Extraction Of Antioxidant Compounds Research Articles

Valorisation of white wine lees: optimisation of subcritical water extraction of antioxidant compounds

This study explored the extraction of antioxidant compounds from white wine lees using subcritical water extraction (SWE). First, SWE was compared to extraction using conventional solvents mixed with water: 50 % methanol, 50 % ethanol and 50 % acetonitrile. The antiradical activity of the extract increased to 12.8 mg TE/g of extract dry matter (DM) using conventional solvents and to 29.2 mg TE/g DM with SWE, compared to the antiradical activity of dried lees, which was 5.7 mg Trolox Equivalent/g of dry matter (mg TE/g DM). Second, SWE conditions were optimised to obtain lees extracts with a high antioxidant activity by applying a Doehlert design and response surface methodology (RSM). The extraction parameters modulated during RSM optimisation were extraction time (t, 15 – 60 min), temperature (T, 100 – 250 °C) and stirring speed (S, 100 – 1000 RPM). Antioxidant activity was assessed using DPPH and FRAP tests, as well as by measuring the Oxygen Consumption Rate (OCR) of lees extracts. Temperature was found to be the main parameter that had a significant effect on antioxidant activity. The results of the RSM showed the optimal conditions (temperature, duration and speed) for attaining maximum antioxidant activity to be: 240 °C, 15 min and 550 RPM respectively. The best-known antioxidant compounds in white wine lees, Total Polyphenol Content (TPC), Glutathione (GSH) and Total Sulfhydryl groups (TSH) were also quantified. Extracts with the highest antioxidant capacity had the highest TPC and TSH concentrations. In conclusion, this study showed (i) that subcritical water extraction is a green process that has potential as an alternative to using conventional solvents for extracting white wine lees, (ii) the chemical components involved in their antioxidant capacity, and (iii) the potential of the lees for oenological and other industrial applications.

Ethanolic extraction and GC-MS analysis of antioxidant and anticancer bioactive compounds from Mentha arvensis and Aegle marmelos

Bioactive components used to treat human ailments are abundant in medicinal plants. Mentha arvensis and Aegle marmelos have therapeutic properties due to the presence of many phytonutrients. Gas chromatography–mass spectrometry (GC-MS) was used to evaluate the properties of the antioxidant and anticancer bioactive components found in the ethanolic extracts of Mentha arvensis and Aegle marmelos leaves. The major constituents identified in the leaf extracts were octadecanoic acid, heptadecanoic acid, 15-methyl-9,12,15-octadecatrienoic acid, ethyl ester, hexadecanoic acid, neophytadiene, pentadecane, hexadecane, and 1-octadecanol. Some of these components have antibacterial, antioxidant, anticancer, and anti-inflammatory properties. Among the identified compounds, octadecanoic acid and n-hexadecanoic acid are pivotal for their anticancer and antioxidant effects. The GC–MS characterisation indicated the existence of abundant bioactive compounds, confirming their potential therapeutic activities. This study showed that the leaves of Mentha arvensis and Aegle marmelos could be used as novel sources of antioxidants and anticancer medicines.

Analysis of the composition of Brazilian black soybean seeds and mathematical modelling of intermittent drying and extraction of antioxidant compounds using fractional calculus

AbstractThe present study aims to analyze the composition of black soybean seeds, evaluate the intermittent drying of black soybean seeds by fractional calculus, optimize the extraction conditions of the antioxidant compounds by varying the solvent ratio and the extraction time, fit traditional models of extraction kinetics, and compare with the fractional order model. Regarding the oil content, it is analyzed that black soybeans have a high lipid content (18.86%), an oil source of interest for research and industrial applications. Regarding drying, it was found that the first order model cannot be used to describe the kinetics of intermittent drying for black soybean seeds and the best kinetic fits were obtained with the Page and fractional order models, which can be applied in simulations of drying and dryer designs. Regarding the extraction process, ethanol/water 45/55 (v/v) solvent proportion obtained the highest antioxidant compound content during 1 h of extraction. So and MacDonald's and hyperbolic kinetic models presented the best fitting to experimental data. About the fractional order model, it is found that for extraction conditions with more significant amounts of water in the ethanolic solution, the α value obtained is less than 1, resulting in the phenomenon of subdiffusion. For the extraction condition with a low amount of water in the ethanolic solution, the α value was greater than 1, depicting a superdiffusion process.

