Optimal Ultrasound-assisted Extraction Conditions Research Articles

Response Surface Methodology for Optimization of Ultrasound-Assisted Antioxidants Extraction from Blackberry, Chokeberry and Raspberry Pomaces.

An investigation of the ultrasound-assisted extraction (UAE) of polyphenol-rich aqueous extracts from blackberry, chokeberry and raspberry pomaces was carried out. The aim of the study was to choose optimal conditions for UAE in order to obtain extracts rich in phenolic compounds. The optimization was carried out based on response surface methodology. The variable conditions were amplitude of ultrasound wave and extraction time, whereas responses were total polyphenol content and antioxidant capacity. Based on the ANOVA analysis, mathematical models were fitted and verified. The most effective conditions of amplitude and time were 98% and 5.00 min, 78% and 10.32 min and 90% and 11.56 min for blackberry pomace, chokeberry pomace and raspberry pomace, respectively. The actual results obtained in optimized conditions were comparable to the results predicted by the models. Additionally, the anthocyanin content in extracts was determined in the high-performance liquid chromatography assay. It was proven that response surface methodology could be a useful tool in the optimization of UAE processes for obtaining polyphenol-rich extracts from berry fruit pomaces.

Efficiency of Supercritical CO2 and Ultrasound-Assisted Extraction Techniques for Isolation of Bioactive Molecules from Sea Buckthorn (Elaeagnus rhamnoides (L.) A. Nelson) Berry Oils and Cakes

This study compared the efficiency of advanced supercritical CO2 extraction (SC-CO2) and conventional Soxhlet extraction (SE) in the isolation of lipophilic bioactive molecules (BAMs) from the oils of different sea buckthorn (SB) berries (Leikora and Ascola). A SB cake, a valuable by-product of oil extraction, was analyzed for phenolic compounds and antioxidant activity (AA). For this purpose, ultrasound-assisted extraction (UAE) with 70% (v/v) ethanol was optimized, and the following optimal UAE conditions were determined: ultrasonic power of 60%, temperature of 50 °C, and extraction time of 20 min. The individual BAMs in the oils and cake extracts were analyzed chromatographically, while the AAs were determined using the ORAC method. The oils extracted with SC-CO2 had a higher content of lipophilic BAMs and a higher AA value than the oils extracted with SE. Palmitic and palmitoleic acids, β-sitosterol, and α-tocopherol dominated the Leikora oil, while a higher content of oleic, linoleic, and α-linolenic acids and carotenoids was found in the Ascola oil. The highest phenolic content was found in the Ascola cake, with the flavonols isorhamnetin-3-hexoside, isorhamnetin-3-rutinoside, and quercetin-3-glucoside being the most abundant. Oil and cake extracts of the Ascola variety also had a higher AA.

Extraction of bioactive compounds of Hypnea flagelliformis by ultrasound-assisted extraction coupled with natural deep eutectic solvent and enzyme inhibitory activity

This study aimed to couple natural deep eutectic solvents (NADESs) with an ultrasound-assisted extraction (UAE) to obtain bioactive compounds (antioxidant and phenolic) from Hypnea flagelliformis with enzyme inhibitory activity against enzymes affecting hypertension (angiotensin I-converting enzyme-ACE) and diabetes (alpha-glucosidase and alpha-amylase). The results showed that NADES based on choline chloride and lactic acid (ChCl-LA) with a molar ratio of 1: 2 with 20 % water was selected as a suitable solvent to extract bioactive compounds of H. flagelliformis. Optimal conditions of UAE process with three variables of ultrasonic powers (40, 60, and 80 %), extraction time (20, 25, and 30 min), and solvent-to-sample ratio (20: 1, 30: 1, and 40: 1 mL/g) with the highest extraction efficiency (87.98 ± 1.22 mg/100 g) and the highest desirability (0.997), including solvent-to-solids ratio of 29.12: 1, 80 % ultrasound power, and extraction time of 30 min. The results of Fourier-transform infrared spectroscopy (FTIR) analysis verified the presence of active functional groups in the extract. Phenolic content and antioxidant activity [by ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl), and FRAP (ferric reducing antioxidant power,) test methods] of the extract obtained by UAE and NADES (ChCl-LA) methods were higher than the extract prepared with conventional solvents (water, 80 % ethanol and 80 % methanol). The bioactive compounds extracted from of H. flagelliformis have very little toxicity against healthy human cells. The algae extract of H. flagelliformis obtained under optimal UAE conditions by ChCl-LA was able to inhibit ACE, alpha-glucosidase, and alpha-amylase enzymes and had good anti-diabetic and anti-hypertensive activity.

