Special Issue "Antioxidant Natural Products in Foods"

A special issue of Foods (ISSN 2304-8158). This special issue belongs to the section "Nutraceuticals and Functional Foods".

Deadline for manuscript submissions: closed (30 September 2020).

Special Issue Editors

Prof. Dr. Maria Eduarda Machado Araújo
Website
Guest Editor
Chemistry and Biochemistry Department, Faculty of Sciences, University of Lisbon, Campo Grande Ed. C8, 1749-016 Lisbon, Portugal
Interests: food chemistry; natural product chemistry; plant extracts; nutraceuticals; antioxidant activity
Prof. Dr. Alice Martins
Website
Guest Editor
MARE-Marine and Environmental Sciences Centre, Polytechnic of Leiria, Av. Porto de Pesca, Ed. Cetemares, 2520-630 Peniche, Portugal
Interests: pytochemistry; marine bioactive compounds; nutraceuticals; antioxidant activity

Special Issue Information

Dear Colleagues,

Molecular oxygen is essential for the production of energy by cells. However, the metabolism also generates unstable molecules or ions with an unpaired electron, called ‘free radicals’, which are highly reactive and can combine with electrons from other molecules, causing severe damage to cellular constituents like lipids, proteins, and DNA. Although the human body uses some of these radicals to fight external threats like virus and bacteria, if these radicals are produced in an excessive amount, cells cannot cope with them, causing irreversible damage. This can lead to certain chronic diseases, e.g., neurodegenerative, inflammatory, and cardiovascular impairments, and even to some forms of cancer. An excessive production of harmful oxidant species can be accelerated by stress, smoking, alcohol consumption, sunlight, and pollution, among other factors. Many natural products can act as antioxidants, helping the body to destroy the excess of endogenous radical species if they are included in the diet—the most natural and easy way to provide the body with antioxidants.

Foods is launching a Special Issue on natural products with antioxidant activity that can be, or are already, included in the diet.

Original articles or reviews including but not limited to the following topics are welcome:

  • History of the development of the research about natural products with antioxidant activity and foods that naturally contain antioxidants;
  • Summary of the most used in vitro tests for antioxidant evaluation;
  • Do different antioxidant tests give the same information? Which tests must be used? A critical approach;
  • New approaches to evaluating antioxidant activity;
  • Antioxidants of marine origin;
  • New natural sources of antioxidants;
  • Rich antioxidant foods and beverages and their relation to local diets.

Prof. Maria Eduarda Machado Araújo
Prof. Alice Martins
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Foods is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Antioxidant compounds
  • Antioxidant activity evaluation
  • Phytochemicals
  • Marine antioxidant compounds
  • Antioxidant foods
  • Nutraceuticals

Published Papers (14 papers)

