Research

14 pages, 2828 KiB

Open AccessArticle

New Functional Ingredients Based on Microencapsulation of Aqueous Anthocyanin-Rich Extracts Derived from Black Rice (Oryza sativa L.)

by Iuliana Aprodu, Ștefania Adelina Milea, Roxana-Mădălina Anghel, Elena Enachi, Vasilica Barbu, Oana Crăciunescu, Gabriela Râpeanu, Gabriela Elena Bahrim, Anca Oancea and Nicoleta Stănciuc

Molecules 2019, 24(18), 3389; https://doi.org/10.3390/molecules24183389 - 18 Sep 2019

Cited by 20 | Viewed by 3830

Abstract

The aqueous anthocyanin-rich extract derived from black rice (Oryza sativa L.) was encapsulated by freeze drying using milk proteins and peptides as coating materials. The molecular modelling approach indicated that all major casein fractions and whey proteins were able to bind at [...] Read more.

The aqueous anthocyanin-rich extract derived from black rice (Oryza sativa L.) was encapsulated by freeze drying using milk proteins and peptides as coating materials. The molecular modelling approach indicated that all major casein fractions and whey proteins were able to bind at least one anthocyanin molecule. The hydrophobic interactions and hydrogen bonding across the interfaces appeared to be mainly responsible for the stabilizations of the complexes formed between the coating material and bioactive compounds. Two dark purple colored powders, differentiated by the ratio of the encapsulation materials used, rich in phytochemicals were obtained, with an encapsulation efficiency of up to 99%. The powders were tested for antioxidant activity, cytocompatibility, and thermal stability. The morphological structure of the powders highlighted the presence of encapsulated anthocyanins. Both powders showed a remarkable antioxidant activity of about 46 mM Trolox/g D.W., and cytocompatibility on the L929 fibroblast culture. At certain concentrations, both powders stimulated cell proliferation. The powders showed a good thermal stability between 75 and 100 °C for 15 min. The powders were tested in a food model system and checked for stability of phytochemicals during storage. The added value of the powders was demonstrated throughout the antioxidant activity, which remained unchanged during storage. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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13 pages, 9139 KiB

Open AccessArticle

Effect of Nanocrystallization of Anthocyanins Extracted from Two Types of Red-Fleshed Apple Varieties on Its Stability and Antioxidant Activity

by Jihua Xu, Xinxin Li, Shifeng Liu, Peilei Zhao, Heqiang Huo and Yugang Zhang

Molecules 2019, 24(18), 3366; https://doi.org/10.3390/molecules24183366 - 16 Sep 2019

Cited by 5 | Viewed by 2337

Abstract

Red-fleshed apple (Malus sieversii f. neidzwetzkyana (Dieck) Langenf) has attracted more and more attention due to its enriched anthocyanins and high antioxidant activity. In this study we extracted total anthocyanins and phenols from two types of red-fleshed apples—Xinjing No.4 (XJ4) and Red [...] Read more.

Red-fleshed apple (Malus sieversii f. neidzwetzkyana (Dieck) Langenf) has attracted more and more attention due to its enriched anthocyanins and high antioxidant activity. In this study we extracted total anthocyanins and phenols from two types of red-fleshed apples—Xinjing No.4 (XJ4) and Red Laiyang (RL)—to study the stability and antioxidant activity of anthocyanins after encapsulation onto Corn Starch Nanoparticles (CSNPs). The results indicated the anthocyanins and total phenol levels of XJ4 were 2.96 and 2.25 times higher than those of RL respectively. The anthocyanin concentration and loading time had a significant effect on CSNPs encapsulation, and XJ4 anthocyanins always showed significantly higher loading capacity than RL. After encapsulation, the morphology of RL-CSNPs and XJ4-CSNPs was still spherical with a smooth surface as CSNPs, but the particle size increased compared to CSNPs especially for RL-CSNPs. Different stress treatments including UV light, pH, temperature, and salinity suggested that XJ4-CSNPs exhibited consistently higher stability than RL-CSNPs. A significantly enhanced free radical scavenging rate under stress conditions was observed, and XJ4-CSNPs had stronger antioxidant activity than RL-CSNPs. Furthermore, XJ4-CSNPs exhibited a slower released rate than RL-CSNPs in simulated gastric (pH 2.0) and intestinal (pH 7.0) environments. Our research suggests that nanocrystallization of anthocyanins is an effective method to keep the anthocyanin ingredients intact and active while maintaining a slow release rate. Compared to RL, encapsulation of XJ4 anthocyanins has more advantages, which might be caused by the significant differences in the metabolites of XJ4. These findings give an insight into understanding the role of nanocrystallization using CSNPs in enhancing the antioxidant ability of anthocyanins from different types of red-fleshed apples, and provide theoretical foundations for red-fleshed apple anthocyanin application. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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15 pages, 1392 KiB

