Antioxidant Capacity of Natural Products

A special issue of Antioxidants (ISSN 2076-3921). This special issue belongs to the section "Natural and Synthetic Antioxidants".

Deadline for manuscript submissions: closed (31 July 2024) | Viewed by 12360

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Guest Editor
School of Food Biotechnology and Nutrition, Kyungsung University, Busan 48434, Republic of Korea
Interests: food chemistry and experiment; food chemistry; food analysis; functional food science
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Special Issue Information

Dear Colleagues,

This Special Issue aims to highlight studies relating to the antioxidant capacity of natural products. Excessive oxidative stress results from an imbalance between the production of oxidant derivatives and the defense mechanisms of antioxidants. This stress can result in the impairment of cells, proteins and DNA, contributing to the aging process. Moreover, oxidative stress is a critical factor in the pathogenesis and progression of diabetes, cancer and neurodegenerative disorders such as Alzheimer's disease.

Reactive oxygen species (ROS) are generally recognized as detrimental to health, capable of damaging cellular macromolecules and leading to processes such as apoptosis and necrosis. There are numerous substances from nature that can act as antioxidants. Among these, dietary phytochemicals, including phenolic compounds, vitamins and carotenoids, are potent antioxidants that can scavenge and intercept free radicals to prevent cellular damage. Researchers are actively investigating the properties and activities of promising antioxidants derived from natural sources as potential countermeasures against metabolic disorders.

Therefore, this Special Issue welcomes original research papers or review articles focusing on the antioxidant effects of diverse natural resources, as well as the mechanisms underlying their antioxidant actions both in vivo and in vitro.

We look forward to your contribution.

Sincerely,

Prof. Dr. Younghwa Kim
Guest Editor

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Published Papers (8 papers)

