Ultrasound-assisted Extraction Method Research Articles

Physicochemical properties and antioxidant activities of white dragon fruit peel pectin extracted with conventional and ultrasound-assisted extraction

AbstractThe objective of this study was to investigate the optimal condition for extracting dragon fruit peel (DFP) pectin with the best physicochemical properties and high antioxidant activity by using conventional extraction (CE) and ultrasound-assisted extraction (UAE). DFP was extracted using CE and UAE method at 45, 60 and 75°C for 30 and 60 min. In this study, UAE significantly improved antioxidant activity of the extracted DFP pectin when comparing to CE. DFP extracted with UAE at 45°C for 30 min had the highest antioxidant activity (51.58 ± 0.30 by DPPH, 39.81 ± 1.43 mgGAE/100 g by ABTS) (p < 0.05). Moreover, UAE also increased the production yield of sample at 45°C for 30 min (9.38 ± 0.50%) (p < 0.05) which was higher than the treatments with CE. The chemical properties of DFP pectin including equivalent weight, degree of esterification, methoxyl content and total anhydroronic acid revealed that DFP pectin could be categorized as low-methoxyl pectin. Present study demonstrated that DFP pectin was...

High-pressure ultrasonic-assisted extraction of polysaccharides from Mentha haplocalyx: Structure, functional and biological activities

In the present study, Mentha haplocalyx polysaccharides (MHP) were extracted using a high-pressure ultrasound-assisted extraction (HUAE) method. Response surface methodology (RSM) was used to select the conditions for the extraction of MHP; this method predicted that optimized extraction is obtained using 300 W of ultrasonic power, an extraction temperature and time of 70 °C and 28 min, respectively, and 29 mL of water for every gram of raw material used in the extraction. Results showed that MHP mainly contained neutral sugar (69.09 ± 0.81%), uronic acid (3.89 ± 0.14%), and protein (7.97 ± 0.42%). Specifically, MHP was comprised of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose with molar percentages of 2.13, 0.89, 1.14, 3.79, 39.3, 44.85, and 7.89%, respectively, and with an average molecular weight of 59.58 kDa for its major component (accounting for 66.20% of MHP). Functional analyses demonstrated that MHP exhibits favorable oil-holding capacity, foaming qualities, emulsifying capacity, hygroscopicity, and moisture retention capacity. The results obtained from the X-ray diffraction pattern and rheological measurements confirmed a semi-crystalline nature of the sample and shear thinning behavior of MHP, respectively. Additionally, in vitro antioxidant activity experiments suggested that MHP exhibits strong DPPH and hydroxyl radical scavenging activities and considerable reducing power. The results presented herein have larger implications for the use of MHP as a functional additive in the food and pharmaceutical industries.

Increased bio-oil yield from Nannochloropsis salina through tuning the polarity of subcritical water

Changing solvent polarity at subcritical conditions, by an appropriate co-solvent, may be used to enhance oil extraction from different raw materials. As a newly commercially interested process, oil extraction from Nannochloropsis salina as a valuable bio-resource, by subcritical water-ethanol mixture as a polarity altered solvent, was investigated. Response surface methodology (RSM) was applied to achieve the best operating conditions. Three factors including temperature (90–150 °C), water-ethanol concentration (25–75 wt%) and flow rate (1.0–4.0 ml/min) were investigated. The best separation conditions were determined at 90 °C, 75 wt% ethanol and 4 ml/min. The oil composition was compared with four other methods including subcritical water extraction (SCWE), ultrasound-assisted extraction (UAE), Soxhlet (SOX) and Folch methods. The main fatty acids were identified as C16:0, C18:0, C18:1c and C18:3c. The highest extraction efficiency of 33.93 wt% was achieved for subcritical water/ethanol mixture.