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Research

Open AccessArticle
Assessment of Bioactive Phenolic Compounds and Antioxidant Activity of Blackberry Wines
Foods 2020, 9(11), 1623; https://doi.org/10.3390/foods9111623 - 07 Nov 2020
Abstract
Blackberry wine is a natural source of bioactive phenolic compounds that have profound antioxidant potential. The objectives of the present research were to assess the phenolic compounds and antioxidant activity of blackberry wines (BW), and to use the chemometric analysis to differentiate among [...] Read more.
Blackberry wine is a natural source of bioactive phenolic compounds that have profound antioxidant potential. The objectives of the present research were to assess the phenolic compounds and antioxidant activity of blackberry wines (BW), and to use the chemometric analysis to differentiate among the two groups of samples, i.e., conventional and organic. Fifteen BW samples were analyzed for their total polyphenol index, total polyphenols, total flavonoids, total tannins, total monomeric anthocyanins and antioxidant activity by the appropriate spectrophotometric methods. The concentrations of individual phenolic acids (gallic acid, chlorogenic acid, caffeic acid, p-coumaric acid and cinnamic acid) and trans-resveratrol were determined by high-performance liquid chromatography. A comparison between the two groups of investigated BW samples revealed a statistically significant difference in the concentration of caffeic acid and p-coumaric acid, both being higher in the organic BW samples. Furthermore, the results showed a series of statistically highly significant relationships between the analyzed constituents (caffeic acid and p-coumaric acid). The antioxidant activity of the investigated wines was proportional to the concentrations of bioactive phytochemicals. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Polyphenolic Composition and In Vitro Antioxidant Activity of Red Grape Seeds as Byproducts of Short and Medium-Long Fermentative Macerations
Foods 2020, 9(10), 1451; https://doi.org/10.3390/foods9101451 - 13 Oct 2020
Abstract
The polyphenolic composition and antioxidant activity of grape seeds, as byproducts of red winemaking, depend on various factors, such as grape cultivar, vintage effect, grape maturity and winemaking methods. In the present work, the influence of the maceration length on the polyphenolic and [...] Read more.
The polyphenolic composition and antioxidant activity of grape seeds, as byproducts of red winemaking, depend on various factors, such as grape cultivar, vintage effect, grape maturity and winemaking methods. In the present work, the influence of the maceration length on the polyphenolic and antioxidant characteristics of the seeds of four Italian red grape cultivars (‘Barbera’, ‘Grignolino’, ‘Nebbiolo’, and ‘Uvalino’), sampled from the fermentation tanks after short (two days) and medium-long (7–21 days) macerations, was studied with spectrophotometric methods, high-performance liquid chromatography (HPLC), and three different antioxidant assays (2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power (FRAP) and 2,2 diphenyl-1-picrylhydrazyl (DPPH)). The total polyphenolic content (gallic acid equivalent (GAE)) of the seeds sampled after short macerations ranged between 24.5 and 60.1 mg/g dry weight (DW), and it dropped to 20.0–37.5 mg/g DW after medium-long macerations. The polyphenolic profile of the shortly macerated seeds was related to the varietal characteristics, while, after longer macerations, the influence of the maceration length prevailed on the cultivar effect. The multiple in vitro antioxidant activity tests (ABTS, FRAP and DPPH), although based on different mechanisms capable of highlighting behavioral differences between the different polyphenolic compounds, were highly correlated with each other and with the polyphenolic parameters; the qualitative differences between the matrices in the polyphenolic profile were probably less important than the quantitative differences in the polyphenolic content. The relations with the polyphenolic content were linear, except for the Efficient Concentration (EC20) parameter, whose relation was better described by a hyperbolic equation. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Effect of Baking Time and Temperature on Nutrients and Phenolic Compounds Content of Fresh Sprouts Breadlike Product
Foods 2020, 9(10), 1447; https://doi.org/10.3390/foods9101447 - 13 Oct 2020
Abstract
Sprouting has received increasing attention because of the enhanced nutritional values of the derived products. Baking affects the nutrient availability of the end products. The aim of this study was to evaluate how different baking time and temperature affect the nutritional values of [...] Read more.
