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Keywords = antioxidant capacity assays

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20 pages, 1761 KB  
Article
Valorization of Turnip Greens (Brassica rapa subsp. sylvestris) Wastes: Investigation on the Sustainable Recovery of Bioactive Extracts with Antioxidant and Antibiofilm Properties
by Anna Maria Maurelli, Davide Coniglio, Francesco Milano, Sara Mancarella, Barbara Laddomada, Vincenzo De Leo, Francesco Longobardi, Francesca Coppola, Florinda Fratianni, Michelangelo Pascale, Filomena Nazzaro and Lucia Catucci
Molecules 2026, 31(2), 388; https://doi.org/10.3390/molecules31020388 (registering DOI) - 22 Jan 2026
Abstract
The valorization of agri-food residues is crucial for advancing circular bioeconomy strategies and mitigating environmental impacts. Turnip greens (Brassica rapa subsp. sylvestris) are a traditional vegetable cultivated in southern Italy. While the edible portions include flower sprouts, buds, and young leaves, [...] Read more.
The valorization of agri-food residues is crucial for advancing circular bioeconomy strategies and mitigating environmental impacts. Turnip greens (Brassica rapa subsp. sylvestris) are a traditional vegetable cultivated in southern Italy. While the edible portions include flower sprouts, buds, and young leaves, the more leathery leaves and stems are typically discarded. These wastes represent valuable sources of compounds with antioxidant and antimicrobial potential. This study aims to develop the extraction of phenolic compounds from turnip green residues using two techniques: silent maceration and ultrasound-assisted extraction (UAE). Ethanol was selected over methanol as a food-safe alternative solvent, with preliminary tests confirming equivalent efficiency. A Design of Experiments (DoE) approach was applied to both leaves and stems to assess the effects of solvent composition, solvent-to-matrix ratio, and extraction time on Total Phenolic Content and Trolox Equivalent Antioxidant Capacity. DoE results identified UAE as the most effective method for stems, while for leaves, the solvent-to-dry-mass ratio was the key parameter. HPLC-DAD analysis was performed to identify and quantify the phenolic acids in selected extracts. The antibacterial activity of these extracts against biofilms of six pathogenic strains was evaluated using crystal violet and MTT assays, confirming efficacy in both biofilm formation and mature stages. Full article
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27 pages, 2553 KB  
Article
Biotechnological Potential of Algerian Saffron Floral Residues: Recycling Phytochemicals with Antimicrobial Activity
by Nouria Meliani, Bouchra Loukidi, Larbi Belyagoubi, Nabila Belyagoubi-Benhammou, Salim Habi, Alessia D’Agostino, Antonella Canini, Saber Nahdi, Nassima Mokhtari Soulimane, Angelo Gismondi, Abdel Halim Harrath, Erdi Can Aytar and Gabriele Di Marco
Biology 2026, 15(2), 197; https://doi.org/10.3390/biology15020197 - 21 Jan 2026
Abstract
This study investigates the phytochemical profile, antioxidant capacity, and antimicrobial potential of Crocus sativus L. (saffron) tepal extracts obtained via different solvent systems. Here, a biochemical screening was performed using spectrophotometry and HPLC-DAD, while molecular docking simulations were carried out to evaluate the [...] Read more.
This study investigates the phytochemical profile, antioxidant capacity, and antimicrobial potential of Crocus sativus L. (saffron) tepal extracts obtained via different solvent systems. Here, a biochemical screening was performed using spectrophotometry and HPLC-DAD, while molecular docking simulations were carried out to evaluate the possible interactions between saffron tepal metabolites and bacterial target proteins. In parallel, antioxidant activity was assessed using radical scavenging assays, whereas antimicrobial potential (i.e., MIC, MBC, and MFC) was tested against selected bacterial strains. Results indicated that aqueous successive and crude extracts yielded the highest concentrations of polyphenols, flavonoids, and condensed tannins. In detail, HPLC-DAD analysis specifically identified significant levels of gallic acid, epicatechin, and various anthocyanins. These extracts demonstrated robust antioxidant and antimicrobial activities. This latter evidence was corroborated by the docking analyses, which revealed that chlorogenic acid and petunidin-3-glucoside exhibited high binding affinities for 2NRK and 2NZF, whereas epicatechin and pelargonidin effectively targeted 8ACR. These findings underscore the therapeutic potential of C. sativus tepals as natural bioactive agents, suggesting a promising role in overcoming antibiotic resistance and supporting their development for pharmaceutical applications. Full article
(This article belongs to the Special Issue Young Researchers in Plant Sciences)
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23 pages, 1897 KB  
Article
Investigation of Antioxidant Properties of Propolis Products Collected from Different Regions
by Aynur Cetin, Sena Bakir, Tugba Ozdal and Esra Capanoglu
Int. J. Mol. Sci. 2026, 27(2), 1046; https://doi.org/10.3390/ijms27021046 - 21 Jan 2026
Abstract
Propolis, a sticky bee hive product collected from resinous plant sources by Apis mellifera bees, exhibits a wide range of biological and pharmacological properties, primarily attributed to its rich composition of bioactive constituents, including phenolic acids, esters, and flavonoids. In this study, the [...] Read more.