Ultrasound‐assisted extraction of sulfated polysaccharide from Nizamuddinia zanardinii: Process optimization, structural characterization, and biological properties

AbstractSingle‐factor experiment and Box‐Behnken design were used to evaluate and optimize the effect of extraction time (40, 50, and 60 min), ultrasonic power (100, 150, and 200 W), water‐solid ratio (60, 70, and 80 mL/g), and extraction temperature (70, 80, and 90 °C) on the recovery of fucoidan from Nizamuddinia zanardinii by ultrasound‐assisted extraction method (UAE). The optimal extraction conditions were as follows: extraction time of 58 min, ultrasonic power of 196 W, water‐to‐raw‐material ratio of 80 mL/g, and extraction temperature of 70 °C. Under these conditions, the polysaccharide yield was 3.51%. Extracted fucoidan was composed of fucose (32.33%), galactose (29.95%), mannose (27.97%), xylose (6.56%), and glucose (3.19%). The UAE‐extracted fucoidan had appreciable DPPH radical scavenging and reducing power. The fucoidan exhibited notable cell growth inhibition against HeLa (62.36%) and HepG2 (56.83%) cancer cell lines, and induced RAW264.7 murine macrophage cells to release considerable amount of nitric oxide (41 μmol).Practical applicationsSeaweeds are rich sources of diverse bioactive compounds with valuable nutraceutical, pharmaceutical and cosmeceutical potentials. Nizamuddinia zanardinii is a marine brown seaweed and belong to Sargassaceae family. Iranian South Coasts have abundant supply of N. zanardinii which has a great potential for mariculture and can be utilized as a source of natural compounds. Fucoidan, which is a sulfated polysaccharide found in brown seaweeds, have shown promising health benefits for humans. In this study, the effects of extraction time, ultrasonic power, water–solid ratio, and extraction temperature were investigated on yield, structural, molecular, and biological properties of ultrasound extracted fucoidan. This study provides a practical and effective instruction into the application of ultrasound in the extraction of fucoidan. Additionally, the ultrasound extracted fucoidan exhibited appreciable antioxidant, anticancer, and macrophage‐stimulating capacity indicating its potential value for health and food industry.

A magnetic graphitic carbon nitride as a new adsorbent for simple separation of Ni (II) ion from foodstuff by ultrasound-assisted magnetic dispersive micro solid-phase extraction method

In this research, a magnetic graphitic carbon nitride (g-C3N4-SnFe2O4) was successfully synthesized and utilized as an efficient adsorbent for nickel (Ni2+) separation/extraction from vegetable samples by ultrasound-assisted magnetic dispersive micro solid-phase extraction (UA-M-D-μSPE). After separation and preconcentration step, Ni ions were determined via micro-sampling flame atomic absorption spectrometry (MS-FAAS). A successful synthesis of g-C3N4-SnFe2O4 was investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and vibrating sample magnetometer (VSM). The optimization of adsorption and desorption steps was effectively studied by the on-at-a time method. In addition, under the optimum experimental conditions, the limits of detection (LODs), the linear ranges (LR) and relative standard deviations (RSDs%, for n = 5) were obtained 1.0 μg.L−1, 4.0 ─ 500.0 μg.L−1, and 1.4 respectively.

Antioxidant activity and cytotoxicity of Jerusalem artichoke tubers and leaves extract on HaCaT and BJ fibroblast cells

