Optimization Of Ultrasound-assisted Extraction Research Articles

Isolation and Identification of Indole Alkaloids from Aspergillus amstelodami BSX001 and Optimization of Ultrasound-Assisted Extraction of Neoechinulin A

This study aimed to investigate the alkaloid secondary metabolites of Aspergillus amstelodami BSX001, a fungus isolated from Anhua dark tea, and to improve the extraction yield of the active ingredients by optimizing the extraction process. The structural characterization of the compounds was investigated using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. The antioxidant activity of echinulin-related alkaloids was evaluated by determining the total reducing power and DPPH radical scavenging capacity. The extraction process of the compound with optimum activity was optimized by a single-factor test and response surface methodology (RSM) combined with Box–Behnken design (BBD). The optimized result was validated. Finally, a new alkaloid 8-hydroxyechinulin (1), and four known alkaloids, variecolorin G (2), echinulin (3), neoechinulin A (4), and eurocristatine (5), were isolated. Echinulin-related compounds 1, 3, and 4 possessed certain antioxidant activities, with IC50 values of 0.587 mg/mL, 1.628 mg/mL, and 0.219 mg/mL, respectively, against DPPH radicals. Their total reducing power at a concentration of 0.5 mg/mL was 0.29 mmol/L, 0.17 mmol/L, and 4.25 mmol/L. The extraction process of neoechinulin A was optimized with the optimum extraction parameters of 72.76% methanol volume fraction, 25 mL/g solid–liquid ratio, and 50.8 °C soaking temperature. Under these conditions, the extraction yield of neoechinulin A was up to 1.500 mg/g.

Investigation on Optimized Flavonoid Extraction from Leucas zeylanica and Its Anthelmintic Activity

Extraction has been the primary method of concentrating and obtaining a crude essence of plants, and to an extend fruits and nuts. In modern times, there are many methods of extraction developed from simple maceration to using Soxhlet extractor to microwave assisted extraction and ultrasound assisted extraction. However, the more time saving and energy efficient method for the extraction of plants needs to be investigated. This research explored optimization of ultrasound assisted extraction of flavonoids from Leucas zeylanica and the optimization was done on parameters of sonication time (minutes), water bath temperature (°C), volume of solvent to solid ratio (ml/g) and solvent concentration (%) using response surface methodology (RSM). By measuring the total flavonoid content using aluminium colorimetric method and UV visible spectrophotometry, highest flavonoid yield is achieved with 30.38% increase compared to unoptimized method. This occurred with sonication time of 42 minutes, temperature of 55°C, solvent to solid ratio of 40 ml/g and solvent concentration of 100%. The resulting extract was then tested for its anthelmintic (anti-worm) ability, obtaining 40% efficacy of that of Albendazole.

Optimization of Ultrasound-Assisted Extraction of Verbascum sinaiticum Leaves: Maximal Phenolic Yield and Antioxidant Capacity.

Verbascum sinaiticum (Qetetina or yeahya Joro) is a medicinal plant with secondary metabolites such as phenolics, flavonoids, glycosides, saponins, and alkaloids. This study was designed to optimize the ultrasonic-assisted extraction (UAE) parameters to enhance the phenolic content and characterize the phenolic compounds using ultra-high-performance liquid chromatography, coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-QTOF-MS/MS), and antioxidant activities in Verbascum sinaiticum extract. Extraction time, sample-to-solvent ratio, and extraction temperature were considered for UAE optimization. It was found that UAE generated the highest extraction yield (21.6%), total phenolic content (179.8 GAE mg/g), total flavonoid content (64.49 CE mg/g), DPPH (61.85 µg/mL), and ABTS (38.89 µg/mL) when compared to maceration extraction. Metabolite analysis in this study showed the detection of 17 phenolic compounds, confirming antioxidant capacities. The optimization parameters have significant effects on phenolic compounds. Scanning electron microscopy showed the presence of structural changes when UAE was used over the maceration method. The optimized UAE parameters for extraction temperature (41.43 °C), sample-to-solvent ratio (36.32 g/mL), and extraction time (33.22 min) for TPC were obtained. This study shows the potential application for UAE of Verbascum sinaiticum leaves in the development of pharmaceutical and nutraceutical products.