Using natural deep eutectic solvents for the extraction of antioxidant compounds from cornelian cherry (Cornus mas L.) fruits

Traditionally used extraction methods are usually based on toxic and/or flammable solvents. Therefore, currently, increased attention has been focused on environmentally friendly green extraction techniques. We aimed to develop a green extraction procedure by using natural deep eutectic solvents (NADES) to recover antioxidant compounds from cornelian cherry fruits (Cornus mas L.). Natural deep eutectic systems combined with maceration with shaking extraction were tested to recover of antioxidant compounds from cornelian cherry fruits. In this study, four different independent variables, namely solvent type (Glu-CA; Glu-Gly; LA-Glu), water concentration (30, 50, and 70 %; v/v), extraction time (30, 60, 90, and 120 min), and extraction temperature (25, 40, and 50 °C) were investigated. Glucose-glycerin (Glu-Gly; 1:1 M ratio) based solvent provided the best results. In addition, one-factor-at-a-time (OFAT) optimization showed that a temperature of 25 °C, 120 min of extraction time, and water concentration of 50 % (v/v) to be the best extraction parameters for Glu-Gly based NADES extraction. The developed method has been successfully applied for the extraction of antioxidant compounds from 13 different cornelian cherry cultivars. NADES can be used safely to extract phenolic compounds from cornelian cherry fruits compared to conventional extraction solvents (water and 80 % (v/v) ethanol).

Extraction of polyphenols and antioxidant compounds from SCOBY, as a by-product of Kombucha, using different types of extraction

Kombucha is obtained through a symbiosis fermentation of bacteria and yeast, generating a floating film called SCOBY (Symbiotic Culture of Bacteria and Yeast). After a period of use, SCOBY becomes a production waste. Thus, alternative uses of SCOBY can add value to Kombucha production. In this way, this work aimed to produce and evaluate antioxidant activity and total phenolic contents of SCOBY ethanolic extracts, which were obtained by two different solid–liquid extraction with three different waste weight/extractor solvent volume ratios. The SCOBY evaluated had a high concentration of cellulose (9.42 ± 1.00%) and low concentrations of proteins (0.84 ± 0.04%) and lipids (0.29 ± 0.05%). All evaluated extracts showed a high concentration of total phenolics (40.7–64.3 mg GAE/100 g of SCOBY) and high antioxidant activity (ABTS•+, FRAP and ORAC assays). The most efficient extraction of bioactive compounds was obtained by decoction using the highest solvent volume (ratio 1:20). The PCA showed clusters of the samples both by the type of extraction and by the different ratios of the weight of SCOBY to the solvent volume. Of our knowledge, our work is the first in the literature that describes such data. Therefore, the present work showed the possibility of using this industrial waste mainly to obtain active compounds and antioxidants.

Phenolic Composition and Bioactivities of Invasive Ailanthus altissima (Mill.) Swingle Leaf Extracts Obtained by Two-Step Sequential Extraction.

Ailanthus altissima, a highly invasive species, contains valuable compounds in different plant parts, indicating great practical potential. This paper proposes the use of non-polar (n-hexane) and polar (ethanol) solvents for the extraction of antioxidant compounds from A. altissima (family Simaroubaceae) leaves in a sequential two-step process. Fresh and dried leaves were examined for their microstructure by scanning electron microscopy, and for color changes in the CIELAB color space co-ordinates. An investigation of the harvesting season, processing (freezing and drying), and solvent indicates ethanol can be used for the highly efficient extraction of phenolics, flavonoids, tannins, and carotenoids. Statistically significant differences were found between the autumn and summer samples for phenolic content, and between dried and frozen samples for tannin content. The HPLC phenolic profile indicates more phenolics (nine polyphenols) in dried leaves harvested in both seasons compared to those in frozen ones (five to six polyphenols). Frozen leaves showed a higher antioxidant activity in a ferric-reducing antioxidant power assay than that of the dried samples, which exhibited a higher antioxidant activity using the 1, 1-diphenyl-2-picryl-hydrazyl assay, but it was not statistically significant. The phenolic, flavonoid, and carotenoid contents significantly influenced the antioxidant activities. Among the ethanolic extracts, those from dried leaves showed better antibacterial activity, in particular, on Staphylococcus aureus and Enterococcus faecalis. The high bioactive content and activity of A. altissima leaves make them suitable natural raw materials for various applications.