Sprouting has received increasing attention because of the enhanced nutritional values of the derived products. Baking affects the nutrient availability of the end products. The aim of this study was to evaluate how different baking time and temperature affect the nutritional values of bakery products derived from fresh wheat sprouts. Results indicate that the breadlike products showed comparable total polyphenol content and the thermal processes affected the free and bound fractions. Low temperature and high exposure time appear to promote the availability of the free polyphenols and sugars, while high temperature and low exposure time appear to preserve bound polyphenols and starch. Sugar profiles were influenced by baking programs with a higher simple sugar content in the samples processed at low temperature. Phenolic acids showed a strong decrease following processing, and free and bound phenolic acids were positively influenced by high baking temperatures, while an opposite trend was detected at low temperatures. Significant differences in phenolic acid profiles were also observed with a redistribution of hydroxycinnamic acids among the bound and free fractions. It may be concluded that grain type, germination conditions, and the baking programs play a fundamental role for the production of high-nutritional-value bakery products. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Phytochemical Components and Bioactivity Assessment among Twelve Strawberry (Arbutus unedo L.) Genotypes Growing in Morocco Using Chemometrics
Foods 2020, 9(10), 1345; https://doi.org/10.3390/foods9101345 - 23 Sep 2020
Cited by 1
Abstract
There are not many exhaustive works emphasizing the amount of genetic diversity among the strawberry tree (Arbutus unedo L.) genotypes in Morocco. This work aims to assess the biochemical composition of strawberry tree fruits, as well as to establish the variation of [...] Read more.
There are not many exhaustive works emphasizing the amount of genetic diversity among the strawberry tree (Arbutus unedo L.) genotypes in Morocco. This work aims to assess the biochemical composition of strawberry tree fruits, as well as to establish the variation of this composition among them. In this study, total phenols (TP), total flavonoids (TF), condensed tannins (CT) and hydrolyzable tannins (HT), total anthocyanins (TA), and free radical scavenging activity through ABTS were investigated in strawberry tree fruits. Furthermore, qualitative and quantitative analyses of individual phenolic compounds by high-performance liquid chromatography (HPLC) were carried out. Color parameters such as lightness (L*), Chroma (c*), and hue angle (h°) were also investigated. All studied variables showed highly significant differences among all samples with the exception of hydrolyzable tannins and chromatic coordinates. TP varied from 22.63 ± 1.74 to 39.06 ± 2.44 mg GAE/g DW, TF varied from 3.30 ± 0.60 to 8.62 ± 1.10 mg RE/g DW, and TA ranged between 0.12 ± 0.06 and 0.66 ± 0.15 mg cya-3-glu/100 g DW. In addition, CT and HT amounts were in the range of 10.41 ± 1.07–16.08 ± 1.50 mg TAE/g DW and 4.08 ± 2.43–6.34 ± 3.47 TAE/g DW, respectively. Moreover, the IC50 value (ABTS) ranged between 1.75 and 19.58 mg AAE/g DW. 17 phenolic compounds were detected in strawberry tree fruits. Gallocatechol and catechin were the most abundant phenolic compounds. Matrix of correlations revealed significant positive and negative correlations among variables particularly c*, a*, and b*. Principal component analysis (PCA) showed that the first three components formed than 68% of the total inertia. The following variables gallic acid, protocatechuic, gallocatechin, gallic acid derivative, chlorogenic acid, syringic acid, ellagic acid derivative II, L*, and h* were the most involved in the total variance explained. Hierarchical clustering classified samples into one main cluster, with a single branch. The results highlight a high biochemical diversity within studied strawberry genotypes, which is probably more genetically related. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessCommunication
Thai Curcuma Species: Antioxidant and Bioactive Compounds
Foods 2020, 9(9), 1219; https://doi.org/10.3390/foods9091219 - 02 Sep 2020
Cited by 1
Abstract
For the functional food applications, antioxidant properties and the bioactive compounds of the 23 Curcuma species commercially cultivated in Thailand were studied. Total phenolic content and DPPH radical scavenging activity were determined. The concentrations of eight bioactive compounds, including curcumin (1), [...] Read more.
