Microwave-assisted Extraction Research Articles

Sonochemical-assisted synthesis of copper oxide nanoparticles with the plant-mediated approach and comparative evaluation of some biological activities.

The present study reported a green approach for the sonochemical-assisted synthesis (SAS) of copper oxide nanoparticles (CuO NPs) by using the aqueous extract of the Ficus johannis plant. The aqueous extract was obtained using ultrasonic-assisted extraction (15min, 45°C) and microwave-assisted extraction (15min, 450 w). Next, the as-prepared extracts were used in a plant-mediated approach for the green synthesis of CuO NPs. The synthesized CuO NPs have been characterized via different techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), ultraviolet-visible absorption, photoluminescence, and Fourier-transformed infrared (FT-IR) spectroscopic techniques. As observed, a broad absorption band around 375nm clarified the successful synthesis of CuO NPs. From the SEM analysis, the average particle size of the prepared CuO NPs was estimated below 50nm. In addition, the antimicrobial, antioxidant, and antifungal properties of the aqueous extracts as well as the as-prepared CuO NPs were evaluated by different assays. These included the release of protein, nucleic acids, disk diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and time-killing assays.

Advances in Ascorbic Acid (Vitamin C) Manufacturing: Green Extraction Techniques from Natural Sources

Ascorbic acid (AA), or vitamin C, is one of the most important vitamins consumed through the diet due to its critical role in many biological processes. Although the human body cannot synthesize it, AA is essential in maintaining healthy bodily structure, acting as a cofactor of many enzymes involved in collagen synthesis and an efficient immune system. At the same time, AA is used in the cosmetic field for its antioxidant and antipigmentary properties, in the food industry as additive, and in chemical synthesis as reducing agent. AA can be chemically synthesized, produced by the oxidative fermentation of bacteria, or extracted from natural sources. This review addresses the most recent developments in its manufacture, including techniques for extracting vitamin C from plants, fruits, vegetables, algae, and leaves, and focusing on the most commonly used green methods, i.e., ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction, and supercritical fluid extraction. These methods are based on mild extraction conditions, environmentally friendly solvents, low time, cost, and energy consumption. In contrast, their extraction yields are comparable to or even higher than those of conventional methods.

Synthesis and Characterization of Corn Husk (Zea Mays L.) Cellulose Using Microwave-Assisted Extraction (MAE)

This research focuses on synthesizing cellulose from corn husks using microwave-assisted extraction (MAE), which aims to produce cellulose from corn husks through liquefaction, delignification, and bleaching processes. The total time required is only 14 minutes, thus shortening the process time. This study used three power variations: 450 W, 600 W, and 800 W. The results showed that the optimum conditions occurred at 800 W power. Hence, the higher the power caused the high cellulose content obtained, which amounted to 75.23% and decreased the lignin value to 15.78%, along with the increase in microwave power. FTIR analysis also confirmed the cellulose results obtained and indicated that the lignin groups were weakened or lost. Furthermore, morphological analysis of cellulose fibers by SEM showed that the surface of cellulose fibers was rough, oval, and irregular due to cracks caused by erosion. Then, the result of cellulose crystallinity using XRD was 45.8%. Compared to conventional methods, microwave-assisted cellulose synthesis exhibits better and more promising potential. This is because microwave radiation can be used to improve process time efficiency and achieve higher yields. Moreover, the proposed method is easier, faster, and straightforward.

