Antioxidative and anti-inflammatory activities of Citrus unshiu peel extracts using a combined process of subcritical water extraction and acid hydrolysis

Antioxidant and in vitro anti-inflammatory activities of citrus (Citrus unshiu) peel extracts and their acid hydrolysates were evaluated. Citrus peel extracts were extracted by subcritical water, hot water, and ethanol. Subcritical water extraction led to extract more phenolic compounds than hot water or ethanol extraction. Acid hydrolysis more than doubled the extracts’ total phenolics and flavonoids. Acid hydrolysates showed greater DPPH-radical scavenging activities and antioxidant activities, as assayed by β-carotene bleaching and ferric thiocyanate, than the initial extracts. Anti-inflammatory activities of citrus peel extracts and hydrolysates, determined by the inhibition of hyaluronidase activity, showed that the inhibition activities of hot water and ethanol extracts increased from 2.1 and 1.8% to 37.0 and 18.5%, respectively, upon acid hydrolysis; however, the anti-inflammatory activity of the subcritical water extract was not improved. These results indicated that acid hydrolysis of citrus peel extracts regardless of their extraction methods improved the antioxidative and anti-inflammatory activities.     

Optimizing the Tyrosinase Inhibitory and Antioxidant Activity of Mango Seed Kernels with a Response Surface Methodology

This study describes the optimization of polyphenol extraction from mango seed kernels by using response surface methodology (RSM). In the solid-to-liquid selection, the extraction yield, total phenolic content (TPC), antioxidant activity, and tyrosinase inhibitory activity are all significantly increased with a decrease in the solid-to-liquid ratio (P?<?0.05). Between the Nam-Dok-Mai kernel (NDK) and the Tong-Dam kernel (TDK), the TDK was chosen for RSM with a fixed ratio of 1:30 solid-to-liquid. The variables in the independent processing were the concentrations of ethanol, the temperature, and the time applied to RSM. Ethanol concentration, temperature, and duration had significant individual and interactive effects on phenolic yield and antioxidant activities (P?<?0.05). The optimized condition that maximized the extraction yields, TPC, and antioxidant activities from TDK was an ethanol concentration of 62 %, a temperature of 63 °C, and a duration of 150 min. The obtained and validated optimized model could be used to describe the effect of these variables on the extraction of phenolic compounds from mango seed kernels.     

Simultaneous Determination of Antioxidants and Ultraviolet Absorbers by Ultra-Performance Liquid Chromatography in Food Simulants

An efficient analytical method for the quantitative determination of migration levels of antioxidants and UV absorbers in food contact materials by ultra-performance liquid chromatography has been developed. The analytical method showed good linearity, presenting regression coefficients (R ²?≥?0.9981) for all compounds. The limits of detection and quantification were between 0.03 and 0.32 mg L^?1 and between 0.08 and 1.06 mg L^?1 for 29 analytes, respectively. According to European Union Directive No. 10/2011, five food simulants were investigated: 3 % (w/v) acetic acid, 10 % (v/v) ethanol, 20 % (v/v) ethanol, 50 % (v/v) ethanol, and fatty food simulant (isooctane). Recoveries were in the range of 88.43?～?115.28 %, with relative standard deviations between 0.33?～?8.43 %. Migration levels of antioxidants and UV absorbers were determined. Irganox 1010, Irganox 1076, and Tinuvin 120 were found in the majority of the samples generally together with the phosphate Irgafos 168 and its oxidized product. These levels were lower than limits allowed by legislation.     

