Contribution of organic acids to α-terpinene antioxidant activity

Novel assaying method for the accurate and rapid analysis of antioxidant total capacity based on hexachloroiridate(IV)

We introduce a novel method, namely IrRAC, for assessing total antioxidant capacity utilizing the single electron oxidant hexachloroiridate(IV). This method leverages the 488 nm absorption band of [IrCl6]2- largely reducing interferences from antioxidants and their oxidation products. [IrCl6]2- is stable 6 h in phosphate-buffered saline (PBS) ensuring consistent and reproducible absorbance readings and rendering spectrophotometric determinations under physiological neutrality. Individual assessments of 23 antioxidants reveal a linear correlation between decreasing absorbance and increasing antioxidant concentration. When the IrRAC assay was compared with several established water-based methods, strong correlations were found. Importantly, [IrCl6]2- shows a minimal oxidation of non-antioxidative substances. Moreover, IrRAC performs well with synthetic antioxidant mixtures and real samples, highlighting that the nature of antioxidants dominates the assay without much disturbance. Commercial availability of K2[IrCl6] eliminates the need of pretreatment of the oxidant. Undoubtedly, the new method confers a compelling and cost-effective alternative to the existing electron transfer-based methodologies.

Microencapsulation of phenolic compounds extracted from soybean seed coats by spray-drying

This study aimed to characterize and microencapsulate soybean seed coats phenolic compounds by spray-drying, evaluating physicochemical properties and storage stability. Different extraction methodologies were used to obtain crude extract (SCE), ethyl acetate fraction, water fraction, and bound phenolic extract. Extraction yield, total phenolic and flavonoid contents, and antioxidant capacity were determined. HPLC-electrospray ionization source-MS/MS analysis was performed on SCE. Microencapsulation by spray-drying of SCE incorporating 10%, 20%, and 30% maltodextrin (MD) was carried out. Drying yield (DY), encapsulation efficiency (EE), moisture, morphology and particle size, dry, and aqueous storage stability were evaluated on the microcapsules. SCE had 7.79 g/100 g polyphenolic compounds (mainly isoflavones and phenolic acids) with antioxidant activity. Purification process by solvent partitioning allowed an increase of phenolic content and antioxidant activity. Microcapsules with 30% MD exhibited the highest DY, EE, and stability. Microencapsulated polyphenolic compounds from soybean seed coats can be used as functional ingredients in food products. PRACTICAL APPLICATION: Soybean seed coat is a usually discarded agro-industrial by-product, which presents antioxidant compounds of interest to human health. These compounds are prone to oxidation due to their chemical structure; therefore, microencapsulation is a viable and reproducible solution to overcome stability-related limitations. Microencapsulation of soybean seed coats polyphenols is an alternative which protects and extends the stability of phenolic compounds that could be potentially incorporated into food products as a natural additive with antioxidant properties.

In Vitro Bioactivities of Commonly Consumed Cereal, Vegetable, and Legume Seeds as Related to Their Bioactive Components: An Untargeted Metabolomics Approach Using UHPLC-QTOF-MS2

We conducted a comprehensive evaluation of the antioxidant, anti-obesity, anti-diabetic, and anti-glycation activities associated with the consumption of broccoli, red cabbage, alfalfa, and buckwheat seeds. Additionally, we explored the relationship between these biological activities and the profiles of amino acids, polyphenols, and organic acids identified in the seeds. Our findings demonstrated that red cabbage, broccoli, and buckwheat extracts exhibited significantly higher antioxidant potential compared to the alfalfa extract. Moreover, buckwheat displayed the most significant capacity for inhibiting alpha-glucosidase. Remarkably, broccoli and red cabbage demonstrated substantial anti-glycation and lipase inhibitory potentials. We identified the presence of amino acids, polyphenols, and organic acids in the extracts through untargeted metabolomics analysis. Correlation analysis revealed that pyroglutamic acid positively correlated with all the investigated functional properties. Most polyphenols made positive contributions to the functional properties, with the exception of ferulic acid, which displayed a negative correlation with all tested biological activities. Furthermore, gluconic acid and arabinonic acid among the organic acids identified displayed a positive correlation with all the functional properties. These results strongly support the anti-diabetic, anti-obesity, and anti-glycation potential of red cabbage, broccoli, and buckwheat seeds.

