Extraction Of Phenolic Antioxidants Research Articles

Optimization of Parameters for the Extraction of Phenolic Antioxidants from Boxberry Tree (Myrica esculenta) Bark Using Response Surface Methodology

The boxberry tree (Myrica esculenta) bark has been known to have multiple health benefits and is used as a traditional medicine. A critical gap in knowledge exists on a simple but effective method to isolate the bioactive components from the bark. This study aimed to optimize the operating conditions, including temperature, ethanol concentration, and time, for the extraction of phenolic antioxidants from the boxberry bark sample using a response surface methodology. Results showed that the second-order polynomial regression models were statistically significant and sufficient to estimate the responses. Response surface optimization for all responses was successfully carried out to determine the optimum extraction conditions, which were a temperature, an ethanol concentration, and an extraction time of 75.8 °C, 48.3% (v/v), and 117 min, respectively. At these conditions, total phenolic and total flavonoid contents, 3-ethylbenzothiazoline-6-sulphonic acid diammonium salt (ABTS) scavenging capacity, and ferric-reducing antioxidant power were predicted to be 205.9 mg GAE/100 g, 37.8 mg CE/100 g, 271.3 mg AAE/100 g, and 111.4 mg AAE/100 g, respectively. The insignificant difference between the estimated and the experimental values suggested that the predictive models were valid to predict the process outcomes.

Optimization of Ethanolic Extraction of Phenolic Antioxidants from Lychee and Longan Seeds Using Response Surface Methodology.

Lychee seeds (LS) and longan seeds (LoS) are excellent sources of phenolic compounds (PCs) with strong antioxidant activity (AOA). The aim of this study was to optimize the extraction conditions regarding extraction yield (EY), extractable phenolic compound (EPC), and AOA from LS and LoS using surface response methodology (RSM). Solvent concentration, extraction temperature, time, and solid to liquid ratio were optimized using RSM. Increasing the solid to solvent ratio from 1:05 to 1:40 (w/v), increased EY for LoS, however, EY did not change from 1:20 to 1:40 for LS. Solid-liquid ratio 1:20 was chosen for this study. Increasing the quantity of solvent leads to higher EPC and FRAP. The results showed that LoS exhibited higher AOA than LS measured as DPPH, ABTS, and FRAP, respectively. Ethanol concentrations and temperatures significantly (p < 0.05) affect EY, EPC, and AOA. The results (R2 > 0.85) demonstrated a good fit to the suggested models and a strong correlation between the extraction conditions and the phenolic antioxidant responses. The ethanol concentrations of 41 and 53%, temperatures of 51 and 58 °C, and the corresponding times of 139 and 220 min were the optimal conditions that maximized the EY, EPC, and AOA from LS and LoS.

Deep Eutectic Solvents-Based Ultrasound-Assisted Extraction of Antioxidants from Kudingcha (llex kudingcha C.J. Tseng): Process Optimization and Comparison with Other Methods.

Kudingcha (KDC) is an important tea substitute containing abundant antioxidants. Herein, a ultrasonic-assisted extraction (UAE) technique based on deep eutectic solvents (DESs) was applied to optimize the total phenolic/total flavonoid content (TPC/TFC) from the KDC extracts. Results indicated that DES composed of L-proline and glycerol (Pro-Gly) had excellent extraction performance for TPC, TFC, ABTS•+ and FRAP, which were significantly better than other solvents. Response surface methodology (RSM) was used to obtain optimal extraction parameters for simultaneously maximizing the TPC, TFC and antioxidant activity. Results revealed that water content in Pro-Gly, liquid to solid ratio (L/S), ultrasonic temperature and extraction time were the major influence factors of the TPC, TFC, ABTS•+ and FRAP of the KDC extracts. The optimal conditions included water content in Pro-Gly of 46.4%, L/S of 25:1 (mL/g), ultrasonic temperature of 55 °C and extraction time of 50 min. Meanwhile, HPLC-MS/MS was adopted to identify the KDC extracts, which revealed the presence of major phytochemicals, including 5-chlorogenic acid, 4,5-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, kaempferol 3-rutinoside, myricetin and isorhamnetin. Moreover, UAE-Pro-Gly achieved further higher individual phenolics contents, TPC, TFC, ABTS•+ and FRAP than other methods. In conclusion, UAE-Pro-Gly is a highly efficient method for extraction of phenolic antioxidants from KDC.