Open AccessArticle

Inhibitory Effects of Scutellaria baicalensis Root Extract on Linoleic Acid Hydroperoxide-induced Lung Mitochondrial Lipid Peroxidation and Antioxidant Activities

by Pei Ru Liau, Ming Shun Wu and Ching Kuo Lee

Molecules 2019, 24(11), 2143; https://doi.org/10.3390/molecules24112143 - 06 Jun 2019

Cited by 25 | Viewed by 3331

Abstract

In this study, we evaluated the ability of Scutellaria baicalensis Georgi to protect lipid-peroxidation (LPO) in lung tissue after free radical-induced injury. We prepared S. baicalensis root (SBR) extracts using different solvents. The total flavonoid and total phenol contents of each extract were [...] Read more.

In this study, we evaluated the ability of Scutellaria baicalensis Georgi to protect lipid-peroxidation (LPO) in lung tissue after free radical-induced injury. We prepared S. baicalensis root (SBR) extracts using different solvents. The total flavonoid and total phenol contents of each extract were measured, and the ROS damage protection was evaluated by analyzing linoleic acid hydroperoxide (LHP)-induced LPO in rat lung mitochondria. Moreover, evaluating diphenylpicrylhydrazyl (DPPH), hydrogen peroxide, superoxide anion radical, and hydroxyl radical scavenging abilities and using metal chelating assays were used to determine in vitro antioxidant activity. The ethyl acetate (EtOAc) extract showed high ROS scavenging ability, and four compounds were subsequently isolated and purified from this extract: baicalin, baicalein, wogonin, and oroxylin A. Baicalein in rat lung mitochondria the most significant LHP-induced LPO inhibition was shown and extracted with EtOAc that contained the highest amount of baicalein. Thus, baicalein and the EtOAc extract of SBR may be efficient in conferring ROS damage protection and inhibiting LHP-induced LPO in rat lung mitochondria. Additional studies are warranted to investigate their use as antioxidant therapy for respiration infections, nutrition supplements, and lead compounds in pharmaceuticals. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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17 pages, 4602 KiB

Open AccessArticle

Preparation and Identification of Antioxidative Peptides from Pacific Herring (Clupea pallasii) Protein

by Xueqin Wang, Huahua Yu, Ronge Xing, Song Liu, Xiaolin Chen and Pengcheng Li

Molecules 2019, 24(10), 1946; https://doi.org/10.3390/molecules24101946 - 21 May 2019

Cited by 25 | Viewed by 2793

Abstract

The aim of this study was to isolate and purify antioxidative peptides from Pacific herring (Clupea pallasii) protein. Five enzymes (pepsin, trypsin, papain, flavourzyme, and neutrase) were used for protein hydrolysis, and Pacific herring protein hydrolysates (PHPH) were separated by ultrafiltration. [...] Read more.

The aim of this study was to isolate and purify antioxidative peptides from Pacific herring (Clupea pallasii) protein. Five enzymes (pepsin, trypsin, papain, flavourzyme, and neutrase) were used for protein hydrolysis, and Pacific herring protein hydrolysates (PHPH) were separated by ultrafiltration. The fraction with the molecular weight below 3500 Da exhibited the highest in vitro antioxidant activities and cellular antioxidant activity. The PHPH was isolated and purified by consecutive chromatographic methods including gel filtration chromatography and reverse high-performance liquid chromatography (RP-HPLC). The purified antioxidant peptides were identified as Leu-His-Asp-Glu-Leu-Thr (MW = 726.35 Da) and Lys-Glu-Glu-Lys-Phe-Glu (MW = 808.40 Da), and the IC₅₀ values of cellular antioxidant activity were 1.19 ± 0.05 mg/mL and 1.04 ± 0.06 mg/mL. The results demonstrate that is possible to produce natural antioxidative peptides from Pacific herring protein via enzymatic hydrolysis and purification. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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13 pages, 725 KiB

Open AccessArticle

Effects of Pecan Nut (Carya illinoiensis) and Roselle Flower (Hibiscus sabdariffa) as Antioxidant and Antimicrobial Agents for Sardines (Sardina pilchardus)

by Juliana Villasante, Marina Girbal, Isidoro Metón and María Pilar Almajano

Molecules 2019, 24(1), 85; https://doi.org/10.3390/molecules24010085 - 27 Dec 2018

Cited by 18 | Viewed by 4550

Abstract

The effects of pecan nut (Carya illinoinensis) and roselle flower (Hibiscus sabdariffa) as antioxidant and antimicrobial agents on shelf life extension of sardines (Sardina pilchardus) were evaluated over a period of 5 days at 7 ± 1 [...] Read more.