Antioxidant activity and phenolic content of brick caps mycelium (Naematoloma sublateritium) extracts

A total of 5 subfractions were obtained from methanol extracts of N. sublateritium mycelia via systemic extraction using n-hexane, chloroform, ethyl acetate, n-butanol, and water. The trolox equivalent antioxidant capacity of the chloroform subfraction was 649.40 μmol/g of sample. The highest ferric reducing/antioxidant power (FRAP) assay value was found in the chloroform subfraction (299.24 μmol of FeSO₄·7H₂O/g). The chloroform and ethyl acetate subfractions exhibited the highest total phenolic compound contents, with ferulic acid equivalents of 31.66 and 48.57 mg/g, respectively. The phenolic acids in the subfractions were further identified using liquid chromatography-tandem mass spectrometry. The 5 phenolic acids of 4-hydroxybenzoic acid, α-resorcylic acid, 4-coumaric acid, salicylic acid, and gentisic acid were found to be the major phenolics in the mushroom.     

Antioxidative Effect of Seaweed Extracts in Chilled Storage of Minced Atlantic Mackerel (<Emphasis Type="Italic">Scomber scombrus</Emphasis>): Effect on Lipid and Protein Oxidation

In this study, antioxidant activity of absolute ethanol, 50 % ethanol and water extracts of two species of seaweeds namely, Fucus serratus and Polysiphonia fucoides were evaluated for their ability to retard lipid and protein oxidation in minced mackerel. Mackerel mince added with 0.5 g/kg of extracts was prepared. For comparison, BHT at 0.2 g/kg and a control with no added extracts were also prepared. The samples were stored at 5 °C for 8 days, and sampling was done at time 0, 1, 2, 4, 5 and 8 days. The 50 % ethanolic extracts of P. fucoides were found to be very effective in retarding lipid and protein oxidation, as it resulted in low levels of peroxide value, volatiles and carbonyl compounds and protected against the loss of α-tocopherol and tryptophan residues. In spite of the higher phenolic content, the absolute ethanol extracts of both species showed a pro-oxidative tendency in minced mackerel. Water extract with lowest phenolic content showed no antioxidant effect in minced mackerel. In conclusion, the 50 % ethanolic extracts of P. fucoides can be a potential source of natural antioxidants, as these extracts have antioxidant activities similar to synthetic antioxidants such as BHT. However, the extent of protection offered by these extracts against protein oxidation was not clear and further studies are needed to understand the nature of the interaction between proteins and these extracts.     

Preparation and Release Behavior of Gelatin-Based Capsules of Antioxidants from Ethanolic Extracts of Thai Riceberry Bran

This study aimed to devise an environment-friendly and effective, yet simple and practicable, antioxidant extraction and encapsulation method from Riceberry bran, whose extract was used thereafter for developing highly efficient antioxidant capsules. Ethanolic Riceberry bran extracts with high total phenolic content, total flavonoid content, total anthocyanin content, and antioxidant activity (using DPPH radical scavenging activity and ferric reducing antioxidant power assay) were obtained using ultrasonic-assisted extraction. The optimum conditions for producing the capsules, such as types of gelatin, concentrations of gelatin, and the Riceberry bran extract concentrations, were studied. Capsules produced by incorporating 1% (w/v) of acid-treated gelatin (type A) and 1% (w/v) of Riceberry bran extract yielded higher chemical properties. When dispersed in water at 37 °C, the capsules exhibited a high release of antioxidants. Moreover, the capsule showed a lower degradation rate of antioxidants under simulated gastrointestinal conditions compared to the crude extract.     

Ultrasound-assisted extraction and antioxidant activity of phenolic and flavonoid compounds and ascorbic acid from rugosa rose (<Emphasis Type="Italic">Rosa rugosa</Emphasis> Thunb.) fruit

The present study aimed to extract total phenolic compounds (TPC), total flavonoid compounds (TFC), and ascorbic acid (AA) from the fruit of rugosa rose (Rosa rugosa Thunb.) by ultrasound-assisted extraction (UAE), and to evaluate their antioxidant activities. UAE significantly increased the extract yield compared with that obtained using the conventional method. TPC, TFC, and AA were extracted, depending on the extraction conditions (temperature, time, and ethanol concentration), in the range of 50.73–96.69, 15.93–31.88, and 3.06–6.08 mg/g, respectively. TPC and TFC were effectively extracted at a relatively high temperature (50 °C) than AA was (30 °C). The solvent condition used to extract TPC, TFC, and AA was 50% ethanol. The UAE condition for the highest antioxidant activity was obtained 30 °C, 30 min, and 50% ethanol, which were the same condition for the highest AA extraction. Among the extracts, AA showed a strong correlation with antioxidant activity at p-value of 0.001.     