Improved Curcumin Recovery and In Vitro Biological Activity of Turmeric Extracts Using Nipa Palm Syrup– and Nipa Palm Vinegar–Based Natural Deep Eutectic Solvent (NADES) Hybridized with Microwave-Assisted Extraction

Improved Curcumin Recovery and In Vitro Biological Activity of Turmeric Extracts Using Nipa Palm Syrup– and Nipa Palm Vinegar–Based Natural Deep Eutectic Solvent (NADES) Hybridized with Microwave-Assisted Extraction

Conversion of artichoke leftovers to levulinic acid: A biorefinery approach

The valorization of agrifood leftovers from an herbaceous plant widely cultivated in Mediterranean areas (Italy and Spain), Cynara scolymus L., is reported here as part of a zero-waste biorefinery approach. The Globe artichoke (GlobART) variety was selected as the source of artichoke leftovers, which were valorized using the following cascade approach: (i) the recovery of antioxidant compounds (AC) still present in the matrix through sustainable microwave-assisted subcritical water extraction (MA-SWE); and, (ii) the subsequent production of levulinic acid (LevA) via the MW-assisted conversion (225ºC, 2 min, 1500 W) of the cellulosic fraction recovered after initial extraction. Preliminary MW-assisted conversion tests on the post MA-SWE GlobART matrix yielded about a 37% yield of LevA (molar yield) using HCl and p-toluenesulfonic acid (p-TsA). Furthermore, performing a delignification step, mediated by either ultrasound (UAD) or MW (MAD), on the post-MA-SWE GlobART matrix before conversion considerably increased LevA yield (55% and 71% from post-UAD and post-MAD GlobART matrices, respectively, with p-TsA). Finally, reducing the KBr/biomass ratio, when using p-TsA, by half afforded an enhancement in LevA yield up to 80% when starting from the post-extraction and delignified (post MA-SWE-& MAD) GlobART matrix.

Purification and separation of glucomannan from porang tuber flour (Amorphophallus muelleri) using microwave assisted extraction as an innovative gelatine substituent

Gelatine is frequently used as a food ingredient. However, Indonesia imports almost all of its gelatine, totaling 3990152 tons annually. Gelatine could be replaced with glucomannan compound which was found in porang tubers. However, it also contains calcium oxalate, which is harmful for the human body. In this study, calcium oxalate was first eliminated by the purification process using 10 % NaCl (w/w). Moreover, the microwave-assisted extraction method was used to extract the glucomannan compound by applying 300 W of microwave power with different extraction times (5, 10, 15, and 20 min) and different ethanol concentrations (60, 70, 80, and 96 %). Statistical analysis was used to optimize and identify significant parameters influencing the glucomannan concentration. The best conditions for glucomannan extraction were an extraction time of 10 min and an ethanol concentration of 80 % (v/v), resulting in a glucomannan yield of ≥96 %. Machine learning was successfully applied for data modelling using a Long Short-Term Memory block with an average R-square of 0.9772 (97.72 % accuracy) and an average MSE of 4.7719. Furthermore, physical and chemical characteristics of the extracted porang flour were accorded with SNI gelatine standards 06–3735 in 1995, which consisted of glucomannan (96.359 ± 1.164 %), calcium oxalate (0.009 ± 0.001 %), water (2.290 ± 0.986 %), ash (0.018 ± 0.002 %), fat (0.0235 ± 0.120 %), heavy metals (not identified), and pH (6.455 ± 0.191). Finally, the extracted glucomannan can be used as a potential regional substitute for gelatine production.

A Rapid Evaluation Method for Transformer Insulation Status

A method for rapid analysis of transformer insulation status indicated by moisture content in insulation paper was developed by microwave-assisted solvent extraction coupled with Fourier transform infrared spectroscopy (FTIR). The results show that acetonitrile is the best extraction solvent, and the second derivative based on the difference spectrum is obviously better than the difference spectrum. For the acetonitrile spectrum of extracting water, the sensitivity of hoh bending vibration 1680 cm−1 is higher than that of OH stretching vibration 3615 cm−1. For all test samples, the results of this method are basically consistent with the standard method and show excellent precision. The study shows that it is feasible to rapidly analyze the moisture content of transformer insulation paper by solvent extraction coupled with FTIR.