Optimization of ultrasound-assisted extraction of Imperata cylindrica polysaccharides and evaluation of its anti-oxidant and amelioration of uric acid stimulated cell apoptosis

An efficient, cost-effective and environmentally friendly ultrasound-assisted hot water method for Imperata cylindrica polysaccharide (ICPs) extraction was developed. According to the response surface results, the optimal ultrasonic time was 85 min, ultrasonic power was 192.75 W, temperature was 90.74 °C, liquid–solid ratio was 26.1, and polysaccharide yield was 28.50 %. The polysaccharide mainly consisted of arabinose (Ara), galactose (Gal), and glucose (Glc), with a molecular weight of 62.3 kDa. Ultrasound-assisted extraction of Imperata cylindrica polysaccharide (UICP) exhibited stronger anti-oxidant activity and ability to ameliorate cellular damage due to uric acid stimulation compared with traditional hot water extraction of Imperata cylindrica polysaccharide (ICPC-b). It also exhibited higher thermal stability, indicating its potential value for applications in the food industry.

Optimization of ultrasound-assisted extraction of Nigella sativa seed oil for enhancement of yield and antioxidant activity

The seeds of Nigella sativa have been shown to contain a number of constituents that have nutritional and therapeutic characteristics. The oil extracted from the seeds of Nigella sativa has been traditionally used in food systems with reference to its medicinal properties. The different bioactive compounds present in the Nigella sativa seed oil consist of polyphenols which offer a fair amount of antioxidant activity to the oil. Most of these bioactive compounds are generally heat sensitive and prone to oxidation. During the processing and storage, there is loss of antioxidant activity of the oil and the associated bioactivity. This occurs primarily due to the effects of temperature and other environmental factors during processing and storage. Under this background, this study was undertaken with the aim of extracting the Nigella sativa seed oil in order to ensure the improved retention of antioxidant and bioactive characteristics in the essential oil. The extraction of Nigella sativa seed oil was carried out using ultrasound-assisted extraction technique using hexane as solvent. The process was optimized using response surface methodology in order to enhance the yield and antioxidant activity of the extracted Nigella sativa seed oil. The effect of different processing parameters was evaluated on the yield and antioxidant activity. The process variables included the extraction temperature, extraction time and solvent concentration. It was observed that all the factors had significant effect on the yield and antioxidant activity of the extracted Nigella sativa oil. The optimized conditions for maximizing the yield and antioxidant activity obtained were a solvent concentration of 42.82 mL/5 g of sample, the extraction temperature of 69.09 °C and extraction time of 86.60 min, which were validated and found close to the experiment values. Under this set of conditions, the yield was maximized to 34.53% with enhanced antioxidant activity, having IC50 value of 203.56 µg/mL.

Wild Blackberry Fruit (Rubus fruticosus L.) as Potential Functional Ingredient in Food: Ultrasound-Assisted Extraction Optimization, Ripening Period Evaluation, Application in Muffin, and Consumer Acceptance.

The aim of the present study is to evaluate the antioxidant properties of wild blackberry fruits as well as their possible use in powdered form as a functional ingredient. For this, ultrasound-assisted extraction optimization, ripening stage evaluation, and wild blackberry powder incorporation into a real food matrix were applied. The optimum conditions for extraction were as follows: 60% MeOH, 20 min of extraction time, acidification with 0.5% HCl, and a 1:40 g/mL solid-to-solvent ratio, which allowed the following yields: total polyphenol content (TPC): 53.8 mg GAE/g; total flavonoid content (TFC): 5.78 mg QE/g; total monomer anthocyanin content (TMA): 11.2 mg CGE/g; 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH): 71.5 mg AAE/g; IC50: 52.3 µg/mL. The study also highlighted that, during the ripening process, the TPC (41.4%), TFC (17.0%), and DPPH levels (66.4%) of the fruits decreased while the TMA yield increased. The incorporation of blackberry powder at different levels (5-20%) increased the TPC, TFC, TMA, and antioxidant properties of muffins. Although the muffins enriched with 20% wild blackberry powder had the best chemical properties (TPC: 3.15 mg GAE/g; TFC: 0.52 mg QE/g; TMA: 0.23 mg CGE/g; DPPH: 1.70 mg AAE/g; IC50: 1.65 mg/mL), the sensory analysis showed that the addition of blackberry fruit at a concentration of 10% to the muffins resulted in the best consumer acceptability.