Propolis, a sticky bee hive product collected from resinous plant sources by Apis mellifera bees, exhibits a wide range of biological and pharmacological properties, primarily attributed to its rich composition of bioactive constituents, including phenolic acids, esters, and flavonoids. In this study, the antioxidant properties of 76 liquid propolis solutions from 18 different countries were investigated based on their dry matter, total phenolic and total flavonoid contents, antioxidant capacities, and phenolic profiles. The antioxidant activities of propolis from various geographic regions, including Latvia, Croatia, New Zealand, San Marino, Russia, France, Romania, Italy, Estonia, Brazil, Belgium, Germany, Slovenia, Japan, the United States of America (USA), the United Arab Emirates (UAE), Spain, and Korea, were compared. Total phenolic and flavonoid contents, as well as total antioxidant capacity (Cupric Reducing Antioxidant Capacity—CUPRAC method), were analyzed by spectrophotometry, and the major constituents were investigated by liquid chromatography–mass spectrometry (LC-MS/MS). Antioxidant test results indicated that 29 products scored below 10 mg Trolox equivalent (TE)/mL, and only 14 were scored above 100 mg TE/mL. The results showed that the total phenolic content of the samples ranged from 0.1 to 107.5 mg Gallic acid equivalent (GAE)/mL, while total flavonoid content varied between 0.1 and 174.5 mg Catechin equivalent (CE)/mL. Based on the CUPRAC assay, total antioxidant capacity values ranged from 0.1 to 492.3 mg TE/mL. Among the 76 analyzed samples, nine products exhibited antioxidant capacity values exceeding 150 mg TE/mL. In all of these samples, phenolic profiling confirmed the presence of propolis, and the analytical results were consistent with the information declared on the product labels. Hence, this study provides a comprehensive, real-market evaluation of commercial propolis products by integrating spectrophotometric assays with LC-MS-based targeted metabolomics profiling, highlighting formulation- and product type-driven differences in phenolic composition and antioxidant capacity beyond geographical origin. Full article
(This article belongs to the Section Bioactives and Nutraceuticals)
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22 pages, 6486 KB  
Article
Regenerative Skin Remodeling by a Dual Hyaluronic Acid Hybrid Complex in Multimodal Preclinical Models
by Hyojin Roh, Ngoc Ha Nguyen, Jinyoung Jung, Jewan Kaiser Hwang, Young In Lee, Inhee Jung and Ju Hee Lee
Int. J. Mol. Sci. 2026, 27(2), 1027; https://doi.org/10.3390/ijms27021027 - 20 Jan 2026
Abstract
Skin aging arises from extracellular matrix degradation, inflammation, and pigmentation dysregulation, yet most existing rejuvenation strategies target only a subset of these processes. This study investigated the multimodal rejuvenation potential of a dual hyaluronic acid compound (DHC), composed of low- and high-molecular-weight HA [...] Read more.