The Synergy between Glutathione and Phenols-Phenolic Antioxidants Repair Glutathione: Closing the Virtuous Circle-A Theoretical Insight

Glutathione (GSH) and phenols are well-known antioxidants, and previous research has suggested that their combination can enhance antioxidant activity. In this study, we used Quantum Chemistry and computational kinetics to investigate how this synergy occurs and elucidate the underlying reaction mechanisms. Our results showed that phenolic antioxidants could repair GSH through sequential proton loss electron transfer (SPLET) in aqueous media, with rate constants ranging from 3.21 × 10⁶ M^-1 s^-1 for catechol to 6.65 × 10⁸ M^-1 s^-1 for piceatannol, and through proton-coupled electron transfer (PCET) in lipid media with rate constants ranging from 8.64 × 10⁶ M^-1 s^-1 for catechol to 5.53 × 10⁷ M^-1 s^-1 for piceatannol. Previously it was found that superoxide radical anion (O₂^•-) can repair phenols, thereby completing the synergistic circle. These findings shed light on the mechanism underlying the beneficial effects of combining GSH and phenols as antioxidants.

Chinese Traditional Pear Paste: Physicochemical Properties, Antioxidant Activities and Quality Evaluation

As a traditional folk medicine, pear paste has important nutritional and health effects. The physicochemical properties and antioxidant activities of pear pastes prepared from 23 different cultivars were investigated, including color parameters ( L*, a*, b* and h°), transmittance, pH, titratable acidity (TA), soluble sugar content, total phenolics content (TPC), total flavonoids content (TFC), DPPH and ^•OH radical scavenging activity (RSA), and ferric reducing antioxidant power (FRAP). It was demonstrated that the physicochemical properties and antioxidant activities of pear pastes from various cultivars differed significantly. Pear cultivars of "Mantianhong", "Xiangshui" and "Anli" possessing higher TPC and TFC exhibited excellent antioxidant activity determined by DPPH RSA, ^•OH RSA and FRAP, while the lowest TPC and TFC was observed for the cultivars of "Xueqing", "Nansui", "Hongxiangsu", and "Xinli No. 7", which also demonstrated the poor antioxidant activity. Multivariate analyses, including factor and cluster analysis, were used for the quality evaluation and separation of pear pastes based on their physicochemical and antioxidant properties. Factor analysis reduced the above thirteen parameters to final four effective ones, i.e. DPPH RSA, color b*, FRAP and TA, and subsequently these four parameters were used to construct the comprehensive evaluation prediction model for evaluating the quality of pear pastes. The pear pastes could be separated into three clusters and differentiated for the diverse of pear cultivars via cluster analysis. Consistently, "Mantianhong", "Xiangshui" and "Anli" pear with higher quality clustered into one group, in contrast, "Xueqing", "Nansui", "Hongxiangsu", and "Xinli No. 7" with lower quality clustered into the other group. It provided a theoretical method to evaluate the quality of pear paste and may help the fruit processing industry select the more suitable pear cultivars for pear paste making.

Assessment of the antioxidant, antimicrobial and antibiofilm activities of essential oils for potential application of active chitosan films in food preservation

In the food industry, the development of microbial biofilms is a serious problem that leads to the contamination and deterioration of food products. To overcome that, our aim consists of searching for natural antimicrobial and non-toxic compounds (essential oils EOs), which might be used alone or adsorbed on natural biopolymer films (chitosan). In this work, the antioxidant activity of eight EOs was evaluated by DPPH radical-scavenging method while their antibacterial activity was determined by diffusion on agar and microdilution methods. Among all tested EOs, Eugenia caryophyllus, Cinnamomum zeylanicum Blume and Thymus satureioides Cosson showed high antioxidant activities at the concentration of 25.6 mg/mL, with respective values of (86.26%, 81.75%, and 76%), and strong antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Enterococcus hirae, with (MIC) values ≤ 4 µL/mL. At the concentration of 1 µL/mL, these EOs tested alone, showed values of antibiofilm-forming activity ranging from 79.43 to 99.33% and from 44.18 to 94.17%, when they are adsorbed onto chitosan film. These promising results confirm that these three EOs have a good potential for an eventual application in the food industry, as antimicrobial and antioxidant agents, or as active biodegradable food packaging, if combined with chitosan.