Optimizing the extraction of phenolic antioxidants from date palm fruit by simplex-centroid solvent mixture design

Date palm (Phoenix dactylifera L.) fruits are rich in various bioactive compounds, such as phenolic acids, hydroxycinnamates, flavonoid glycosides, coumarins, alkaloids, and proanthocyanidin oligomers. The focus of this study was to develop a simplex-centroid mix design method to identify the most suitable mixture of solvents (water, acetone, and methanol) to extract bioactive compounds from date fruits. Three extraction solvents (water, methanol, and acetone) were investigated during this study to determine, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (free radical DPPH) and ferric reduction ability (FRAP). The results showed that polar mixtures were effective in extracting antioxidant phenolics. The optimum solvent for extraction was Binary mixture water-acetone (50%) presenting TPC, TFC, DPPH and FRAP values of 502.88 mg GAE.100 g-1 DW, 206.23 mg QE.100 g−1 DW, 77 0.01% and 1688.66 μmol.100 g−1 respectively. The results also confirmed a strong correlation between the amount of polyphenols in a given extract and the antioxidant activities observed in the DPPH and FRAP assays. This study presents a pragmatic and efficient way to choose a solvent combination to extract polyphenols from date palm fruits.

Response Surface Modeling and Optimization of the Extraction of Phenolic Antioxidants from Olive Mill Pomace

Bioactive compounds from olive mill pomace (OMP) were extracted through a two-step solid-liquid extraction procedure considering four factors at five levels of a central composite rotatable response surface design. The influence of the process variables time of the primary extraction (2.0-4.0 h), solvent-to-sample ratio during the primary extraction (5.0-10.0 mL/g), time of the secondary extraction (1.0-2.0 h), and the solvent-to-sample ratio during the secondary extraction (3.0-5.0 mL/g) were examined. The content of bioactive compounds was determined spectrophotometrically, and the individual phenolic compounds were evaluated by reserved-phase high-performance liquid chromatography (RP-HPLC). The Derringer's function was used to optimize the extraction process, and the best conditions were found to be 3.2 h for the primary extraction, 10.0 mL/g for the solvent-to-sample ratio and 1.3 h for the secondary extraction associated with a solvent-to-sample ratio of 3.0 mL/g, obtaining a total phenolic content of 50.0 (expressed as mg gallic acid equivalents (GAE)/g dry weight (dw). The response surface methodology proved to be a great alternative for reducing the number of tests, allowing the optimization of the extraction of phenolic antioxidants from OMP with a reduced number of experiments, promoting reductions in cost and analysis time.

Optimization of ultrasound-assisted extraction of phenolic antioxidants from turkey berry (Solanum torvum Sw) fruits using response surface methodology

The extraction of phenolic antioxidants from turkey berry fruits (TBF) was evaluated using ultrasound-assisted extraction (UAE) technique. Box-Behnken design was used to optimize the extraction variables (ethanol concentration, extraction temperature, time, and solvent-solid ratio), to maximize total phenolic content (TPC), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities of the extracts. The model significantly explained the responses and the phenolic contents and antioxidant activity were significantly influenced by ethanol concentration, extraction temperature, and solvent-solid ratio. The optimum UAE conditions for achieving maximum TPC (192.3 mg GAE/g), DPPH (47.4 μg AA/g) and ABTS (116.2 μmol TE/g) scavenging activity were 56.7% ethanol concentration, 80 °C, extraction temperature, 17.3 min extraction time, and 49.7 mL/g solvent-solid ratio. The experimental values of TPC and radical scavenging activity obtained were in agreement with the predicted values. Also, the results confirmed that UAE can recover higher phenolic antioxidants from TBF in shorter time than the conventional solvent extraction (CSE) process. Furthermore, the main phenolic compounds found in the TBF extract were catechin, kaempferol, quercetin, rutin and syringic acid. Consequently, this study revealed the aptness of UAE and RSM in improving the extraction conditions of phenolic antioxidants from TBF.