Optimization of ultrasound-assisted extraction of galactomannan from carob seeds “ceratonia siliqua L” and evaluation of their functional properties and in vitro anti-inflammatory activity

ABSTRACT Ultrasound-assisted extraction (UAE) of galactomannan from the endosperm of ripe carob seeds (LBG.S3) was investigated through response surface methodology (RSM). The optimized UAE conditions were an extraction time of 40 minutes, a temperature of 45°C, and a solid-liquid ratio of 1:50 g/mL. Under these settings, the experimental yield of galactomannan was 47.53 ± 2.55%, which is closely aligning with the expected value of 49.78 ± 3.15%. The yield of galactomannan extracted from unripe carob seeds (LBG.S2) under the same optimal conditions was significantly higher 56.73 ± 2.76% (p < 0.05) than the yield of LBG.S3. The infrared spectroscopy (FT-IR) characterization revealed the existence of various functional groups in the spectrum of galactomannan extracted from unripe seeds, not found in LBG.S3. The galactomannan from ripe carob seeds exhibited superior functional properties, including solubility, emulsion and stability capacity, water and oil holding capacity, and viscosity, compared to LBG.S2. In vitro, tests demonstrated notable anti-inflammatory activity for both LBG.S2 and LBG.S3, as observed through the inhibition of bovine serum albumin (BSA) protein denaturation by heat and the membrane stabilization test. Carob galactomannan is a potential source of bioactive polysaccharides with anti-inflammatory and functional properties that can be used in the food and pharmaceutical industries.

Ultrasound assisted extraction of polyphenols from Randia monantha: Optimization, characterization and antifungal activity

Randia monantha is an important source of high-value biological compounds (HVBC) due to its interesting content of phenolic compounds. However, the antifungal activity of HVBC in the extract remains unexplored. Thus, ultrasound-assisted extraction (UAE) is a technique respects the sample and achieves high yields. Then, to find the optimal UAE conditions for HVBC extraction, a Box-Behnken design was used. The variables included amplitude (40–60%), time (5–10 min), and ratio sample:solvent (1:10–1:30 g:mL. The response variables were yield, total phenolic content (TPC) and 2,2-azinobis (3-ethylbenzthiazoline sulfonate) radical scavenging activity (ABTS+ RSA). Response surface methodology (RSM) revealed that 60% amplitude, 10 min, and 1:30 ratio, produced the extract with the highest yield (11.05 ± 0.23%), TPC (69.26 ± 1.15 mg Gallic Acid Equivalents/g dry sample) and ABTS+ RSA (219.64 ± 6.99 mg Trolox Equivalents /g dry sample). Optimal ethanolic extract evaluated against Colletotrichum gloeosporioides and Penicillium digitatum showed minimum inhibitory concentrations (MIC) of 17.65 and 20.51 mg/mL, respectively. The important antioxidant activity and phenolic content found in the extract are responsible for the inhibitory effect.

Ultrasound-assisted extraction of phenolic compounds from Moringa oleifera leaves by response surface methodology

Background: Moringa oleifera is a tree that grows in tropical and subtropical areas around the world. Its leaves, seeds, bark, roots, and flowers are used as ingredients in meals and medicinal applications. Moringa leaf extracts have been studied to contain antioxidant compounds such as phenolic molecules. Recent extraction techniques such as ultrasound and microwaves are alternatives to increase the extraction performance of phenolic compounds while preserving their antioxidant activity.Objective: The approach consisted of optimizing, using a Composite Central Design of Response Surface Methodology (CCD-RMS), the process conditions, for ultrasound-assisted extraction (UAE) of antioxidant phenolic compounds from Moringa oleifera leaves. Methods: A 33 CCD-RMS was used; three independent variables were studied: ethanol concentration (25%, 50%, 75%), time (10, 20, and 30 min), and temperature (25, 37.5, and 50°C). The results showed that the optimal UAE conditions were an ethanol concentration of 52.4%, extraction time of 3.2 min, and temperature of 58.5°C; under these conditions the phenolic content was 13.92±0.21 mg GAE/g sample the total flavonoid content was 10.60±0.06 mg QE/g sample, and 52.22±2.01% and 72.81±1.58% of DPPH• and ABTS•+ radicals were inhibited, respectively.Conclusion: This optimization will make it possible to assess better use of M. oleifera leaves as an antioxidant ingredient in functional food development.Keywords: Moringa oleifera, composite central design, optimization, flavonoids, phenols, antioxidant activity.