Evaluation of Synurus deltoides for antioxidant,antimicrobial, and anti-proliferative activities using In vitro assays

The antioxidant, antimicrobial, and anti-proliferative activities of water and ethanol extracts from leaves of Synurus deltoides (SD) were investigated. Extracts showed strong reductive powers, nitrite-scavenging activities, DPPH, ABTS, hydroxyl, and superoxide radical scavenging activities, and DNA damage prevention activities. SD extracts also showed strong cellular antioxidant activities in a dose-dependent manner with IC₅₀ values of 0.93 and 0.65 mg/mL for water and ethanol extracts, respectively. Antimicrobial activities were evaluated against 4 microorganisms. SD extracts showed high inhibitory activities against Pseudomonas aeruginosa and Staphylococcus aureus. The anti-proliferative activity was dose-dependent against human colon adenocarcinoma (HT-29) and mouse rectum carcinoma cells (CMT-93). In addition, HPLC analyses of SD leaf extracts revealed the presence of different phenolic compounds. SD can be considered as a source of functional foods and pharmaceuticals.     

Design of Sonotrode Ultrasound-Assisted Extraction of Phenolic Compounds from <Emphasis Type="Italic">Psidium guajava</Emphasis> L. Leaves

Psidium guajava L. has gained a special attention as health plant due to the presence of phenolic compounds. Box-Behnken design (BBD) has been applied for the extraction of target compounds from guava leaves via sonotrode ultrasound-assisted extraction (UAE). Different extraction times (5, 30, and 55 min), ratios of ethanol/water (50, 75, and 100% (v/v)), and ultrasound (US) power (80, 240, and 400 W) were tested to find their effect on the sum of phenolic compound (SPC), flavonols and flavan-3-ols via HPLC-ESI-QqQ-MS, and antioxidant activity (DPPH and TEAC assays). The best process conditions were as follows: 40 min, 60% ethanol/water (v/v), and 200 W. Established method has been used to extract phenolic compounds in two guava leaves varieties (pyrifera and pomifera). Pyrifera var. showed greater values of the SPC via HPLC-ESI-QqQ-MS (49.7 mg/g leaf dry weight (d.w.)), flavonols (12.51 mg/g d.w.), flavan-3-ols (7.20 mg/g d.w.), individual phenolic compounds, and antioxidant activity (8970 ± 5 and 465 ± 6 μmol Trolox/g leaf d.w, respectively) than pomifera var. Conventional extraction showed lower amounts of phenolic compounds (7.81 ± 0.03 and 4.64 ± 0.01 mg/g leaf d.w. for flavonols and flavan-3ols, respectively) in comparison to the ultrasound-assisted ones.     

Optimization of Extraction of Bioactive Compounds from Black Carrot Using Response Surface Methodology (RSM)

In this study, optimum conditions for the extraction of black carrot anthocyanins were determined by response surface methodology. Central composite design of extraction factors (pH 2.5–6.5, temperature 4–72 °C, solvent/solid ratio 5:1–25:1 v/w, ethanol/water ratio 0:100–100:0?v/v) was generated as two replicates. Total phenolic content, total monomeric anthocyanin content, polymeric color, total antioxidant activity, and anthocyanin composition determined by high-performance liquid chromatography were used as responses. Except for color analysis, higher temperature, solid/solvent ratio, and ethanol concentration were observed to increase the extraction yield. However, polymeric color results were found to have minimum values at lower pH and solid/solvent ratio, lower or moderate temperature, and higher ethanol concentration. Optimum extraction conditions were found as follows: 50 °C, pH 3.5, solvent solid ratio 10:1 (v/w), and ethanol/water ratio 75:25 (v/v) when all responses were considered. The validation of the optimum conditions for black carrot extraction was performed at specified values.     