Optimization of ultrasound assisted extraction and characterization of functional properties of dietary fiber from oat cultivar S2000

This study was executed to explore efficacy of ultrasound assisted extraction of dietary fiber from oat cultivar S2000. Extraction (variables time, temperature and amplitude) was optimized by using response surface methodology (RSM) conducted by Box Behnken Design (BBD). The effect of time, temperature and amplitude were studied at three levels. It was observed that time and temperature exerted more impact on extraction efficiency as compared to amplitude. The highest yield of total dietary fiber (TDF), soluble dietary fiber (SDF) and In-soluble dietary fiber (IDF) fractions were observed under ultrasound processing, for 20 min at 40 °C with 80% amplitude. Characterization of extracted dietary fiber showed that it had better crystallinity, thermal properties and good fibrous structure. It also showed better functional properties as compared to traditionally extracted dietary fiber. Furthermore, dietary fibers from oat may offer high-value utilization, and the expansion of comprehensive utilization in functional food and nutraceutical development.

Valorization of Corn Silk as an Agricultural By-Product through the Optimization of Ultrasound-Assisted Extraction

Corn silk, derived from the stigmas of corn (Zea mays, Poaceae) flowers, possesses valuable bioactive compounds that can be harnessed for therapeutical, nutritional, and industrial purposes. This research aimed to optimize the extraction of bioactive compounds from corn silk, specifically flavonoids and total antioxidant capacity, by comparing it with classical extraction (infusion and maceration). The study identified significant factors influencing total flavonoid content (TFC) and antioxidant activity (assessed through an ABTS assay), including ethanol concentration, ultrasonic amplitude, and their quadratic interactions. This optimized combination of independent variables (37.89% ethanolic concentration, 48.58% ultrasound amplitude, and an extraction time of 38.72 min) yielded a balanced extraction, maximizing both TFC and antioxidant activity. Further analyses revealed significant total phenolic content, total flavonoid content (50.69 ± 0.36 mg GAE, 23.54 ± 0.01 mg QE, and 78.33 ± 0.94 mg TE/g extract, respectively), and potent in vitro antioxidant activity, affirming the efficacy of the optimized extraction. The study also explored the inhibitory effects on α-glucosidase (IC50 = 411.67 ± 25.39 µg/mL), acetylcholinesterase (IC50 = 1166.4 ± 399.38 µg/mL), and pancreatic lipase (IC50 = 1519.67 ± 209.04 µg/mL), showcasing potential antidiabetic and neuroprotective properties. While tyrosinase inhibition activity was not observed, the research emphasizes the nutraceutical potential of corn silk, offering valuable insights for its utilization and further exploration in the pharmaceutical and functional food industries.

Optimization of ultrasound-assisted extraction of fatty acids from royal jelly and its effect on the structural and antioxidant property

Fatty acids are the key active components in royal jelly (RJ) with various biological activities. In this study, a novel ultrasound-assisted extraction (UAE) method was established to extract fatty acids from RJ and their structural and antioxidant property were further evaluated. The optimum extraction conditions were as follows: liquid-to-solid ratio of 10:1, ultrasonic power of 450 W and ultrasonic duration of 20 min, resulting in a better extraction yield of 16.48 % and 10-hydroxy-2(E)-decenoic acid (10-HDA) content of 4.12 %. Furthermore, compared with the solvent extraction method, the antioxidant activity of extract by ultrasound was enhanced significantly by at least 448 %. GC–MS showed that ultrasound didn’t change the chemical composition of fatty acids, while it significantly increased the content of fatty acids. SEM image illustrated that extracts by UAE showed a rougher, looser microstructure compared to the solvent method. Overall, UAE is a promising method to obtain fatty acids in RJ with high efficiency.

Study on the preparation and enzyme inhibitory activity of polyphenols from Sargassum pallidum.

