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969 result(s) for "total phenol content"
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Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants
Antioxidant activity is an essential aspect of oxygen-sensitive merchandise and goods, such as food and corresponding packaging, cosmetics, and biomedicine. Technical lignin has not yet been applied as a natural antioxidant, mainly due to the complex heterogeneous structure and polydispersity of lignin. This report presents antioxidant capacity studies completed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The influence of purification on lignin structure and activity was investigated. The purification procedure showed that double-fold selective extraction is the most efficient (confirmed by ultraviolet-visible (UV/Vis), Fourier transform infrared (FTIR), heteronuclear single quantum coherence (HSQC) and 31P nuclear magnetic resonance spectroscopy, size exclusion chromatography, and X-ray diffraction), resulting in fractions of very narrow polydispersity (3.2–1.6), up to four distinct absorption bands in UV/Vis spectroscopy. Due to differential scanning calorimetry measurements, the glass transition temperature increased from 123 to 185 °C for the purest fraction. Antioxidant capacity is discussed regarding the biomass source, pulping process, and degree of purification. Lignin obtained from industrial black liquor are compared with beech wood samples: antioxidant activity (DPPH inhibition) of kraft lignin fractions were 62–68%, whereas beech and spruce/pine-mixed lignin showed values of 42% and 64%, respectively. Total phenol content (TPC) of the isolated kraft lignin fractions varied between 26 and 35%, whereas beech and spruce/pine lignin were 33% and 34%, respectively. Storage decreased the TPC values but increased the DPPH inhibition.
Effect of extraction solvent on total phenol content, total flavonoid content, and antioxidant activity of Limnophila aromatica
Limnophila aromatica is commonly used as a spice and a medicinal herb in Southeast Asia. In this study, water and various concentrations (50%, 75%, and 100%) of methanol, ethanol, and acetone in water were used as solvent in the extraction of L. aromatica. The antioxidant activity, total phenolic content, and total flavonoid content of the freeze-dried L. aromatica extracts were investigated using various in vitro assays. The extract obtained by 100% ethanol showed the highest total antioxidant activity, reducing power and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity. The same extract also exhibited the highest phenolic content (40.5 mg gallic acid equivalent/g of defatted L. aromatica) and the highest flavonoid content (31.11 mg quercetin equivalent/g of defatted L. aromatica). The highest extraction yield was obtained by using 50% aqueous acetone. These results indicate that L. aromatica can be used in dietary applications with a potential to reduce oxidative stress.
Subcritical Water Extraction of Onosma mutabilis: Process Optimization and Chemical Profile of the Extracts
The aboveground and root parts of Onosma mutabilis were extracted using subcritical water and the process was optimized with response surface methodology. The composition of the extracts was determined by chromatographic methods and compared to that of conventional maceration of the plant. The optimum total phenolic contents for the aboveground part and the roots were 193.9 and 174.4 μg/g, respectively. These results were achieved at a subcritical water temperature of 150 °C, an extraction time of 180 min, and a water/plant ratio of 0.1, for both parts of the plant. Principal component analysis revealed that the roots contained mainly phenols, ketones, and diols, with the aboveground part mostly alkenes and pyrazines, whereas the extract from maceration contained mainly terpenes, esters, furans, and organic acids. The quantification of selected phenolic substances showed that subcritical water extraction compared favorably to maceration, especially with respect to pyrocatechol (1062 as compared to 10.2 μg/g) and epicatechin (1109 as compared to 23.4 μg/g). Furthermore, the roots of the plant contained twice as much of these two phenolics compared to the aboveground part. Subcritical water extraction of O. mutabilis is an environmentally friendly method that can extract selected phenolics at higher concentrations compared to maceration.
In Vitro Digestion Assessment (Standard vs. Older Adult Model) on Antioxidant Properties and Mineral Bioaccessibility of Fermented Dried Lentils and Quinoa
The growing number of older adults necessitates tailored food options that accommodate the specific diseases and nutritional deficiencies linked with ageing. This study aims to investigate the influence of age-related digestive conditions in vitro on the phenolic profile, antioxidant activity, and bioaccessibility of minerals (Ca, Fe, and Mg) in two types of unfermented, fermented, and fermented dried quinoa and lentils. Solid-state fermentation, combined with drying at 70 °C, significantly boosted the total phenolic content in Castellana and Pardina lentils from 5.05 and 6.6 to 10.5 and 7.5 mg gallic acid/g dry weight, respectively, in the bioaccessible fraction following the standard digestion model, compared to the unfermented samples. The phenolic profile post-digestion revealed elevated levels of vanillic and caffeic acids in Castellana lentils, and vanillic acid in Pardina lentils, while caffeic acids in Castellana lentils were not detected in the bioaccessible fraction. The highest antioxidant potency composite index was observed in digested fermented dried Castellana lentils, with white quinoa samples exhibiting potency above 80%. Mineral bioaccessibility was greater in fermented and fermented dried samples compared to unfermented ones. Finally, the digestive changes that occur with ageing did not significantly affect mineral bioaccessibility, but compromised the phenolic profile and antioxidant activity.
