Extraction and Characterization of Antioxidant Peptides from Fruit Residues

Screening of wine industry by-products as a source of bioactive peptides: Fractionation, in vitro antihypertensive activity and peptidomics analysis

The suitability of grape pomace and wine lees protein isolates as a source of bioactive peptides with antihypertensive activity was evaluated through hydrolysis with different proteolytic enzymes. Peptides were initially fractionated by ultrafiltration. The determination of the angiotensin-converting enzyme inhibitory activity evidenced that hydrolysates of Flavourzyme from grape pomace and of Alcalase from wine lees showed higher bioactivities. The fractions <3 kDa of these hydrolysates were further purified by semipreparative reversed-phase liquid chromatography. The peptidome of the fractions showing the highest angiotensin-converting enzyme inhibitory activities was characterised by nano-liquid chromatography-Orbitrap tandem mass spectrometry. The analysis of the chemical features of identified peptides like hydrophobicity and the frequency of angiotensin-converting enzyme inhibitory-active di-, tri- and tetrapeptide motives was associated with the antihypertensive activity. The peptides GPCKFYYGK, FSSFYYGK and YYGKF, among others, appear to contribute significantly to the antihypertensive activity of the hydrolysates.

Effect of sheep placenta extract on D-galactose-induced aging mouse

Introduction

Sheep placenta extract (SPE) is a representative traditional medicinal substance that exhibits multiple experimentally validated physiological properties, including anti-aging effects, wound healing acceleration, antioxidant activity, and anti-inflammatory mechanisms. However, the mechanism by which SPE influences the delay of aging is still not yet clear.

Methods

Exploring the effects of sheep placenta extract on D-gal induced senescence in a mouse model of aging by macrogenomics and metabolomics.

Results

In the serum of aging mice treated with SPE, the levels of antioxidant function such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were notably higher compared to those in the blank group, whereas malondialdehyde (MDA) levels decreased. We revealed that SPE alleviated the changes in gut microbiota caused by aging in mice, with a significant decrease in the Firmicutes/Bacteroidetes (F/B) ratio in the gut. Furthermore, Akkermansia muciniphila (A. muciniphila), which is known for its regulating immune response and potential anti-aging effects, showed a significant increase of 1177.94%. The analysis of UHPLC-QE-MS combined with orthogonal partial least squares discriminant analysis (OPLS-DA) screening of differential metabolites in mouse serum metabolic profiles revealed a significant upregulation of cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and triptolide in serum metabolites, following SPE treatment, which are commonly believed to have immunosuppressive, anti-inflammatory, anti-proliferative, and anti-tumor effects.

Discussion

The role of SPE in ameliorating aging may be associated with the increased abundance of A. muciniphila in the gut microbiota and the accumulation of two metabolites, EPA and triptolide, in the serum.

The Extraction Using Deep Eutectic Solvents and Evaluation of Tea Saponin

Tea saponins have high surface-active and biological activities and are widely used in chemicals, food, pharmaceuticals, and pesticides. Tea saponins are usually extracted using ethanol or water, but both methods have their disadvantages, including a negative impact on the environment, high energy consumption, and low purity. In this study, we explored an effective process for extracting tea saponins from tea meal using deep eutectic solvents combined with ultrasonic extraction and enzymatic techniques. The experimental results showed that a high extraction efficiency of 20.93 ± 0.48% could be achieved in 20 min using an ultrasonic power of 40% and a binary DES consisting of betaine and ethylene glycol (with a molar ratio of 1:3) at a material-liquid ratio of 1:35 and that the purity of the tea saponins after purification by a large-pore adsorption resin reached 95.94%, which was higher than that of commercially available standard tea saponin samples. In addition, the extracted tea saponins were evaluated for their antioxidant and bacteriostatic activities using chemical and biological methods; the results showed that the tea saponins extracted using these methods possessed antioxidant properties and displayed significant antibacterial activity. Therefore, the present study developed a method for using deep eutectic solvents as an environmentally friendly technological solution for obtaining high-purity tea saponins from tea meal oil. This is expected to replace the current organic solvent and water extraction process and has great potential for industrial development and a number of possible applications.