The effects of pecan nut (Carya illinoinensis) and roselle flower (Hibiscus sabdariffa) as antioxidant and antimicrobial agents on shelf life extension of sardines (Sardina pilchardus) were evaluated over a period of 5 days at 7 ± 1 °C. Treatments consisted of the addition of 5% and 10% w/w pecan nut, 5% w/w roselle flower and a combination of 5% of each. Physicochemical (lipid oxidation, fatty acids, hexanal and biogenic amines), sensory and microbiological characteristics of fish samples were periodically analyzed. All treatments effectively improved physicochemical quality parameters, with 10% w/w pecan nut having the highest effectiveness. The presence of roselle flower reduced microbial growth. Our findings suggest that addition of a natural preservative combining pecan nut and roselle flower may extend the shelf life of fresh sardines during chilled storage while maintaining quality indexes. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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12 pages, 868 KiB

Open AccessArticle

Use of Red Wine Polyphenols as a Natural Preservative in Health-Promoting Omega-3 Fatty Acids-Enriched Lamb Patties

by Iria Muíño, Jesús de la Fuente, Concepción Pérez, Elizabeth Apeleo, Cristina Pérez-Santaescolástica, Vicente Cañeque, Sara Lauzurica, Rubén Bermejo-Poza and María Teresa Díaz

Molecules 2018, 23(12), 3080; https://doi.org/10.3390/molecules23123080 - 25 Nov 2018

Cited by 7 | Viewed by 2916

Abstract

Meat consumption has been related to a higher risk of heart disease due to its saturated fat content. As a consequence, there has been a growth in research on how to increase unsaturated fat content in meat. However, a high content of unsaturated

[...] Read more.

Meat consumption has been related to a higher risk of heart disease due to its saturated fat content. As a consequence, there has been a growth in research on how to increase unsaturated fat content in meat. However, a high content of unsaturated fat favours the development of oxidative processes. The aim of the study was to evaluate the effectiveness of a red wine extract (RWE) rich in polyphenols (50, 100, and 200 mg gallic acid equivalents/kg meat) as a natural antioxidant in lamb meat patties enriched with omega-3 polyunsaturated fatty acids (n-3 PUFA) (100 mg n-3 PUFA/100 g meat), compared to using -tocopherol (TOC) (100 mg/kg meat). Adding RWE delayed metmyoglobin formation, lipid oxidation and loss of n-3 PUFA relative to controls, while TOC had no effect on preventing meat oxidation. Lamb odour was lower (p < 0.01) and odd odour higher (p < 0.001) in patties at the highest dose of RWE, compared to controls, but the overall liking score was not affected. The results suggest that RWE could be used as a natural antioxidant in the meat industry, even when n-3 PUFA content is high.

Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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10 pages, 1755 KiB

Open AccessCommunication

Steric Effect of Antioxidant Diels-Alder-Type Adducts: A Comparison of Sanggenon C with Sanggenon D

by Xican Li, Zhenxing Ren, Zimei Wu, Zhen Fu, Hong Xie, Langyu Deng, Xiaohua Jiang and Dongfeng Chen

Molecules 2018, 23(10), 2610; https://doi.org/10.3390/molecules23102610 - 11 Oct 2018

Cited by 8 | Viewed by 3161

Abstract

Sanggenons C and D are two Diels-Alder-type adducts from Chinese crude drug Sang-bai-pi. Structurally, both sanggenons construct stereoisomers. In the study, they were comparatively determined using four antioxidant assays, including ferric ion reducing antioxidant power (FRAP) assay, Cu²⁺-reducing assay, 1,1-diphenyl-2-picryl-hydrazl (DPPH•)-scavenging [...] Read more.

