v), it was found that the concentration of astaxanthin increased proportionally to 2.47 ㎍/mL. When evaluating the effect of rotation speed and extraction temperature, astaxanthin concentration was maximized to 3.93 g/mL at 15,318 rpm (impeller tip speed = 5.67 ㎧) and 52.5℃. In addition, as extraction time increased, the concentration of extract was increased and resulted in a maximum of 4.76 ㎍/mL at 16.6 min which was a 10.9-fold increase compared to ethanol extraction indicating that acetone is more effective than conventional solvents in the extraction of astaxanthin.

Promoted reaction microextraction for determining pesticide residues in environmental water samples using gas chromatography-mass spectrometry

A microextraction technique termed promoted reaction microextraction (PRME) based on a liquid-liquid microextraction was developed by applying a chemical reaction for promoting the extraction of the analytes into the extracting solvent. PRME is a very simple, rapid and high-performance method for extraction and pre-concentration of organic compounds from water samples. In PRME, different types of chemical reactions can be used. In the present work, an acid-base reaction that produces a gaseous product is employed. In this method, appropriate amounts of auxiliary solvent (methanol), acidic promotor (oxalic acid), and extraction solvent (chloroform) were added rapidly into a water sample containing a basic promotor (sodium bicarbonate). After adding the solution containing the acidic promoter to the water sample containing the basic promoter, the acid-base reaction started with high intensity. The reaction product consisted of salt, water, and carbon dioxide gas. The produced carbon dioxide generated bubbles in the reaction medium that promoted the extraction of the analytes into the extracting solvent. After centrifuging, the fine particles of the extraction solvent were sedimented in the bottom of the conical tube. The denes phase was analyzed by gas chromatography-mass spectrometry (GC/MS). Several parameters affecting the extraction of 17 target pesticides by PRME-GC/MS (i.e., a selection of extraction solvent, extraction solvent volume, selection of auxiliary solvent, basic promotor content, and acidic promotor content) were investigated. Under the optimum conditions, the calibration graph was linear in the range of 0.035–40.0 µgL−1 with the detection limit of 0.003–0.035 µgL−1 for pesticides. The relative standard deviations (RSDs) of the PRME-GC/MS method were in the ranges of 2.29–4.76% (n = 3 and c = 0.30 µgL−1).

An integrated approach for the valorization of mango seed kernel: Efficient extraction solvent selection, phytochemical profiling and antiproliferative activity assessment.

A novel valorization strategy is proposed in this work for the sustainable utilization of a major mango processing waste (i.e. mango seed kernel, MSK), integrating green pressurized-liquid extraction (PLE), bioactive assays and comprehensive HRMS-based phytochemical characterization to obtain bioactive-rich fractions with high antioxidant capacity and antiproliferative activity against human colon cancer cells. Thus, a two steps PLE procedure was proposed to recover first the non-polar fraction (fatty acids and lipids) and second the polar fraction (polyphenols). Efficient selection of the most suitable solvent for the second PLE step (ethanol/ethyl acetate mixture) was based on the Hansen solubility parameters (HSP) approach. A comprehensive GC- and LC-Q-TOF-MS/MS profiling analysis allowed the complete characterization of the lipidic and phenolic fractions obtained under optimal condition (100% EtOH at 150 °C), demonstrating the abundance of oleic and stearic acids, as well as bioactive xanthones, phenolic acids, flavonoids, gallate derivatives and gallotannins. The obtained MSK-extract exhibited higher antiproliferative activity against human colon adenocarcinoma cell line HT-29 compared to traditional extraction procedures described in literature for MSK utilization (e.g. Soxhlet), demonstrating the great potential of the proposed valorization strategy as a valuable opportunity for mango processing industry to deliver a value-added product to the market with health promoting properties.