Transesterification of Microalgae from Food Waste via Acid Catalyst for Biodiesel Production

Recently, numerous studies have presented the potential of various feedstock of biodiesel catalysed with acid catalysts and its performance. This study examines the potential of microalgae from food waste for biodiesel production by a homogeneous acid catalyst in a transesterification reaction. Initially, lipid was extracted from the microalgae using the microwave-assisted extraction (MAE) method. Then, the lipid was transesterified using a sulphuric acid catalyst under different conditions to decide the optimum condition. About 50% of the lipid was extracted from the microalgae when 400 W of microwave power was used for 15 minutes. The biodiesel yield of 76% has been attained from transesterifying the extracted lipid with methanol using 9:1 of methanol to oil molar ratio, 2.5 wt% of catalyst dosage for 3 hours at 65°C. Overall, this study has shown the potential of microalgae from food waste as one of the options for biodiesel’s feedstock catalysed by acid.
 Keywords: Biodiesel, food waste, microalgae, transesterification, acid catalyst, microwave assisted extraction (MAE)

Exploring green extraction methods to obtain polyphenols from partially defatted chia (Salvia hispanica L.) flour

Aim: The extraction of polyphenols is commonly accomplished using conventional techniques such as solid-liquid and liquid-liquid extraction, which are associated with the use of high quantities of organic solvents, long extraction times, and low selectivity and reproducibility. These limitations have led to the development of innovative extraction technologies. The purpose of this study was to investigate the ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of polyphenols from partially defatted chia flour (PDCF). Methods: The effect of four factors on the extraction of polyphenols (percentage in relation to the initial weight of PDCF) and on the antioxidant activity [quantified by 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and ferric reducing antioxidant power (FRAP) methods] was investigated and the UAE and MAE processes were optimized using the response surface methodology (RSM). Results: It was found that MAE improved the extraction yield (polyphenol content and antioxidant activity) in shorter extraction times when compared to UAE. Conclusions: The application of these alternative green technologies improved the performance of the polyphenol extraction process from PDCF. Overall, both techniques could be used as efficient green alternatives.

Polyphenol Composition by HPLC-DAD-(ESI-)MS/MS and Bioactivities of Extracts from Grape Agri-Food Wastes.

Grape agri-food wastes, such as skin, seeds, and other discarded by-products, contain phytochemical compounds that offer potential health benefits. This study aimed to investigate the polyphenol composition and bioactivities of different extracts obtained from grape marc and seeds, with the goal of exploring their potential for application as natural food additives. Regardless of the extraction method used (dynamic maceration, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE)), all extracts exhibited relatively high concentrations of phenolic compounds. The chemical characterization of the extracts revealed the presence of specific compounds and chemical groups associated with each extraction methodology. Moreover, the extracts displayed satisfactory antioxidant activities, especially in inhibiting lipoperoxidation as assessed by the TBARS assay. Additionally, the extracts demonstrated effective inhibition against different strains of bacteria and fungi known as food contaminants. Taken together, these findings indicate that those extracts have the potential to be tested as natural antioxidants and preservatives with sustainable origins in food and beverage systems. Among the extraction methods evaluated, traditional maceration and UAE provided extracts with the highest antioxidant and antimicrobial activities. Our results suggest the opportunity to explore grape marc and seeds discarded by the winery industry in Portugal as natural sources of bioactive compounds, which could be employed as functional food ingredients or technological additives. The valorization of grape biowastes offers a promising strategy to reduce waste and harness their potential health benefits.

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

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

Microwave-Assisted Extraction of Phenolic Components in Olive Leaves and its Kinetics, and Antioxidant Properties of Extracts