Green extraction of berberine from Coscinium fenestratum (Gaertn.) Colebr. using ultrasound-assisted aqueous solutions of organic acids, polyalcohols, and deep eutectic solvents

Berberine displays many potential bioactivities and is found in several medicinal herbs, such as Coscinium fenestratum. The extraction of berberine from biomass was carried out using volatile organic solvents, inorganic acid solutions, and more recently, ionic liquids and deep eutectic solvents. In order to develop more efficient and sustainable extraction processes, this study used inexpensive green solvents, such as carboxylic acid and polyalcohol aqueous solutions, to extract berberine from Coscinium fenestratum. Initial screening was performed to compare the berberine extraction performance of various solvents, including aqueous solutions of carboxylic acids, polyalcohols, and their deep eutectic solvents. The obtained results showed that lactic acid was a potential solvent for extracting berberine. After optimizing the process using response surface methodology (RSM), the optimal ultrasound-assisted extraction conditions were determined to be a lactic acid concentration of 60 % (w/w), a liquid-to-solid ratio of 17.25 mL/g, an extraction time of 20 min, and an extraction temperature of 66 °C. This resulted in an extraction efficiency of 38.23 ± 0.69 mg/g, corresponding to a berberine concentration of 2.22 ± 0.04 mg/mL. Additionally, the use of lactic acid as the extraction solvent yielded superior extraction efficiency and berberine purity compared to conventional volatile organic solvents, and inorganic acids, bases. The recovery of berberine was achieved using macroporous resins, allowing for the recovery of 99.52 ± 0.67 % of berberine from aqueous lactic acid solutions. The lactic acid solvent and the AB-8 resin were successfully recovered and reused for a minimum of three consecutive extraction cycles, maintaining their full effectiveness throughout the entire process. The recovered berberine from the lactic acid extract exhibited stronger antibacterial activity than the extracts obtained using ethanol, methanol, and acetone, as well as berberine recovered from the limewater and sulfuric acid extracts. Furthermore, the lactic acid solvent and its extracts demonstrated no cytotoxicity toward the human embryonic kidney cell line. The findings of this investigation establish a foundation for future studies utilizing eco-friendly solvents for alkaloid extraction from medicinal plants. This lays the groundwork for implementing a large-scale extraction process of natural active compounds in a safe and environmentally conscious manner.

Inhibitory Effects of Saponin-Rich Extracts from Pouteria cambodiana against Digestive Enzymes α-Glucosidase and Pancreatic Lipase.

Pouteria cambodiana is a perennial plant that has a wide distribution in tropical regions. It is commonly referred to as 'Nom-nang' in the northern region of Thailand. The bark of this plant has been used for the purpose of promoting lactation among breastfeeding mothers. Moreover, P. cambodiana bark has a high nutraceutical potential due to the presence of saponins, which are secondary metabolites. The purpose of this study was to determine the optimal conditions for ultrasound-assisted extraction (UAE) of saponins from the bark of P. cambodiana and to assess the in vitro inhibitory activities of saponin-rich extracts. The most effective extraction conditions involved a temperature of 50 °C and a 50% concentration level of ethanol as the solvent, which allowed the extraction of saponin at a concentration of 36.04 mg/g. Saponin-rich extracts and their hydrolysates from P. cambodiana bark were evaluated for their ability to inhibit α-glucosidase and pancreatic lipase. The IC50 values for saponin- and sapogenin-rich extracts inhibiting α-glucosidase were 0.10 and 2.98 mg/mL, respectively. Non-hydrolysed extracts also had a stronger inhibitory effect than acarbose. In the case of pancreatic lipase, only the hydrolysed extracts exhibited inhibitory effects on pancreatic lipase (IC50 of 7.60 mg/mL). Thus, P. cambodiana bark may be an applicable natural resource for preparing ingredients for functional products with inhibitory activity against α-glucosidase and pancreatic lipase. The phenolic contents, saponin contents, and antioxidant activities of the dried extract stored at a low temperature of 25 °C for 2 months showed the best stability, with more than 90% retention.