Optimized extraction of phenolic antioxidants from red pitaya (Hylocereus polyrhizus) seeds by subcritical water extraction using response surface methodology

Optimized extraction of phenolic antioxidants from red pitaya (Hylocereus polyrhizus) seeds by subcritical water extraction using response surface methodology

Effect of Different Solvents on Extraction of Phenolic Antioxidants by Reflux Method from Wild Pomegranate Flavedo, their Antioxidant and Antibacterial Properties

In this study wild pomegranate flavedo powder was used for the extraction of phenolics through various solvents by reflux method. A significant difference in all parameters was observed among the different extracts with varying solvents and extraction time after oven drying. The highest total phenolics, total flavonoids, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, ferric reducing antioxidant power and metal chelating activity among different extracts of wild pomegranate flavedo were recorded when combination of ethanol and distilled water in the ratio of 50:50 was used (1 h extraction time) after oven drying. Cluster analysis based on Ward’s method showed that all treatments were divided in nine major groups and three major clusters after the application of cluster analysis. The two best selected extracts were further compared after drying in lyophilizer and tested against Staphylococcus aureus and Escherichia coli for antibacterial activity. In conclusion, ethanol and distilled water lyophilized extract contained higher bioactive compounds than oven dried extract, which have higher antioxidant and antibacterial effects and could be useful in the extraction of natural antioxidants. The study concluded that fruit flavedo is rich source of total phenolics, total flavonoids and antioxidant activity which have beneficial natural antioxidants for health and have many health promoting properties which makes the flavedo suitable for future processing into various functional/nutraceutical foods.

Optimizing the Extraction of Phenolic Antioxidants from Date Palm Fruit by Simplex Centroid Solvent Mixture Design

Optimizing the Extraction of Phenolic Antioxidants from Date Palm Fruit by Simplex Centroid Solvent Mixture Design

Customized Deep Eutectic Solvents as Green Extractants for Ultrasonic-Assisted Enhanced Extraction of Phenolic Antioxidants from Dogbane Leaf-Tea.

This study evaluates the application of eco-friendly deep eutectic solvents (DESs) in the extraction of phenolic antioxidants from dogbane leaf-tea (DLT). The results showed DESs with lower viscosity allowed an efficient extraction of significantly higher contents of total phenolics or flavonoids. An innovative and high-efficient solvent, choline chloride-levulinic acid (ChCl-LevA), was screened and used in ultrasonic-assisted extraction (UAE) of phenolic compounds from DLT. According to full factorial design experimental results, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and anti-α-glucosidase activity (α-GIA) of the DLT extracts were simultaneously optimized by response surface methodology. Sonication temperature and water content in ChCl-LevA were found to be the major factors affecting the TPC, TFC, antioxidant activity, and α-GIA of DLT extracts. Under the optimum parameters (water content in ChCl-LevA was 45%, sonication temperature was 50 °C, and extraction time was 30 min), the measured results for all the responses were obtained as follows: TPC-91.38 ± 7.20 mg GAE/g DW, TFC-84.12 ± 3.47 mg RE/g DW, ABTS+-492 ± 7.33 mmol TE/g DW, FRAP-6235 ± 121 μmol Fe(II)/g DW and α-GIA-230 ± 7.59 mmol AE/g DW, which were consistent with the predicted values. In addition, strongly significant positive correlations were observed between TPC/TFC and bio-activities of the DLT extracts. HPLC results indicated high contents of (-)-epigallocatechin (4272 ± 84.86 μg/g DW), catechin (5268 ± 24.53 μg/g DW), isoquercitrin (3500 ± 86.07 μg/g DW), kaempferol 3-O-rutinoside (3717 ± 97.71 μg/g DW), and protocatechuic acid (644 ± 1.65 μg/g DW) were observed in the DLT extracts. In contrast to other extraction methods, ChCl-LevA-based UAE yielded higher TPC, TFC, individual phenolic contents, stronger antioxidant activity, and α-GIA. Scanning electron microscope (SEM) analysis further confirmed that ChCl-LevA-based UAE enhanced the disruption of cell wall structure, thereby making more phenolic antioxidants released from DLT. In short, ChCl-LevA-based UAE was confirmed to be an innovative and high-efficient method for extraction of phenolic antioxidants from DLT. Dogbane leaves can be considered as a good tea source rich in natural antioxidants.