Son zamanlarda, çeşitli gıda üretim yan ürünlerinden antioksidan aktivite gibi sağlık yararları nedeniyle fenolik bileşen ekstraksiyonuna artan bir ilgi olduğu dikkat çekmektedir. Mevcut çalışmada, zeytin yapraklarından (ZY) fenoliklerin ekstraksiyonu için verimli bir alternatif ve yeşil teknik olarak nitelendirilen mikrodalga destekli ekstraksiyon (MDE) tekniği çalışılmıştır. Değişen mikrodalga gücünün toplam fenoliklerin salınım kinetiği üzerindeki etkisi K1, Bo,Ceq, k, ve SEE parametreleri belirlenerek mikrodalga gücünün etkisini ekstraksiyon süresi açısından açıklamak için kinetik modeller oluşturulmuştur. Üç farklı güçte (100, 300 ve 500W) artan süre ile birlikte ekstraksiyon verimi ve ekstraktların antioksidan özellikleri değerlendirilmiştir. 100 W uygulama için artan süre ile birlikte 15. dakikaya kadar ekstraktların antioksidan özelliklerinin arttığı görülmüştür. 300 W güç uygulamasında ekstraktların fenolik bileşen içeriği ve 2,2-difenil-1-pikrilhidrazil (DPPH) radikali süpürücü aktivite değerleri 10. dakikaya kadar artış göstermiştir. 500 W güç uygulaması için ekstraktların hem fenolik içeriğinin hem de antioksidan özelliklerinin 4. dakikaya kadar arttığı ve daha sonra ilerleyen uygulama süresiyle doğru orantılı olarak azaldığı görülmüştür. Tüm ekstraktlar arasında en yüksek toplam fenolik bileşen içeriği ve antioksidan kapasite değerleri 500 W güçte ve 4 dakika süre ile ekstrakte edilen örnekte gözlemlenmiştir. Aynı örnek için toplam fenolik bileşen içeriği, DPPH radikali süpürücü aktivite ve metal şelatlama aktivite değeri sırasıyla 9.52±0.21 mg gallik asit eşdeğeri (GAE)/mL, 15.22±0.45 mg Trolox eşdeğeri (TE)/g ZY ve 98.13±0.04 µmol etilenediaminetetraasetik asit (EDTA)/g zeytin yaprağı (ZY) olarak elde edilmiştir. Ekstraksiyon kinetiğine ait sonuçlara göre MDE için Peleg modelinin daha uygun olduğu görülmüştür. Sonuçlar göz önüne alındığında zeytin yapraklarından MDE için artan güç, ekstraksiyon süresinin kısalmasını sağlamıştır. Ayrıca yüksek güçlerde uzun uygulama sürelerinin ekstraksiyon verimini azalttığı görülmüştür.

Studies on the extraction of Jerusalem artichoke tuber phenolics using microwave-assisted extraction optimized conditions

Microwave-assisted extraction (MAE), which is a known method for the extraction of phenolic compounds from plants, was employed to extract the polyphenols in Jerusalem artichoke tuber (JAT) using response surface methodology optimized conditions of microwave power (MP), extraction-time (TE) and temperature (Temp). The MAE was used to improve polyphenols extraction yield from JAT. The ethanolic extracts of JAT obtained by MAE were quantitatively analyzed for total polyphenol content (TPC), total flavonoid content (TFC) 2, 2′-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP). The optimal conditions obtained were as follows: Temp of 79.18 °C, TE of 11.96 min, and MP of 13.49 W. Based on these conditions, the extraction yield of TPC, TFC,% DPPH and FRAP could reach 4483.33 mg GAE/kg, 2731.59 mg RE/kg, 82.69 % and 2.65 mmol/L respectively with a predicted general-desirability value of 0.82. DPPH (r = 0.972) and FRAP (r = 0.982) significantly (p < 0.05) correlated to TPC suggesting that TPC was the main phenolic contributing to the antioxidant activity. The extraction yield recorded was higher than that of the liquid and ultrasound extraction methods.