Skin aging arises from extracellular matrix degradation, inflammation, and pigmentation dysregulation, yet most existing rejuvenation strategies target only a subset of these processes. This study investigated the multimodal rejuvenation potential of a dual hyaluronic acid compound (DHC), composed of low- and high-molecular-weight HA integrated within a minimally cross-linked hybrid complex. In vitro assays using dermal fibroblasts, melanoma cells, and macrophages demonstrated that DHC enhanced fibroblast viability, collagen I/III and elastin production, antioxidant enzyme activity, and wound-healing capacity while reducing senescence markers. DHC markedly suppressed melanogenesis by downregulating the gene expression of MITF, TYR, and TRP1, and exerted strong anti-inflammatory activity by decreasing nitric oxide (NO) production and key cytokines, including TNF-α, IL-1β, IL-6, and CCL1. In a UVB-induced photoaging rat model, DHC reduced wrinkle depth, epidermal thickening, and melanin accumulation while improving elasticity, collagen density, hydration, and barrier integrity. Across these outcomes, DHC demonstrated biological effects that were comparable to, and in selected endpoints greater than, those of commonly used biostimulators and HA fillers in preclinical models. Collectively, these laboratory findings suggest that DHC exhibits broad preclinical bioactivity through combined biostimulatory, antioxidant, anti-inflammatory, and pigmentation-modulating effects. Further mechanistic and clinical studies are required to determine its translational relevance. Full article
(This article belongs to the Collection Advances in Cell and Molecular Biology)
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20 pages, 1746 KB  
Article
Antimycobacterial Mechanisms and Anti-Virulence Activities of Polyphenolic-Rich South African Medicinal Plants Against Mycobacterium smegmatis
by Matsilane L. Mashilo, Mashilo M. Matotoka and Peter Masoko
Microorganisms 2026, 14(1), 239; https://doi.org/10.3390/microorganisms14010239 - 20 Jan 2026
Abstract
The rise of multidrug-resistant tuberculosis (TB) necessitates alternative therapeutic sources. This study investigated the polyphenolic content and the antioxidant, antimycobacterial, and anti-virulence activities of selected medicinal plants traditionally used to treat TB and related symptoms. Total phenolics, tannins, and flavonoids were quantified using [...] Read more.
The rise of multidrug-resistant tuberculosis (TB) necessitates alternative therapeutic sources. This study investigated the polyphenolic content and the antioxidant, antimycobacterial, and anti-virulence activities of selected medicinal plants traditionally used to treat TB and related symptoms. Total phenolics, tannins, and flavonoids were quantified using colorimetric assays. Antioxidant capacity was assessed via DPPH and ferric-reducing power assays. Antimycobacterial activity against Mycobacterium smegmatis was evaluated using broth microdilution, growth kinetics, cell constituent leakage, and respiratory chain dehydrogenase inhibition assays. Anti-virulence effects were examined using crystal violet biofilm and swarming motility assays. Tarchonanthus camphoratus showed the highest polyphenolic levels and, together with Combretum hereroense, strong antioxidant activity. Extracts of Senecio macroglossus, Nerium oleander, and Tetradenia riparia displayed potent antimycobacterial activity (MIC = 0.16 mg/mL), characterized by delayed exponential growth, membrane damage, and metabolic inhibition. Tabernaemontana elegans exhibited the weakest activity (MIC > 2.5 mg/mL). Most extracts also significantly impaired motility (12–100%) and early-stage biofilm formation. Polyphenolic-rich plant extracts demonstrated promising antimycobacterial and anti-virulence properties against M. smegmatis, highlighting their potential as leads for developing novel anti-TB agents. Full article
(This article belongs to the Section Antimicrobial Agents and Resistance)
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13 pages, 418 KB  
Article
Synergistic Mechanisms and Comprehensive Functional Evaluation of Bioactive Components from Olive and Chinese Olive
by Hongyang Pan, Zhaojun Wang and Jie Chen
Molecules 2026, 31(2), 359; https://doi.org/10.3390/molecules31020359 - 20 Jan 2026
Abstract
Olive and Chinese olive are rich sources of bioactive compounds with reported sensory and hepatoprotective activities; however, the synergistic effect between their functional components have not been systematically evaluated. In this study, DF3 (functional fraction isolated from olive) and GF3 (functional fraction isolated [...] Read more.