Ultrasound-assisted lactic acid based deep eutectic solvent extraction of phenolic antioxidants from Thymus broussonetii: A Box – Behnken design approach for optimization

Developing of an eco-friendly, sustainable and efficient solvents with low toxicity and cost has always been a tremendously important goal for industries. In this context, green solvent, such as natural deep eutectic solvent, have been developed as a promising solvent capable of replacing organic ones. The combination of lactic acid: glucose (5:1) was investigated as an extraction medium for bioactive phenolic compounds from Thymus broussonetii. The ultrasonication method was established and optimized by a systematic investigation of the influencing factors: water content in solvent (0/35/70 %), extraction time (30/60/90 min), and temperature (30/50/80°C). A Box – Behnken design was adopted including 17 experiments with three center points. The results obtained presented an excellent efficacy of polyphenols extraction ranging from 25.53 ± 0,02 to 153.23 ± 0,03 mg GAE/g dm and a high scavenging activity attending 80.64 %, the optimized conditions selected for both responses were 66.47 min, at 80°C and a 40.72 % of water, with an extraction yields of 144.394 ±0,02 mg GAE/g dm and 75.9 % for phenolic compounds and antioxidant activity, respectively. Regression analysis showed a good fit of the experimental data which indicates the suitability of the model employed and the successful application of Box – Behnken design in optimizing the extraction conditions. Furthermore, the developed procedure represents an excellent alternative for the extraction of natural products from sample matrices.

Inajá oil processing by-product: A novel source of bioactive catechins and procyanidins from a Brazilian native fruit

Agro-industrial activities generate large amounts of solid residues, which are generally discarded or used as animal feed. Interestingly, some of these by-products could serve as natural sources of bioactive compounds with great potential for industrial exploitation. This study aimed to optimize the extraction of phenolic antioxidants from the pulp residue (oil processing by-product) of inajá (Maximiliana maripa, a native species found in the Brazilian Amazon). The antioxidant properties of the optimized extract and its phenolic profile by high-resolution mass spectrometry (LC-ESI-QTOF-MS) were further determined. Central composite rotatable design and statistical analysis demonstrated that the temperature of 70 °C and 50% (v/v) ethanol concentration improved the extraction of phenolic compounds with antioxidant properties. The optimized extract also showed scavenging activity against the ABTS radical cation and reactive oxygen species (ROS; peroxyl and superoxide radical, and hypochlorous acid). Moreover, the optimized extract was able to reduce NF-κB activation and TNF-α release, which are modulated by ROS. Flavan-3-ols were the major phenolics present in the optimized extract. Collectively, our findings support the use of inajá cake as a new source of bioactive catechins and procyanidins. This innovative approach adds value to this agro-industrial by-product in the functional food, nutraceutical, pharmaceutical, and/or cosmetic industries and complies with the circular economy agenda.

Optimization of phenolic antioxidants extraction from Fucus vesiculosus by pressurized liquid extraction

This study aimed to optimize pressurized liquid extraction (PLE) of phenolic compounds from the brown seaweed Fucus vesiculosus to obtain extract with high yield, rich in phenolic compounds, with good radical scavenging, and with metal chelating ability. The extraction was optimized with a Box–Behnken design experiment and response surface tool. Optimal condition was found at 137.18 °C, 58.65% v/v ethanol in water and 4.68 min extraction time which resulted in yield of 31.16% dry basis, total phenolic content (TPC) of 3.69 g gallic acid equivalent (100 g dry seaweed)−1, effective concentration for 50% inhibition (EC50) of DPPH radical (92.6 μg mL−1), ABTS radical (2.35 mg mL−1), and metal chelating (1.10 mg mL−1). The TPC value and radical scavenging activity of the PLE extract were insignificantly different from the one obtained from conventional solvent extraction, which proved PLE advantages in terms of shorter time and less solvent requirement. Gallic, protocatechuic, and gentisic acids were identified in the PLE extracts.