BackgroundExtracts from plants, rich in antioxidants may be used as active ingredients of many preparations, mainly due to their antioxidant, regenerative and anti-aging properties. The work involved a comprehensive evaluation of the Jerusalem artichoke (Helianthus tuberosus L.) leaf and tuber extract as a multifunctional raw material.MethodsThe plant extracts were prepared by using ultrasound-assisted extraction method (UAE).The content of total phenolic and flavonoid compounds of extracts were determined spectrophotometrically using the Folin-Ciocalteu method and aluminium nitrate nonahydrate, respectively. Antioxidant activity of extract was analyzed using DPPH free radical scavenging assay and the effect of the investigated extracts on the proliferation of keratinocytes (HaCaT) and fibroblasts (BJ) was measured. To detect of intracellular reactive oxygen species level in tested cells, the fluorogenic dye H2DCFDA was used. In the next step, the ability of obtained extracts to regulate the expression of genes (SOD-1, Nox-4) involved in oxidative stress in cells was evaluated.ResultsAs a result of the conducted research, it was shown that leaf extract exhibit a higher content of phenols and flavonoids comparing to tuber extracts (5.07 and 7.14 fold higher, respectively). The opposite trend was observed after proliferation assay with Neutral Red test. It was shown that tuber extract in all applied concentrations (25–500 μg·ml− 1) had a positive effect on fibroblast growth. The leaf extract showed proliferative activity only for the smallest tested concentrations (25–100 μg·ml− 1). Similar trends were observed for HaCaT cells. The distinct effect of leaves and tuber extract on the generation of ROS was observed in HaCaT cells. In the present study, it was shown that tuber and leaf extracts may increase the expression of the ROS SOD-1 inactivating enzyme gene in the fibroblast cell line. There were no significant differences in gene expression of the ROS Nox-4 producing enzyme. In the case of keratinocytes, the opposite effect was observed.ConclusionsThe study suggest that Jerusalem artichoke leaves and tubers extracts affect the cell proliferation and can alter the expression of genes related to oxidative stress.

Free phenolic compounds extraction from Brazilian halophytes, soybean and rice bran by ultrasound-assisted and orbital shaker methods.

In several countries halophytes are commercially cultivated in low saline or even irrigated with seawater, as well as with saline aquaculture effluent, like a sea asparagus Sarcocornia ambigua, that show a biotechnological potential for bioactive compounds production. However, their recovery from matrix is sometimes inefficient because the lignocellulosic materials difficult the solvent action when drastic conditions are not applied. The ultrasound-assisted extraction (UAE) was optimized by a central composite rotational design for recovery free phenolic compounds (FPC) from the sea asparagus S. ambigua. Optimum conditions were validated and compared with orbital shaker extraction for S. ambigua, other Brazilian halophytes (Apium graveolens, Myrsine parvifolia, Paspalum vaginatum, and Schinus terebinthifolius), soybean and rice bran. Except for P. vaginatum, soybean and rice bran, UAE yielded 18-29% higher FPC than that of the orbital shaker. Besides this analytical performance UAE method optimized is faster than the orbital shaker, providing shorter exposure of the analyst to the extractor solvent and applicable in matrices with different compositions. It was also demonstrated that halophytes species showed to be good natural sources of FPC in a better way as soybean and rice bran. This work was the first to report FPC in M. parvifolia and P. vaginatum.

Extraction, characterization and antioxidant activity analysis of the polysaccharide from the solid-state fermentation substrate of Inonotus hispidus

A polysaccharide from Inonotus hispidus was prepared by solid-state fermentation (SSF), and an efficient ultrasound-assisted extraction method was used to optimize the extraction process of Inonotus hispidus solid-state fermentation polysaccharide (IHSFP). The optimal extraction parameters were as follows: solid-liquid ratio of 1:40, ultrasound time of 34 min, ultrasound power of 350 W and ultrasound temperature of 70 °C. The yield of IHSFP was 51.06 ± 0.34% under the optimal conditions. Two types of polysaccharide fractions (IHSFP-1 and IHSFP-2) were isolated by DEAE-52 and Sephadex G-200 columns. IHSFP-2 had stronger antioxidant activity than IHSFP-1, and it can reduce H2O2-induced oxidative damage to cells in vitro. Therefore, the properties of IHSFP-2 were further characterized. The results showed that the molecular weight of IHSFP-2 was 14.44 kDa, it was composed of glucose (Glc), mannose (Man), galactose (Gal), glucuronic acid (GlcUA), galactosamine (GalN), arabinose (Ara) and ribose (Rib), and the contents of these monosaccharides were 51%, 21%, 20%, 3%, 2%, 2% and 1%, respectively. The results of this study may contribute to the efficient production of the polysaccharide of Inonotus hispidus, and provide new ideas for its application in functional foods and cosmetics.