Hydrothermal Hydrolysis of Cocoa Bean Shell to Obtain Bioactive Compounds

Cocoa bean shell (CBS), a by-product from the chocolate industry, is an interesting source of bioactive compounds. In this work, the effects of time and pH on the hydrothermal hydrolysis of CBS were evaluated with the aim of maximizing the extraction of antioxidant and functional compounds from this biomass. In general, all treatments tested led to improvements in the extraction of bioactive compounds compared to untreated samples. The maximum values for antioxidant activity (187 µmol TE/g CBS dw) and phenolic compounds (14.5 mg GAE/g CBS dw) were obtained when CBS was treated at pH 4 for 10 min. In addition, maximum amounts of flavonoids (10.1 mg CE/g CBS dw), tannins (6.5 mg CE/g CBS dw) and methylxanthines (9 mg/g CBS dw) were obtained under mild pH conditions (4–5). It is noteworthy that these values are higher than those reported in the literature for other vegetable substrates, highlighting the potential of CBS to be valorized as a source of different value-adding products.

Enzyme-mediated ultrasound-assisted extraction of rutin, quercetin, and other antioxidant and antidiabetic compounds from Holarrhena antidysenterica seeds and optimization as per RSM

Rutin and quercetin are valuable bioactive natural products. The current study successfully discovered an efficient extraction protocol for these and other bioactive compounds from Holarrhena antidysenterica (HA) seeds based on an enzyme-mediated ultrasound-assisted extraction (EM-UAE). Extraction process optimization was done based on response surface methodology with seven response factors including total extraction yield (%), amount of rutin (AOR, mg/g), amount of quercetin (AOQ, mg/g), total phenolic content (TPC, mg gallic acid equivalents/g dry weight (mg GAE/g DW), total flavonoids content (TFC, mg rutin equivalents/g DW (mg RE/g DW) anti-radical activity (ARA, %), and α-amylase inhibitory activity (AIA, %). High-performance liquid chromatography (HPLC) was used for quantification of rutin and quercetin. The optimal extraction yield, AOR, AOQ, TPC, TFC, ARA, and AIA were 32.39 %, 71.43 mg/g, 23.68 mg/g, 178.63 mg GAE/g DW, 100.22 mg RE/g DW, 76.41 %, and 77.48 %, respectively. The optimal conditions were 91 min time, 6.1 mL enzyme cocktail, pH 4.8, and 48 ℃ temperature. For ARA, EC50 (µg/mL) of HA was 9.75 ± 0.27 compared to 6.10 ± 0.38 of ascorbic acid standard. For AIA, IC50 (µg/mL) of HA and acarbose standard were 51.97 ± 0.21 and 47.89 ± 0.61 μg/mL, respectively. The validation study strongly supported the predicted model with a very low relative standard deviation (0.45–3.37 %). The model was statistically significant and efficient for obtaining rutin, quercetin, and other antioxidant and antidiabetic compounds from Holarrhena antidysenterica seeds on the industrial level.

Green Solvent Extraction of Antioxidants from Herbs and Agro-Food Wastes: Optimization and Capacity Determination