Optimization Conditions of Ultrasound-Assisted Extraction for Phenolic Compounds and Antioxidant Activity from Rubus alceifolius Poir Leaves.

Rubus alceifolius Poir (R.A. Poir) leaves are rich in phenolic compounds, offering many health benefits due to their incredible antioxidant potential. In this study, conditions for the ultrasound-assisted extraction (UAE) of phenolic compounds and antioxidant activity from R.A. Poir leaves were optimized using response surface methodology (RSM). This methodology assessed the effects of ultrasound power (X1: 100-500 W), extraction temperature (X2: 30-60°C), and extraction time (X3: 5-55 min). The optimized UAE conditions were then compared with conventional extraction methods (Soxhlet extraction: SE and maceration extraction: ME) for extracting total phenolics. A phenolic profile using GC-MS and antioxidant activity (ABTS) was also compared. According to the RSM, the best conditions for UAE to extract the highest total polyphenol content and ABTS radical scavenging activity were 320 W ultrasound power, 40°C extraction temperature, and 35.5 min sonication duration. Under these optimal conditions, the TPC and antioxidant activity reached 16.68 mg GAE/g dm and 21.9 mg TE/g, respectively, closely aligning with the predicted values. The UAE extraction technique proved to be more efficient in extracting phenolics and antioxidant capacity (ABTS (2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)) radical scavenging activity, and enzyme inhibition) compared to the conventional extraction methods (SE and ME). A GC-MS analysis identified 12 components, including 5 phenolics and 3 flavonoids, which likely contribute to the antioxidant activity. Consequently, the UAE method improved extraction efficiency within a shorter time frame, suggesting that UAE is a promising, efficient, and ecofriendly technology for extracting bioactive compounds from R.A. Poir leaves.

Kinetic Ultrasound-Assisted Extraction as a Sustainable Approach for the Recovery of Phenolics Accumulated through UVA Treatment in Strawberry By-Products.

Ultrasound-assisted extraction (UAE) is an efficient and sustainable method for extracting bioactive compounds from agro-industrial by-products. Moreover, it has been reported that ultraviolet A (UVA) radiation can induce the biosynthesis and accumulation of bioactive phenolic compounds. This study optimized the efficiency of ultrasound-assisted extraction (UAE) for recovering ultraviolet A (UVA)-induced phenolic compounds in strawberry by-products (RF-N). The impact of three factors (solid-liquid ratio, ethanol concentration, and ultrasound power) on total phenolic compound (TPC) kinetics using Peleg's model was investigated. The developed model showed a suitable fit for both RF-N and strawberry by-products treated with UVA (RF-E). The optimal UAE conditions obtained were of a 1:30 ratio, 46% ethanol, and 100% ultrasound power, resulting in an average yield of 13 g total phenolics kg-1. The bioaccessibility of phenolic compounds during in-vitro digestion was 36.5%, with agrimoniin being the predominant compound. UAE combined with UVA treatment increased the bioactivity of RF extracts, displaying significant anti-proliferative effects on HT29 and Caco-2 cancer cell lines, as well as anti-inflammatory potential and cellular antioxidant activity. The ultrasound proved to be a sustainable and effective technique for extracting phenolic compounds from RF, contributing to the valorization of strawberry agro-industrial by-products, and maximizing their nutraceutical potential.

OBTAINING DRY EXTRACTS FROM LICORICE ROOTS (GLYCYRRHIZA GLABRA) AND ITS STANDARDIZATION

Licorice (Glycyrrhiza glabra) root has long been used in traditional medicine due to its various therapeutic properties. One of the main active components in licorice root is glycyrrhizin, which has been shown to possess numerous pharmacological effects. Glycyrrhizin, one of the major compounds present in licorice root, has been shown to possess anti-inflammatory, antioxidant, and anti-tumor propertiesas well as antiviral properties against influenza virus and coronavirus COVID-19. The demand for licorice root extracts is increasing, particularly for use in the food and pharmaceutical industries. However, the quality and consistency of licorice extracts can vary depending on the extraction method used. Therefore, the aim of this study was to optimise the technology for obtaining dry extracts from licorice roots and standardise the process for increased consistency and quality of the final product. In this study, two different methods for extraction were compared: ultrasound-assisted extraction using water and alcohol-water solvents. The extracted samples were then subjected to various quality control tests, including glycyrrhizin content and moisture content. The content of glycyrrhizin in the obtained dry extracts was determined using high-performance liquid chromatography (HPLC). The standardisation of the dry extract was performed according to the Pharmacopoeia of the Eurasian Economic Union. The results showed that the optimised technology for obtaining dry extracts from licorice roots was water extraction with ultrasound, as it yielded a higher content of glycyrrhizin compared to ethanol extraction with ultrasoundand the optimal conditions for ultrasound-assisted extraction were an extraction time of 60 minutes, frequency of ultrasound bath at 40 kHz, an extraction temperature of 30°C, and a solid-to-liquid ratio of 1:6. The standardisation process confirmed the presence of glycyrrhizic acid and purity of the obtained dry extract.