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Research

14 pages, 5955 KiB  
Article
Actinidia chinensis Planch Ameliorates Photoaging in UVB-Irradiated NIH-3T3 Cells and SKH-1 Hairless Mice by Controlling the Reactive Oxygen Species/AKT Pathway
by Jong-Min Jung, Seo-Young Kim, Oh-Yun Kwon and Seung-Ho Lee
Antioxidants 2024, 13(9), 1091; https://doi.org/10.3390/antiox13091091 - 6 Sep 2024
Viewed by 833
Abstract
In this study, we evaluated the antiphotoaging properties of Actinidia chinensis Planch (ACP) and the molecular mechanisms underlying its ability to prevent UVB-mediated photoaging. Administration of the ethanolic extract of ACP (EEACP) to the dorsal area of hairless mice effectively ameliorated UVB-mediated wrinkle [...] Read more.
In this study, we evaluated the antiphotoaging properties of Actinidia chinensis Planch (ACP) and the molecular mechanisms underlying its ability to prevent UVB-mediated photoaging. Administration of the ethanolic extract of ACP (EEACP) to the dorsal area of hairless mice effectively ameliorated UVB-mediated wrinkle formation, epidermal thickening, and loss of lipid droplets in the epidermis. Additionally, the UVB-induced loss of collagen content in the epidermis was significantly attenuated in mouse skin treated with EEACP. The expression of procollagen type 1 and metalloproteinase-1a, which are related to collagen content in the epidermis, was restored by EEACP treatment in UVB-irradiated mice and NIH-3T3 mouse skin fibroblast cells. Interestingly, EEACP effectively ameliorated UVB-induced reactive oxygen species overproduction. Furthermore, the activation/phosphorylation of AKT, rather than mitogen-activated protein kinases, has been identified as a major target of EEACP in preventing UVB-mediated photoaging. Additionally, N-(1 deoxy-1-fructosyl) valine and phenethylamine glucuronide were identified as analytical indicators of EEACP using high-performance liquid chromatography/mass spectrometry. These results suggest that EEACP can be developed as a functional natural agent capable of preventing photoaging by attenuating UVB-induced activation of the reactive oxygen species/AKT pathway. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Natural Products)
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13 pages, 5296 KiB  
Article
Natural Product Auraptene Targets SLC7A11 for Degradation and Induces Hepatocellular Carcinoma Ferroptosis
by Donglin Li, Yingping Li, Liangjie Chen, Chengchang Gao, Bolei Dai, Wenjia Yu, Haoying Yang, Junxiang Pi and Xueli Bian
Antioxidants 2024, 13(8), 1015; https://doi.org/10.3390/antiox13081015 - 20 Aug 2024
Cited by 2 | Viewed by 909
Abstract
The natural product auraptene can influence tumor cell proliferation and invasion, but its effect on hepatocellular carcinoma (HCC) cells is unknown. Here, we report that auraptene can exert anti-tumor effects in HCC cells via inhibition of cell proliferation and ferroptosis induction. Auraptene treatment [...] Read more.
The natural product auraptene can influence tumor cell proliferation and invasion, but its effect on hepatocellular carcinoma (HCC) cells is unknown. Here, we report that auraptene can exert anti-tumor effects in HCC cells via inhibition of cell proliferation and ferroptosis induction. Auraptene treatment induces total ROS and lipid ROS production in HCC cells to initiate ferroptosis. The cell death or cell growth inhibition of HCC cells induced by auraptene can be eliminated by the ROS scavenger NAC or GSH and ferroptosis inhibitor ferrostatin-1 or Deferoxamine Mesylate (DFO). Mechanistically, the key ferroptosis defense protein SLC7A11 is targeted for ubiquitin–proteasomal degradation by auraptene, resulting in ferroptosis of HCC cells. Importantly, low doses of auraptene can sensitize HCC cells to ferroptosis induced by RSL3 and cystine deprivation. These findings demonstrate a critical mechanism by which auraptene exhibits anti-HCC effects via ferroptosis induction and provides a possible therapeutic strategy for HCC by using auraptene or in combination with other ferroptosis inducers. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Natural Products)
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24 pages, 6425 KiB  
Article
Bioaffinity Ultrafiltration Combined with HPLC-ESI-qTOF-MS/MS for Screening Potential Bioactive Components from the Stems of Dendrobium fimbriatum and In Silico Analysis
by Yu-Hui Hsieh, Wu-Chang Chuang, Ming-Chung Lee, Yu-Hsin Fan, Nai-Kuei Huang and Jih-Jung Chen
Antioxidants 2024, 13(8), 918; https://doi.org/10.3390/antiox13080918 - 29 Jul 2024
Viewed by 1076
Abstract
