In Vitro Antioxidant Activities of Enzymatic Hydrolysate from Schizochytrium sp. and Its Hepatoprotective Effects on Acute Alcohol-Induced Liver Injury In Vivo

Bioactive peptides as a novel strategy to prevent alcoholic liver injury

Alcohol intake has become one of the leading risks to human health and wellness, among which acute and/or chronic alcohol-induced liver injury is a leading threaten, with few therapeutic options other than abstinence. In recent years, studies suggested that certain bioactive peptides from food sources could represent natural and safe alternatives for the prevention of alcoholic liver injury. Hence, this chapter focus on the advanced research on bioactive peptides exerting hepatoprotective activity against alcoholic liver injury. The main sources of protein, strategies for the preparation of hepatoprotective hydrolysates and peptides, underlying mechanisms of peptides on hepatoprotection, and possible structure-activity relationship between peptides and hepatoprotective activity were summarized and discussed, aiming to give a systematic insight into the research progress of hepatoprotective peptides. However, more efforts would be needed to give a clearer insight into the underlying mechanisms and structure-activity relationship before using hepatoprotective peptides as functional food ingredients or dietary supplements.

Ethanol extracts of Isochrysis zhanjiangensis alleviate acute alcoholic liver injury and modulate intestinal bacteria dysbiosis in mice

BACKGROUND

Alcoholic liver disease (ALD) is responsible for 3.3 million deaths per annum. Efficacious therapeutic modalities or drug treatments for ALD have not yet been found, so it is urgent to seek new agents for preventing ALD and its related disease. Many experiments have indicated that modulating the gut microbiota and regulating the toll-like receptor 4 (TLR4)/nuclear transcription factor-κB (NF-κB) inflammatory pathway can provide a new target for prevention and treatment of ALD. Marine microalgae have their natural metabolic pathways to synthesize various of bioactive compounds as promising candidates for hepatoprotection. In this study, we investigated ethanol extracts from Isochrysis zhanjiangensis (EEIZ) to evaluate their ability to alleviate acute alcoholic liver injury, regulate TLR4/NF-κB inflammatory pathway and modulate intestinal bacteria dysbiosis in mice for ALD treatment.

RESULTS

In the acute ALD mouse model, EEIZ reduced levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, triacylglyceride, total cholesterol and low-density lipoprotein, while increasing the level of high-density lipoprotein. Besides, TLR4, myeloid differentiation factor 88, NF-κB and tumor necrosis factor-α expression levels in liver tissue were effectively downregulated by EEIZ. Furthermore, treatment with EEIZ enhanced intestinal homeostasis and significantly alleviated the damage caused by alcohol.

CONCLUSION

EEIZ showed effective hepatoprotective activity against alcohol-induced acute liver injury in mice as it could alleviate hepatocyte damage, suppress the TLR4/NF-κB inflammatory pathway and regulate the intestinal flora structure. EEIZ could be a good candidate for preventing acute alcoholic liver injury. © 2024 Society of Chemical Industry.

Influence of a Mixture of Protein Hydrolysate from Black Soldier Fly Larvae and Schizochytrium on Palatability, Plasma Biochemistry, and Antioxidative and Anti-Inflammatory Capacity in Cat Diets

The objective of this research was to evaluate palatability, plasma biochemistry, antioxidative and anti-inflammatory capacity, and immune levels in cats by feeding supplementing inclusion of different levels of a mixture of protein hydrolysate from black soldier fly larvae and schizochytrium (BSFPs) in diets. In the feed experiment, a total of 24 adult cats (12 females and 12 males; BW: 3.02 ± 0.06 kg) were randomly divided into four groups: (1) diet with chicken and fish meal as primary protein resource (CON); (2) diet with 5% BSFPs replacing chicken meal, fish meal, chicken oil, and fish oil (5% BSFPs); (3) 10% BSFPs; and (4) 15% BSFPs. The body weight and feed intake were recorded, and a blood sample was collected for analysis. In the palatability experiment, three diets containing 5%, 10%, and 15% BSFPs were evaluated by comparing with CON. These results suggested that different levels of BSFPs could improve palatability in cat diets by enhancing the first sniff, the first bite, and feed intake (p < 0.05). However, no significant influence existed in body weight and average daily feed intake (p > 0.05). In comparison to the CON group, 5% and 15% BSFPs significantly increased the total protein content, and all treatment groups decreased the triglyceride content and enhanced the calcium concentration in plasma; in addition, the activity of aspartate aminotransferase and alanine aminotransferase and the content of creatinine and urea nitrogen were significantly reduced by the supplementation inclusion of BSFPs in the diets (p < 0.05). The enzyme activity of glutathione peroxidase was dramatically enhanced by the supplementation of 10% and 15% BSFPs in diets compared with the CON diet, and the activity of superoxide dismutase was increased and the malondialdehyde concentration was remarkably reduced in all three treatments (p < 0.05). Compared with the CON group, different levels of BSFPs in the diets significantly increased the immunoglobulin A content in plasma; similarly, the immunoglobulin G concentration was significantly enhanced by the supplementation of 10% and 15% BSFPs in the diets (p < 0.05). Furthermore, the interleukin-1β content was significantly reduced in the inclusion of 10% and 15% BSFPs in the diets, and 15% BSFPs remarkably decreased the content of interleukin-8 in plasma compared with the CON diet (p < 0.05). To sum up, the supplementation of different levels of BSFPs exhibited a positive effect on palatability and enhanced the antioxidant, anti-inflammatory, and immune capacity. Particularly, the addition levels of 10% and 15% BSFPs were more effective in antioxidation, anti-inflammation, and immunity.