Microwave irradiation, evolutionary algorithm and ultrafiltration can be exploited in process intensification for high-purity and advanced inulin powder production

This study investigated the effect of microwave-assisted aqueous extraction followed by ultrafiltration protocols on Jerusalem artichoke inulin powder's yield and functional properties. The standard inulin production method was also practiced, and the effectiveness of process parameters for two different techniques was investigated through response surface methodology as well as genetic algorithm. The proposed parameters of the genetic algorithm further increased the extraction yields, and the inulin contents reached 94 – 95% after applying the 5 kDa cut-off ultrafiltration. Microwave-assisted extraction significantly improved lyophilized inulin powder's physical and chemical properties, such as Carr index, Hausner ratio, wettability, viscosity, dispersibility, and solubility. The water-holding capacity of inulin powder produced by conventional and microwave-assisted methods were 9% and 11%, respectively, while it was 7.2% for untreated Jerusalem artichoke powder. As for oil binding capacity, the value of 12.9% in the raw material increased to 14.1% and 13.3%, respectively. The loss modulus (G″) values were dominant over storage modulus (G′) values, and microwave treatment resulted in lower modulus values. The Fourier transform infrared spectroscopy (FTIR) spectra and scanning electron microscope (SEM) images clearly depicted the chemical and structural modifications in the powders. Results showed that microwave application could significantly enhance inulin powder's yield and physicochemical properties. Genetic programming was beneficial in promoting the extraction parameters. Sequentially applying microwave-assisted extraction and ultrafiltration could be a convenient process for inulin powder as a functional ingredient for the food, pharmaceutical, and chemical industries.

Optimisation of Microwave-Assisted Extraction of Artocarpus integer Peel Pectin with Choline Chloride based Deep Eutectic Solvent

Extraction of pectin from natural resources using a biodegradable solvent is an alternative to wasteful and corrosive acidic extraction. Traditionally, attempts to extract pectin from biomass have resulted in low yields and a large consumption of corrosive solvents. Therefore, microwave-assisted extraction (MAE) with deep eutectic solvents (DES) of choline chloride and malonic acid (ChCl:MA) at a mole ratio of 1:2 was used in this study. The objective of this study was to extract pectin from Artocarpus integer peels (AIP) and to optimise the extraction conditions in terms of the percentage of DES, solid-to-liquid ratio of AIP to DES, microwave power, and extraction time. The results showed that the pectin yield increased as the percentage of DES, solid-to-liquid ratio, power, and time increased. The extraction of pectin up to 30.17 % with MAE was optimised at a 1:50 ratio, 50 W, 4 min, and 5 % DES. These results indicate that the proposed MAE-DES technique is excellent for extracting pectin with high yield from AIP.

Extraction and Isolation of Tyrosine Ammonia Lyase (TAL) and Diosgenin from &lt;i&gt;Persea americana&lt;/i&gt; as Potent Inhibitors of Melanin Synthesis Involving &lt;i&gt;In Vivo&lt;/i&gt; Study on Zebrafish Embryos

Tyrosine ammonia lyase is an enzyme in the natural phenol biosynthesis pathway. L-tyrosine is deaminated to p-Coumaric acid with the help of the enzyme tyrosine ammonia lyase. Tyrosine Ammonia Lyase (TAL) is extracted from the leaves of Persea americana. Diosgenin involved in the inhibition of intracellular tyrosinase is extracted along with the enzyme Tyrosine Ammonia Lyase from leaves of Persea americana, significantly increasing the activity of Tyrosine Ammonia Lyase. Diosgenin in the current study on analysis is highly increasing the activity of enzymes. The ability of the enzyme along with diosgenin to increase the activity of the enzyme is analysed in the current study. The enzyme along with diosgenin is used for depigmentation of skin. The methodology of protein separation on treatment with acetone was utilized for the extraction of the enzyme. p-Coumaric acid formation detected using a UV-Visible spectrophotometer at 380nm confirmed the presence of the enzyme. Defatting followed by microwave-assisted extraction and ultrasound-assisted extraction methodology were used for the extraction of diosgenin from leaves of Persea americana. The role of diosgenin in increasing the activity of the enzyme was carried out by analysing the enzyme activity at 410nm. The enzyme-activating ability of diosgenin was compared with that of magnesium sulphate-purified Tyrosine Ammonia Lyase enzyme and sodium sulphate-purified Tyrosine Ammonia Lyase enzyme. Zebrafish embryos were used as model organisms for the conduction of in vivo studies. kojic acid was used as a control in the in vivo studies to compare the effect of the enzyme extracted along with the diosgenin with that of kojic acid.