Antidiabetic, Antihypertensive and Antioxidant Properties of Grapevine Leaf Extracts Obtained by Ultrasound, Microwave Assisted, and Classical Solvent Extraction

Grapevine leaves are consumed as a food in Mediterranean countries. At the same time, it is a byproduct of the wine industry. Antioxidant, antihypertensive and antidiabetic properties of grapevine leaves after ultrasound-assisted extraction (UAE), microwave assisted extraction (MAE) and classical solvent extraction (CSE) were evaluated and compared by using water and methanol as solvent. DPPH radical scavenging activity, total phenolic content (TPC), total antioxidant capacity (TEAC), metal chelating activity, ACE inhibitory activity and α‑glucosidase inhibitory activity of grapevine leaves extracts were determined. The highest values of grapevine leave extracts for antioxidant properties; DPPH (61.60%), TPC (910.18 mg GAE g−1), TEAC (6.23 µg Trolox mg−1) and metal chelating activity (IC50; 3.18 mg mL−1) were obtained from UAE when the methanol was used extracting solvent. However antihypertensive activity (13.68%) and antidiabetic activity (83.00%) values obtained from MAE by using water as a solvent were relatively highest. The effectiveness of UAE, MAE and CSE methods in terms of antioxidant, antihypertensive and antidiabetic properties of grapevine leaves were significantly (p < 0.05) different from each other. This differences depending on the solvent used.

Comparision of Green and Conventional Extraction Methods on Lipid Yield and Fatty Acid Profiles of Fish Species

The efficiency of the green extraction methods ultrasound‐assisted extraction (UAE) and microwave‐assisted extraction (MAE), and conventional methods (Soxhlet and Bligh and Dyer), on lipid content and fatty acid profiles of six fish species (Mullus barbatus, red mullet; Upeneus moluccensis, goldband goatfish; Mullus surmuletus, surmullet; Anguilla anguilla, European eel; Pagellus erythrinus, common pandora, and Saurida undosquamis, brushtooth lizardfish) are evaluated. The results of lipid content of fish species show that the Bligh and Dyer method and UAE in general are more efficient than other methods. There are statistical differences in the fatty acid composition of fish oil by four extraction methods (p &lt; 0.05). Saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acid (PUFA) contents of fish species range from 29.51 mg 100 g−1 fish (Soxhlet)–1400 mg 100 g−1 (UAE), 15.52 mg 100 g−1 (UAE)–2237.18 mg 100 g−1 (Bligh and Dyer), and 14.36% (Soxhlet)–646 mg 100 g−1 (Bligh and Dyer), respectively. Generally, Bligh and Dyer give the higher values in surmullet, red mullett, and common pandora in terms of SFA, MUFA, PUFA, and the dominant fatty acids (C16:0, C18:0, C16:1, C18:1n9, C18:1n7, C22:1n9, EPA, DHA), whereas MAE and UAE methods give better results in goldband goldfish and European eel, respectively. Thus, extraction methods affect the lipid yield and fatty acid profiles of extracted oil of different fish species.Practical Application: Total lipid content of seafood is an important parameter used in biochemical, physiological, and nutritional studies. Thus, reliable methods for the quantitative extraction of lipids from this type of food are of critical importance. The effects of green and conventional extraction methods on lipid yield and fatty acid profiles of fish species are compared in order to determine the most effective method for extracting lipid with high yield and high content of PUFA, especially EPA and DHA.The effects of green and conventional extraction methods on lipid yield and fatty acid profiles of fish species are evaluated. The extraction methods affect the lipid yield and fatty acid profiles of extracted oil of fish species. The Bligh and Dyer method and UAE in general are more efficient than other methods. In terms of SFA, MUFA, PUFA, EPA, and DHA; Bligh and Dyer gave the higher values in surmullet, redmullet, and common pandora whereas MAE and UAE methods gave better results in goldband goldfish and European eel, respectively.