The Use of Microwave and Pulsed Electric Field as a Pretreatment Step in Ultrasonic Extraction of Polyphenols from Defatted Hemp Seed Cake (Cannabis sativa) Using Response Surface Methodology

The use of microwave and pulsed electric field (PEF) processing to optimize polyphenol extraction from defatted hemp seed cake in mixed solvent of methanol, acetone and water (MAW, 7:7:6 v/v/v) was investigated using the Box-Behnken response surface method. A variables combination for microwave processing of time, microwave power and liquid to solid (L:S) ratio and for PEF (ethanol concentration, time, frequency and voltage) were used in the investigation. Following microwave or PEF treatments, the polyphenols were extracted from the samples under ultrasound with fixed variables (200 W of ultrasonic power, water bath of 70 °C and 20 min of extraction time). The measured responses were total phenolics (TP), total flavonoids (TF), DPPH˙ scavenging activity and ferric reducing/antioxidant power (FRAP). The optimum variables combination for microwave processing (5 min treatment time, L:S ratio of 6, 700 W power and volume 30 mL) and PEF-assisted extraction (voltage (30 V), frequency (30 Hz), ethanol concentration (10 %) and time (10 s)) resulted in maximum yields in all measured responses. The results suggest that microwave processing and PEF can be integrated in processing defatted hemp seed cake to enhance polyphenol extraction and maximize the yield.     

Comparison of phenolic compound contents and antioxidant capacities of loquat (Eriobotrya japonica Lindl.) fruits

The characteristics, phenolic compound contants, and antioxidant capacities of 6 cultivars of loquat fruit grown in China were evaluated. HPLC was used to identify and quantify phenolics. Chlorogenic acid, neochlorogenic acid, 4-O-caffeoylquinic acid, protocatechuic acid, 4-hydroxybenzoic acid, caffeic acid, ferulic acid, ellagic acid, and o-coumaric acid were the main phenolic compounds of mature loquat fruits. Contents of chlorogenic acid, neochlorogenic acid, 4-hydroxybenzoic acid, protocatechuic acid, and o-coumaric acid were all significantly correlated with antioxidant capacities determined using DPPH, ABTS radical scavenging activity, and ferric reducing/antioxidant power assays. The ‘Taxiahong’ cultivar contained the highest amounts of total phenolics and flavonoids and the highest antioxidant capacity, while ‘Taipingbai’ showed the lowest. The high level of phenolic compounds and antioxidant capacities of some cultivars indicates that these cultivars can be sources of bioactive compounds that are relevant to human health.     

Biological activity of fluidized bed ethanol extracts from several edible mushrooms

In vitro antioxidant and anti-inflammatory activities of fluidized bed ethanol extracts of Pleurotus ostreatus PQMZ91109, PBS281009, M2191 (obtained from a laboratory greenhouse), Agaricus bisporus, Marasmius oreades, Craterellus cornucopioides, and Tuber melanosporum were investigated using free radical scavenging activities, metal chelating effects, inhibition of lipid peroxidation (inhibition of peroxyl radicals), xanthine oxidase, and lipoxygenase, and identification of antioxidant compounds. Levels of different compounds with antioxidant properties demonstrated the presence of more tocopherols than polyphenol carboxylic acids and flavones. HPLC showed that T. melanosporum extracts had high correlation values between levels of different active compounds and antioxidant assay results. Tocopherol levels were highly correlated (R ²=0.867) with anti-inflammatory activities and inhibition of lipid peroxidation. Fluidized bed ethanol extracts from dried mushroom fruit bodies can be a source of products rich in tocopherols, and can constitute an important ingredient in food supplements.     