Herbs and agro-food wastes are rich sources of bioactive compounds vital for organisms and valuable for many fields of industry. Therefore, in this study, green deep eutectic solvents (DESs) such as choline chloride/citric acid (ChCl:CitA), glucose/citric acid (Gu:CitA), glucose/urea (Gu:U), betaine/citric acid (B:CitA), and betaine/urea (B:U) at a molar ratio of 1:1 for ultrasound-assisted extraction (UAE) of antioxidants from four herbs (chamomile—Cha, lemon balm—LB, mint—M, and nettle—N) and two agro-food wastes (buckwheat husk—BH and chokeberry pomace—ChoP) were proposed. The antioxidant capacity (AC) of the obtained extracts was evaluated utilizing three antioxidant assays: cupric reducing antioxidant capacity (CUPRAC = 0.0–429.9 μmol of Trolox (TE)/g); 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS = 0.0–146.5 μmol TE/g); and 2,2-diphenyl-1-picrylhydrazyl (DPPH = 11.9–170.3 μmol TE/g). The LB extracts revealed the highest CUPRAC (59.3–429.9 μmol TE/g), ABTS (30.7–144.3 μmol TE/g), and DPPH (32.6–170.3 μmol TE/g) values. Due to the lowest antioxidant potential of LB extracts prepared using ChCl:CitA (AC = 30.7–59.3 μmol TE/g) and the highest AC demonstrated by extracts based on B:U (AC = 144.3–429.9 μmol TE/g), the UAE conditions using a new DES consisting of ChCl and U were optimized by the Box–Behnken design (BBD). Effects of three independent variables, molar ratios of the ChCl and U (mol/mol), water content (%), and sonication time (t) on the AC of LB extracts were studied by response surface methodology (RSM). The results of principal component analysis (PCA) and hierarchical cluster analysis (HCA) demonstrated that different DESs had great differences in the extraction of antioxidant compounds from herbs and agro-food residues.

The Effect of Brewing Time on the Antioxidant Activity of Tea Infusions

Many studies have found that tea has an antioxidant, anti-inflammatory, anti-cancer, anti-obesogenic and anti-diabetic effect, mostly associated with the content of anti-oxidant compounds. Polyphenols, being the main secondary metabolites in tea, are often considered the physiological markers determining a tea’s quality. Apart from the tea production process and tea components, brewing conditions can also influence the levels of antioxidants in tea. This study aimed to verify whether the brewing time of various tea types (5, 10 and 15 min) affects the level of extraction of antioxidant compounds into infusions and their antioxidant activity. We examined 11 types of tea: green leaf tea, green tea bags, white tea bags, black tea bags, red tea bags, black leaf tea, yerba mate, raspberry tea bags, butterfly pea flower (Clitoria ternatea) tea, white lychee plum tea and hibiscus flower tea. Total polyphenol (TPC), flavonoids and anthocyanins content, as well as determination of antiradical and antioxidant capacity with DPPH radical and ABTS radical cation, were determined using spectrophotometric assays. Due to the antioxidant activity of tea infusions, the optimum brewing time for green tea (leaf and bags), black tea (leaf and bags), butterfly pea flower tea, white tea, white lychee plum tea, raspberry tea and yerba mate is 15 min. Red tea brewing time should be ten minutes, and for hibiscus flower tea it should be five minutes. The results refer to the brewing temperature recommended by tea manufacturers.

Extraction of Antioxidant Compounds from Eugenia uniflora L. Leaves by Energized Dispersive Guided (EDGE) System

The leaves of Pitanga (Eugenia uniflora L.) present recognized antioxidant potential that has practical applications in pharmaceuticals, food, perfume, agrochemical, and cosmetic industries. The Energized Dispersive Guided Extraction (EDGE) system, which combines dispersive solid-phase extraction with the Accelerated Solvent Extraction system, was employed in "combined mode" with extraction cycles to obtain antioxidant compounds from Pitanga leaves. The results showed that extraction cycles with different solvents produce similar extraction yields. At the same time, their ability to scavenge free DPPH radicals exhibited variations according to the polarity of the extraction solvent. Thus, acetone was the optimal solvent for extracting antioxidant compounds from E. uniflora leaves in the combined mode.

Mathematical modeling by fractional calculus applied to separation processes

Process modeling is a way of representing real problems through equations and while the traditional models of mass and heat transfer processes consider the transient term as a first-order derivative, fractional order modeling is applied to verify that the order of the derivative of the transient term would not be represented by a non-integer number. In this context, the objective of this work was to apply fractional calculus to the kinetics study of adsorption and extraction processes and compare the results obtained with traditional models. The Caputo derivative was used to solve the proposed equations, and the analyzed processes were the adsorption of glycerol for biodiesel at different temperatures and the solid–liquid extraction of antioxidant compounds from corn for different proportions of solvent. For the adsorption, the fractional order model was compared with the pseudo-first, pseudo-second, and first-order models, and the fractional order model represented adsorption satisfactorily, with method efficiencies of 0.9603 and 0.9433 for the temperatures of 45 °C and 60 °C, respectively, while the performance of traditional models depends on the mechanisms that control the process. In addition, the α values obtained with the fractional order model were less than 1, indicating that glycerol adsorption does not follow an integer order derivative and implies that the adsorption exhibits a level of complexity that is not fully characterized by traditional models. The extraction of antioxidant compounds was analyzed and compared with the first-order and So and MacDonald’s models. It was verified that the derivative order values for the fractional order model were close to 1 and, therefore, the behavior is similar to the first order model and with indications that diffusion occurs as described by Fick’s law of diffusion. Thus, the results indicated that fractional order modeling can be used efficiently to describe chemical engineering processes such as adsorption and extraction.