Microwave-assisted aqueous two-phase extraction of polysaccharides from Hippophae rhamnoide L.: Modeling, characterization and hypoglycemic activity

Natural polysaccharides are concerned for their high biological activity and low toxicity. Two kinds of polysaccharides were extracted from Hippophae rhamnoide L. by microwave-assisted aqueous two-phase system. Under the optimal conditions predicted by RSM model (K2HPO4/ethanol (18.93 %/28.29 %), liquid to material ratio 77 mL/g, power 625 W and temperature 61 °C), the yield of total polysaccharides reached 35.91 ± 0.76 %. Moreover, the polysaccharides extraction was well fitted to the Weibull model. After purification by Sepharose-6B, the polysaccharides from top phase (PHTP, purity of 81.44 ± 1.25 %) and bottom phase (PHBP, purity of 88.85 ± 1.40 %) were obtained. GC, FT-IR, methylation and NMR analyses confirmed the backbone of PHTP was composed of a repeated unit →4)-β-D-Glcp-(1 → 2)-α-L-Rhap-(1 → 4)-β-D-Galp-(1 → 4)-α-D-GalAp-(1 → 3)-α-L-Araf-(1 → 3)-α-D-Manp-(1→, while the repeated unit in PHBP was →3)-α-L-Araf-(1 → 2)-α-L-Rhap-(1 → 4)-β-D-Glcp-(1 → 3)-α-D-Manp-(1 → 4)-β-D-Galp-(1 → 4)-α-D-GalAp-(1→. Compared with PHTP (6.46 × 106 g/mol), PHBP with relatively low molecular weight (8.2 × 105 g/mol) exhibited the smaller particle size, better water-solubility, thermal and rheological property, stronger anti-glycosylation and α-amylase inhibitory effects. Moreover, PHTP and PHBP displayed a reversible inhibition on α-amylase in a competitive manner. This study provides a high-efficient and eco-friendly method for polysaccharides extraction, and lays a foundation for sea buckthorn polysaccharides as potential therapeutic agents in preventing and ameliorating diabetes.

Ultrasound-assisted extraction followed by liquid chromatography coupled to tandem mass spectrometry for the simultaneous determination of multiclass herbicides in soil.

An analytical methodology based on ultrasound-assisted extraction (UAE) followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has been developed for the identification and quantification of 9 authorized herbicides in soil (dimethenamid-P, imazamox, S-metolachlor, nicosulfuron, pendimethalin, prosulfuron, bentazone, terbuthylazine, and mesotrione). Preliminary experiments dealing with solvent extraction, theextraction technique, and herbicide response comparison in soil, with and without organic amendments, were carried out with the purpose of obtaining high sample throughput and sensitivity. UAE and thesolvent mixture water:methanol demonstrated higher efficiency and they were selected as sample treatment and extraction solvent, respectively. Critical parameters affecting UAE were optimized by experimental design. In the present research, the extraction technique used in the official EPA microwave-assisted extraction (MAE) methodology (United States Environmental Protection Agency) and UAE optimized methodology were compared. The results indicated that the developed method showed better efficacy since microwave extraction gave very poor responses for nicosulfuron and prosulfuron. The temperature extraction was also optimized; room temperature wasthe most suitable to work with. Under the optimized conditions, the proposed UAE-LC-MS/MS method was assessed in terms of linearity (R2 ≥ 0.9912), accuracy (recoveries around 100%), and precision (relative standard deviation, RSD < 13%). The absence of significant matrix effects allowed quantification in real samples by external calibration with standards prepared in water:methanol. Method sustainability was also evaluated using the metric tool AGREEPrep. Finally, the analysis of real contaminated samples revealed the presence of 7 out of the 9 studied herbicides with S-metolachlor at high concentrations in all samples.