Lobularia libyca: Phytochemical Profiling, Antioxidant and Antimicrobial Activity Using In Vitro and In Silico Studies
Lobularia libyca (L. libyca) is a traditional plant that is popular for its richness in phenolic compounds and flavonoids. The aim of this study was to comprehensively investigate the phytochemical profile by liquid chromatography, electrospray ionization and tandem mass spectrometry (LC-ESI-MS), the mineral contents and the biological properties of L. libyca methanol extract. L. libyca contains significant amounts of phenolic compounds and flavonoids. Thirteen compounds classified as flavonoids were identified. L. libyca is rich in nutrients such as Na, Fe and Ca. Moreover, the methanol extract of L. libyca showed significant antioxidant activity without cytotoxic activity on HCT116 cells (human colon cancer cell line) and HepG2 cells (human hepatoma), showing an inhibition zone of 13 mm in diameter. In silico studies showed that decanoic acid ethyl ester exhibited the best fit in β-lactamase and DNA gyrase active sites; meanwhile, oleic acid showed the best fit in reductase binding sites. Thus, it can be concluded that L. libyca can serve as a beneficial nutraceutical agent, owing to its significant antioxidant and antibacterial potential and due to its richness in iron, calcium and potassium, which are essential for maintaining a healthy lifestyle.
Phytochemical Profiling, Mineral Elements, and Biological Activities of Artemisia campestris L. Grown in Algeria
Artemisia campestris L. is commonly used in folk medicine due to its antioxidant, antidiabetic, nutritional, and culinary properties. Our study assessed the total phenolics contents, antioxidant, and pharmacological activities of various organic extracts prepared from the aerial parts of Artemisia campestris, and its mineral elements and chemical profile were analyzed. ICP-OES was used to analyze the mineral profile and the LC-MS/MS analysis was used to characterize the phytochemical profiling. A series of antioxidant tests were carried out using DPPH, ABTS, beta-carotene, GOR, RP, CUPRAC, and O-Phenanthroline assays. In vitro potent inhibitory actions of A. campestris extracts were investigated to evaluate their anti-cholinesterase, anti-lipase and anti-diabetic activities. The photoprotective effect of the plant was measured by the sun protection factor. The most powerful inhibitor of α-amylase was AcPEE (IC50 = 11.79 ± 0.14 μg/mL), which also showed a significant butyrylcholinesterase inhibitory effect (IC50 = 93.50 ± 1.60 μg/mL). At IC50 = 23.16 ± 0.19 μg/mL, AcEAE showed the most powerful inhibitory effects on acetylcholinesterase. A. campestris was found to have a strong photoprotective ability, absorbing UV radiations with SPF values ranging from 26.07 ± 0.22 to 40.76 ± 0.11. The results showed that A. campestris extract has strong antioxidant activity in all the test samples except for the carotene bleaching assay. The LC/MS-MS results showed that AcDE, AcEAE, and AcBE identified 11 compounds belonging to Polyphenols Compounds. Our result also showed that A. campestris contains a high concentration of essential minerals, including macro-and micro-elements with their values close to the FAO’s recommended concentration. A. campestris has the capacity to improve pharmaceutical formulations, health, and medical research, due to its compositions and potent biological properties.