Optimization of the extraction process of Moringa oleifera flower by using Deep Eutectic Solvents (DES)

Moringa oleifera is a plant native to India and its flowers are an excellent source of phenols, flavonoids, and antioxidants. DES (Deep Eutectic Solvents) based solvents have a vast majority of benefits, such as they are non-toxic, green solvents, with a highly efficient method of extraction of phenolic, antioxidant, and flavonoid compounds. DES solvents are made by combining two solvents, out of which one must be a hydrogen bond donor (HBD) and another must be a hydrogen bond acceptor (HBA) whereas, combining these two types reduces the melting point of the solvents. Six different types of DESs combinations were used in different ratios, for the optimization of the extraction process. The six combinations used were ChCl-Gly, ChCl-MA, ChCl-LA, ChCl-Glu, Pro-Gly, and Pro-LA. Total phenolic content, flavonoid content, antioxidant activity, lipase activity and glucose uptake assay of Moringa oleifera flower (MOFs) extracts were calculated in vitro at different temperatures ranging from 50 to 80 ℃ by using the statistical tool Anova single factor. Maximum yield, of phytochemicals were found at 70 ℃ with the DES combination Pro-Gly in 1:2 M ratio where phenolic content (32.4 mg GAE/g DW), Flavonoid content (42.1 mg QE/g DW), and antioxidant activity (65.82 %).

Application of Pulsed Electric Field‐Ultrasound Technique for Antioxidant Extraction from Yarrow: ANFIS Modeling and Evaluation of Antioxidant Activity

Oxidation reactions negatively impact the taste and shelf life of the oils. Antioxidants are commonly employed to mitigate the development of off‐flavors and rancidity and thereby extend the shelf life of oil. In response to consumers’ increasing demand for healthy foods, there is a notable focus on incorporating naturally sourced antioxidants. Yarrow plant is a good source of natural antioxidants which could be used in improving the quality of the oils. Therefore, in this study, adaptive ANFIS was employed to investigate the extraction of antioxidant compounds from the yarrow plant using the pulsed electric field‐ultrasound method. The extraction process was performed at varying pulsed electric field intensities (0.25, 3.25, and 6.25 kV/cm) and different ultrasound durations (20, 40, and 60 minutes). Then, the impact of incorporating the plant extract on the oxidation parameters of sesame oil was assessed during storage. Results demonstrated that the extraction efficiency consistently increased with rising pulsed electric field intensity and ultrasound treatment time. However, the levels of total phenol, DPPH, and ascorbic acid content initially increased and then decreased at higher pulsed electric field intensity during longer ultrasound treatment. Furthermore, an increase in acidity and thiobarbituric acid index was found during prolonged storage time, while the peroxide level in the samples peaked on the 5th day of storage before declining. The high correlation coefficients between experimental results and model outputs underscored the models’ accuracy, representing their efficacy in controlling the extraction conditions using the pulsed electric field intensity‐ultrasound extraction method and utilizing the extract in sesame oil.

Sustainable Valorization of Sour Cherry (Prunus cerasus) By-Products: Extraction of Antioxidant Compounds

Prunus cerasus, commonly known as sour cherry, is a fruit widely consumed during the summer season. Processing of sour cherries results in the generation of substantial amounts of by-products. Following the extraction of juice, the residual pomace (comprising of skin and flesh) and pits remain as by-products. This study delves into the antioxidant potential derived from the phenolic compounds present in sour cherry pomace and the oil derived from its seeds, both demonstrating significant implications for human health and longevity. The increasing demand for bioactive compounds from natural resources, to be used as ingredients in functional foods, as well as the increased global production of sour cherries, has spurred considerable interest in these by-products. The growing demand for more sustainable practices has necessitated the use of industrial fruit by-products. To this end, many articles have been published regarding sour cherry skin and pits utilization. This comprehensive review aims to elucidate advanced techniques for extracting antioxidants from sour cherries and discern optimal strategies for broad-scale industrial implementation.