Extraction of Hyssopus officinalis L. essential oil using instant controlled pressure drop process

To determine the optimum condition for the extraction of Hyssopus officinalis L. essential oil (EO) by instant controlled pressure drop (in French: Détente Instantanée Contrôlée or DIC), the influential parameters of pressure, heating time per cycle, number of cycles, mean particle diameter of the herb, and water concentration in the steam generator feed were evaluated using response surface methodology (RSM). The impact of using an ethanol-water mixture to generate the required vapor in the DIC process on EO extraction was investigated. The optimum condition was found to be at pressure = 1 bar, heating time = 100 s, cycles = 12, particle diameter = 1 mm, and water concentration = 80 v%. The addition of ethanol turned out to be more efficient at higher heating times and cycle numbers. The optimum yield in DIC was highest compared with hydrodistillation (HD), ultrasound-assisted extraction (UAE), and Soxhlet (SOX) methods; their values, expressed as total area percentages per internal standard area percentage, were 39.04, 10.98, 1.58, and 7.71, respectively. Comparison of the four methods also indicated that the DIC-EO was of a superior quality. The analysis of the DIC-treated residual herb in the optimum experiment revealed that unlike the low amount of valuable oxygenated monoterpenes, the availability of sesquiterpenes increased, which proved that DIC performs selectively while extracting more valuable EO components. The DIC-EO and its extract were examined for total phenolic content (TPC) and antioxidant activity using Folin-Ciocalteu and DPPH assay, respectively. Comparison of these results with those obtained from HD demonstrated higher TPC and antioxidant activity of the DIC-EO. Moreover, scanning electron microscopy (SEM) of the raw material and residual herb in the optimum experiment showed significant structure modifications induced by the DIC process.

Toxicological evaluation of a standardized hydroethanolic extract from leaves of Plantago australis and its major compound, verbascoside

Ethnopharmacological relevancePlantago australis is a perennial plant widely distributed in Latin America, and its seeds and leaves are used in folk medicine to treat many diseases and conditions. Among its various chemical compounds, verbascoside is one of the most present, and has several pharmacological activities described, but there is not much information about its toxicity. Aims of the studyThe aims of this study were to optimize the extraction of verbascoside from P. australis leaves with ultrasound methods, to develop a validated HPLC method to quantify verbascoside, and to evaluate the toxicological safety of the extract and verbascoside using in vitro and in vivo assays. Materials and methodsDried leaves of P. australis were submitted to different extraction methods (percolation and ultrasound). The optimization of the ultrasound extraction was carried out by complete factorial design (22) and response surface methodology (RSM), followed by HPLC analysis for marker compounds. HPLC analysis was performed to verify the presence of the marker compounds aucubin, baicalein, oleanolic acid, ursolic acid and verbascoside. Mutagenicity was assessed by Salmonella/microsome mutagenicity assay. Cytotoxicity and genotoxicity were evaluated in V79 cells by reduction of tetrazolium salt (MTT) and neutral red uptake (NRU) assays, and alkaline comet assay, respectively. Verbascoside phototoxicity was assessed in 3T3 cells by the NRU phototoxicity assay. Wistar rats were used to perform the acute and sub-chronic toxicity tests. ResultsAmong the marker compounds, only verbascoside was found in the hydroethanolic extract of P. australis leaves (PAHE); its highest concentration was obtained with the ultrasound-assisted extraction (UAE) method, optimized in 40 min and 25 °C, and the method validation was successfully applied. Neither PAHE nor verbascoside showed mutagenic or genotoxic activities. Cytotoxicity assays demonstrated that both PAHE and verbascoside reduced cell viability only at the highest concentrations, and verbascoside had no phototoxic properties. The in vivo toxicity evaluation of PAHE suggested that the LD50 is higher than 5000 mg/Kg, indicating that this extract is safe for use. In addition, no signs of toxicity were found in subchronic exposure. ConclusionThe HPLC method to quantify verbascoside was validated, and the extraction of verbascoside from P. australis leaves through ultrasound method was optimized, yielding an extract with 6% verbascoside. Our results suggest the toxicological safety of PAHE and verbascoside, corroborating the use of P. australis in folk medicine, and also indicate verbascoside as a potential ingredient in topical formulations.