Sanggenons C and D are two Diels-Alder-type adducts from Chinese crude drug Sang-bai-pi. Structurally, both sanggenons construct stereoisomers. In the study, they were comparatively determined using four antioxidant assays, including ferric ion reducing antioxidant power (FRAP) assay, Cu²⁺-reducing assay, 1,1-diphenyl-2-picryl-hydrazl (DPPH•)-scavenging assay, and 2,2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid radical (ABTS•⁺)-scavenging assay. Their Fe²⁺-binding reactions were explored using UV-Vis spectra. Finally, their cytoprotective effects were evaluated using flow cytometry. In electron transfer (ET)-based FRAP and Cu²⁺-reducing assays, sanggenon D was found to have lower IC₅₀ values than sanggenon C; however, in multi-pathway-based DPPH•-scavenging and ABTS•⁺-scavenging assays, sanggenon C possessed lower IC₅₀ values than sanggenon D. UV-Vis spectra suggested that sanggenon C generated a bathochromic-shift (286 nm → 302 nm) and displayed stronger UV absorption than sanggenon D. In flow cytometry, sanggenon C and sanggenon D, respectively, exhibited 31.1% and 42.0% early apoptosis-percentages towards oxidative-stressed mesenchymal stem cells (MSCs). In conclusion, both sanggenons may undergo multiple pathways (e.g., ET and Fe²⁺-binding) to protect MSCs against oxidative stress. In the mere ET aspect, sanggenon D possesses a higher level than sanggenon C, while in multi-pathway-based radical-scavenging, Fe²⁺-binding, and cytoprotection aspects, sanggenon C is more active than sanggenon D. These discrepancies can conclusively be attributed to the steric effect. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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22 pages, 1510 KiB

Open AccessArticle

A Comprehensive Study on the Biological Activity of Elderberry Extract and Cyanidin 3-O-Glucoside and Their Interactions with Membranes and Human Serum Albumin

by Paulina Strugała, Sabrina Loi, Barbara Bażanów, Piotr Kuropka, Alicja Z. Kucharska, Aleksandra Włoch and Janina Gabrielska

Molecules 2018, 23(10), 2566; https://doi.org/10.3390/molecules23102566 - 08 Oct 2018

Cited by 19 | Viewed by 4933

Abstract

In our research we used the extract from dietary supplement of elderberry (EE) and its dominant anthocyanin—cyanidin 3-O-glucoside (Cy 3-gluc). By interacting with a model membrane that reflects the main lipid composition of tumor membranes, the extract components, including Cy 3-gluc, [...] Read more.

In our research we used the extract from dietary supplement of elderberry (EE) and its dominant anthocyanin—cyanidin 3-O-glucoside (Cy 3-gluc). By interacting with a model membrane that reflects the main lipid composition of tumor membranes, the extract components, including Cy 3-gluc, caused an increase in packing order, mainly in the hydrophilic region of the membrane. It can thus be stated that EE caused a rigidifying effect, which is fundamental for understanding its anticancer and antioxidant activity. This study represents the first attempt to unravel the mechanism of interaction of elderberry extract with membranes. The results of the interaction with human serum albumin (HSA) proved that the studied substance quenches the fluorescence of HSA through a static mechanism in which the main interaction forces are Van der Waals and hydrogen bonding. The antioxidant activity of EE and Cy 3-gluc on liposomal membranes, antiradical properties and ability to inhibited the activity of the enzymes cyclooxygenase-1 and cyclooxygenase-2 were also demonstrated. Moreover, the anticancer activity of EE and Cy 3-gluc on human breast adenocarcinoma cell line were investigated. In addition, EE also exhibited the ability to form lipid aggregates in the form of liposomal capsules that can be applied as carriers of active biological substances, and the highest efficacy of EE encapsulation was obtained for multilayered liposome formulations. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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22 pages, 4049 KiB

Open AccessArticle

Composition Analysis by UPLC-PDA-ESI (−)-HRMS and Antioxidant Activity Using Saccharomyces cerevisiae Model of Herbal Teas and Green Teas from Hainan

by Hua Li, Lanying Wang and Yanping Luo

Molecules 2018, 23(10), 2550; https://doi.org/10.3390/molecules23102550 - 06 Oct 2018

Cited by 11 | Viewed by 3543

Abstract

Different teas from everywhere are very useful and have been extensively studied. We studied the antioxidant activity of herbal teas and green teas from Hainan, Mallotus oblongifolius Muell. Arg. (MO), Ilex kudingcha C.J. Tseng (KD), Camellia sinensis var. assamica (J. W. Mast.) Kitam. [...] Read more.

Different teas from everywhere are very useful and have been extensively studied. We studied the antioxidant activity of herbal teas and green teas from Hainan, Mallotus oblongifolius Muell. Arg. (MO), Ilex kudingcha C.J. Tseng (KD), Camellia sinensis var. assamica (J. W. Mast.) Kitam. Hainan Dayezhong (DY), and Camellia sinensis (L.) O. Ktze. (produced from Hainan Baisha (BS)). The total phenol content and total flavonoid content from water extracts, resin extracts and fractions of herbal teas and green teas were compared. Later, eight fractions of herbal teas and green teas were subjected to UPLC-PDA-ESI-(−)-HRMS. We determined 1-diphenyl -2-picryl-hydrazyl radical and hydroxyl free radical scavenging activity by electron paramagnetic resonance spectroscopy. We subjected Saccharomyces cerevisiae to hydrogen peroxide, stress and evaluated antioxidant activity of herbal teas and green teas in cellulo. The experiment identified more than 14 potential antioxidant compounds from herbal teas and green teas. The herbal teas and green teas had a clearance rate higher than ferulic acid at the same concentrations. MO best reduced intracellular oxidation levels and increased catalase, glutathione reductase activities, glutathione reduced and glutathione oxidized content. KD had the highest cell survival rate and reduced cell lipid peroxidation. DY best improved superoxide dismutase activity and BS was the most active in the halo test. Therefore, we concluded that MO had stronger antioxidant activity than other herbal teas and green teas from Hainan, especially, which reduce S. cerevisiae oxidative stress under H₂O₂ stress. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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13 pages, 1269 KiB