Olive and Chinese olive are rich sources of bioactive compounds with reported sensory and hepatoprotective activities; however, the synergistic effect between their functional components have not been systematically evaluated. In this study, DF3 (functional fraction isolated from olive) and GF3 (functional fraction isolated from Chinese olive) were obtained using a combination of solvent extraction, supercritical fluid extraction, and polyamide column chromatography. To investigate potential synergistic effects, the two fractions were blended at different ratios (1:1, 2:1, and 1:2), and their taste-modulating properties, antioxidant capacity, and anti-intoxication and hepatoprotective activities were assessed using sensory analysis, radical scavenging assays, and biochemical indicators. Compared with the individual fractions, the blended formulations exhibited enhanced taste intensity, improved antioxidant capacity, and stronger hepatoprotective effects, as evidenced by greater reductions in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Quantitative assessment using a combination index approach revealed a clear positive interaction between DF3 and GF3, with the GF3–DF3 (2:1) blend showing the most pronounced overall enhancement across multiple functional endpoints. Overall, this study provides a systematic and quantitative evaluation of synergistic effect between functional bioactive fractions and offers methodological guidance for the rational optimization of functional formulations. Full article
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31 pages, 1713 KB  
Article
In Vitro Antioxidant, Anti-Platelet and Anti-Inflammatory Natural Extracts of Amphiphilic Bioactives from Organic Watermelon Juice and Its By-Products
by Emmanuel Nikolakakis, Anna Ofrydopoulou, Katie Shiels, Sushanta Kumar Saha and Alexandros Tsoupras
Metabolites 2026, 16(1), 81; https://doi.org/10.3390/metabo16010081 - 19 Jan 2026
Viewed by 63
Abstract
Background/Objectives: Watermelon (Citrullus lanatus) processing generates substantial quantities of rind, seeds, and residual pulp that are typically discarded despite being rich in polyunsaturated fatty acids, polar lipids, carotenoids, and phenolic compounds. These amphiphilic bioactives are increasingly recognized for their roles in [...] Read more.
Background/Objectives: Watermelon (Citrullus lanatus) processing generates substantial quantities of rind, seeds, and residual pulp that are typically discarded despite being rich in polyunsaturated fatty acids, polar lipids, carotenoids, and phenolic compounds. These amphiphilic bioactives are increasingly recognized for their roles in modulating oxidative stress, inflammation, and platelet activation; however, the lipid fraction of watermelon by-products remains insufficiently characterized. This study examined organic watermelon juice and its by-products to isolate, characterize, and evaluate extracts enriched in amphiphilic and lipophilic bioactives, with emphasis on their in vitro antioxidant, anti-inflammatory, and antithrombotic properties. Methods: total lipids were extracted using a modified Bligh–Dyer method and fractionated into total amphiphilic compounds (TAC) and total lipophilic compounds (TLC) via counter-current distribution. Phenolic and carotenoid levels were quantified, and antioxidant capacity was assessed using DPPH, ABTS, and FRAP assays. Anti-platelet and anti-inflammatory activities were evaluated against ADP- and PAF-induced platelet aggregation. Structural characterization of polar lipids was performed using ATR–FTIR, and LC–MS was used to determine fatty acid composition and phospholipid structures. Results and Discussion: Carotenoids were primarily concentrated in the TLC fractions with high ABTS values for antioxidant activity, while phenolics mostly in the juice, the TACs of which showed the strongest total antioxidant capacity based on DPPH. TAC fractions of both samples showed also higher FRAP values of antioxidant activity, likely due to greater phenolic content. TAC extracts also exhibited notable inhibition of PAF- and ADP-induced platelet aggregation, associated with their enriched ω-3 PUFA profiles and favorable ω-6/ω-3 ratios based on their LC-MS profiles. Conclusions: Overall, watermelon products (juice) and by-products represent a valuable and sustainable source of amphiphilic bioactives with significant antioxidant, anti-inflammatory, and anti-platelet potential, supporting their future use in functional foods, nutraceuticals, and cosmetic applications. Full article
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20 pages, 323 KB  
Article
Phenolic Compounds, Antioxidant and Antimicrobial Activities of Punica granatum L. Fruit Extracts
by Mijat Božović, Vanja Tadić, Alessandra Oliva, Milan Mladenović, Roberta Astolfi and Rino Ragno
Molecules 2026, 31(2), 334; https://doi.org/10.3390/molecules31020334 - 19 Jan 2026
Viewed by 60
Abstract
Pomegranate is valued for its abundant polyphenolic content and its capacity to promote health. In this study, pomegranate juice or pericarp extracts from two Mediterranean regions (Montenegro and Italy) were systematically and comparatively evaluated for the first time with respect to their polyphenolic [...] Read more.