Dendrobium fimbriatum is a perennial herb, and its stems are high-grade tea and nourishing medicinal materials. Various solvent extracts of D. fimbriatum were evaluated for their anti-inflammatory, anti-acetylcholinesterase (AChE), antioxidant, and anti-α-glucosidase properties. Acetone and EtOAc extracts showed significant antioxidant effects. Acetone, n [...] Read more.
Dendrobium fimbriatum is a perennial herb, and its stems are high-grade tea and nourishing medicinal materials. Various solvent extracts of D. fimbriatum were evaluated for their anti-inflammatory, anti-acetylcholinesterase (AChE), antioxidant, and anti-α-glucosidase properties. Acetone and EtOAc extracts showed significant antioxidant effects. Acetone, n-hexane, and EtOAc extracts revealed potent inhibition against α-glucosidase. EtOAc, n-hexane, and dichloromethane extracts displayed significant anti-AChE activity. Among the isolated constituents, gigantol, moscatin, and dendrophenol showed potent antioxidant activities in FRAP, DPPH, and ABTS radical scavenging tests. Moscatin (IC50 = 161.86 ± 16.45 μM) and dendrophenol (IC50 = 165.19 ± 13.25 μM) displayed more potent anti-AChE activity than chlorogenic acid (IC50 = 236.24 ± 15.85 μM, positive control). Dendrophenol (IC50 = 14.31 ± 3.17 μM) revealed more efficient anti-NO activity than quercetin (positive control, IC50 = 23.09 ± 1.43 μM). Analysis of AChE and iNOS inhibitory components was performed using molecular docking and/or the bioaffinity ultrafiltration method. In bioaffinity ultrafiltration, the binding affinity of compounds to the enzyme (acetylcholinesterase and inducible nitric oxide synthase) was determined using the enrichment factor (EF). Among the main components of the EtOAc extract from D. fimbriatum stem, moscatin, dendrophenol, gigantol, and batatasin III with acetylcholinesterase exhibited the highest binding affinities, with affinity values of 66.31%, 59.48%, 54.60%, and 31.87%, respectively. Moreover, the affinity capacity of the identified compounds with inducible nitric oxide synthase can be ranked as moscatin (88.99%) > dendrophenol (65.11%) > gigantol (44.84%) > batatasin III (27.18%). This research suggests that the bioactive extracts and components of D. fimbriatum stem could be studied further as hopeful candidates for the prevention or treatment of hyperglycemia, oxidative stress-related diseases, and nervous disorders. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Natural Products)
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17 pages, 5229 KiB  
Article
Resveratrol-Enriched Rice Callus Extract Inhibits Oxidative and Cellular Melanogenic Activities in Melan-A Cells
by Chaiwat Monmai, Jin-Suk Kim and So-Hyeon Baek
Antioxidants 2024, 13(6), 625; https://doi.org/10.3390/antiox13060625 - 21 May 2024
Cited by 1 | Viewed by 1015
Abstract
The excessive production of melanin can cause skin diseases and hyperpigmentation. In this study, resveratrol contained in Dongjin rice seed (DJ526) was increased through callus induction. The antioxidant capacity of resveratrol-enriched rice callus was evaluated using the ABTS radical scavenging method and was [...] Read more.
The excessive production of melanin can cause skin diseases and hyperpigmentation. In this study, resveratrol contained in Dongjin rice seed (DJ526) was increased through callus induction. The antioxidant capacity of resveratrol-enriched rice callus was evaluated using the ABTS radical scavenging method and was equivalent to that of vitamin C. DJ526 rice callus extract significantly increased antioxidant activities in a concentration-dependent manner. The anti-melanogenesis effects of DJ526 rice callus extract were also evaluated in melan-a cells. Resveratrol-enriched rice callus extract significantly (i) decreased the size and number of melanin-containing cells, (ii) suppressed the activity of cellular tyrosinase and melanin content, (iii) downregulated the expression of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2, (iv) increased the expression of phosphorylated extracellular signal-regulated kinase 1/2 and protein kinase B, and (v) inhibited the activation of phosphorylated p38 in melan-a cells. From the above observations, DJ526 rice callus extract showed strong antioxidant and anti-melanogenesis activity at the concentration test. These findings indicate the potential of resveratrol-enriched rice callus as a novel agent for controlling hyperpigmentation. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Natural Products)
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17 pages, 4490 KiB  
Article
Therapeutic Effects of Hinokitiol through Regulating the SIRT1/NOX4 against Ligature-Induced Experimental Periodontitis
by Tae-Yeon Kim, Eun-Nam Kim and Gil-Saeng Jeong
Antioxidants 2024, 13(5), 550; https://doi.org/10.3390/antiox13050550 - 30 Apr 2024
Cited by 2 | Viewed by 1355
Abstract