Open AccessArticle

Synthesis and Structure-Activity Relationship of Daphnetin Derivatives as Potent Antioxidant Agents

by Yangliu Xia, Chen Chen, Yong Liu, Guangbo Ge, Tongyi Dou and Ping Wang

Molecules 2018, 23(10), 2476; https://doi.org/10.3390/molecules23102476 - 27 Sep 2018

Cited by 20 | Viewed by 4400

Abstract

In this study, daphnetin 1 was chosen as the lead compound, and C-3 or C-4-substituted daphnetins were designed and synthesized to explore the potential relationship between the antioxidant activities and the chemical structures of daphnetin derivatives. The antioxidant activities of the generated compounds [...] Read more.

In this study, daphnetin 1 was chosen as the lead compound, and C-3 or C-4-substituted daphnetins were designed and synthesized to explore the potential relationship between the antioxidant activities and the chemical structures of daphnetin derivatives. The antioxidant activities of the generated compounds were evaluated utilizing the free radical scavenging effect on 2,2′-diphenyl-1-picrylhydrazyl, 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonate) cation, and the ferric reducing power assays, and were then compared with those of the standard antioxidant Trolox. The results showed that the catechol group was the key pharmacophore for the antioxidant activity of the daphnetins. The introduction of an electron-withdrawing hydrophilic group at the C-4 position of daphnetin enhanced the antioxidative capacity, but this trend was not observed for C-3 substitution. In addition, introduction of a a hydrophobic phenyl group exerted negative effects on the antioxidant activity in both the C-3 and C-4 substitutions. Among all of the derivatives tested, the most powerful antioxidant was 4-carboxymethyl daphnetin (compound 9), for which the strongest antioxidant activity was observed in all of the assays. In addition, compound 9 also displayed strong pharmaceutical properties in the form of metabolic stability. To summarize, compound 9 holds great potential to be developed as an antioxidant agent with excellent antioxidant activity and proper pharmacokinetic behavior. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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14 pages, 1385 KiB

Open AccessArticle

Avocado Seed: A Comparative Study of Antioxidant Content and Capacity in Protecting Oil Models from Oxidation

by Francisco J. Segovia, Gádor Indra Hidalgo, Juliana Villasante, Xavier Ramis and María Pilar Almajano

Molecules 2018, 23(10), 2421; https://doi.org/10.3390/molecules23102421 - 21 Sep 2018

Cited by 49 | Viewed by 9237

Abstract

Increasingly, consumers want products containing little or no synthetic compounds. Avocado seeds, which are a residue of the food industry, could be used to obtain extracts with high antioxidant power. In the present study, the most popular radical scavenging methods are presented, establishing [...] Read more.

Increasingly, consumers want products containing little or no synthetic compounds. Avocado seeds, which are a residue of the food industry, could be used to obtain extracts with high antioxidant power. In the present study, the most popular radical scavenging methods are presented, establishing a comparison between them, besides working with two different extractions: pure methanol and ethanol–water (50:50 v/v). The radical scavenging assay methods ORAC and ABTS were performed, as well as a novel method: the reaction to methoxy radical, as determined by electron paramagnetic resonance (EPR). Peroxide value and thiobarbituric acid reactive compounds (TBARs) were used to monitor the oxidation of avocado seed oil, as well as the power of the avocado seed extract (ASE) to delay oil oxidation by oxidation induction time (OIT) and measured by differential scanning calorimetry (DSC). Radical scavenging methods have values between 1310–263 µmol TE/g of mass dissolved for ORAC and ABTS, respectively. The individual contribution of each of the compounds present in the extract was analyzed. The sum of all of them contributed up to 84% of the total radical scavenging activity. The concentration of 0.75% ASE causes a delay in the oxidation that is close to 80%, as measured by OIT. This implies that avocado seed residue may have a use as a natural antioxidant source, providing added value to organic waste. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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14 pages, 1750 KiB