Optimization of Extraction and Separation Process of Notoginsenoside Fc from Panax notoginseng Leaves.

Response surface methodology (RSM) was used to determine the optimal conditions for ultrasound-assisted extraction (UAE) of Notoginsenoside Fc (Fc) from panax notoginseng leaves. The experiment utilized a Box-Behnken design (BBD) and separation conditions were optimized. The optimum extraction conditions were as follows: extraction time = 1.5 h, ethanol concentration = 86%, liquid-to-solid ratio = 19:1. The experimentally obtained values were in accordance with the values predicted by the RSM model. We determined that the RSM model was able to successfully simulate the optimal extraction of Fc from the leaves. Further, Fc was enriched from Panax notoginseng through nine macroporous resins, and HPD-100 macroporous resins were selected for preliminary enrichment of Fc due to its economic costs and benefits. Subsequently, octadecyl silane (ODS) column chromatography was used to improve the purity of Fc to over 90% after separation by ODS column chromatography. Fc with a purity greater than 95% can be obtained by recrystallization. This is the first study that has focused on the extraction and enrichment of Fc from Panax notoginseng leaves using macroporous resin combined with ODS column chromatography, which provides the possibility for further application of Fc.

Response Surface Optimization of Extraction Conditions for the Active Components with High Acetylcholinesterase Inhibitory Activity and Identification of Key Metabolites from Acer truncatum Seed Oil Residue.

The State Council of China has called for the comprehensive development and utilization of Acer truncatum resources. However, research on one of its by-products, namely seed oil residue (ASR), from seed oil extraction is seriously insufficient, resulting in a waste of these precious resources. We aimed to optimize the conditions of ultrasound-assisted extraction (UAE) using a response surface methodology to obtain high acetylcholinesterase (AChE) inhibitory components from ASR and to tentatively identify the active metabolites in ASR using non-targeted metabolomics. Based on the results of the independent variables test, the interaction effects of three key extracting variables, including methanol concentration, ultrasonic time, and material-to-liquid ratio, were further investigated using the Box-Behnken design (BBD) to obtain prior active components with high AChE inhibitory activity. UPLC-QTOF-MS combined with a multivariate method was used to analyze the metabolites in ASR and investigate the causes of activity differences. Based on the current study, the optimal conditions for UAE were as follows: methanol concentration of 85.06%, ultrasonic time of 39.1 min, and material-to-liquid ratio of 1.06:10 (g/mL). Under these optimal conditions, the obtained extracts show strong inhibitions against AChE with half maximal inhibitory concentration (IC50) values ranging from 0.375 to 0.459 µg/mL according to an Ellman's method evaluation. Furthermore, 55 metabolites were identified from the ASR extracted using methanol in different concentrations, and 9 biomarkers were subsequently identified as potential compounds responsible for the observed AChE inhibition. The active extracts have potential to be used for the development of functional foods with positive effects on Alzheimer's disease owing to their high AChE inhibition activity. Altogether, this study provides insights into promoting the comprehensive utilization of A. truncatum resources.