Pomegranate is valued for its abundant polyphenolic content and its capacity to promote health. In this study, pomegranate juice or pericarp extracts from two Mediterranean regions (Montenegro and Italy) were systematically and comparatively evaluated for the first time with respect to their polyphenolic composition, antioxidant capacity, and antimicrobial activity. The extraction of juice extracts was accomplished by means of the Kutscher–Steudel liquid–liquid extraction technique, which was employed to selectively recover phenolics. In contrast, the extraction of pericarp extracts from the solid matrix was achieved via Soxhlet extraction. A thorough high-performance liquid chromatography (HPLC) analysis was conducted to identify and quantify the major phenolic compounds present in the sample. This analysis revealed the presence of ellagitannin punicalagin isomers, with concentrations reaching up to 254.75 mg/g of the sample, as well as ellagic acid and gallic acid. The antioxidant potential of the samples was assessed using the antioxidant activity index (AAI) from the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test and by a ferric reducing antioxidant power (FRAP) assay. Juice extracts demonstrated a range of activity levels, with AAI values ranging from 0.17 to 2.12 and FRAP values ranging from 2.49 to 19.41 mmol Fe2+/g. In contrast, pericarp extracts exhibited notably higher activity, with AAI values ranging from 0.18 to 27.57 and FRAP values ranging from 2.99 to 372.17 mmol Fe2+/g. This study demonstrates the markedly higher functional potential of pericarp extracts compared to juice extracts by linking detailed phenolic profiles with bioactivity data. Antimicrobial testing, inclusive of the determination of minimum bactericidal concentration (MBC), demonstrated that certain pericarp extracts manifested bactericidal properties at low concentrations against selected clinically pertinent strains, including methicillin-resistant Staphylococcus aureus (0.109% p/v), methicillin-sensitive S. aureus (0.109% p/v), carbapenem-resistant Acinetobacter baumannii (0.109% p/v), and Escherichia coli (0.563% p/v). Candida albicans and Klebsiella pneumoniae strains exhibited minimal sensitivity to these extracts. The findings indicate that pomegranate pericarp is a valuable by-product, and they demonstrate the potential of both juice and pericarp extracts as functional ingredients. Full article
(This article belongs to the Special Issue Analyses and Applications of Phenolic Compounds in Food—3rd Edition)
17 pages, 1782 KB  
Article
Production of Antimicrobial and Antioxidant Metabolites by Penicillium crustosum Using Lemon Peel as a Co-Substrate in Submerged Fermentation
by Arely Núñez-Serrano, Refugio B. García-Reyes, Juan A. Ascasio-Valdés, Cristóbal N. Aguilar-González and Alcione García-González
Foods 2026, 15(2), 348; https://doi.org/10.3390/foods15020348 - 18 Jan 2026
Viewed by 126
Abstract
Fungal secondary metabolites are valuable sources of natural antioxidants and antimicrobials. This study evaluated the submerged fermentation of Penicillium crustosum OR889307 supplemented with lemon peel as a co-substrate to enhance the production of bioactive compounds. Lemon peel was selected for its phenolic precursors [...] Read more.
Fungal secondary metabolites are valuable sources of natural antioxidants and antimicrobials. This study evaluated the submerged fermentation of Penicillium crustosum OR889307 supplemented with lemon peel as a co-substrate to enhance the production of bioactive compounds. Lemon peel was selected for its phenolic precursors and sustainable availability as an agro-industrial byproduct. Crude extracts, aqueous and organic fractions, and molecular-weight partitions were assessed for antioxidant activity using the DPPH assay and for antimicrobial activity against Escherichia coli, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, and Candida albicans. Semi-purified extracts from co-substrate fermentations exhibited enhanced bioactivity, showing MIC values of 185 µg/mL against P. aeruginosa and 225 µg/mL against MRSA, along with strong ABTS radical-scavenging capacity (238.95 ± 2.17 µmol TE). RP-HPLC-ESI-MS profiling revealed phenolic acids, flavanones, flavonols, and lignans, including ferulic acid 4-O-glucoside, bisdemethoxycurcumin, secoisolariciresinol, and quercetin 3-O-xylosyl-glucuronide. These findings demonstrate that lemon peel supplementation promotes the biosynthesis of antimicrobial and antioxidant metabolites by P. crustosum. This approach supports sustainable agro-waste valorization and offers a promising strategy for obtaining natural bioactive compounds with potential applications in food preservation and health-related formulations. Full article
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35 pages, 13715 KB  
Article
Engineered Sporopollenin Exine Capsules for Colon-Targeted Delivery and Antioxidant Therapy of Pogostemon Oil in Ulcerative Colitis
by Jia Si, Shasha Dai, Huaiyu Su, Zhongjuan Ji, Cong Dong, Xinao Lyu, Shuhuan Lyu, Lin Chen, Jianwei Sun, Xiangqun Jin and Haiyan Li
Antioxidants 2026, 15(1), 116; https://doi.org/10.3390/antiox15010116 - 16 Jan 2026
Viewed by 228
Abstract
Ulcerative colitis (UC) is an inflammatory bowel disease associated with oxidative stress. Pogostemon oil (PO) exhibits potent antioxidant and anti-inflammatory activities but is limited by high volatility and poor gastrointestinal stability. In this study, sporopollenin exine capsules (SECs) were engineered as natural micro-carriers [...] Read more.