Open AccessArticle

Comparative Phytochemical Profiles and Antioxidant Enzyme Activity Analyses of the Southern Highbush Blueberry (Vaccinium corymbosum) at Different Developmental Stages

by Yueting Sun, Min Li, Sangeeta Mitra, Rizwan Hafiz Muhammad, Biswojit Debnath, Xiaocao Lu, Hongxiang Jian and Dongliang Qiu

Molecules 2018, 23(9), 2209; https://doi.org/10.3390/molecules23092209 - 31 Aug 2018

Cited by 45 | Viewed by 5704

Abstract

In this study, the fruit quality, anthocyanin content and antioxidant enzyme activities of skin and pulp of southern blueberries (Vaccinium corymbosum) from China y at five developmental stages (green, pink, red, purple and blue) were investigated and anthocyanins were characterized and [...] Read more.

In this study, the fruit quality, anthocyanin content and antioxidant enzyme activities of skin and pulp of southern blueberries (Vaccinium corymbosum) from China y at five developmental stages (green, pink, red, purple and blue) were investigated and anthocyanins were characterized and quantified by HPLC during the considered developmental stages. The results indicatated that the contents of phenolic, flavonoids and anthocyanin as well as antioxidant enzyme activities varied depending on the developmental stages. The correlation values between total phenolic content (TPC), total flavonoids content (TFC) and total anthocyanin content (TAC) were significant. The highest activity of peroxidase (POD) and catalase (CAT) was found in red fruit, and the variety of monomeric anthocyanin increased gradually, skin from blue fruit possessed higher TAC. However, the highest activity of polyphenol oxidase (PPO) and superoxide dismutase (SOD) were detected in green and blue fruit, respectively. In the present work, the differences regarding phytochemical profiles and antioxidant enzyme activities were mainly correlated with developmental stages of fruit. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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12 pages, 3393 KiB

Open AccessArticle

pH Effect and Chemical Mechanisms of Antioxidant Higenamine

by Yulu Xie, Xican Li, Jingyu Chen, Yuman Deng, Wenbiao Lu and Dongfeng Chen

Molecules 2018, 23(9), 2176; https://doi.org/10.3390/molecules23092176 - 29 Aug 2018

Cited by 31 | Viewed by 3472

Abstract

In this article, we determine the pH effect and chemical mechanism of antioxidant higenamine by using four spectrophotometric assays: (1) 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide radical (PTIO•)-scavenging assay (at pH 4.5, 6.0, and 7.4); (2) Fe³⁺-reducing power assay; (3) Cu²⁺-reducing power assay; and [...] Read more.

In this article, we determine the pH effect and chemical mechanism of antioxidant higenamine by using four spectrophotometric assays: (1) 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide radical (PTIO•)-scavenging assay (at pH 4.5, 6.0, and 7.4); (2) Fe³⁺-reducing power assay; (3) Cu²⁺-reducing power assay; and (4) 1,1-diphenyl-2-picryl-hydrazyl (DPPH•)-scavenging assay. The DPPH•-scavenging reaction product is further analyzed by ultra-performance liquid chromatography, coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) technology. In the four spectrophotometric assays, higenamine showed good dose-response curves; however, its IC₅₀ values were always lower than those of Trolox. In UPLC-ESI-Q-TOF-MS/MS analysis, the higenamine reaction product with DPPH• displayed three chromatographic peaks (retention time = 0.969, 1.078, and 1.319 min). The first gave m/z 541.2324 and 542.2372 MS peaks; while the last two generated two similar MS peaks (m/z 663.1580 and 664.1885), and two MS/MS peaks (m/z 195.9997 and 225.9971). In the PTIO•-scavenging assays, higenamine greatly decreased its IC₅₀ values with increasing pH. In conclusion, higenamine is a powerful antioxidant—it yields at least two types of final products (i.e., higenamine-radical adduct and higenamine-higenamine dimer). In aqueous media, higenamine may exert its antioxidant action via electron-transfer and proton-transfer pathways. However, its antioxidant action is markedly affected by pH. This is possibly because lower pH value weakens its proton-transfer pathway via ionization suppression by solution H⁺, and its electron-transfer pathway by withdrawing the inductive effect (-I) from protonated N-atom. These findings will aid the correct use of alkaloid antioxidants. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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14 pages, 1308 KiB

Open AccessArticle

Antioxidant Activity as Biomarker of Honey Variety

by Małgorzata Dżugan, Monika Tomczyk, Patrycja Sowa and Dorota Grabek-Lejko

Molecules 2018, 23(8), 2069; https://doi.org/10.3390/molecules23082069 - 18 Aug 2018

Cited by 127 | Viewed by 11284

Abstract

Honey variety is commonly defined by beekeepers based on nectar flow availability and the only laboratory method to provide verification is the melissopalynological analysis. Therefore, a quick and simple method for accurate assessment of honey variety is still being researched. The aim of [...] Read more.