Distilled Spirit Extraction of Phenolic Antioxidants from Fruit and Vegetable Residues

Distilled Spirit Extraction of Phenolic Antioxidants from Fruit and Vegetable Residues

Optimizing the extraction of phenolic antioxidants from chestnut shells by subcritical water extraction using response surface methodology

The objective of this study was to evaluate the optimal Subcritical Water Extraction (SWE) conditions of antioxidants and polyphenols from chestnut shells using Response Surface Methodology (RSM). A central composite design (CCD) was conducted to analyse the time (6–30 min) and temperature (51–249 °C) effects in antioxidant activity (ABTS, DPPH and FRAP) and Total Phenolic Compounds (TPC). TPC ranged from 315.21 to 496.80 mg gallic acid equivalents (GAE)/g DW; the DPPH from 549.23 to 1125.68 mg Trolox equivalents (TE)/g DW; ABTS varied between 631.16 and 965.45 mg ascorbic acid equivalents (AAE)/g DW and FRAP from 2793.95 to 11393.97 mg ferrous sulphate equivalents (FSE)/g DW. The optimal extraction conditions were 30 min/220 °C, revealing excelling scavenging efficiencies against HOCl (IC50 = 0.79 µg/mL) and O2− (IC50 = 12.92 µg/mL) without toxicity on intestinal cells (0.1 µg/mL). The phenolic composition revealed high amounts of pyrogallol and protocatechuic acid. SWE can be a useful extraction technique for the recovery of polyphenolics from chestnut shells.

The antioxidant index and chemometric analysis of tannin, flavonoid, and total phenolic extracted from medicinal plant foods with the solvents of different polarities

This study aimed to evaluate the effect of four solvents (water, methanol, ethyl acetate, and n‐hexane) on the extraction of total phenolic content (TPC), tannin, flavonoid, ferric reducing power (FRAP), and radical scavenging activity from Centella asiatica, Musa acuminata, Peperomia pellucida, and Psophocarpus tetragonolobus. The extraction of TPC, tannin, flavonoid, and antioxidant activity varied significantly according to solvent polarity and plant species. The strong linear correlation found between solvent polarity index and TPC, tannin, FRAP as well as radical scavenging activity indicated solvents with increasing polarity favored the extraction of phenolic antioxidants. Plant species and extraction solvents contributed to 51.7% and 21.8% of total activity variation, respectively. C. asiatica, M. acuminata flower, and P. pellucida were best extracted with 80°C distilled water for a short duration, while methanol was preferred for P. tetragonolobus. The antioxidant index could be a potential ranking tool to identify the ideal extraction solvent for medicinal plants. PRACTICAL APPLICATIONS: Considering the high commercial and health‐oriented values of natural phenolic antioxidants such as tannin and flavonoid, efficient extraction of these phytochemicals from different plant sources remains a challenging task due to their varying physicochemical characteristics and solubility. This study has addressed that the choice of solvents and types of plant species are critical extraction parameters for natural plant products. Comparison of tannin and flavonoid content among the different solvent extracts could reveal the ideal solvent which maximizes the extraction of phenolic antioxidants from different medicinal plants. The finding in this study may inspire nutraceutical, pharmaceutical, and cosmetic industries to re‐evaluate their procedure in selecting the optimal extraction solvent and condition for different plant materials. The proposed antioxidant index in this study could serve as a potential tool to rank extraction solvents based on the antioxidant values extracted from different medicinal plants.

Pulsed electric field-assisted extraction of phenolic antioxidants from tropical almond red leaves

The main objective of this study is to compare the extraction efficiency, phenolic composition and antioxidant activity of fallen red leaves of the tropical almond (Terminalia catappa) using two extraction methods. The leaf was extracted under different conditions: soaking (12 and 24 h) and pulse electric fields (0.5 and 0.75 kV/cm). The results demonstrated that the highest total phenolic content (TPC) and higher antioxidant activity were related to the 50% concentration of red leaf extract. The evaluation of the two extraction methods revealed that the extract of red leaf obtained via PEF with 0.75 kV/cm field strength had the highest TPC and antioxidant activity (DPPH). Finally, red leaf phenolic compounds were identified and reported by HPLC.