Ulcerative colitis (UC) is an inflammatory bowel disease associated with oxidative stress. Pogostemon oil (PO) exhibits potent antioxidant and anti-inflammatory activities but is limited by high volatility and poor gastrointestinal stability. In this study, sporopollenin exine capsules (SECs) were engineered as natural micro-carriers for PO, achieving efficient encapsulation (η > 69%) and a high adsorption capacity (27.64 g/g). A pH-sensitive calcium alginate shell was subsequently applied to construct colon-targeted microspheres (Ca-Alg@PO-SECs). The resulting system improved the thermal and photostability of PO. In vitro dissolution assays confirmed the system’s pH-responsiveness, maintaining integrity under simulated gastric conditions while enabling localized release at intestinal pH. In a DSS-induced acute UC mouse model, Ca-Alg@PO-SECs effectively alleviated clinical symptoms, as evidenced by improved body weight, colon length, and disease activity index. At the inflammatory level, the formulation modulated key cytokines (IL-1β, IL-6, and IL-10). Overall, Ca-Alg@PO-SECs provides a biocompatible, colon-targeted delivery strategy that preserves the bioactivity of essential oils and offers a promising preclinical approach for localized UC therapy. Full article
(This article belongs to the Special Issue Antioxidants as Adjuvants for Inflammatory Bowel Disease Treatment)
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27 pages, 8058 KB  
Article
Quality Evaluation and Antioxidant Activity of Cultivated Gentiana siphonantha: An Ethnic Medicine from the Tibetan Plateau
by Jiamin Li, Liyan Zang, Xiaoming Song, Zixuan Liu, Hongmei Li and Jing Sun
Molecules 2026, 31(2), 312; https://doi.org/10.3390/molecules31020312 - 16 Jan 2026
Viewed by 181
Abstract
Gentiana species are widely used in traditional and modern medicine, and Gentiana siphonantha is an important medicinal representative. To evaluate the quality characteristics of cultivated G. siphonantha roots, the accumulation patterns of iridoid glycosides and antioxidant activities across different cultivation ages and harvest [...] Read more.
Gentiana species are widely used in traditional and modern medicine, and Gentiana siphonantha is an important medicinal representative. To evaluate the quality characteristics of cultivated G. siphonantha roots, the accumulation patterns of iridoid glycosides and antioxidant activities across different cultivation ages and harvest months were investigated. Five major iridoid glycosides were quantified, and antioxidant capacity was assessed through DPPH, ABTS, and FRAP assays. Quality was subsequently multidimensionally evaluated using principal component analysis (PCA), orthogonal partial least squares–discriminant analysis (OPLS-DA), membership function analysis, and entropy weight–TOPSIS analysis, and the relationship between iridoid glycoside content and antioxidant activity was analyzed. Results showed that 3-year-old cultivated roots had the highest total iridoid glycoside content (134.60 mg·g−1 DW), indicating the optimal cultivation age. Peak glycoside accumulation occurred in 4-year-old plants harvested in June–July, identifying this period as the optimal harvest time, as supported by multivariate statistical and comprehensive evaluation. Antioxidant activity increased with cultivation age, with samples collected in June or August showing higher capacities, and it was positively correlated with total iridoid glycoside content, particularly with FRAP (p < 0.05). In conclusion, cultivated G. siphonantha exhibits stable quality and favorable antioxidant activity, providing a basis for standardized cultivation, quality evaluation, and rational utilization. Full article
(This article belongs to the Section Analytical Chemistry)
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21 pages, 4628 KB  
Article
Effect of Popping and Steam Cooking on Total Ferulic Acid, Phenolic and Flavonoid Contents, and Antioxidant Properties of Sukhothai Fragrant Black Rice
by Thayada Phimphilai, Onsaya Kerdto, Kajorndaj Phimphilai, Phronpawee Srichomphoo, Wachiraporn Tipsuwan, Pornpailin Suwanpitak, Yanping Zhong and Somdet Srichairatanakool
Foods 2026, 15(2), 320; https://doi.org/10.3390/foods15020320 - 15 Jan 2026
Viewed by 181
Abstract
This study investigated the effects of thermal processing and extraction solvents on the phytochemical composition, antioxidant potential, and cytotoxic activity of Sukhothai fragrant rice (Oryza sativa L.). Rice subjected to three processing methods, unprocessed (raw), popped/puffed and steam-cooked, was extracted using hot [...] Read more.