Endophytic fungi and their bioactive secondary metabolites in medicinal leguminosae plants: Nearly untapped medical resources

There are many species of Chinese traditional leguminosae family plants that are well known for their medicinal applications, such as Astragalus membranaceus, Catsia tora, Glycyrrhiza uralensis, Sophora flavescens and Albacia acacia. Their unique bioactive composition and internal phenological environment contribute to the formation of specific and unique endophytic fungal communities, which are important resources for new compounds used in a variety of pharmacological activities. Nonetheless, they have not been systematically studied. In the last decade, nearly 64 genera and thousands of species of endophytic fungi have been discovered from leguminosae plants, as well as 138 secondary metabolites (with 34 new compounds) including flavonoid, alkaloids, phenol, anthraquinone, macrolide, terpenoid, phytohormone and many more. They were shown to have diverse applications and benefits, such as antibacterial, antitumor, antioxidative, immunoregulatory and neuroprotective properties. Here, we provide a summarized overview with the aim of raising awareness of endophytic fungi from medicinal leguminosae plants and providing a comprehensive review of the discoveries of new natural products that may be of medicinal and pharmaceutical importance.

Synergistic Antioxidant Activity and Enhanced Stability of Curcumin Encapsulated in Vegetal Oil-Based Microemulsion and Gel Microemulsions

Curcumin, due to its antioxidant, antibacterial, anti-inflammatory, and antitumoral activity, has attracted huge attention in applications in many fields such as pharmacy, medicine, nutrition, cosmetics, and biotechnology. The stability of curcumin-based products and preservation of antioxidant properties are still challenges in practical applications. Stability and antioxidant properties were studied for curcumin encapsulated in O/W microemulsion systems and three related gel microemulsions. Only biodegradable and biocompatible ingredients were used for carriers: grape seed oil as oily phase, Tween 80, and Plurol^® Diisostearique CG as a surfactant mix, and ethanol as a co-solvent. For the gel microemulsions, water-soluble polymers, namely Carbopol^® 980 NF, chitosan, and sodium hyaluronate were used. The influence of UVC irradiation and heat treatment on the degradation kinetics of curcumin in the formulations was studied. Because of the antioxidant character of the microemulsion oily phase, the possibility of a synergistic effect between grape seed oil and curcumin was explored. In this study, the high efficiency of the studied drug delivery systems to ensure protection from external degradative factors was confirmed. Also, the influence of the encapsulation in microemulsion and derived gel microemulsion systems on the antioxidant capacity curcumin was studied, and a synergistic effect with vegetal oil was demonstrated.

Composition analysis and antioxidant activity evaluation of a high purity oligomeric procyanidin prepared from sea buckthorn by a green method

Procyanidin is an important polyphenol for its health-promoting properties, however, the study of procyanidin in sea buckthorn was limited. In this paper, sea buckthorn procyanidin (SBP) was obtained through a green isolation and enrichment technique with an extraction rate and purity of 9.1% and 91.5%. The structure of SBP was analyzed using Ultraviolet–visible spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FT-IR), and liquid chromatography-mass spectrometry (LC-MS/MS). The results show that SBP is an oligomeric procyanidin, mainly composed of (−)-epicatechin gallate, procyanidin B, (+)-gallocatechin-(+)-catechin, and (+)-gallocatechin dimer. SBP showed superior scavenging capacity on free radicals. Furthermore, the cleaning rate of the ABTS radical was 4.8 times higher than vitamin C at the same concentration. Moreover, SBP combined with vitamin C presented potent synergistic antioxidants with combined index values below 0.3 with concentration rates from 5:5 to 2:8. SBP also provided significant protection against oxidative stress caused by hydrogen peroxide (H₂O₂) on RAW264.7 cells. These findings prove the potential of SBP as a natural antioxidant in food additives and support the in-depth development of sea buckthorn resources.

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A green method for the extraction of procyanidin was proposed.

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An oligomeric procyanidin in sea buckthorn was identified for the first time.

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SBP combined with VC exerted strong synergistic antioxidant.

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SBP provided protection of macrophages against oxidative damage.

Evaluation of easy-removing antioxidant films of chitosan with Melaleuca alternifolia essential oil

Chitosan - tea tree essential oil (TTEO) films were obtained as a new biodegradable material. Malic acid or lactic acid solvents were evaluated to obtain easy-removing films. The microstructure by SEM and FT-IR, the thermal properties by TGA/DSC, the mechanical properties, the water vapor permeability, the antioxidant (DPPH^• and ABTS^•+) activity and the optical properties of the formulated films were evaluated. A complete dissolution of the film in water was obtained. The elongation to break was higher in the films with malic acid (145.88-317.33%), comparing with those with lactic acid (25.54-44.08%). Chitosan film obtained in malic acid with TTEO showed the highest antioxidant activity. The colour and transparency of the samples did not suffer significant variations by TTEO addition. Films showed good UV-barrier properties, with a slightly improvement by TTEO addition. The films obtained showed a great potential for food packaging applications.