For the functional food applications, antioxidant properties and the bioactive compounds of the 23 Curcuma species commercially cultivated in Thailand were studied. Total phenolic content and DPPH radical scavenging activity were determined. The concentrations of eight bioactive compounds, including curcumin (1), demethoxycurcumin (2), bisdemethoxycurcumin (3), 1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol (4), germacrone (5), furanodienone (6), zederone (7), and ar-turmerone (8), were determined from the Curcuma by HPLC. While the total phenolic content of C. longa was highest (22.3 ± 2.4 mg GAE/g, mg of gallic acid equivalents), C. Wan Na-Natong exhibited the highest DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical scavenging activity. Twenty-three Curcuma species showed characteristic distributions of the bioactive compounds, which can be utilized for the identification and authentication of the cultivated Curcuma species. C. longa contained the highest content of curcumin (1) (304.9 ± 0.1 mg/g) and C. angustifolia contained the highest content of germacrone (5) (373.9 ± 1.1 mg/g). It was noteworthy that 1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol (4) was found only from C. comosa at a very high concentration (300.7 ± 1.4 mg/g). It was concluded that Thai Curcuma species have a great potential for the application of functional foods and ingredients. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Impact of Aqueous Extract of Arbutus unedo Fruits on Limpets (Patella spp.) Pâté during Storage: Proximate Composition, Physicochemical Quality, Oxidative Stability, and Microbial Development
Foods 2020, 9(6), 807; https://doi.org/10.3390/foods9060807 - 19 Jun 2020
Abstract
Limpets are molluscs widely used in food diet and much appreciated in many regions. The consumption of fishery products rich in polyunsaturated fatty acids has been increasing through filleted products and restructured products. Since food oxidation is the major cause of nutritional quality [...] Read more.
Limpets are molluscs widely used in food diet and much appreciated in many regions. The consumption of fishery products rich in polyunsaturated fatty acids has been increasing through filleted products and restructured products. Since food oxidation is the major cause of nutritional quality deterioration in fish products, the interest in the replacement of synthetic antioxidants with natural sources, namely in the preparation of restructured animal products such as burgers, sausages and pâtés, has been increasing. Phenolic compounds from fruits and vegetables have recognised antioxidant properties and are therefore currently considered as good alternatives to synthetic antioxidants in the food industry. In this study, the effects of the extracts of Arbutus unedo fruits, at two concentration levels (3% and 6%), on proximate composition, physicochemical properties, oxidative stability and safety of limpets pâté, during 90 days at refrigerated storage, were investigated. After processing, the addition of 3% and 6% of A. unedo extracts into limpets pâté contributed to an increase of 18% and 36% in the total phenolic content and 5% and 36% in the antioxidant capacity, respectively. During storage, the enriched limpets pâté with A. unedo fruit extracts at 6% was more efficient as an enhancer of oxidative stability, with 34% inhibition of lipid oxidation, highlighting the potential use of A. unedo fruits as a functional ingredient in the fish industry. Overall, the limpets pâté with 6% of A. unedo fruit extracts proved to be more efficient regarding microbial control, and had the lowest changes in the quality parameters such as in colour, texture and pH during 90 days at refrigerated storage. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Bioactive Compounds and Antioxidant Capacity of Small Berries
Foods 2020, 9(5), 623; https://doi.org/10.3390/foods9050623 - 13 May 2020
Cited by 1
Abstract
The popularity of small berries has rapidly increased in Western countries given their antioxidant, anti-inflammatory, and antimicrobial activities and health-promoting properties. The aim of this study was to compare the fatty acid (FA) profile, phenolic compounds, and antioxidant capacity of extracts of 11 [...] Read more.