This study investigated the effects of thermal processing and extraction solvents on the phytochemical composition, antioxidant potential, and cytotoxic activity of Sukhothai fragrant rice (Oryza sativa L.). Rice subjected to three processing methods, unprocessed (raw), popped/puffed and steam-cooked, was extracted using hot water or 70% (v/v) ethanol, yielding six extracts. Trans-ferulic acid, γ-oryzanol and anthocyanins were quantified using HPLC-DAD and HPLC-ESI-MS, while total phenolic and flavonoid contents, and antioxidant activities were evaluated using Folin–Ciocalteu, aluminium chloride, DPPH and ABTS assays. Cytotoxicity was assessed in Huh7 hepatocellular carcinoma cells. Water extracts consistently produced higher yields and contained greater total phenolic, flavonoid and anthocyanin contents, resulting in stronger antioxidant activity. Unprocessed rice water extract exhibited the highest trans-ferulic acid recovery and antioxidant capacity. Thermal processing, particularly steamed cooking, markedly reduced phytochemical contents, likely due to heat-induced degradation. In contrast, ethanolic extracts yielded lower quantities but higher concentrations of less polar bioactive compounds and exhibited greater cytotoxic effects. Overall, minimal thermal processing combined with aqueous extraction best preserved antioxidant compounds, while ethanolic extraction enhanced biological potency. These findings highlight the importance of processing intensity and solvent polarity in optimizing the nutraceutical and functional potential of black rice. Full article
(This article belongs to the Special Issue Health Benefits of Bioactive Compounds from Vegetable Sources)
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17 pages, 672 KB  
Article
Unlocking the Antioxidant Potential of Pigeon Peas (Cajanus cajan L.) via Wild Fermentation and Extraction Optimization
by Tamara Machinjili, Chikondi Maluwa, Chawanluk Raungsri, Hataichanok Chuljerm, Pavalee Chompoorat Tridtitanakiat, Elsa Maria Salvador and Kanokwan Kulprachakarn
Foods 2026, 15(2), 310; https://doi.org/10.3390/foods15020310 - 15 Jan 2026
Viewed by 512
Abstract
Oxidative stress contributes significantly to chronic disease burden, necessitating identification of accessible dietary antioxidant sources. Pigeon peas (Cajanus cajan L.) contain substantial bioactive compounds, yet most exist in bound forms with limited bioavailability. This study evaluated wild fermentation combined with systematic extraction [...] Read more.
Oxidative stress contributes significantly to chronic disease burden, necessitating identification of accessible dietary antioxidant sources. Pigeon peas (Cajanus cajan L.) contain substantial bioactive compounds, yet most exist in bound forms with limited bioavailability. This study evaluated wild fermentation combined with systematic extraction optimization to enhance antioxidant recovery from pigeon peas. Seeds underwent wild fermentation in brine solution, followed by extraction under varying conditions (seven solvent systems, three temperatures, and three-time durations). Multiple complementary assays assessed antioxidant capacity (total phenolic content, DPPH radical scavenging, ferric reducing power, and ABTS activity). Fermentation substantially improved antioxidant properties across all parameters, with particularly pronounced effects on radical scavenging activities. Extraction optimization identified 70% methanol at 40 °C for 24 h as optimal, demonstrating marked improvements over conventional protocols. Strong intercorrelations among assays confirmed coordinated enhancement of multiple antioxidant mechanisms rather than isolated changes. The findings demonstrate that both biotechnological processing and analytical methodology critically influence antioxidant characterization in pigeon peas. This integrated approach offers practical guidance for developing antioxidant-rich functional foods, particularly relevant for resource-limited settings where pigeon peas serve as dietary staples. The study establishes foundation for translating fermentation technology into nutritional interventions, though further research addressing bioavailability, microbiological characterization, and bioactive compound identification remains essential. Full article
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14 pages, 2076 KB  
Article
EjMYB15 Improves Cold Tolerance of Postharvest Loquat Fruit via Upregulating Antioxidant Enzyme Genes
by Weiqi Liang, Jiahui Wan, Jing Lin, Yanting Wu, Wenbing Su and Zhongqi Fan
Foods 2026, 15(2), 301; https://doi.org/10.3390/foods15020301 - 14 Jan 2026
Viewed by 202
Abstract
As cold-sensitive fruits, loquats easily develop chilling injury (CI) during cold storage, which leads to quality deterioration and economic losses. Our prior research indicated that exogenous melatonin (MT) treatment can mitigate CI in postharvest loquats by regulating reactive oxygen species (ROS) metabolism, but [...] Read more.