Enhancing lutein extraction from marigolds through ultrasound-assisted optimization using response surface methodology

This research aimed to enhance and optimize the ultrasound-assisted extraction (UAE) of lutein from marigold flowers. The Response Surface Methodology (RSM) was the primary optimization technique. Three key independent variables were considered to determine the best conditions for the highest lutein yield: ultrasonic amplitude, extraction temperature, and extraction time. These variables were systematically varied following the Central Composite Design (CCD). Lutein quantitation was achieved using ultraviolet-visible spectrophotometry analysis. Using both the RSM and CCD frameworks, the study established specific ranges for the operational conditions: 21.6–38.4% for ultrasonic amplitude, 23.18–56.82 °C for extraction temperature and 3.18–36.82 minutes for extraction duration. The study determined the optimal extraction conditions to be 32.76% ultrasonic amplitude, 40.08 °C extraction temperature, and 25.82 minutes of extraction time. Under these optimized conditions, the experimental lutein yield closely matched the yield predicted by the RSM model, thus confirming the model's accuracy. The UAE demonstrated a notably superior lutein yield compared to traditional extraction techniques. The RSM is a robust tool for refining and determining optimal UAE conditions for lutein extraction from marigold flowers. With its efficiency, speed, and eco- friendliness, the optimized UAE technique presents significant potential for widespread industrial use.

Improvement of Sinapine Extraction from Mustard Seed Meal by Application of Emerging Technologies.

Sinapine is a phenolic compound found in mustard (Brassica juncea) seed meal. It has numerous beneficial properties such as antitumor, neuroprotective, antioxidant, and hepatoprotective effects, making its extraction relevant. In this study, the extraction of sinapine was investigated using three methods: (i) from a mustard seed meal defatted by a supercritical CO2 (SC-CO2) pretreatment, (ii) by the implementation of high-voltage electrical discharges (HVEDs), (iii) and by the use of ultrasound. The use of SC-CO2 pretreatment resulted in a dual effect on the valorization of mustard seed meal, acting as a green solvent for oil recovery and increasing the yield of extracted sinapine by 24.4% compared to the control. The combination of ultrasound and SC-CO2 pretreatment further increased the yield of sinapine by 32%. The optimal conditions for ultrasound-assisted extraction, determined through a response surface methodology, are a temperature of 75 °C, 70% ethanol, and 100% ultrasound amplitude, resulting in a sinapine yield of 6.90 ± 0.03 mg/g dry matter. In contrast, the application of HVEDs in the extraction process was not optimized, as it led to the degradation of sinapine even at low-energy inputs.

Enhancement of bioactive compounds through bioconversion of Oenanthe javanica using Lactiplantibacillus plantarum

The purpose of this study is to investigate the effect of bioconverted Oenanthe javanica extract (BOE) using Lactiplantibacillus plantarum SM4 on production of bioactive compounds. Response surface methodology was used to determine the optimal ultrasound-assisted extraction conditions including the extraction time, extraction temperature, and ethanol concentration for the enhancement of bioactive compounds production. The predicted optimum UAE conditions were extraction time of 26.0 min, extraction temperature of 92.8 °C, and 59.9% ethanol, respectively, and 5.14 mg GAE/g DM of TPC and 0.59 mg QE/g DM of TFC were produced under the optimum condition. Then, O. javanica extraction (OJE) has been bioconverted by using L. plantarum SM4 to increase the bioactive compounds. In HPLC-mass spectrometry analyses, higher concentration of p-coumaric acid was identified in BOE than in OJE, and chlorogenic acid in OJE was converted to quinic acid, confirming an increase in bioactive compounds by bioconversion. Thus, we have concluded that optimization of UAE and the BOE is an effective process for enhancement bioactive compounds from O. Javanica and this finding provides a scientific basis of bioactive compounds in natural product can be utilized as food, cosmetics, and pharmaceutical materials from BOE.

Valorization of Phenolic and Carotenoid Compounds of Sechium edule (Jacq. Swartz) Leaves: Comparison between Conventional, Ultrasound- and Microwave-Assisted Extraction Approaches.

Chayote leaves are known for culinary and traditional medicine applications. This work intended to recover carotenoids and phenolic compounds from chayote leaves using the ultrasound-assisted extraction (UAE). A Box-Behnken design was employed to investigate the impact of extraction time, temperature, and ultrasonic power on the recovery of total carotenoids, total phenolic compounds, and antioxidant activities. For comparative purposes, chayote leaf extracts were prepared by maceration (ME) and microwave-assisted extraction (MAE), using the same time and temperature conditions optimized by UAE. Extraction at 50 °C and 170 Watts for 30 min provided the optimal UAE conditions. UAE showed better extraction efficacy than ME and MAE. The HPLC analysis of the extracts showed that the xanthophyll class was the main class of carotenoids, which constituted 42-85% of the total carotenoid content, followed by β-carotene and tocopherol. Moreover, 26 compounds, classified as phenolic acids, flavonols, flavonoids and other polar compounds, were identified in the chayote leaf extracts. Flavonols accounted for 55% of the total compounds quantified (the major compound was myricetin) and phenolic acids represented around 35%, mostly represented by ferulic acid, chlorogenic acid and (+)-catechin. This study revealed the potential of UAE as an effective green extraction technique to recover bioactive compounds from chayote leaves, for food, and for pharmaceutical and cosmetic applications.