This study aimed to obtain a high yield and purity of Sargassum pallidum polyphenol extracts (SPPE) and study its enzyme activity. Fresh Sargassum pallidum seaweed was selected for optimization of ultrasound-assisted extraction (UAE) conditions and purification conditions using macroporous resin and Sephadex LH20 to obtain SPPE. The SPPE was characterized using UPLC-QTOF-MS/MS and α-amylase, α-glucosidase, tyrosinase, and AchE inhibitory activity were determined. The maximum extraction rate of SPPE was 7.56 mg GAE/g and the polyphenol purity reached 70.5% after macroporous resin and Sephadex LH-20 purification. A total of 50 compounds were identified by UPLC-QTOF-MS/MS. The IC50 values of SPPE were 334.9 μg/mL, 6.290 μg /mL, 0.834 mg /mL and 0.6538 mg /mL for α-amylase, α-glucosidase, tyrosinase and AchE, respectively. Molecular docking technology further revealed the effects of SPPE on the above enzymes. This study provided information on the potential hypoglycemic, whitening and anti-Alzheimer's disease biological activities of SPPE, which had guiding significance for the purification and development of other seaweed polyphenols.

Optimization of ultrasound-assisted extraction using response surface methodology and quantification of polyphenol compounds in Avicennia officinalis L. from Vietnam

Response surface methodology was used to estimate the optimum extraction parameters, for which the total phenolic content and total flavonoid content of Avicennia officinalis L. extract were the highest. Based on the 3D surface plots and regression analysis of the independent variables, the optimal conditions for the ultrasound-assisted extraction were as follows: methanol content, 55.27%; liquid-to-solid ratio, 14:1 (mL/g, v/w); temperature, 48.8 °C, and time, 9.66 min. Optimal extraction conditions were applied to validate the quantification. The bioactive compounds from the Avicennia officinalis L. extract were identified through ultra-fast liquid chromatography coupled to diode array detector for the first time. These methods were applied to quantify phenolic acids and flavonoids from A. officinalis extracts collected at six different locations in Vietnam. The results showed that the concentrations of these compounds varied from 0.319 ± 0.022 to 3.524 ± 0.125 mg/g in the methanol extract. The result showed that cinnamic acid is the major compound in A. officinalis collected in Vietnam. In the present study, an optimized ultrasound-assisted extraction was first designed to improve the content of phenolic acids and flavonoid compounds from A. officinalis. Additionally, the bioactive compounds from the A. officinalis extract were identified through UFLC-DAD for the first time.

Optimization of ultrasound-assisted extraction of phenolic compounds from Populus nigra as potential myeloperoxidase inhibitors

Optimization of ultrasound-assisted extraction of phenolic compounds from Populus nigra as potential myeloperoxidase inhibitors

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.

Optimization of ultrasound-assisted extraction (UAE) of (poly)phenolic compounds from blueberry (Vaccinium myrtillus) leaves using full-factorial design

Abstract In this work, the influence of process parameters (temperature: 25 - 65 °C, ethanol content in the extraction solvent: 30 - 90 vol.%, and solid-to-solvent ratio: 1:15 - 1:45 w/v) on the process of ultrasound-assisted extraction (UAE) of (poly)phenols from blueberry leaves (Vaccinium myrtillus) was investigated. Statistical analysis was performed using the MINITAB 21 software, with the application of three-level full factorial designs. The Responses in the study are the content of total (poly)phenols, flavonoids and anthocyanins in the obtained extracts. The extraction of blueberry leaf was significantly (p &lt; 0.05) impacted by process variables. The R2, Adjusted R2, and Predicted R2 values in the study are high, showing a significant relationship between the independent variables and the Response. The optimal temperature for all three Responses is 65 °C, the optimal solid-to-solvent ratio for total (poly)phenols and anthocyanins is 1:45 w/v and for flavonoids is 28.03 w/v, while the optimal ethanol content in the solvent for total (poly)phenols, flavonoids and anthocyanins is 51.21 vol.%, 50.61 vol.% and 83.33 vol.%, respectively.