A new extraction procedure to abate the burden of non-extractable antibiotic residues in manure

Through agricultural soil fertilization using organic manure, antibiotic residues can accumulate in the environment. In order to assess the risks of environmental pollution by veterinary drugs, monitoring of manure for antibiotic residues is necessary. As manure is a complex matrix, extraction of antibiotics proved to be challenging. In this study, 24 extraction solvents were assessed for the extraction of residues from manure representing ten antibiotics from the antibiotic classes tetracyclines, quinolones, macrolides, lincosamides and sulfonamides. Especially for the tetracyclines and quinolones the extraction solvent selection is critical, due to high fractions of non-extractable residues especially when using aqueous solvents (62–77% and 90–95% respectively when using milli-Q water). In contrast, sulfonamides can effectively be extracted with aqueous solvents. Overall, 0.125% trifluoroacetic acid in acetonitrile in combination with McIlvain-EDTA buffer proved to be the most effective extraction solvent. A longitudinal study pointed out that most antibiotics bind to solid manure particles instantaneously after addition. Trimethoprim is an exception, but because by using the optimal extraction solvent, the optimum fraction of bound residues is desorbed, this does not hamper quantitative analysis when using spiked manure quality control samples. Based on these new insights, the current in-house multi-residue LC-MS/MS method for manure analysis, containing 48 antibiotics, was revised, additionally validated and applied to 34 incurred manure samples.

Uninfected agarwood branch extract possess cytotoxic and inhibitory effects on MCF-7 breast cancer cells

Apart from the highly sought agarwood resin primarily for perfumery industry, agarwood or gaharu (Aquilaria spp.) in general has been one of basic components in traditional medicine including Ayurvedic, Traditional Chinese Medicine and other communities in the Asian region. While the resin is formed in infected trees, this present study reported the cytotoxicity and attachment inhibition effects of leaf and branch extracts from uninfected agarwood tree against breast cancer cells. Qualitative extraction screening process was first conducted to screen for suitable extraction solvents and parts of plant (leaf or branch). Then, the in vitro anti-cancer screening assays including cytotoxicity and attachment assays were conducted. Branch sample extracted using ethanol and distilled water resulted in higher yield and more potent cancer inhibiting effects as compared to other solvents. Crude extract obtained after drying process using ethanol as solvent yielded 9.47 % g/g (branch) and 13.2 % g/g (leaf); distilled water as solvent yielded 9.33 % g/g (branch) and 12.8 % g/g (leaf), respectively. However, branch extract exhibited more potent cancerinhibiting effects with IC50 of 23 µg/mL (ethanol) and 38 µg/mL (distilled water) as compared to leaf (no intersection points in the plot). To this end, it can be concluded that extracts from uninfected agarwood tree (Aquilaria subintegra) possesses cytotoxic and anti-attachment effects on MCF-7 breast cancer cells with ethanolic branch extract being the most promising. The screening and selection of extraction solvent and plant type are crucial steps towards cost-effective extraction and further bioprocessing of bioactive compounds from agarwood tree.

Effects of the extraction solvents in hydrothermal liquefaction processes: Biocrude oil quality and energy conversion efficiency

One prevailing issue for assessing the performance of hydrothermal liquefaction is understanding the role of the extraction solvent used for product separation. This study evaluated the extraction agent's impact on the hydrothermal liquefaction products and energy efficiency. Three representative solvents (acetone, dichloromethane, and toluene) were chosen with three representative high-carbohydrate, protein, and ash content feedstocks (Chlorella sp., Nannochloropsis sp., and Enteromorpha pr., respectively). Extraction of the oil using dichloromethane led to the highest biocrude oil yield (dry biomass) for Chlorella sp. (48.8%), toluene for Nannochloropsis sp. (23.3%), and acetone for Enteromorpha pr. (9.8%). The solvent selection led to a maximum variation of 20.4% for all oil yields. Dichloromethane produced high energy recovery values (maximum: 67.1%) and low energy consumption ratios (minimum: 0.06) regardless of the feedstock chemical composition. Dichloromethane also led to consistently high net energy values and high fossil energy ratios amongst all feedstocks. We speculate that the solvent polarity, chemical structure, hydrogen bonding, and dipole-dipole interactions influenced output parameters by the selective isolation and extraction of the chemical compounds in the biocrude oil. This study suggested that the extraction solvent selection should be carefully considered and normalized for the reporting of hydrothermal liquefaction yields and energy efficiency values.