HPLC determination of Ursolic acid in flowers of an Iranian Pomegranate (Punica granatum L.) Cultivar

Ursolic acid (UA), is a major bioactive compound in several traditional medicinal plants including pomegranate (Punica granatum L.) flower. This study presents the HPLC analysis of UA content in flowers of an Iranian pomegranate cultivar. The analytical method’s accuracy and the repeatability were satisfactory. The Linear ranges were 100-400 µg/ml for UA with a good correlation. On the average, the recovery rate of UA was 100%. Here, the extraction of UA from an Iranian pomegranate flower cultivar by employing an ultrasound-assisted extraction method was reported, and several extraction solvents were studied to improve extraction yield of UA. Remarkable quantities of UA were found in cultivar of pomegranate flower evaluated. Our results showed that Iranian pomegranate flower cv. Ghorj Tafti Torsh is a good source for extraction and isolation of UA.&#x0D;

Application of Box-Behnken design for ultrasound-assisted extraction and recycling preparative HPLC for isolation of anthraquinones from Cassia singueana.

Cassia singueana Del. (Fabaceae) is a rare medicinal plant used in the traditional medicine preparations to treat various ailments. The root of C. singueana is a rich source of anthraquinones that possess anticancer, antibacterial and antifungal properties. The objective of this study was to develop an ultrasound-assisted extraction (UAE) method for achieving a high extraction yield of anthraquinones using the response surface methodology (RSM), Box-Behnken design (BBD), and a recycling preparative high-performance liquid chromatography (HPLC) protocol for isolation of anthraquinones from C. singueana. Optimisation of UAE was performed using the Box-Behnken experimental design. Recycling preparative HPLC was employed to isolate anthraquinones from the root extract of C. singueana. The BBD was well-described by a quadratic polynomial model (R2 =0.9751). The predicted optimal UAE conditions for a high extraction yield were obtained at: extraction time 25.00min, temperature 50°C and solvent-sample ratio of 10mL/g. Under the predicted conditions, the experimental value (1.65±0.07%) closely agreed to the predicted yield (1.64%). The obtained crude extract of C. singueana root was subsequently purified to afford eight anthraquinones. The extraction protocol described here is suitable for large-scale extraction of anthraquinones from plant extracts.

Development and evaluation of semi-destructive, ultrasound assisted extraction method followed by gas chromatography coupled to mass spectrometry enabling discrimination of red lipstick samples

In this study, the effective and robust semi-destructive ultrasound assisted extraction (UAE) method followed by gas chromatography coupled to mass spectrometry (GC–MS) method used for analysis of red lipsticks samples was developed, optimized and evaluated. 43 red lipsticks of a very similar hue representing of 21 different manufacturers were investigated. The red lipsticks (approximately 0.05 mg) were applied on a disc (of ø 2 mm) placed on specially designed stand printed with a 3D printer. In order to optimize the main factors affecting extraction process, Doehlert experimental design with response surface methodology was applied. The optimal for all analysed lipsticks UAE extraction conditions were: 21 min – time, 35 °C – temperature of the ultrasonic bath, and the 100 μL of extraction mixture of acetonitrile, methanol and acetone (50:30:20, v/v/v). The developed, qualitative UAE/GC–MS method was evaluated and then successfully used for the differentiation of 43 red lipsticks. In this case, the two approaches were utilized: the visual inspection of chromatograms and the likelihood ratio model. The results confirmed that the proposed method has a great potential in lipsticks differentiation and after adaptation to real samples it seems to be a good alternative to the methods routinely used in forensic science investigations.