Hinokitiol (HKT) is one of the essential oil components found in the heartwood of Cupressaceae plants, and has been reported to have various bioactive effects, including anti-inflammatory effects. However, the improving effect of HKT on periodontitis, which is characterized by periodontal tissue inflammation [...] Read more.
Hinokitiol (HKT) is one of the essential oil components found in the heartwood of Cupressaceae plants, and has been reported to have various bioactive effects, including anti-inflammatory effects. However, the improving effect of HKT on periodontitis, which is characterized by periodontal tissue inflammation and alveolar bone loss, has not been clearly revealed. Therefore, we investigated the periodontitis-alleviating effect of HKT and the related molecular mechanisms in human periodontal ligament cells. According to the study results, HKT downregulated SIRT1 and NOX4, which were increased by Porphyromonas gingivalis Lipopolysaccharide (PG-LPS) stimulation and were found to regulate pro-inflammatory mediators and oxidative stress through SIRT1/NOX4 signals. Additionally, by increasing the expression of osteogenic makers such as alkaline phosphatase, osteogenic induction of human periodontal ligament (HPDL) cells, which had been reduced by PG-LPS, was restored. Furthermore, we confirmed that NOX4 expression was regulated through regulation of SIRT1 expression with HKT. The in vitro effect of HKT on improving periodontitis was proven using the periodontal inflammation model, which induces periodontal inflammation using ligature, a representative in vivo model. According to in vivo results, HKT alleviated periodontal inflammation and restored damaged alveolar bone in a concentration-dependent manner in the periodontal inflammation model. Through this experiment, the positive effects of HKT on relieving periodontal tissue inflammation and recovering damaged alveolar bone, which are important treatment strategies for periodontitis, were confirmed. Therefore, these results suggest that HKT has potential in the treatment of periodontitis. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Natural Products)
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14 pages, 1742 KiB  
Article
Comparison of the Antioxidant Potency of Four Triterpenes of Centella asiatica against Oxidative Stress
by Jinyeong Lim, Hana Lee, Seonghwa Hong, Junsoo Lee and Younghwa Kim
Antioxidants 2024, 13(4), 483; https://doi.org/10.3390/antiox13040483 - 18 Apr 2024
Cited by 1 | Viewed by 2414
Abstract
We comparatively evaluated the antioxidant properties of key triterpenes from Centella asiatica, including asiatic acid (AA), asiaticoside, madecassic acid, and madecassoside, in several cell types, including skin fibroblasts, macrophages, hepatocytes, and endothelial cells, under conditions promoting oxidative stress. AA conferred the highest [...] Read more.
We comparatively evaluated the antioxidant properties of key triterpenes from Centella asiatica, including asiatic acid (AA), asiaticoside, madecassic acid, and madecassoside, in several cell types, including skin fibroblasts, macrophages, hepatocytes, and endothelial cells, under conditions promoting oxidative stress. AA conferred the highest viability on Hs68 cells exposed to ultraviolet B (UVB) irradiation. Triterpene pretreatment attenuated the UVB-induced generation of reactive oxygen species (ROS) and malondialdehyde (MDA), as well as the UVB-induced depletion of glutathione (GSH) in skin fibroblasts. AA most potently inhibited UVB-induced MMP generation, resulting in increased intracellular collagen levels. Pretreatment with triterpenes, particularly AA, significantly improved cell viability and attenuated TBHP-induced levels of ROS, alanine aminotransferase, and aspartate aminotransferase in HepG2 cells. Triterpenes attenuated ROS levels and reduced MDA and GSH expression in EA.hy926 cells. In RAW264.7 macrophages, production of nitric oxide, tumor necrosis factor-α, and interleukin-6 (indicators of LPS-induced oxidative damage) was significantly reduced by treatment with any of the triterpenes. Statistical analyses of triterpene biological activities using principal component analysis and hierarchical clustering revealed that AA exerted the greatest overall influence and showed remarkable activity in Hs68 and HepG2 cells. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Natural Products)
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18 pages, 1906 KiB  
Article
Unveiling Glucosinolate Diversity in Brassica Germplasm and In Silico Analysis for Determining Optimal Antioxidant Potential
by Kanivalan Iwar, Kebede Taye Desta, Kingsley Ochar and Seong-Hoon Kim
Antioxidants 2024, 13(3), 376; https://doi.org/10.3390/antiox13030376 - 19 Mar 2024
Viewed by 1683
Abstract