The popularity of small berries has rapidly increased in Western countries given their antioxidant, anti-inflammatory, and antimicrobial activities and health-promoting properties. The aim of this study was to compare the fatty acid (FA) profile, phenolic compounds, and antioxidant capacity of extracts of 11 berries cultivated in the North West of Italy. Berry samples were extracted and evaluated for FA profile and total anthocyanin (TAC), total flavonoid contents (TFC), ferric-reducing antioxidant power (FRAP), and for their radical scavenging activities against 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical. The main polyphenols of berry extracts were characterized by HPLC-DAD-UV-ESI HRMS in positive ion mode. Results showed that the highest TAC and TFC contents were recorded in black currants, blackberries, and blueberries. Maximum and minimum DPPH radical scavenging activities, Trolox Equivalent Antioxidant Capacity, and FRAP measurements confirmed the same trend recorded for TAC and TFC values. HPLC-HRMS analyses highlight how blueberries and blackberries have the highest concentration in polyphenols. Palmitic, stearic, oleic, linoleic, α-linolenic, and γ-linolenic acids significantly differ between berries, with oleic and α-linolenic acid representing the most abundant FAs in raspberries. Among the berries investigated, results of phytochemical characterization suggest choosing black currants and blueberries as an excellent source of natural antioxidants for food and health purposes. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Antioxidant Properties and Nutritional Composition of Matcha Green Tea
Foods 2020, 9(4), 483; https://doi.org/10.3390/foods9040483 - 12 Apr 2020
Cited by 2
Abstract
Matcha green tea (Camellia sinensis), which originates from Japan, is commonly considered as particularly beneficial to health. A large content of polyphenols, amino acids (mainly tannins) and caffeine potentially increase the antioxidant properties of the drink. The aim of the study [...] Read more.
Matcha green tea (Camellia sinensis), which originates from Japan, is commonly considered as particularly beneficial to health. A large content of polyphenols, amino acids (mainly tannins) and caffeine potentially increase the antioxidant properties of the drink. The aim of the study was to determine the antioxidant potential and the content of substances with an antioxidant effect—vitamin C, total polyphenol content including flavonoids—in infusions made from Traditional Matcha (from the first and second harvests) and Daily Matcha (from the second and third harvests) at different temperatures. The infusions were made by pouring 100 mL of distilled water once at various temperatures (25 °C, 70 °C, 80 °C and 90 °C) over 1.75 g of the plant material. Matcha tea is characterized by a high level of antioxidant substances (flavonoids 1968.8 mg/L; polyphenols 1765.1 mg/L; vitamin C 44.8 mg/L) as well as antioxidant potential (41.2% DPPH (10× dilution); 6129.5 µM Fe(II)/dm3 FRAP). The concentration of these compounds depends on the time at which the plant material was harvested as well as on the temperature of water used to prepare the infusions. For most parameters, the highest values were observed in infusions prepared at 90 °C and from the daily Matcha. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Bioaccessibility of Antioxidants and Fatty Acids from Fucus Spiralis
Foods 2020, 9(4), 440; https://doi.org/10.3390/foods9040440 - 06 Apr 2020
Cited by 2
Abstract
Fucus spiralis is an edible brown seaweed (SW) found in the Portuguese Coast. It has been reported to have high antioxidant activity, which may elicit a potential use for the food industry. However, little information is available on how the SW behaves during [...] Read more.
Fucus spiralis is an edible brown seaweed (SW) found in the Portuguese Coast. It has been reported to have high antioxidant activity, which may elicit a potential use for the food industry. However, little information is available on how the SW behaves during the digestive process and how the freeze-drying process might affect the bioaccessibility of the different compounds. Therefore, antioxidant activity, total polyphenols, lipid, and fatty acid contents were measured before and after in vitro simulation of the human digestive process, both in fresh and freeze-dry SW. F. spiralis had a lipid content of 3.49 ± 0.3% of dry weight (DW), which is a usual amount described for this SW genus. The total lipid bioaccessibility was 12.1 ± 0.1%. The major omega-3 fatty acid detected was eicosapentaenoic acid, 7.5 ± 0.1%, with a bioaccessibility percentage of 13.0 ± 1.0%. Four different methods—total phenolic content (TPC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH)—were used to assess the antioxidant activity of F. spiralis. The bioaccessibility of the antioxidants studied, ranged between 42.7% and 59.5%, except the bioaccessibility of polyphenols in freeze-dried SW (23.0% ± 1.0%), suggesting that the freeze-drying process reduces the bioaccessibility of these compounds. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
Open AccessArticle
Physicochemical Characterization, Antioxidant Activity, and Phenolic Compounds of Hawthorn (Crataegus spp.) Fruits Species for Potential Use in Food Applications
Foods 2020, 9(4), 436; https://doi.org/10.3390/foods9040436 - 04 Apr 2020
Cited by 6
Abstract