Antioxidant Activity and Determination of Phenolic Compounds from <Emphasis Type="Italic">Eugenia involucrata</Emphasis> DC. Fruits by UHPLC-MS/MS

Fruits have been the focus of several studies aimed at finding new antioxidant sources for protection against the damage caused by reactive species. In this study, the antioxidant activity and the presence of phenolic compounds in all parts (peel, pulp, and seeds) of Eugenia involucrata DC. fruits were evaluated. DPPH^·, ABTS^·+, and ORAC methods were used to determine the antioxidant activity, and an UHPLC-MS/MS method was developed for determining the phenolic compounds (gallic, chlorogenic, ferulic, p-coumaric and ellagic acids, quercetin, and myricetin). In the determination of both antioxidant activity and phenolic composition, the efficiency of solvents with different polarities—methanol/H₂O (80:20, v/v), ethanol/H₂O (80:20, v/v), methanol/acidified water with phosphoric acid pH 3.00 (80:20, v/v), and ethyl acetate—for the extraction of the phenolic compounds, was also evaluated. All parts of E. involucrata fruits showed antioxidant activity, in the range of 36.68 ± 1.44 to 873.87 ± 18.24 μmol TE g^?1, being the highest values found in the seeds and peel when more polar extraction solvents were used. Six, five, and three phenolic compounds were identified and quantified in the pulp, peel, and seeds, respectively, with the highest abundance as p-coumaric acid (14 ± 2 mg kg^?1) in the pulp, quercetin (47 ± 5 mg kg^?1) in the peel, and gallic acid (74 ± 4 mg kg^?1) in the seeds, also when more polar solvents were used. Although antioxidant activity methods suggested that the peel and seeds have more antioxidant potential, a wider variety of compounds were determined in the pulp.     

Characterization of Antioxidants Extracted from Thai Riceberry Bran Using Ultrasonic-Assisted and Conventional Solvent Extraction Methods

Riceberry bran (RBB), a waste product from rice processing, contains several antioxidants with potential health benefits. This study aims to compare the two main parameters affecting the extraction efficiency of antioxidants from RBB, namely, the extraction technique (ultrasonic-assisted extraction (UAE) and conventional solvent extraction) and solvent (ethanol and d-limonene). The highest values of total phenolic content, total flavonoid content, total anthocyanin content, and antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) assays were detected in ethanolic extracts obtained by UAE. High-performance liquid chromatography investigation of the chemical composition of RBB revealed five major groups of antioxidants: (1) phenolic acids, including protocatechuic acid, vanillic acid, p-coumaric acid, ferulic acid, and sinapic acid; (2) flavonoids, including rutin, myricetin, and quercetin 3-glucuronide; (3) anthocyanins, including cyanidin 3-glucoside and peonidin 3-glucoside; (4) vitamin E, including γ-tocotrienol, β-tocotrienol, δ-tocopherol, γ-tocopherol, and α-tocopherol; and (5) γ-oryzanol. Protocatechuic acid exhibited the highest DPPH radical scavenging activity and FRAP values, whereas the lowest values were observed for γ-oryzanol.     

Optimization of Extraction Parameters of Total Phenolics from <Emphasis Type="Italic">Annona crassiflora</Emphasis> Mart. (Araticum) Fruits Using Response Surface Methodology

In this study, response surface methodology was used to optimize the extraction temperature (25–75 °C) and ethanol concentration (0–70 %, ethanol/water, v/v) to maximize the extraction of total phenolic compounds (TPC) from araticum pulp. The efficiency of the extraction process was monitored over time, and equilibrium conditions were reached between 60–90 min. A second-order polynomial model was adequately fit to the experimental data with an adjusted R ² of 0.9793 (p < 0.0001) showing that the model could efficiently predict the TPC content. Optimum extraction conditions were ethanol concentration of 46 % (v/v), extraction temperature of 75 °C and extraction time of 90 min. Under the optimum conditions, the araticum pulp showed high TPC content (4.67 g GAE/100 g dw) and also high antioxidant activity in the different assays used (46.56 μg/mL, 683.65 μmol TE/g and 1593.72 μmol TE/g for DPPH IC₅₀, TEAC and T-ORAC_FL, respectively). From our extraction procedure, we successfully recovered a significantly higher amount of TPC compared to other studies in the literature to date (1.5–22-fold higher). Furthermore, TPC and antioxidant activity were present in the fruit in levels that are difficult to find in other common fruits. These results expose a potential approach for improving human health through consumption of araticum fruit.     