This study explored the glucosinolate (GSL) content in Brassica plants and utilized in silico analysis approach to assess their antioxidant capabilities. GSLs, present abundantly in Brassica vegetables, offer potential health advantages, including antioxidant effects. Employing Ultra-Performance Liquid Chromatography (UPLC) coupled with tandem mass [...] Read more.
This study explored the glucosinolate (GSL) content in Brassica plants and utilized in silico analysis approach to assess their antioxidant capabilities. GSLs, present abundantly in Brassica vegetables, offer potential health advantages, including antioxidant effects. Employing Ultra-Performance Liquid Chromatography (UPLC) coupled with tandem mass spectrometry (MS/MS), major GSLs were identified in 89 accessions from diverse species and subspecies. Statistical analysis and principal component analysis unveiled significant GSL variation and potential correlations among the Brassica germplasms. This study unveils the dominance of aliphatic GSLs over aromatic and indolyl compounds in all the accessions. Notably, Gluconapin (GNA) (33,049.23 µmol·kg−1 DW), Glucobrassicanapin (GBN) (9803.82 µmol·kg−1 DW), Progoitrin (PRO) (12,780.48 µmol·kg−1 DW) and Sinigrin (SIN) (14,872.93 µmol·kg−1 DW) were the most abundant compounds across the analyzed accessions. Moreover, in silico docking studies predicted promising antioxidant activity by evaluating the interactions of each GSL with antioxidant enzymes. Specifically, Sinigrin and Gluconapin exhibited a notably weaker influence on antioxidant enzymes. This provides key insights into the antioxidant potential of Brassica germplasm and highlights the importance of in silico analysis for evaluating bioactive properties. In general, the results of this study could be utilized in breeding programs to maximize GSL levels and antioxidant properties in Brassica crops and for developing functional foods with enhanced health benefits. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Natural Products)
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20 pages, 3844 KiB  
Article
Insights on the Nutraceutical Properties of Different Specialty Teas Grown and Processed in a German Tea Garden
by Patricia Carloni, Federico Girolametti, Elisabetta Giorgini, Tiziana Bacchetti, Cristina Truzzi, Silvia Illuminati and Elisabetta Damiani
Antioxidants 2023, 12(11), 1943; https://doi.org/10.3390/antiox12111943 - 31 Oct 2023
Cited by 2 | Viewed by 2080
Abstract
European countries have recently started experimenting with growing and producing their own teas in small quantities, mainly for the specialty tea sector. To characterize European teas, this study investigated a set of five tea types obtained from different Camellia sinensis varieties/cultivars, representing various [...] Read more.
European countries have recently started experimenting with growing and producing their own teas in small quantities, mainly for the specialty tea sector. To characterize European teas, this study investigated a set of five tea types obtained from different Camellia sinensis varieties/cultivars, representing various oxidation grades (green, white, yellow, oolong, black), all grown and processed in the only tea garden in Europe (in Germany) that focuses on all five types. Hot and cold brews were studied by measuring the total phenolic (TPC) and flavonoid contents (TFC), the antioxidant capacity and UV-Vis spectra, also with the objective of discriminating between the different tea types and the different plant varieties. The dried leaves were analyzed to measure the content of essential and toxic elements and by ATR-FTIR spectroscopy to determine a chemical fingerprint for identifying the tea varieties and types. The average levels of TPC (hot brew = 5.82 ± 2.06; cold brew = 5.4 ± 2.46 mM GAEq), TFC (hot brew = 0.87 ± 0.309; cold brew = 0.87 ± 0.413 mM CAEq), and antioxidant capacity (ORAC assay-hot brew = 20.9 ± 605; cold brew = 21.8 ± 8.0 mM TXEq, ABTS assay-hot brew = 15.2 ± 5.09; cold brew = 15.1 ± 5.8 mM TXEq, FRAP assay-hot brew = 9.2 ± 3.84; cold brew = 10.4 ± 5.23 mM AAEq) observed compared well with those from other parts of the world such as China, Africa, and Taiwan. The hazard quotient <1 and the hazard index of 0.14 indicate that there is no non-carcinogenic risk from consumption of these teas. The obtained information is essential for elucidating the characteristics and the impact of tea processing and tea variety on the health benefits of these tea products coming from a single European tea garden. This multifaceted approach would help tea growers in Europe increase their knowledge on the health attributes of the teas they grow, ultimately leading to optimization of the nutraceutical properties of these teas. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Natural Products)
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