Honey variety is commonly defined by beekeepers based on nectar flow availability and the only laboratory method to provide verification is the melissopalynological analysis. Therefore, a quick and simple method for accurate assessment of honey variety is still being researched. The aim of the study was to evaluate the antioxidant activity of honey as an indicator of variety through the use of multivariate statistical analysis. Materials for the study consisted of 90 samples of varietal Polish honeys (rape-12, tilia-10, goldenrod-11, dandelion-5, buckwheat-6, multifloral-17, nectar-honeydew-8 and coniferous honeydew-16 and leafy honeydew-5) obtained directly from apiaries. Honeys were investigated in aspect of antioxidant capacity by photochemiluminescence (PCL) methods using standard ACW and ACL kits. As the reference FRAP and DPPH methods were used. The total phenolics content (TPC) was determined through the Folin-Ciocalteu method. The strongest antioxidant activity was found for buckwheat, while the weakest was found for rape honeys regardless of the used method. Results of the used methods were positively correlated (r = 0.42 to 0.94). Analysis conducted by PCL method confirmed that the minor fraction of honey antioxidants exhibits hydrophobic properties. Clear separation of honey varieties using PCA and Clustering method indicate that antioxidant activity can be a useful parameter for determining the botanical origin of honey. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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11 pages, 2995 KiB

Open AccessArticle

Antioxidation and Melanogenesis Inhibition of Various Dendrobium tosaense Extracts

by Chin-Feng Chan, Chin-Tung Wu, Wen-Ying Huang, Wen-Shin Lin, Han-Wei Wu, Teng-Kuan Huang, Min-Yun Chang and Yung-Sheng Lin

Molecules 2018, 23(7), 1810; https://doi.org/10.3390/molecules23071810 - 21 Jul 2018

Cited by 33 | Viewed by 4593

Abstract

This study investigated the polyphenol content, antioxidant activity, and inhibition ability of mushroom tyrosinase and melanogenesis of Dendrobium tosaense (DT) extract. Ground DT was extracted using deionized water (W) or 50% ethanol (50E) at room temperature (RT) or 50 °C (50T) for 20 [...] Read more.

This study investigated the polyphenol content, antioxidant activity, and inhibition ability of mushroom tyrosinase and melanogenesis of Dendrobium tosaense (DT) extract. Ground DT was extracted using deionized water (W) or 50% ethanol (50E) at room temperature (RT) or 50 °C (50T) for 20 min. The 50T + 50E extract exhibited the highest total phenol content 47.0 ± 4.0 mg gallic acid equivalent/g DT extract, the highest level of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free-radical scavenging 66.0 ± 3.0 mg Trolox equivalent/g DT extract, and the highest reducing power 12.00 ± 0.50 mg vitamin C equivalent/g DT extract. The RT + W extract had the highest total flavonoid content 110.0 ± 3.0 mg quercetin equivalent/g DT extract. The RT + 50E extract had the lowest half maximal inhibitory concentration 1.30 ± 0.00 mg/mL for 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging, and the lowest half maximal inhibitory concentration 6.40 ± 0.30 mg/mL for mushroom tyrosinase inhibition activity. DT extracts, especially RT + W and 50T + W, exhibited potent inhibitory effects on melanogenesis of B16/F10 cells. These results demonstrated the application potential of DT extract for skincare. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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12 pages, 1347 KiB

Open AccessFeature PaperArticle

Continuous or Batch Solid-Liquid Extraction of Antioxidant Compounds from Seeds of Sterculia apetala Plant and Kinetic Release Study

by Federica Mosca, Gádor Indra Hidalgo, Juliana Villasante and María Pilar Almajano

Molecules 2018, 23(7), 1759; https://doi.org/10.3390/molecules23071759 - 18 Jul 2018

Cited by 24 | Viewed by 4725

Abstract

This work has been intended to investigate the antioxidant properties of compounds extracted from seeds of Sterculia apetala (a plant from Central America) in order to add further results to the relatively poor existing literature on the beneficial properties of this plant. Different [...] Read more.