DES-based microwave- and ultrasound-assisted extraction of natural products from Rumex hastatus as per response surface methodology

Rumex hastatus D. Don is a medicinal wild herb that abundantly grows in many parts of the world. The current work explores the extraction of its polyphenolic and antioxidant compounds using glycerol-choline chloride deep eutectic solvent and two modern techniques, ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE). The optimization was done as per the response surface methodology. Six responses were studied including total phenolic content (TPC), total flavonoid content (TFC), total condensed tannin content (TCT), ferrous iron-chelating (FIC) activity, DPPH radical scavenging activity (RSA), and ferric reducing antioxidant potential (FRAP). The optimal factors for MAE were 10 s extraction time, 229.40 W power, 40 mL/g SSR (solvent-to-solid ratio) and 60 % DES concentration with the predicted TPC, TFC, TCT, FIC, RSA and FRAP as 64.46 mg GAE/g PM, 155.78 mg RE/g PM, 129.73 mg CE/g PM, 51.46 mg EDTAE/g PM, 235.84 mg AAE/g PM and 129.14 mg AAE/g PM, respectively. For UAE, the predicted optimal factors were 24.30 min sonication time, 47 °C extraction temperature, 40 mL/g SSR and 60 % DES concentration with the predicted TPC, TFC, TCT, FIA, RSA, and FRAP as 56.54 mg GAE/g PM, 148.24 mg RE/g PM, 155.60 mg CE/g PM, 57.83 mg EDTAE/g PM, 240.56 mg AAE/g PM and 111.71 mg AAE/g PM, respectively. Both the models were strongly supported by the validation study with minimal % errors; 2.53–6.38 % for MAE and 1.14–5.30 % for UAE. MAE was more efficient than UAE in terms of time input and recovery of total polyphenols. Therefore, the method based on DES-MAE can safely be recommended for use on an industrial level for obtaining bioactives from R. hastatus.

A new prototype reactor for the fast microwave-assisted decarboxylation and extraction of cannabinoids in olive oil from Cannabis inflorescences

Several different Cannabis-based pharmaceutical preparations have been approved for medical treatments. Standardization to ensure specified phytocannabinoid contents and to maintain the integrity of the product is therefore required. Olive oil is clearly a safe and edible solvent suitable for the galenic preparation of ready-to-use Cannabis extracts. Pharmacists can use several non-standard procedures for this purpose, most of which involve the heat treatment of the plant matrix (i.e. the female inflorescences) for 2 h. In order to allow the “neutral” and more biologically active forms of the major phytocannabinoids to be extracted, prior thermal treatment of the plant matrix is desirable. This work investigates a new prototype microwave (MW) reactor (Ethos Lean) specifically designed for the decarboxylation of the acidic cannabinoids in Cannabis inflorescences and their subsequent extraction into oil. Both of the steps to produce the oily extract were carried out in the Ethos Lean's cavity with special accessories; a rotating drum for the decarboxylation process and a glass reactor with a stirrer for the extraction step. The variables considered in the process optimization were time and temperature, according to which the instrument automatically calibrated the power output. In collaboration with a hospital pharmacy, the efficiency of the device has been evaluated by comparing the results obtained with those of exhaustive decarboxylation in a conventional oven and ethanol extraction. A comparison was also made with conventional procedures in olive oil. Thanks to the rotating drum, which is sensitive to dielectric heating, the complete and homogeneous decarboxylation of phytocannabinoids was rapidly achieved (30 min, 120 °C), even with discrete quantities of inflorescences (150 g) and without releasing the characteristic intense odor into the laboratory. The exhaustiveness (100% yields of both CBD and THC) of MW-assisted extraction process in olive oil was achieved with 30 min irradiation at 90 °C. Furthermore, the possible decarboxylation occurring during MW-assisted extraction in oil and the effect of cooling time on the final yields have also been evaluated.