Microwawe–assisted extraction of antioxidant compounds from Vaccinium Myrtillus leaves

<p><em>Vaccinium myrtillus </em>L. (bilberry, Ericaceae), a perennial, wild, and small deciduous shrub that grows in the mountains and forests of Europe. The leaf extracts are widely used in traditional medicine due to their astringent, antiseptic, antioxidant, anti-inflammatory, hypolipidemic, and hypoglycemic activities. Microwave-assisted extraction provides various benefits, including reducing solvent consumption and extraction time and increasing extraction yield. In the present study, bilberry extracts were prepared using dried leaves, pure ethanol, or an ethanol-water mixture, and different temperatures in a microwave reactor (60, 100, and 160 <sup>◦</sup>C). The extracts were examined in terms of total polyphenol content (TPC) and antioxidant activity. The TPC of the 96% ethanol extracts rose with the increase of the extraction temperature; the extract obtained at 60 <sup>◦</sup>C (37.2 ± 0.5 mg gallic acid equivalents (GAE)/g of plant material)<the extract at 100 <sup>◦</sup>C (46.6 ± 0.3 GAE/g)<the extract at 160 <sup>◦</sup>C (55.1 ± 0.5 mg/g). The TPC of the 50% ethanol extract prepared at 60 <sup>◦</sup>C was significantly lower (54.9 ± 1.0 mg GAE/g) in comparison to the extracts obtained at 100 and 160 ◦C (58.3 ± 1.0 and 58.0 ± 1.5 mg GAE/g, respectively). ABTS antioxidant capacity was higher in the 50% ethanol extracts compared to 96% ethanol parallels, while in the DPPH assay, there was no statistically significant difference between the 50 and 96% ethanol extracts. Due to higher TPC and anti-ABTS activity and reduced consumption of organic solvent, a 50% ethanol extract of <em>V. myrtillus </em>was favored, while the optimal temperature was 60 <sup><span style="background-color: var(--bs-body-bg); font-weight: var(--bs-body-font-weight); text-align: var(--bs-body-text-align);">◦</span></sup><span style="background-color: var(--bs-body-bg); font-weight: var(--bs-body-font-weight); text-align: var(--bs-body-text-align);">C for the extract </span><span style="background-color: var(--bs-body-bg); font-weight: var(--bs-body-font-weight); text-align: var(--bs-body-text-align);">with the highest antioxidant capacity and 100 <sup>◦</sup>C for the extract with the highest amount of polyphenols.</span></p>

Scanning Electron Microscopy and Triple TOF-LC-MS-MS Analysis of Polyphenols from PEF-Treated Edible Mushrooms (L. edodes, A. brunnescens, and P. ostreatus).

Pulsed electric fields (PEF) technology has been used as a sustainable method for extracting antioxidant bioactive compounds from different food matrices. In the present study, the optimal conditions of PEF extraction for mushrooms (2.5 kV/cm, 50 kJ/kg, 6 h) were applied to Lentinula edodes, Agaricus brunnescens, and Pleurotus ostreatus to evaluate the total antioxidant capacity of the extracts, followed by the Triple TOF-LC-MS-MS analysis of the phenolic profile compared to A. bisporus by high-performance liquid chromatography coupled to mass spectrophotometry. In addition, the microporation effect of the technology on the mushroom surface was evaluated using scanning electron microscopy. A comparison was made with a maceration extraction (aqueous stirring for 6 h). The results showed that PEF-assisted extraction enhanced the recovery of antioxidant compounds such as 3,5-dicaffeoylquinic and cinnamic acid with contents up to 236.85 µg/100 g dry weight and 2043.26 µg/100 g dry weight from A. bisporus, respectively. However, mixed results were obtained for certain phenolic compounds, including vanillic acid from L. edodes, ellagic acid from P. ostreatus, and thymol from all mushrooms. These results indicate that the application of PEF technology is effective for the extraction of antioxidant compounds in fungal matrices by creating micropores in cell membranes that allow great recovery in matrices with high content of bioactive compounds.