This work has been intended to investigate the antioxidant properties of compounds extracted from seeds of Sterculia apetala (a plant from Central America) in order to add further results to the relatively poor existing literature on the beneficial properties of this plant. Different extraction methodologies were used such as batch or continuous extraction conditions using water or ethanol 50% as solvents. The kinetic study has allowed estimation of the effective diffusion coefficients in a continuous solid-liquid extraction, highlighting the strict dependence of the diffusion rate and temperature and kind of solvent, showing the highest diffusion rate with ethanol 50% at 60 °C. The comparison between different techniques and two solvents led to the selection of water as the best extraction solvent while batch mechanically-agitated extraction was the most efficient mode, with the benefits of use of an environmental-friendly solvent and reduction in process time to achieve a high amount of extracted phenolic compounds. The analysis techniques used were ABTS and Folin-Ciocalteau methods to investigate the antioxidant activity and quantify the Total Phenolic Content (TPC) respectively. Also, different fatty acids were extracted from Sterculia apetala seeds and analysed by Gas Chromatography in order to quantify other interesting chemical species besides antioxidants. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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17 pages, 3525 KiB

Open AccessFeature PaperArticle

Radical Scavenging and Antioxidant Activity of Anthyllis Vulneraria Leaves and Flowers

by Manel Ouerfelli, Leila Bettaieb Ben Kâab and María Pilar Almajano

Molecules 2018, 23(7), 1657; https://doi.org/10.3390/molecules23071657 - 07 Jul 2018

Cited by 13 | Viewed by 4392

Abstract

The main targets of this work were to determine the phenolic content of Anthyllis vulneraria (A. vulneraria) leaves and flowers and to evaluate their antioxidant activity. Total polyphenols and flavonoid content (TPC and TFC, respectively) were determined. Antioxidant capacity was evaluated [...] Read more.

The main targets of this work were to determine the phenolic content of Anthyllis vulneraria (A. vulneraria) leaves and flowers and to evaluate their antioxidant activity. Total polyphenols and flavonoid content (TPC and TFC, respectively) were determined. Antioxidant capacity was evaluated by the Ferric Reducing Antioxidant Power (FRAP), the Oxygen Radical Absorbance Capacity (ORAC), the Trolox Equivalent Antioxidant Capacity (TEAC) and the diphenyl picrylhydrazyl (DPPH) assays, and by the analysis of primary and secondary oxidation products in oil-in-water emulsions and in raw beef patties during storage. The results revealed that the flowers of the A. vulneraria contained the highest content of total polyphenols and flavonoids and extracts from these tissues exhibited the strongest antioxidant activity, as they were more effective at retarding lipid oxidation in oil-in-water emulsions and raw beef patties than extracts from the leaves which had a potent antioxidant effect only at the beginning of the oxidation process. The results of this study allowed us to obtain a deep knowledge about the properties of A. vulneraria and confirmed the possibility of using its biologically active extracts in the food, cosmetic and pharmaceutical industries. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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14 pages, 1679 KiB

Open AccessArticle

Green Extraction of Natural Antioxidants from the Sterculia nobilis Fruit Waste and Analysis of Phenolic Profile

by Jiao-Jiao Zhang, Ya Li, Sheng-Jun Lin and Hua-Bin Li

Molecules 2018, 23(5), 1059; https://doi.org/10.3390/molecules23051059 - 02 May 2018

Cited by 12 | Viewed by 3698

Abstract

The waste of Sterculia nobilis fruit was massively produced during food processing, which contains lots of natural antioxidants. In this study, antioxidants in the Sterculia nobilis fruit waste were extracted using the green microwave-assisted extraction (MAE) technique. The effects of five independent variables [...] Read more.

The waste of Sterculia nobilis fruit was massively produced during food processing, which contains lots of natural antioxidants. In this study, antioxidants in the Sterculia nobilis fruit waste were extracted using the green microwave-assisted extraction (MAE) technique. The effects of five independent variables (ethanol concentration, solvent/material ratio, extraction time, temperature, and microwave power) on extraction efficiency were explored, and three major factors (ethanol concentration, extraction time, and temperature) showing great influences were chosen to study their interactions by response surface methodology. The optimal conditions were as follows: 40.96% ethanol concentration, 30 mL/g solvent/material ratio, 37.37 min extraction time at 66.76 °C, and 700 W microwave power. The Trolox equivalent antioxidant capacity value obtained in optimal conditions was in agreement with the predicted value. Besides, MAE improved the extraction efficiency compared with maceration and Soxhlet extraction methods. Additionally, the phenolic profile in the extract was analyzed by UPLC-MS/MS, and eight kinds of phenolic compounds were identified and quantified, including epicatechin, protocatechuic acid, ferulic acid, gallic acid, p-coumaric acid, caffeic acid, quercetin, and p-hydroxycinnamic acid. This study could contribute to the value-added utilization of the waste from Sterculia nobilis fruit, and the extract could be developed as food additive or functional food. Full article

(This article belongs to the Special Issue Antioxidants Chemistry and Applications)

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