Otimização da extração assistida por ultrassom de antocianinas de tomates roxos

ABSTRACT: This study aimed to optimize the ultrasound-assisted extraction (UAE) of total anthocyanins from two stages of ripening purple tomatoes (low and high) and to compare the optimized extraction with the conventional one. In the optimization of UAE, the studied variables were time (5 to 75 min), temperature (30 to 70 °C), and solid: liquid ratio (1:5 to 1:15 m/v). The optimal condition of the UAE process, for low-ripened purple tomatoes, occurs at a time of 75 min, temperature of 40 °C, and solid: liquid ratio of 1:15 m/v, predicting the content of 12.487 mg/100g. For high-ripened purple tomatoes, the optimal condition occurs at a time of 40 min, temperature of 50 °C, and solid: liquid ratio of 1:15 m/v, predicting the content of 8.802 mg/100 g. On validation of these optimized conditions, less than a 3% difference was reported between the predicted and experimental values (12.267 mg/100 g for low-ripened, and 8.894 mg/100 g for high-ripened purple tomatoes). When comparing the optimized UAE with the conventional extraction, it was observed that UAE increased (P &lt; 0.05) the extraction of total anthocyanins content by 73% for low-ripened and by 54% for high-ripened purple tomatoes. Thus, the study indicated that the UAE is an efficient technology for recovering bioactive compounds from purple tomatoes.

Optimization of ultrasound-assisted extraction of glycyrrhizic acid and glabridin from Glycyrrhiza glabra L. using response surface methodology and development of a green analytical method

In this study, ultrasound assisted extraction (UAE) were used to investigate the extraction of glycyrrhizic acid (GA) and glabridin (GD) simultaneously from Glycyrrhiza glabra L. and a green HPLC analytical approach for determining GA and GD was developed. Extraction pocess were optimizing by Response surface methodology (RSM) utilizing Box-Behnken design (BBD). According to the consequences, the ideal extraction situations were: 64% (v/v) ethanol concentration, 22 mL/g liquid-solid ratio, 51 °C and 31 min. Under these conditions, the yields of GA and GD were 2.806 ± 0.107% and 0.252 ± 0.026%, respectively, and the actual experimental extraction values were fundamentally the same as the anticipated values. Meanwhile, the effects of UAE, maceration (MAC) and heat-reflux extraction (HRE) on yeild were assessed, and the UAE possessed highest yields. A green HPLC approach was created to analyze GA and GD with combinations of ethanol and a 0.1% (v/v) trifluoroacetic acid mobile phase (following the gradient elution method). The method validated based on the guidelines of the International Conference on Harmonization (ICH) and the result indicated the method was precise, stable, reliable and valuable, could be used to analyze GA and GD from Glycyrrhiza glabra L.

Optimization of ultrasound-assisted extraction of phenolic compounds and flavonoids from Hortia oreadicaleaf

Hortia oreadica is indiscriminated used by people from Cerrado. However, vegetable raw material quality is decisive in obtaining intermediate and final products. So, this study aimed to establish quality parameters of H. oreadica. For this, we performed the phytochemical screening of H. oreadicaleaf and identified the best extractive conditions for phenolic compounds and flavonoids using factorial experimental design, varying the alcoholic strength, extraction temperature, and solid/liquid ratio in the ultrasound-assisted extraction method. The optimum extraction condition for phenolic compounds and flavonoids was 60% alcoholic strength,40°C temperature, and a solid/liquid ratio of 8 mg/mL. Under this setting, the phenolic and flavonoid contents were 0.171 ± 0.002 mg/mL(predicted value = 0.165) and 0.087 ± 0.002 mg/mL(predicted value = 0.084), respectively. The optimized extraction parameters could be upscaled to develop pharmaceutical drugs or nutraceutical products from this non-traditional plant species using an eco-friendly approach.

Guadua angustifolia Kunth leaves as a source for bioactive phenolic compounds: Optimization of ultrasound-assisted extraction using response surface methodology and antioxidant activities