Extraction, development and validation of HPLC-UV method for rapid and sensitive determination of colchicine from Colchicum autumnale L. Bulbs.

Colchicum autumnale L. also known as the autumn crocus, contains colchicine alkaloid having antifungal properties. The tuber of this plant is rich in terms of colchicine. In this research an ultrasound-assisted extraction (UAE) method was optimized for the extraction of colchicine from Colchicum autumnale L. bulbs before high-performance liquid chromatography with UV detection (HPLC-UV). Optimization of various extraction parameters was performed using response surface methodology (RSM) to evaluate the maximum colchicine yield from Colchicum autumnale L. bulbs. The Box-Behnken design (BBD) and RSM were used to investigate the effect of three key parameters (extraction time (20–60 min), extraction temperature (40–80 °C) and ultrasound power (500–700 W) on extraction efficiency. The variance analysis suggested that the dependent response variable of yield of colchicine may be expressed by a quadratic polynomial model. The optimal theoretical extraction conditions were found to be an ultrasonication power of 602.4 W, an extraction time of 42 min and a temperature of 64 °C. Under these conditions, the optimum foreseen yield was 0.237%. The experimental colchicine yield obtained by following the optimized conditions was found to be 0.238%. These values are very well compatible with each other.

Optimization of heat- and ultrasound-assisted extraction of anthocyanins from Hibiscus sabdariffa calyces for natural food colorants

Heat- and ultrasound-assisted extraction methods were applied to recover anthocyanins from Hibiscus sabdariffa calyces. The extraction variables, time (t), ethanol proportion (S), and temperature (T) or ultrasonic power (P), were combined in a 5-level experimental design and analysed by response surface methodology for process optimization. The delphinidin-3-O-sambubioside (C1) and cyanidin-3-O-sambubioside (C2) levels were monitored by LC-DAD-ESI/MSn and used as response criteria. The developed models were successfully fitted to the experimental data and used to determine optimal extraction conditions. UAE was the most efficient method yielding 51.76 mg C1 + C2/g R under optimal conditions (t = 26.1 min, P = 296.6 W and S = 39.1% ethanol, v/v). The dose-response effects of the solid/liquid ratio on the extraction rate were also determined. The anthocyanin levels herein reported are higher than those found in the literature, which support the potential use of H. sabdariffa as a sustainable source of natural colorants with application in different industrial sectors.

The effect of ultrasound assisted extraction on structural composition, antioxidant activity and immunoregulation of polysaccharides from Ziziphus jujuba Mill var. spinosa seeds

In this study, the polysaccharide was extracted from Ziziphus jujuba Mill var. spinosa seeds (ZSS) with ultrasound assisted extraction method (UAE). Box-Behnken design (BBD) and response surface methodology (RSM) were applied to obtain the optimal conditions for perfect yield of ZSS polysaccharide: extraction temperature 52.5 °C, extraction time 21.2 min, extraction power 134.9 W and ratio of liquid to solid 26.3 mL/g. The yield was 1.05 ± 0.08%, which roughly equated to that 0.93 ± 0.14% of 6 h heating water extraction (HWE). The results illustrated that the polysaccharide extracts by UAE and HWE exhibited obvious difference in chemical structure, including morphological traits, optical rotation, monosaccharides composition, molecular distribution, and Fourier transform infrared spectroscopy (FT-IR) spectra. The two polysaccharide extracts both showed certain antioxidant activities, including scavenging ABTs radical, superoxide radical, hydroxyl radical and Ferrous ion in vitro and inhibiting reactive oxygen species (ROS) accumulation in PC12 cells. Compared with HWE extract, UAE extract scavenged more hydroxyl radical and Ferrous ion in the same concentration (1 and 2 mg/mL). Moreover, the UAE extract exerted significantly stronger effect on inducing Cyclooxygenase-2 (COX-2) expression in RAW264.7 macrophages than HWE extract. In conclusion, UAE could be used as an efficient technique for extracting ZSS polysaccharide.