As cold-sensitive fruits, loquats easily develop chilling injury (CI) during cold storage, which leads to quality deterioration and economic losses. Our prior research indicated that exogenous melatonin (MT) treatment can mitigate CI in postharvest loquats by regulating reactive oxygen species (ROS) metabolism, but the underlying molecular mechanism remains unclear. The primary objective of this study is to decipher the molecular regulatory pathway by which MT alleviates CI in postharvest loquats, focusing on the role of MYB transcription factors (TFs) in modulating antioxidant enzyme genes. Here, MT treatment remarkably reduced CI severity in loquat fruits, as reflected by lower CI index, reduced cell membrane permeability, decreased firmness, lower a* and b* values, and higher L* value, compared with the control group. Moreover, a cold-induced MYB TF, designated EjMYB15, was identified. Compared to non-treated fruits, the expression level of EjMYB15 was maintained at higher levels in MT-treated loquats. Subcellular localization and transactivation assays demonstrated that EjMYB15 is a nuclear-localized transcriptional activator. Electrophoretic mobility shift assay (EMSA) and dual-luciferase reporter (DLR) assays showed that EjMYB15 binds the MYB-binding sites (MBS) in the promoters of four antioxidant enzyme genes (EjCAT1, EjCAT2, EjGST1, and EjGST2), thereby activating their transcription. Taken together, these findings indicate that EjMYB15 positively regulates cold tolerance of loquat fruits by improving ROS scavenging capacity. These results elucidate the regulatory pathway by which MYB TFs mitigate CI and provide new theoretical support for the application of MT in alleviating CI in postharvest fruits. Full article
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20 pages, 828 KB  
Article
Antioxidant and Aromatic Properties of Aqueous Extracts of Pleurotus nebrodensis as Potential Food Ingredients
by Fortunato Cirlincione, Francesca Vurro, Alexandra-Mihaela Ailoaiei, Saba Shahrivari-Baviloliaei, Graziana Difonzo, Agnieszka Viapiana, Alina Plenis, Antonella Pasqualone and Maria Letizia Gargano
Foods 2026, 15(2), 296; https://doi.org/10.3390/foods15020296 - 14 Jan 2026
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Abstract
Pleurotus nebrodensis has raised the interest of the food and nutraceutical industry due to its valuable organoleptic characteristics coupled with antibacterial and antitumor properties. Given this interest, this study aimed to identify effective, cheap, and eco-friendly technologies to prepare extracts able to convey [...] Read more.
Pleurotus nebrodensis has raised the interest of the food and nutraceutical industry due to its valuable organoleptic characteristics coupled with antibacterial and antitumor properties. Given this interest, this study aimed to identify effective, cheap, and eco-friendly technologies to prepare extracts able to convey the bioactive compounds while retaining the typical mushroom aroma. Two aqueous extracts were prepared based on a freeze–thaw (FT) and ultrasound-assisted (UA) method. The extracts, both in liquid and lyophilized form, were analyzed by HPLC to determine the phenolic compounds. Moreover, the volatile organic compounds, total phenolics, total flavonoids, total phenolic acids, procyanidins, and ascorbic acid were determined, while the antioxidant activity was assessed by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS radical scavenging activity, ferric-reducing/antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) assays. The UA extraction showed significantly higher (p < 0.05) phenolics (5.05 vs. 4.02 µg/g DW) and flavonoids (0.74 vs. 0.23 µg/g DW) but lower procyanidins (12.33 vs. 15.93 µg/g DW) and ascorbic acid (6.23 vs. 7.02 µg/g DW) than the FT extracts, resulting in lower antioxidant activity. Among the phenolic constituents, gallic acid was found to be the most abundant in all P. nebrodensis extracts. Regarding aroma, FT more effectively preserved volatile alcohols and aldehydes—particularly 1-octen-3-ol and hexanal—while UA led to greater volatile losses. These results highlight that the extraction method significantly affects both antioxidant composition and volatile integrity, with implications for designing P. nebrodensis-based food ingredients. Full article
(This article belongs to the Section Plant Foods)
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