Recovery of Antioxidants from Tomato Seed Industrial Wastes by Microwave-Assisted and Ultrasound-Assisted Extraction.

Tomato seed (TS) wastes are obtained in large amounts from the tomato processing industry. In this work, microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) of antioxidant compounds from TS were optimized by using response surface methodology. The effect of MAE and UAE main extraction parameters was studied on total phenolic content (TPC) and antioxidant activity (DPPH) responses. Antioxidant, structural, morphological, and thermal properties of MAE and UAE extracts were evaluated. A great influence of ethanol concentration was observed in both extraction methods. Optimal MAE conditions were determined as 15 min, 80 °C, 63% ethanol and 80 mL, with a desirability value of 0.914, whereas 15 min, 61% ethanol and 85% amplitude (desirability = 0.952) were found as optimal conditions for UAE. MAE extracts exhibited higher TPC and antioxidant activity values compared to UAE (1.72 ± 0.04 and 1.61 ± 0.03 mg GAE g TS−1 for MAE and UAE, respectively). Thermogravimetric analysis (TGA) results suggested the presence of some high molecular weight compounds in UAE extracts. Chlorogenic acid, rutin and naringenin were identified and quantified by HPLC-DAD-MS as the main polyphenols found by MAE and UAE, showing MAE extracts higher individual phenolics content (1.11–2.99 mg 100 g TS−1). MAE and UAE have shown as effective green techniques for extracting bioactive molecules with high antioxidant activity from TS with high potential to be scaled-up for valorizing of TS industrial wastes.

Response surface methodology: optimisation of antioxidant activities from Eucalyptus marginata L. by products under maceration and ultrasound-assisted extraction

This study was designed to optimize maceration (ME) and ultrasound-assisted extraction (UAE) parameters (extraction time X1, temperature X2, solvent/mass Ratio X3 and Ethanol concentration X4) of antioxidant activity of Eucalyptus marginata L. leaves’ using response surface methodology (RSM). The antioxidant activity was evaluated using the DPPH assay and ferric reducing antioxidant power (FRAP). The optimal conditions for ME and UAE of antioxidant compounds were: X1 (min) = 88 and 50, X2 (°C) = ~75 and ~79, X3 (ml/g) = 40 and 39.5 and X4 (% of ethanol) = 59.65 and 58.48, respectively. Consequently, these optimized ME and UAE methods have shown a potential application for the efficient extraction of polyphenolic antioxidants from Eucalyptus marginata L. by-products in several industries including nutraceutical and pharmaceutical.

Annona muricata Leaves as a Source of Bioactive Compounds: Extraction and Quantification Using Ultrasound

In this work, the ultrasound-assisted extraction (UAE) (operating conditions of sonication amplitude, pulse-cycle, and extraction time) was investigated to obtain an extract rich in biologically active compounds from Annona muricata leaves. In addition, the content of bioactive compounds from the extract by the optimal UAE conditions (UAE extract) was compared with extracts prepared by decoction and infusion. Moreover, Artemia salina toxicity was evaluated in all extracts. UAE extract (using optimal conditions: 80% amplitude, 0.7 s pulse-cycle, for 4.54 min) contained 178.48 mg/100 mL of soluble phenols, 20.18 mg/100 mL of total flavonoids, 27.81 mg/100 mL of hydrolyzable polyphenols, 167.07 mg/100 mL of condensed tannins, 30.44 mg/100 mL of total alkaloids and 14.62 mg/100 mL of total acetogenins. The UAE extract exhibited a high antioxidant capacity and a higher content of bioactive compounds from ~6 to ~927-fold than decoction or infusion, depending on the type of compound. Twenty-four different phenolic compounds were identified in the samples, and UAE extract produced the highest concentration. All extracts were considered non-toxic using the A. salina test. The UAE extract from A. muricata leaves is a rich source of bioactive compounds and can be utilized to formulate therapeutic drugs or nutraceutical foods.