This study evaluated the ultrasound-assisted extraction of phenolic compounds from Guadua angustifolia leaves, along with their optimization using response surface methodology. The effects of two sonication process conditions were determined using a central composite experimental design, with three levels (low, medium, and high) evaluated for time (10, 20, and 30 min) and temperature (20 °C, 35 °C, and 50 °C). A total of 12 experiments with four replicates were conducted at the central point, with the total phenol and flavonoid contents determined using the Folin-Ciocalteu colorimetric method and complexation with AlCl3, respectively. The optimized extract was analyzed using ultra-performance liquid chromatography (UPLC), and the antioxidant capacity of the optimized extract was determined by DPPH• (2,2-Diphenyl-1-Picrylhydrazyl) and ABTS•+ (2,2′-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) assays. Extraction at 50 °C for 20 min was found to favor the extraction of phenol and total flavonoids. The experimental validation of the total phenol and flavonoid content produced values of 7.39 mg gallic acid equivalents per gram of dry matter and 1.55 mg quercetin equivalents per gram of dry matter, respectively. These values suggest that the extraction process is reproducible, with a relative standard deviation of 22.9 % and 14.1 %, respectively. The chromatographic profile showed that optimization favored the visualization of phenolic compounds compared to the non-optimized extract. The optimized extract had higher antioxidant capacity than the non-optimized extract, with values of 209.23 and 144.76 μmol Trolox per gram extract for the DPPH• and ABTS•+ techniques, respectively. Thus, the conditions evaluated in the ultrasound-assisted extraction were an efficient technique capable of extracting the maximum amount of phenolic compounds with antioxidant activity from the leaves of G. angustifolia, showing its potential application in various industries.

Optimization of Ultrasound-Assisted Extraction and Characterization of the Phenolic Compounds in Rose Distillation Side Streams Using Spectrophotometric Assays and High-Throughput Analytical Techniques

Lately, the essential oils industry has been one of the most expanding markets globally. However, the byproducts generated after the distillation of aromatic plants and their transformation to novel high-added value products consist of a major up-to-date challenge. Thus, the scope of the current study is the optimization of ultrasound-assisted extraction (UAE) for the recovery of phenolic compounds from rose (Rosa damascena) post-distillation side streams using Box–Behnken design. In particular, the highest total phenolic content (TPC) was achieved at 71% v/v ethanol–water solution, at 25 min, 40 mL/g dry sample and 53% ultrasound power, while ethanol content and extraction time were the most crucial factors (p-value ≤ 0.05) for UAE. Both solid (RSB) and liquid (LSB) rose side streams exhibited significant antiradical and antioxidant activities. The interpretation of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra confirmed the presence of compounds with properties such as phenolic compounds, phenolic amide derivatives, and alcohols in the extracts. Moreover, the flavonoids naringenin, quercetin, and kaempferol were the major phenolic compounds, identified in the extracts by liquid chromatography-tandem mass spectrometry analysis (LC-MS/MS), followed by gallic, protocatechuic, p-hydroxybenzoic, and rosmarinic acids. Furthermore, the LC-MS/MS results pinpointed the effect of factors other than the extraction conditions (harvesting parameters, climatic conditions, plant growth stage, etc.) on the phenolic fingerprint of RSB extracts. Therefore, RSB extracts emerge as a promising alternative antioxidant agent in food products.

Vigna unguiculata L. Walp. Leaves as a Source of Phytochemicals of Dietary Interest: Optimization of Ultrasound-Assisted Extraction and Assessment of Traditional Consumer Habits.

Vigna unguiculata L. Walp. is an African crop spread worldwide mainly for pulses production. Despite being a neglected and under-utilized food, cowpea leaves are a rich source of phytochemicals and micronutrients. The aim of the work is to characterize the phytochemical composition of cowpea leaves by an optimized ultrasound-assisted extraction (USAE) and to compare raw and boiled leaves. A three-level factorial design (Box-Behnken) was employed for the optimization of the USAE considering three different parameters (% ethanol, drug-to-solvent ratio, and number of cycles). The optimized extracts were characterized by LC/MS/MS. Finally, leaves were boiled at 100 °C for 30 min to simulate traditional cooking procedures and compared to raw leaves. The best extraction condition was EtOH/H2 O 1 : 2 v/v, drug to solvent ratio 1 : 47 w/v, and 3 extraction cycles. The phytochemicals identified mainly belong to the family of phenolic acids, flavonoids, terpenoids, and alkaloids. Boiled leaves revealed a significant loss of most phytochemicals and a net decrease of their antioxidant activity compared to the raw ones. The results highlight the potential nutraceutical value of cowpea leaves whilst the impoverishment triggered by traditional consumer habits pushes the need to evaluate alternative cooking procedures helpful in the maintenance of their phytochemical properties.