Preparation, purification, and identification of novel antioxidant peptides derived from Gracilariopsis lemaneiformis protein hydrolysates

Identification and molecular docking of novel antioxidant peptides from Candida utilis

The current trend is the promotion of antioxidants that are beneficial for both health and the environment. Candida utilis have garnered considerable attention due to their commendable attributes such as non-toxicity and the ability to thrive in waste. Therefore, Candida utilis was used as raw material to isolate and identify new antioxidant peptides by employing methods such as ultrafiltration, DEAE Sepharose Fast Flow, and liquid chromatography-tandem mass spectrometry. The antioxidant mechanism of peptides was investigated by molecular docking. The properties of antioxidant peptides were evaluated using a variety of computational tools. This study resulted in the identification of two novel antioxidant peptides. According to the molecular docking results, the antioxidant mechanism of Candida utilis peptides operates by obstructing the entry to the myeloperoxidase activity cavity. The (-) CDOCKER energy of antioxidant peptides was 6.2 and 6.1 kcal/mol, respectively. Additionally, computer predictions indicated that antioxidant peptides exhibited non-toxicity and poor solubility.

Identification and evaluation of antioxidant peptides from highland barley distiller's grains protein hydrolysate assisted by molecular docking

The aim of this study was to identify antioxidant peptides from highland barley distiller's grains and evaluate their antioxidant activity in vitro. The results showed that the enzymatic hydrolysate of highland barley distiller's grains prepared by ultrasonic assisted alkaline protease had antioxidant properties, aromatic amino acids accounted for 61.48% of the total free amino acids and acidic/basic amino acids accounted for 40.82% of the total hydrolyzed amino acids in enzymatic hydrolysate. Ultrafiltration component F1 (Mw < 1 kDa) had the highest DPPH, ABTS and hydroxyl radical scavenging activity and ferrous ion chelating activity, which were 93.92%, 69.59%, 50.27% and 0.71, respectively. Four peptides were identified and screened by LC-MS/MS and the P1 (SWDNFFR) and P4 (WDWVGGR) showed high scavenging ability of DPPH free radical (70.23%-62.84%) and ABTS free radical (30.87%-60.54%). Molecular docking showed that P1 and P4 formed multiple hydrogen bonds with central residues of MPO.

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.

Novel antioxidant peptides in fermented pork sausage: Purification, characterization, and cytoprotective functions on Caco-2 cells

In this study, crude peptides from fermented sausages inoculated with Lactobacillus plantarum CD101 and Staphylococcus simulans NJ201 were initially separated by ultrafiltration and molecular-sieve chromatography. The obtained fractions with high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric-reducing antioxidant power values (MWCO-1 and fraction A) were used in Caco-2 cells to evaluate their cytoprotective effect on oxidative damage triggered by H₂O₂. MWCO-1 and A showed slight cytotoxicity. Increased glutathione peroxidase, catalase, and superoxide dismutase activities and decreased malondialdehyde content were observed in the peptide-treated groups. Fraction A was further purified using reversed high-performance liquid chromatography. Eighty potential antioxidant peptides were identified by liquid chromatography with tandem mass spectrometry, and fourteen antioxidant peptides were synthesized. SDEEVEH and FAGDDAPR showed strong DPPH radical scavenging activity, whereas ALELDSNLYR and QEYDESGPSIVHR presented strong ABTS^+· scavenging activity. These peptides might have great potential for food and pharmacological applications.

Comparative assessment of Cucurbita moschata seed polypeptides toward the protection of human skin cells against oxidative stress-induced aging

Skin aging has attracted much attention among the current aging population of society. The seeds of Cucurbita moschata possess a variety of potential biological activities as a healthy diet. However, limited information is available on the skin-antiaging properties of C. moschata seed protein and its hydrolysate. Herein, we developed a novel strategy for protecting human skin cells against oxidative stress-induced aging by C. moschata seed polypeptides. C. moschata seed polypeptides (CSPs) with different molecular weight distributions were successfully prepared by controlling the protease hydrolysis time. The proportions of < 1,000 Da polypeptides of P-1, P-2, and P-3 were 0.11, 20.26, and 92.72%, respectively. P-3 contained the highest proportion of polypeptides of size < 1,000 Da, which was observed to promote human skin fibroblast (HSF) growth by MTT assay, cell cycle, and morphology. P-3 has an efficient repair effect on the H₂O₂-induced aging of HSF cells. To explain this phenomenon, cell lifespan, intracellular ROS level, superoxide dismutase (SOD) activity, and glutathione (GSH) content were investigated to reveal the interactions between P-3 and antiaging. With the increase in P-3 concentration, the ROS level significantly decreased, and the SOD activity and GSH content significantly increased in H₂O₂-induced HSF cells. These findings indicated that CSPs have the potential to inhibit skin aging, which could be advantageous in the health industry for providing personal care.