Hawthorn belongs to the Crataegus genus of the Rosaceae family and is an important medicinal plant. Due to its beneficial effects on the cardiovascular system and its antioxidant and antimicrobial activity hawthorn has recently become quite a popular herbal medicine in phytotherapy and [...] Read more.
Hawthorn belongs to the Crataegus genus of the Rosaceae family and is an important medicinal plant. Due to its beneficial effects on the cardiovascular system and its antioxidant and antimicrobial activity hawthorn has recently become quite a popular herbal medicine in phytotherapy and food applications. In this study, physicochemical characterization (color parameters, pH, titratable acidity, total soluble solids, soluble carbohydrate, total carotenoid, total phenols, and flavonoid contents), antioxidant activity (by ferric-reducing antioxidant power, FRAP assay), and quantification of some individual phenolic compounds of fruits of 15 samples of different hawthorn species (Crataegus spp.) collected from different regions of Iran were investigated. According to findings, the total phenols, total flavonoid content, and antioxidant activity were in the range of 21.19–69.12 mg gallic acid equivalent (GAE)/g dry weight (dw), 2.44–6.08 mg quercetin equivalent (QUE)/g dw and 0.32–1.84 mmol Fe++/g dw, respectively. Hyperoside (0.87–2.94 mg/g dw), chlorogenic acid (0.06–1.16 mg/g dw), and isoquercetin (0.24–1.59 mg/g dw) were found to be the most abundant phenolic compounds in the extracts of hawthorn fruits. The considerable variations in the antioxidant activity and phenolic compounds of hawthorn species were demonstrated by our results. Hence, the evaluation of hawthorn genetic resources could supply precious data for screening genotypes with high bioactive contents for producing natural antioxidants and other phytochemical compounds valuable for food and pharma industries. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
The In Vivo Antioxidant and Hepatoprotective Actions of Selected Chinese Teas
Foods 2020, 9(3), 262; https://doi.org/10.3390/foods9030262 - 02 Mar 2020
Cited by 1
Abstract
Tea is a popular beverage and shows very strong in vitro antioxidant activity. However, the relationship among in vitro and in vivo antioxidant activities in teas is seldom reported. In this study, in vivo antioxidant and hepatoprotective activities of 32 selected Chinese teas [...] Read more.
Tea is a popular beverage and shows very strong in vitro antioxidant activity. However, the relationship among in vitro and in vivo antioxidant activities in teas is seldom reported. In this study, in vivo antioxidant and hepatoprotective activities of 32 selected Chinese teas were evaluated on a mouse model with acute alcohol-induced liver injury. The results showed that most teas significantly reduced the levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, triacylglycerol, and total bilirubin in the sera of mice at a dose of 400 mg/kg. In addition, most teas greatly decreased the malondialdehyde level and increased the levels of superoxide dismutase, glutathione peroxidase, and glutathione in the liver of mice, indicating the antioxidant and hepatoprotective activities of teas. Furthermore, the in vivo antioxidant activity of dark tea was stronger than that of green tea, opposite to the results of the in vitro study. Among these 32 teas, Black Fu Brick Tea, Pu-erh Tea, and Qing Brick Tea showed the strongest antioxidant and hepatoprotective activities. Moreover, total phenolic content as well as the contents of epicatechin, gallocatechin gallate, and chlorogenic acid were found to contribute, at least partially, to the antioxidant and hepatoprotective actions of these teas. Overall, teas are good dietary components with antioxidant and hepatoprotective actions. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Chemical Characterization and Antioxidant Properties of Ethanolic Extract and Its Fractions from Sweet Potato (Ipomoea batatas L.) Leaves
Foods 2020, 9(1), 15; https://doi.org/10.3390/foods9010015 - 23 Dec 2019
Cited by 1
Abstract
Sweet potato (Ipomoea batatas L.) leaf is a natural source of phenolic compounds with strong antioxidant activity and potential utility as an antioxidant. The aim of this study was to evaluate the polyphenol composition and antioxidant activities of ethanol extracts and their [...] Read more.