Antioxidant Capacity and UPLC-PDA ESI-MS Phenolic Profile of Stevia rebaudiana Dry Powder Extracts Obtained by Ultrasound Assisted Extraction

Stevia leaves, which are commonly used as a natural sweetener in food products, have increased in importance for antioxidant delivery due to their high content of phenolic compounds. In this study, the influence of the drying process on stevia leaves, with regards to phenolic content and antioxidant activity during drying kinetics 40 °C for 7 h, was studied. The effect of solvent concentration and extraction time using a 32 factorial design on total phenol content (TPC), and on antioxidant activity of extracts obtained from dried stevia leaves, by ultrasound assisted extraction (UAE) as alternative method was evaluated. Steviol glycosides contents were also evaluated by a conventional and UAE method. Phenols identification, quantification and purification were performed by Ultra Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (UPLC-ESI-MS), Ultra Performance Liquid Chromatography-Photodiode Array (UPLC-PDA) and advanced automated flash purification, respectively. Drying time affected the moisture content of stevia leaves. A constant weight was reached after six hours of drying, and higher antioxidant activity was observed, while the highest TPC was obtained after seven hours of drying. The highest TPC (91.57 ± 8.8 mg GAE/g dw) and antioxidant activity (603.24 ± 3.5 μmol TE/g dw) in UAE method was obtained when ethanol 50% at 5 min was used. Steviol glycosides extracted by UAE were recorded with a content of 93.18 ± 1.36 mg/g dw and 98.97 ± 1.75 mg/g dw for stevioside and rebaudioside A respectively. Six phenolic compounds including four phenolic acids and two flavonoids were identified and quantified by UPLC-PDA, and confirmed by ESI-MS reporting its fragmentation pattern. Diosmin and chlorogenic acid were the most abundant compounds with values of 2032.36 μg/mL and 434.95 μg/mL respectively. As a novelty we found that the antioxidant activity evaluated in partially purified fractions suggested that biological activity might be attributed to the synergistic effect of the six phenols present in the stevia leaves extract. In addition to its sweeting properties, stevia leaves constitute a potential source of polyphenolic compounds, with antioxidant activity that could be used as a food additive.

Response Surface Methodology for Optimizing the Ultrasound-Assisted Extraction of Polysaccharides from Acanthopanax giraldii.

The aim of this study was to investigate and optimize the most important factors affecting the extraction of Acanthopanax giraldii HARMS polysaccharides (AHPs) by ultrasound-assisted extraction (UAE) technology in a systemic manner. The ranges of four factors, including extraction temperature, liquid/solid ratio, extraction time, and ultrasonic power, were first determined by a single-factor experiment, followed by optimization of the UAE conditions using the Box-Behnken design (BBD) for maximum AHPs production. In our study, the models developed from the experimental design predicted the experimental data well and had a high determination coefficient (R2=0.9387). The optimized conditions for AHPs extraction were as follows: extraction temperature, 58°C; liquid/solid ratio, 25 : 1; extraction time, 73 min; and ultrasonic power, 85 W. Under these optimized conditions, the polysaccharide yield was 1.532±0.037% (n=3), being very close to the predicted value of 1.546% by the model. In addition, to investigate whether there was a difference of AHPs content between UAE and traditional hot water extraction (THWE), Fourier-transform (FT) IR spectral analyses was performed. The results showed that the functional groups of the polysaccharides extracted by either UAE or THWE were fundamentally identical. Furthermore, AHPs extracted by UAE could promote macrophage activation, such as enhanced phagocytosis and increased cytokine (interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α)) secretion in RAW264.7 cells. In conclusion, optimization of the UAE conditions by response surface methodology (RSM) was a promising method to improve the extraction yield of AHPs. AHPs extracted by the optimized UAE method can maintain their polysaccharide structure and biological activity.