Metabolite profiles and antidiabetic activity of the green beans of Luwak (civet) coffees

Metabolite profiles of green beans (the caged and the wild) Luwak (civet) coffees were evaluated by NMR techniques combined with chemometrics. The bioactivities of the green coffee beans were examined with antioxidant tests and an alpha-glucosidase inhibitory assay. Both are invitro tests related to the antidiabetic properties. Our results showed the civet coffees possessed unique metabolomes and were different from the regular arabica coffee. Both civet coffees were characterized by higher concentrations of alanine, citrate, lactate, malate, and trigonelline. Lactate and lipids were found as the most important compounds discriminating the caged civet coffee from the wild civet coffee. Bioactivity assays exhibited the antidiabetic activities of the civet coffees were better than the activity of the regular coffee. These results suggested that the civet coffees are promising functional foods reducing the diabetes risk. It is the first report evaluating metabolite profiles of both civet coffees using ¹H NMR-based metabolomics.

Chemistry, Safety, and Challenges of the Use of Organic Acids and Their Derivative Salts in Meat Preservation

Meat industries are constantly facing new waves of changes in the consumer’s nutritional trends, food safety, and quality requirements and legislations leading to an increase in interest for meat biopreservation to respond to all of these modern socioeconomic demands. Hence, to replace synthetic and/or expensive additives, new technologies in preserving meat products from microbial contamination have been established. In this context, organic acids and their salts have been considered as the most popular examples of preservatives that offer several advantages to be applied in meat industry. Here, characteristics of organic acids/salts commonly used in meat preservation were described based on the published literature. Moreover, after outlining the challenges and advantages of their use in meat industry, their current applications as meat preservatives on various meat type matrices such as beef, pork, sheep, and poultry were quite exposed based on previous and recent research works. Then, different application types were highlighted. Besides, some potent synergistic approaches based on several combinations of organic acids/salts with different existing preservative techniques are reported with an emphasised discussion of their application as possible solution tools to mainly overcome some problems linked to organic acids/salts when used solely, thus contributing to ensure the overall safety and improve the quality of meats. Finally, despite their usefulness in meat preservation, organic acids/salts may possess detrimental traits. In this context, a detailed discussion on their limits of use in meat products was provided in the last section of this paper.

Antioxidant Phytochemicals in Pulses and their Relation to Human Health: A Review

Pulses are a staple food cultivated since ancient times, which play an important role in the human diet. From a nutritional point of view, pulses are very interesting foods as they are rich in proteins, carbohydrates and dietary fibre. Dietary antioxidants are a complex mixture of hydrophilic and lipophilic compounds usually present in foods of plant origin, including pulses. In the present study, the phytochemical composition of selected pulses (common beans, fava beans, lentils, chickpeas, peas and lupins) has been reviewed in terms of their content of antioxidant compounds. The content of hydrosoluble antioxidants (organic acids, phenolic compounds), liposoluble antioxidants (tocopherols, carotenoids) and other compounds which exert antioxidant properties, such as dietary fibre and minerals (zinc, selenium), has been studied, reporting that pulses are an interesting source of these compounds, which have important health benefits, including a preventing role in cardiovascular diseases, anticarcinogenic or neuroprotective properties. It is important to take into account that pulses are not usually consumed raw, but they must be processed before consumption in order to improve their nutritional quality and their palatability, therefore, the effect of different technological and heat treatments (germination, cooking, boiling, extrusion) on the antioxidant compounds present in pulses has been also reviewed. In this regard, it has been observed that as a consequence of processing, the content of phytochemicals with antioxidant properties is usually decreased, but processed pulses maintain relevant amounts of these compounds, preserving their beneficial health effect.

Artemisia annua, a Traditional Plant Brought to Light

Traditional remedies have been used for thousand years for the prevention and treatment of infectious diseases, particularly in developing countries. Of growing interest, the plant Artemisia annua, known for its malarial properties, has been studied for its numerous biological activities including metabolic, anti-tumor, anti-microbial and immunomodulatory properties. Artemisia annua is very rich in secondary metabolites such as monoterpenes, sesquiterpenes and phenolic compounds, of which the biological properties have been extensively studied. The purpose of this review is to gather and describe the data concerning the main chemical components produced by Artemisia annua and to describe the state of the art about the biological activities reported for this plant and its compounds beyond malaria.