In this study, peptides with inhibitory activity against porcine pancreatic lipase (PPL) from the alcalase hydrolysate of seabuckthorn seed meal protein were purified by ultrafiltration and macroporous resin separation, and their structures were investigated by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and molecular docking. The peptides had good thermal and pH stability. The PPL inhibitory activity was significantly improved by adding appropriate amounts of Na⁺ and Mg²⁺ but not influenced by short-term exposure to the air. A total of 31 peptides were identified by UPLC/MS-MS, and six peptides were selected by molecular docking, whose contents in the ultrafiltration fraction with molecular mass less than 3 kDa were as follows: VR (2.90%), FR (7.40%), RDR (1.10%), APYR (1.50%), NLLHR (1.40%) and EEAASLR (1.10%), respectively. The half-maximal inhibitory concentration (IC₅₀) values of VR, FR, RDR, APYR, NLLHR and EEAASLR prepared by solid phase synthesis were 371.07, 243.07, 250.50, 350.41, 220.70, and 510.55 μg/mL, respectively. The results of molecular docking showed that each of these peptides could combine with PPL by hydrogen bonding and π-π stacking interactions. Pearson correlation analysis showed that there was a positive correlation between molecular binding energy and the PPL inhibitory activity of the peptides from seabuckthorn seed protein (R² = 0.865, P < 0.05).

The purpose of this study was to screen potential anti-inflammatory peptides from Channa argus. Toll-like receptor (TLR)2 and TLR4 were chosen as the target proteins. Virtual hydrolysis was used to select the best enzyme for obtaining bioactive peptides from C. argus proteins. Anti-inflammatory peptides were selected by the combined use of physicochemical prediction, molecular docking, and a cell model, and their mechanisms of action were elucidated. The results showed that 109 bioactive peptides obtained with papain were not toxic, from which 34 highly water-soluble peptides were selected for analysis of adsorption, distribution, metabolism, excretion and toxicity (ADMET) properties. Peptides KF, PR, NC, YR, WEL, QWWR and DEECWF exhibited high-affinity binding to TRL2 and TRL4 mainly through hydrogen bonding. These peptides were found to increase cell viability and inhibit the overproduction of nitric oxide (NO) and inflammatory factors (tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6) in lipopolysaccharide (LPS)-induced RAW264.7 cells, indicating their anti-inflammatory activity. This study revealed the interaction mechanism between the anti-inflammatory peptides and TLR2 or TLR4 targets and provides theoretical support for understanding the mechanism underlying the immunoregulatory effect of bioactive peptides from C. argus.

This study investigated the effects of different carriers on the digestion and absorption of astaxanthin from Pacific white shrimps aiming to provide a reference for the development and utilization of astaxanthin. Astaxanthin liposomes and astaxanthin microcapsules were successfully prepared by the thin-film ultrasonic method and the antisolvent precipitation method, respectively, and their physiological and biochemical properties were evaluated. Experimental results showed that excess amounts of wall material made the system unstable, thereby impacting the encapsulation efficiency. Additionally, a larger amount of the stabilizer cholesterol in liposomes did not necessarily lead to better results. Under optimized conditions, the encapsulation efficiencies of both astaxanthin liposomes and microcapsules were above 85%, the former being somewhat higher than the latter. The optimized preparation conditions for astaxanthin microcapsules were 2.5% zein concentration, 0.005% astaxanthin stock solution, and ultrapure water at pH 7, and those for astaxanthin were 4% soy lecithin concentration, 0.6% cholesterol concentration, and 0.004% astaxanthin stock solution concentration. Particle size analysis and transmission electron microscopy (TEM) showed that both samples were spherical particles of approximately 100 nm in diameter with smooth surfaces and fully encapsulated structures. In storage stability experiments, freeze-dried microcapsule powder exhibited the highest retention rate of astaxanthin (82.57%), but when preserved in liquid form, the retention rate of astaxanthin microcapsules was lower than that of astaxanthin liposomes. Encapsulated astaxanthin had higher antioxidant capacity than astaxanthin-containing oil at the same concentration. In in vitro simulated gastrointestinal digestion, the digestibilities of both astaxanthin liposomes and microcapsules were above 86%, the former being the latter. Both of them were immune to simulated gastric juice, and astaxanthin was slowly released from them in the simulated intestinal environment after gastric digestion, ensuring its absorption and utilization in the intestine tract. Astaxanthin-containing oil, astaxanthin liposomes and microcapsules diluted 5 and 10 folds were non-toxic to Caco-2 cells, and inhibited the production of reactive oxygen species (ROS) in oxidatively stressed cells. Among them, astaxanthin liposomes exhibited the highest absorption and transport efficiency and the strongest antioxidant activity. Astaxanthin, oil, lecithin, and zein could be absorbed by Caco-2 cells, but due to the limitations of conditions, Caco-2 cells absorbed more astaxanthin liposomes and astaxanthin-containing oil.

The objective of this study is to identify the antioxidant peptides from shrimp by-products and clarify the underlying protective mechanism involved in HepG2 cells with oxidative stress induced by H₂O₂. Protein from shrimp by-products was hydrolyzed by three enzymes (neutral protase, alcalase, and Protamex) and the hydrolysates were separated by using Sephadex G-15 gel filtration, among which the A3 (fraction of alcalase-hydrolysate) displayed a significant 1,1-diphenyl-2-picrylhydrazyl radical and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) cation radical scavenging ability. A total of 3 480 peptides were identified through nano-high performance liquid chromatography-tandem mass spectrometry, with the prediction of five discovered antioxidant peptides (DYPLVPPYF, HFVPVYEGF, GFPPFTGGPFR, EGYPFNPLL, and RVSDGPWLGR). Notably, HFVPVYEGF and EGYPFNPLL emerged as the potent antioxidant peptide, displaying lower half maximal inhibitory concentration. Furthermore, HFVPVYEGF and EGYPFNPLL obviously relieved oxidative stress in HepG2 cells, which strengthened the activity of total-antioxidant capocity, catalase, glutathione peroxidase, and superoxide dismutase, with diminishing the intensity of malondialdehyde and intracellular reactive oxygen species. Molecular docking results revel that HFVPVYEGF and EGYPFNPLL can bind to Kelch-like ECH-associated protein 1 with hydrophobic interactions. The results provided theoretical basis for the production and application of the by-product of shrimp. And a further study should be carried out to examine the bioavailability and in vivo activity of HFVPVYEGF and EGYPFNPLL which identified from shrimp by-products.