Sweet potato (Ipomoea batatas L.) leaf is a natural source of phenolic compounds with strong antioxidant activity and potential utility as an antioxidant. The aim of this study was to evaluate the polyphenol composition and antioxidant activities of ethanol extracts and their various solvent-partitioned fractions (petroleum ether, ethyl acetate, and aqueous fraction) from sweet potato leaves and petioles. Seven caffeoylquinic acid (CQA) derivatives and four flavonoids were detected in sweet potato leaves by HPLC-ESI-MS. The total phenolic content (TPC) and total flavonoid content (TFC) in leaf (112.98 ± 4.14 mg gallic acid equivalent (GAE)/g of dried extract, 56.87 ± 5.69 mg rutin equivalent (RE)/g of dried extract) was more than ten times higher than in petiole (9.22 ± 2.67 mg GAE/g of dried extract, 3.81 ± 0.52 mg RE/g of dried extract). The antioxidant contents of ethyl acetate fractions increased dramatically relative to those of crude extracts for both leaves and petioles. Purification using solvent partition with ethyl acetate increased TPC and TFC of crude extracts, especially the CQA derivatives including 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid, and 3,4,5-tricaffeoylquinic acid. Meanwhile, the ethyl acetate fractions with the highest CQA content were associated with the highest scavenging activities towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) and higher ferric ion reducing antioxidant power (FRAP)-reducing power. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Hydrothermal Treatment Enhances Antioxidant Activity and Intestinal Absorption of Rutin in Tartary Buckwheat Flour Extracts
Foods 2020, 9(1), 8; https://doi.org/10.3390/foods9010008 - 20 Dec 2019
Cited by 1
Abstract
Tartary buckwheat (Fagopyrum esculentum) is widely used in the food industry due to its functionality, which is related to its high rutin content. However, rutin is easily converted into quercetin by an endogenous enzyme during processing, resulting in a bitter taste. [...] Read more.
Tartary buckwheat (Fagopyrum esculentum) is widely used in the food industry due to its functionality, which is related to its high rutin content. However, rutin is easily converted into quercetin by an endogenous enzyme during processing, resulting in a bitter taste. In this study, rutin-enriched Tartary buckwheat flour extracts (TBFEs) were obtained by hydrothermal treatments (autoclaving, boiling, and steaming), and their antioxidant activity was evaluated in human intestinal cells. The intestinal absorption of the hydrothermally treated TBFEs was also investigated using in vitro models of intestinal barriers and an ex vivo model of intestinal absorption. The results demonstrated that all of the hydrothermally treated TBFEs had increased rutin, total polyphenol, and total flavonoid contents, which enhance the in vitro and intracellular radical scavenging activities. Antioxidant enzyme activity, cellular uptake efficiency, in vitro intestinal transport efficacy, and ex vivo intestinal absorption of the hydrothermally treated TBFEs were also enhanced compared with those of native TBFE or standard rutin. These findings suggest the promising potential of hydrothermally treated TBFEs for a wide range of applications in the functional food industry. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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Open AccessArticle
Phenolic Profile and Antioxidant Activity of the Edible Tree Peony Flower and Underlying Mechanisms of Preventive Effect on H2O2-Induced Oxidative Damage in Caco-2 Cells
Foods 2019, 8(10), 471; https://doi.org/10.3390/foods8100471 - 10 Oct 2019
Cited by 8
Abstract
The entire phenolic profiles and antioxidant activities of different organs of the edible tree peony flowers (Fengdan Bai (FDB)) were analyzed. HPLC-quadrupole time-of-flight mass spectrometer (Q-TOF-MS/MS) analyses of individual phenolic compounds revealed that the petal and stamen contained higher levels of flavonoid [...] Read more.
The entire phenolic profiles and antioxidant activities of different organs of the edible tree peony flowers (Fengdan Bai (FDB)) were analyzed. HPLC-quadrupole time-of-flight mass spectrometer (Q-TOF-MS/MS) analyses of individual phenolic compounds revealed that the petal and stamen contained higher levels of flavonoid glycosides than other organs (p < 0.05). Kaempferol-3,7-di-O-glucoside was the dominant flavonoid in these two organs, however, the calyx and ovary contained higher contents of gallic acid derivatives than other organs (p < 0.05). Hexa-O-galloyl-glucose was the dominant species in the calyx and ovary. At the same concentration of total phenolic extract (TPE), the stamen had the highest protection effect on Caco-2 cell oxidative damage induced by H2O2. The antioxidant effect was attributed to potent antioxidant capability; restored redox state due to the increased expression of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD); and improved barrier function of Caco-2 cell owing to increased zonula occludens-1 (ZO-1), CLDN3 (Claudin 3), and occludin mRNA expression. As a new resource food, the edible tree peony flower is a potential functional food material and natural antioxidants resource. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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