Optimization of ultrasonic-assisted extraction of phenolic compounds from <Emphasis Type="Italic">Justicia spicigera</Emphasis> leaves

A Box–Behnken design (Extraction-time, pulse-cycle, sonication-amplitude) was employed to extract phenolic compounds from Justicia spicigera leaves by ultrasonic-assisted extraction. The muicle leaves extracts were analyzed measuring total phenolic compounds and antioxidant capacity. According to response surface methodology the optimal conditions of ultrasonic-assisted extraction to obtain the highest soluble phenolic content were 2 min (extraction time) for 0.7 s (pulse cycle) at 55% of sonication amplitude. Under these optimal conditions, the total phenolic content was higher when was used ultrasonic-assisted extraction (54.02 mg/g) than stirring (46.46 mg/g) and thermal decoction (47.76 mg/g); however, the antioxidant capacity from J. spicigera extracts did not increase by ultrasonic-assisted extraction. The extracts or aqueous infusions from J. spicigera leaves are used for therapeutic proposes, therefore the ultrasonic-assisted extraction is a useful technology to improve the extraction of phytochemicals from J. spicigera leaves.     

LC-ESI-MS/MS Analysis and Extraction Method of Phenolic Acids from Gluten-Free Precooked Buckwheat Pasta

In many countries, common buckwheat (Fagopyrum esculentum Möench) has been cultivated for its nutritive value as food ingredient. This plant is a rich source of vitamins and exogenic amino acids. Many of the health-promoting effects of F. esculentum have been attributed to a large amount of phenolic compounds. Presented in this paper, precooked buckwheat pasta, produced by extrusion cooking, is a gluten-free product without any technological additives. Moreover, it contains natural polyphenolic antioxidants and therefore could be classified as convenience food. The phenolic acid compositions of precooked buckwheat pasta were as follows: gallic, protocatechuic, gentisic, 4-OH-benzoic, vanillic, trans-caffeic, cis-caffeic, trans-p-coumaric, cis-p-coumaric, trans-ferulic, cis-ferulic, and salicylic. A very important step of sample pretreatment before quantitative analysis is the choice of extraction conditions. Therefore, in this study, before quantitative analysis (liquid chromatography-mass spectrometry, LC-ESI-MS/MS), optimization of ultrasound-assisted extraction (UAE) of phenolic acids from precooked buckwheat pasta was performed. The most effective conditions for the isolation of phenolic acids from precooked buckwheat pasta with the use of UAE were as follows: 80 % aqueous ethanol, 60 °C, ultrasound frequency 20 kHz, power 100 W, and time 40 min.     

Enhancement of anti-skin inflammatory activities of Scutellaria baicalensis using an alkaline reduced water extraction process

WE (water extraction at 100°C for 24 h), EE (70% ethanol extraction at 80°C for 24 h), and AWE (alkaline reduced water extraction at 100°C for 24 h) were performed. Nitric oxide production from macrophages of AWE extracts at 1.0 mg/mL was decreased to 3.1 μmol. Secretion of PGE₂ from human fibroblasts was also reduced to 496.47 pg/mL at 1.0 mg/mL of AWE extracts with UV irradiation. Anti-skin inflammatory activities were enhanced by extraction of 8.894 mg/g more baicalein, the major bioactive component in Scutellaria baicalensis, using alkaline reduced water (AWE), compared to 1.157 mg/g for WE and 2.215 mg/g for EE. Improvement was caused by better and more elution of both hydrophobic and hydrophilic substances using alkaline reduced water and also by a synergistic effect between the antioxidant and anti-inflammatory activities of AWE extracts.