Unlocking the Therapeutic Potential of a Manila Clam-Derived Antioxidant Peptide: Insights into Mechanisms of Action and Cytoprotective Effects against Oxidative Stress

Reactive oxygen species (ROS) are implicated in various pathological conditions due to their ability to induce oxidative damage to cellular components. In this study, we investigated the antioxidant properties of a peptide isolated from the hydrolysate of Manila clam (Ruditapes philippinarum) muscle. Purification steps yielded RPTE2-2-4, exhibiting potent scavenging activities against DPPH•, HO•, and O2•-, akin to Vitamin C. Structural analysis showed that the isolated peptide, LFKKNLLTL, exhibited characteristics associated with antioxidant activity, including a short peptide length and the presence of aromatic and hydrophobic amino acid residues. Moreover, our study demonstrated the cytoprotective effects of the peptide against H2O2-induced oxidative stress in HepG2 cells. Pretreatment with the peptide resulted in a dose-dependent reduction in intracellular ROS levels and elevation of glutathione (GSH) levels, indicating its ability to modulate cellular defense mechanisms against oxidative damage. Furthermore, the peptide stimulated the expression of the cytoprotective enzyme heme oxygenase-1 (HO-1), further reinforcing its antioxidant properties. Overall, our findings highlight the potential of the Manila clam-derived peptide as a natural antioxidant agent with therapeutic implications for oxidative stress-related diseases. Further investigation into its mechanisms of action and in vivo efficacy is warranted to validate its therapeutic potential.

From microbes to molecules: a review of microbial-driven antioxidant peptide generation

Oxidative stress, arising from excess reactive oxygen species (ROS) or insufficient antioxidant defenses, can damage cellular components, such as lipids, proteins, and nucleic acids, resulting in cellular dysfunction. The relationship between oxidative stress and various health disorders has prompted investigations into potent antioxidants that counteract ROS's detrimental impacts. In this context, antioxidant peptides, composed of two to twenty amino acids, have emerged as a unique group of antioxidants and have found applications in food, nutraceuticals, and pharmaceuticals. Antioxidant peptides are sourced from natural ingredients, mainly proteins derived from foods like milk, eggs, meat, fish, and plants. These peptides can be freed from their precursor proteins through enzymatic hydrolysis, fermentation, or gastrointestinal digestion. Previously published studies focused on the origin and production methods of antioxidant peptides, describing their structure-activity relationship and the mechanisms of food-derived antioxidant peptides. Yet, the role of microorganisms hasn't been sufficiently explored, even though the production of antioxidant peptides frequently employs a variety of microorganisms, such as bacteria, fungi, and yeasts, which are recognized for producing specific proteases. This review aims to provide a comprehensive overview of microorganisms and their proteases participating in enzymatic hydrolysis and microbial fermentation to produce antioxidant peptides. This review also covers endogenous peptides originating from microorganisms. The information obtained from this review might guide the discovery of novel organisms adept at generating antioxidant peptides.

Plant-derived rennet: research progress, novel strategies for their isolation, identification, mechanism, bioactive peptide generation, and application in cheese manufacturing

Rennet, an aspartate protease found in the stomach of unweaned calves, effectively cuts the peptide bond between Phe105-Met106 in κ-casein, hydrolyzing the casein micelles to coagulate the milk and is a crucial additive in cheese production. Rennet is one of the most used enzymes of animal origin in cheese making. However, using rennet al.one is insufficient to meet the increasing demand for cheese production worldwide. Numerous studies have shown that plant rennet can be an alternative to bovine rennet and exhibit a good renneting effect. Therefore, it is crucial and urgent to find a reliable plant rennet. Based on our team's research on rennet enzymes of plant origin, such as from Dregea sinensis Hemsl. and Moringa oleifer Lam., for more than ten years, this paper reviews the relevant literature on rennet sources, isolation, identification, rennet mechanism, functional active peptide screening, and application in cheese production. In addition, it proposes the various techniques for targeted isolation and identification of rennet and efficient screening of functionally active peptides, which show excellent prospects for development.

Jamun (Syzygium cumini (L.) Skeels) Seed: A Review on Nutritional Profile, Functional Food Properties, Health-Promoting Applications, and Safety Aspects

Jamun (Syzygium cumini L. Skeels) is highly perishable with a very short shelf life, hence, jamun fruit is either consumed fresh as soon as it is harvested or converted to value-added products such as jam, wine, juice, and jellies. The processing of jamun fruit generates a large quantity of seeds as the primary waste. Jamun seeds are a rich source of macronutrients such as carbohydrates, proteins, lipids, minerals, and vitamins, thus making them an important ingredient in the food industry. The valorization of underutilized, nutritionally rich byproducts of the food processing industry has been providing new ways for unlocking their potential in the functional food industry or therapeutic food formulations. This review presents a detailed nutritional profile of jamun seeds and its potent application in the food industry as a possible functional ingredient. Along with its beneficial nutritional profile, the review also throws light upon the safety aspects associated with jamun seed consumption along with its acceptable daily intake. Safety and toxicity studies have motivated researchers and industrialists to search for possible applications in the food industry. Jamun seeds with array of nutritional benefits can be an important functional ingredient; however, further extensive research is necessary to find suitable levels of application of jamun seed in food products for harnessing its nutritional potential without affecting the products’ sensory palatability.