Investigating the relationships between callus browning in Isatis indigotica Fortune, total phenol content, and PPO and POD activities
Browning, as the most important problem to be solved in callus differentiation, occupies an important position in tissue culture. In this study, plant regeneration was induced using leaves from germinated Isatis indigotica Fortune seedlings and mature plants as explants. Activated carbon (AC) and a solidification agent (Phytagel) were added simultaneously to inhibit browning. We measured the total phenol content and the PPO and POD activities in callus-induced seedling leaves and mature plant leaves of different ploidy at various stages. The results demonstrated that single plant growth regulators could induce calli with higher rooting and browning rates. Despite the addition of AC and phytagel to the medium, half of the mature plant calli turned yellow and eventually died. The total phenol content and POD activity in calli from mature leaves showed significant differences within 0–4 weeks (P < 0.05) but were still higher than the biochemical parameters in calli induced from seedlings, while the PPO activity did not differ significantly (P > 0.05). Mature materials of different ploidy yielded similar results. The addition of 2 mg·L−1 BAP, 0.1 mg·L−1 NAA, and 1.5 mg·L−1 AC and solidification with 0.2% phytagel in MS medium resulted in the highest callus regeneration rate and the lowest browning rate. During dedifferentiation, the browning of the two may be associated with PPO activity and total phenol content.Key messageThe regeneration system of Isatis indigotica Fortune was optimized and the browning problem was solved. The browning of callus is related to PPO activity and the total phenol content.
Quality attributes and fatty acid, volatile and sensory profiles of “Arbequina” hydrosostainable olive oil
The use of deficit irrigation techniques on olive orchards is the main trend aiming to optimize water savings while improving functional and sensory characteristics of oils from trees under deficit irrigation techniques. The brand hydroSOStainable has been defined for crops produced under water restriction conditions. HydroSOStainable olive oils obtained under two new regulated deficit irrigation and one sustained deficit irrigation treatments in “Arbequina” olive trees were evaluated by analyzing quality parameters, antioxidant activity, total phenol content, fatty acid profile, volatile compounds, and sensory descriptors. Results showed that some of these irrigation strategies improved the phenol content at “moderate” stress levels, slightly enriched the fatty acid profile (~3.5% increased oleic acid and simultaneously decreased saturated fatty acids), and increased some key volatile compounds and also several key sensory attributes. Therefore, hydroSOStainable olive oil may be more attractive to consumers as it is environmentally friendly, has a higher content of several bioactive compounds, and has improved sensory characteristics as compared to control (fully irrigated) oils
A Systematic Study of the Antioxidant Capacity of Humic Substances against Peroxyl Radicals: Relation to Structure
Humic substances (HS) are natural supramolecular systems of high- and low-molecular-weight compounds with distinct immunomodulatory and protective properties. The key beneficial biological activity of HS is their antioxidant activity. However, systematic studies of the antioxidant activity of HS against biologically relevant peroxyl radicals are still scarce. The main objective of this work was to estimate the antioxidant capacity (AOC) of a broad set of HS widely differing in structure using an oxygen radical absorption capacity (ORAC) assay. For this purpose, 25 samples of soil, peat, coal, and aquatic HS and humic-like substances were characterized using elemental analysis and quantitative 13C solution-state NMR. The Folin–Ciocalteu method was used to quantify total phenol (TP) content in HS. The determined AOC values varied in the range of 0.31–2.56 μmol Trolox eqv. mg−1, which is close to the values for ascorbic acid and vitamin E. Forward stepwise regression was used to reveal the four main factors contributing to the AOC value of HS: atomic C/N ratio, content of O-substituted methine and methoxyl groups, and TP. The results obtained clearly demonstrate the dependence of the AOC of HS on both phenolic and non-phenolic moieties in their structure, including carbohydrate fragments.
Postharvest quality of orange fruit as influenced by salicylic acid, acetic acid, and carboxymethyl cellulose coating
In the present study, orange fruit was coated with 1 mmol L −1 salicylic acid (SA), 10 g L −1 acetic acid (AA), 5 g L −1  AA + 0.5 mmol L −1 SA, 10 g L −1  AA + 1 mmol L −1 SA, and 10 g L −1 carboxymethyl cellulose (CMC) solutions to improve the postharvest quality of orange over 35 days of storage. The weight loss, decay, TPC, TAA, and mold injury increased and the AAC decreased throughout the storage time. The control showed the highest TSS, weight loss, decay, and mold injury and the lowest TA, L *, and b * values than the treated samples. Meanwhile, CMC, SA, and 5 g L −1  AA + 0.5 mmol L −1 SA showed the highest AAC, TPC, and TAA. The loss or increasing rate of AAC, TPC, TAA, decay, and mold damage followed a first-order kinetic model in most cases. The SA samples obtained the highest sensory scores. Overall, the application of SA, AA + SA, and CMC, particularly SA can be recommended for improving the postharvest quality of orange fruit.