Subcritical water extraction of phenolic antioxidants with improved α-amylase and α-glucosidase inhibitory activities from exocarps of Castanea mollissima Blume

Herein, subcritical water extraction (SWE) technology was applied for the recovery of phenolics from chestnut exocarps. Results showed that extracts obtained by SWE had significantly higher extraction yield (Ye), total phenolic contents (TPC), as well as stronger antioxidant (AAs), α-amylase and α-glucosidase inhibitory activities than conventional techniques. The optimal temperature of SWE for reaching the highest Ye, TPC and AAs was 220 °C, while the strongest α-amylase and α-glucosidase inhibitory activities were observed at 120 °C. UPLC-MS/MS, heatmap and radar chart analysis revealed that the phenolic profiles of different extracts varied markedly with extraction methods, and SWE extract at 120 °C had potential application for glycemic control by non-competitively inhibiting α-amylase and/or α-glucosidase. The major components contributed to the inhibitory activities were putative chlorogenic acid and flavonoids, such as rutin and quercetin, etc. These observations suggest that SWE is a promising technology for obtaining bioactive phenolics from chestnut exocarps.

Optimisation of ultrasound-assisted extraction of phenolic antioxidants from Ilex guayusa Loes. leaves using response surface methodology

The present study carried out the optimisation of the total polyphenol content (TPC) extraction assisted by ultrasound in Ilex guayusa leaves applying response surface methodology (RSM). Also, the evaluation of the antioxidant activity of the extract obtained under the optimal extraction conditions was performed. The effect of the variables like, time of sonication, temperature, ethanol/water ratio and solid/liquid relationship and the interactions between them were analysed through the use of a factorial design 2ˆ4. The significant factors were considered for the optimisation, employing a Box-Behnken Design, and the TPC as response variables. It was found that a quadratic model was adequate, with an adjusted R2 value of 0.9367. The optimal conditions proposed, by the response surface model were: an extraction temperature of 60 °C, sonication time of 29.9 min and ethanol/water ratio of 76.8/23.2. The optimised leaves extract of I. guayusa show a TPC of 3.46 (±0.17) g gallic acid equivalents/100 g d.w. Radical scavenger activity of the obtained extract at optimum conditions, was performed through the FRAP and ABTS methods, given as result: 0.080 mmol TROLOX equivalents/100 g d.w. and 40.71 μmol TROLOX equivalents/g d.w., respectively. Due to the present findings, I. guayusa extracts can be proposed as a promising component for functional beverages, cosmetic and pharmaceutical formulation.

Optimized ultrasonic-assisted extraction of phenolic antioxidants from grape (Vitis vinifera L.) skin using response surface methodology.

Currently, the analysis of bioactive compounds is easily carried out by modern chromatographic and spectrometric techniques, but the success of the procedure still depends on the efficiency of the extraction methods. This work aimed at finding the optimal conditions for ultrasonic-assisted extraction (UAE) of phenolic antioxidants from grape skin using single-factor experimentation combined with response-surface methodology. Our extraction parameters were ethanol concentration, time and temperature. Total phenolic content (TPC and TPC-280), 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and oxygen radical absorbance capacity (ORAC) were dependent variables. A second-order polynomial model satisfactorily described the experimental data. Optimized extraction conditions for UAE from grape skin were: 59.5% ethanol, 113.6min and 66.8°C for TPC extraction; 61.1% ethanol, 99.4min and 66.1°C for TPC-280 extraction; 57.1% ethanol, 99.5min and 66.8°C for DPPH radical-scavenging activity; 60.2% ethanol, 82.4min and 66.8°C for ORAC value. Our work provides detailed and useful information to optimize the extraction of grape skin phenols, which are widely used as dietary supplements and nutraceuticals.