Comparative study of factors affecting the recovery of proteins from malt rootlets using pressurized liquids and ultrasounds

Malt rootlets (MR) are a waste from brewing with high protein content. This work proposes to study the impact of extracting parameters on the recovery of proteins and the characteristics of extracts from MR using ultrasound-assisted extraction (UAE) and pressurized liquid extraction (PLE). A Box-Behnken experimental design was employed to study the effect of extracting parameters on the protein yield, while characterization comprised the study of antioxidant properties, the identification of extracted proteins using high-resolution tandem mass spectrometry, and the evaluation of the co-extraction of phenolic compounds. Protein extraction was promoted at an ultrasounds amplitude of 68%, for 20 min at 52 °C in UAE, while adding 33% ethanol resulted in the highest yield in PLE. While UAE extracted 53 ± 5% of MR proteins, PLE reached a 73 ± 7%, using more sustainable conditions. Significant antioxidant activities were observed in the PLE extract, although undermined by gastrointestinal digestion. Proteomic analysis detected 68 proteins from Hordeum vulgare in the UAE extract and 9 in the PLE extract. Proteins in MR are very different to that from barley grains or brewer's spent grains. PLE also co-extracted phenolic compounds while this was not significant by UAE.

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PLE and UAE can extract proteins from malt rootlets, a waste from brewing.

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The use of PLE with low amounts of EtOH promoted the extraction of protein.

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PLE extracted 73% of the proteins in malt rootlets, which is 38% more than the UAE using a shorter time.

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PLE extract showed high antioxidant capacity likely due to the co-extraction of phenolic compounds.

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Extracted proteins were involved in metabolic processes and defence/stress responses.

Discovery of Antioxidant Peptides from Amphibians: A Review

In recent years, bioactive peptide drugs have attracted growing attention due to the increasing difficulty in developing new drugs with novel chemical structures. In addition, many diseases are linked to excessive oxidation in the human body. Therefore, the role of peptides with antioxidant activity in counteracting diseases related to oxidative stress is worth exploring. Amphibians are a major repository for bioactive peptides that protect the skin from biotic and abiotic stresses, such as microbial infection and radiation injury. We characterized the first amphibian- derived gene-encoded antioxidant peptides in 2008. Since then, a variety of antioxidant peptides have been detected in different amphibian species. In this work, the physicochemical properties of antioxidant peptides identified from amphibians are reviewed for the first time, particularly acquisition methods, amino acid characteristics, antioxidant mechanisms, and application prospects. This review should provide a reference for advancing the identification, structural analysis, and potential therapeutic value of natural antioxidant peptides.

Impact of the use of pressurized liquids on the extraction and functionality of proteins and bioactives from brewer's spent grain

A green methodology based on pressurized liquids (PLE) to extract proteins and obtain highly active extracts from brewer's spent grain (BSG) is proposed. Box-Behnken experimental design was employed to study the effect of extraction parameters on the protein content (PC), the total phenolic content (TPC), and the antioxidant activity of extracts. Results were compared with those obtained by conventional alkaline extraction assisted with ultrasounds (UAE). The selection of PLE conditions enabled to tailor the PC and TPC of extracts. PLE extracted 36 % more proteins than UAE. PLE extracts showed higher antioxidant, cholesterol esterase inhibition, and ACE inhibitory activities than UAE extract. HPLC-MS/MS enabled to observe that the extraction technique and experimental conditions significantly affected to the kind and amount of extracted proteins, and released peptides, and phenolic compounds. A higher ratio of hydrophobic peptides was observed in PLE extracts, which justified their higher bioactivity.

Dietary Factors and Supplements Influencing Prostate Specific-Antigen (PSA) Concentrations in Men with Prostate Cancer and Increased Cancer Risk: An Evidence Analysis Review Based on Randomized Controlled Trials

The quest for dietary patterns and supplements efficient in down-regulating prostate-specific antigen (PSA) concentrations among men with prostate cancer (PCa) or increased PCa risk has been long. Several antioxidants, including lycopene, selenium, curcumin, coenzyme Q10, phytoestrogens (including isoflavones and flavonoids), green tea catechins, cernitin, vitamins (C, E, D) and multivitamins, medicinal mushrooms (Ganoderma lucidum), fruit extracts (saw palmetto, cranberries, pomegranate), walnuts and fatty acids, as well as combined supplementations of all, have been examined in randomized controlled trials (RCTs) in humans, on the primary, secondary, and tertiary PCa prevention level. Despite the plethora of trials and the variety of examined interventions, the evidence supporting the efficacy of most dietary factors appears inadequate to recommend their use.