In vitro evaluation of goldfish (Stachys byzantina K. Koch) extracts obtained using natural deep eutectic solvents (NADES)

Chronic diseases are one of the main causes of death worldwide, and the search for antioxidant compounds to prevent these diseases is crucial. These compounds can be extracted using conventional solvents but can pose chemical hazards. Therefore, the research seeks safer and more sustainable alternatives. An unconventional plant called goldfish from the garden (Stachys byzantina K. Koch) has a high antioxidant potential due to its richness of vitamin A, iron, calcium, and total phenolics. In this study, different combinations of natural solvents were proposed to extract antioxidant compounds from the leaves of this plant, comparing them to conventional solvents. The extracts obtained were evaluated for their phenolic and flavonoid content and their antioxidant capacity using DPPH, ABTS, and FRAP methods. The results showed that the levels of bioactive compounds varied according to the combination of solvents, ranging from 0.308 to 0.811 mg EAG.g−1 for total phenolics and from 0.030 to 1.162 mg EQ.g−1 for total flavonoids. The antioxidant capacity of the extracts also varied according to the method used. Through statistical analyses, the LP-Ale-50 % solvent was identified as the best combination for the recovery of bioactive compounds of the species. The results indicate the superiority of NADES over conventional solvents and show that the extracts can be applied in the food and pharmacological industries.

Green extraction of phenolics using deep eutectic solvents: a promising neoteric method

There has been a growing emphasis on developing extraction methods that are not only efficient but also environmentally friendly and sustainable. One promising avenue is the exploration of deep eutectic solvents (DESs) as neoteric extraction media. This study aims to investigate the potential of DESs as neoteric extraction media for phenolics-rich flower clove extracts. Two DESs were synthesised by mixing choline chloride with glycerol and lactic acid at a molar ratio of 1:2. The thermal profiles of the mixture were analysed using differential scanning calorimetry, and the viscosity and density were measured at different temperatures. The phenolic compounds were quantitatively characterised for all of the extractants using high-performance liquid chromatography. The total phenolic content and the antioxidant activities of the extracts were determined. The results showed that DESs significantly improved the extraction of antioxidant compounds from clove, especially for the case of phenolic compounds, and also considerably enhanced the antioxidant activity of the extracts. The use of DESs offers a green, efficient method for extracting value-added products from natural sources.

Ultrasound-Assisted Extraction of Antioxidant Compounds from "Cẩm" Purple Rice Bran for Modulation of Starch Digestion.

Purple rice, locally known as "Cẩm" rice, is cultivated in the southern region of Vietnam. The bran of "Cẩm" rice is often disregarded and underutilized; nevertheless, it harbours substantial nutritive value, particularly in terms of antioxidant compounds. Additionally, sonication, an emerging and "green" technological approach, has been employed to augment the extraction efficiency of these antioxidants. This research is aimed at optimizing and maximizing the antioxidant recovery capacity including phenolic and total flavonoid compounds, along with their antioxidant activities, through the assistance of ultrasound waves. The effect of the extract on the starch digestion process was also investigated. The study employed the Box-Behnken experimental design, encompassing three variables: extraction time (20-40 minutes), temperature (60-80°C), and solvent-to-material ratio (8 : 1 to 12 : 1). Analysis was conducted on total phenolic compounds, total flavonoid content, and antioxidant activities. Results demonstrated that the peak yield of antioxidant compounds and their corresponding activities were attained at an extraction duration of 29.38 minutes, a temperature of 69°C, and a solvent-to-material ratio of 9.92. Under these optimal conditions, the yields were as follows: total phenolic compounds at 60.821 mg GAE/g, total flavonoid compounds at 3.2696 mg QE/g, percentage inhibition of DPPH at 74.778%, and FRAP value at 54.112 μmol Fe (II)/g. The established models were validated and exhibited a strong alignment between predicted and actual values, with disparities of less than 3% under optimal conditions. Furthermore, the extract was codigested with cooked corn starch, revealing a dose-dependent effect on starch digestibility. The sluggishness of digestion rate was observed when 20 mg of the extract was supplemented to 200 mg of cooked corn starch. This suggests that rice bran extract holds promise as an effective ingredient for mitigating starch digestion, particularly beneficial for individuals dealing with diabetes.