Peptide Characterization of Bovine Myocardium Hydrolysates and Its Ameliorative Effects on Doxorubicin-Induced Myocardial Injury in H9c2 Cells and in Mice

The prevalence and mortality of heart disease have a persistent existence, and it is important to develop active substances with cardioprotective properties. It has been reported that peptides from animal heart hydrolysates possess cardioprotective activity, but those mechanisms and the sequence of peptides are still unrevealed. In the present study, the extracts of bovine myocardium were prepared by enzymatic hydrolysis (BHH-A) and water extraction (BHH-W). The cardioprotective function of peptides was verified in the DOX-induced H9c2 cells and myocardial injury mice. The mass spectrometry was used to contrast the differences of active ingredients between BHH-W and BHH-A. Results suggested that both BHH-A and BHH-W could increase the activity of antioxidant enzymes in cardiomyocytes and reduce the inflammatory level and apoptosis of myocardial cells. The improvement effects of BHH-A on myocardial injury in mice were better than those of BHH-W. The analysis of peptide composition demonstrated that the contents with N-segment hydrophobic amino acids were higher in the peptides identified in BHH-A. Hence, BHH-A could be used as a potential active substance to improve DOX-induced myocardial injury by reducing oxidative damage, inflammation, and cardiomyocyte apoptosis, and its activity may be related to the richness of small molecular peptides and hydrophobic amino acids.

Protein Hydrolysates Derived from Animals and Plants—A Review of Production Methods and Antioxidant Activity

There is currently considerable interest on the use of animal, plant, and fungal sources in the production of bioactive peptides, as evidenced by the substantial body of research on the topic. Such sources provide cheap and environmentally friendly material as it often includes waste and by-products. Enzymatic hydrolysis is considered an efficient method of obtaining peptides capable of antioxidant activity. Those properties have been proven in terms of radical-scavenging capacity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2-azinobis-(3-ethyl-benzothiazoline-6-sulphonic acid)), hydroxyl and superoxide radical methods. Additionally, the reducing power, ferrous ion-chelating (FIC), ferric reducing antioxidant power (FRAP), and the ability of the protein hydrolysates to inhibit lipid peroxidation have also been explored. The results collected in this review clearly indicate that the substrate properties, as well as the conditions under which the hydrolysis reaction is carried out, affect the final antioxidant potential of the obtained peptides. This is mainly due to the structural properties of the obtained compounds such as size or amino acid sequences.

Study of the Anticancer Potential of Plant Extracts Using Liver Tumor Microphysiological System

Background: Plants have been considered a vital source of modern pharmaceutics since the paleolithic age. Contemporary chemotherapeutic drugs for cancer therapy are chemical entities sourced from plants. However, synthetic drugs or their derivatives come with severe to moderate side effects for human health. Hence, the quest to explore and discover plant-based novel anticancer drugs is ongoing. Anticancer activities are the primary method to estimate the potential and efficacy of an extract or compound for drug discovery. However, traditional in vitro anticancer activity assays often show poor efficacy due to the lack of in-vivo-like cellular environment. In comparison, the animal-based in vivo assays lack human genetic makeup and have ethical concerns. Aim: This study aimed to overcome the limitations of traditional cell-culture-based anticancer assays and find the most suitable assay for anticancer activity of plant extracts. We first reported utilizing a liver tumor microphysiological system in the anticancer effect assessment of plant extracts. Methodology: Methanolic extracts of Acer cappadocicum Gled were used to assess anticancer activity against liver tumor microphysiological system (MPS), and cell viability, liver function tests, and antioxidant enzyme activities were performed. Additionally, an embedded transepithelial electrical resistance sensor was utilized for the real-time monitoring of the liver tumor MPS. The results were also compared with the traditional cell culture model. Results: The study demonstrated the superiority of the TEER sensor-based liver tumor MPS by its better anticancer activity based on cell viability and biomarker analysis compared to the traditional in vitro cell culture model. The anticancer effects of the plant extracts were successfully observed in real time, and methanolic extracts of Acer cappadocicum Gled increased the alanine transaminase and aspartate aminotransferase secretion, which may reveal the different mechanisms of these extracts and suggest a clue for the future molecular study of the anticancer pathways. Conclusion: Our results show that the liver tumor microphysiological system could be a better platform for plant-based anticancer activity assessment than traditional cell culture models.

Production and antioxidant capacity of bioactive peptides from plant biomass to counteract lipid oxidation

Preventing lipid oxidation, especially with the polyunsaturated fat-based products, is a major concern in sectors as agri-food and cosmetic. Even though the efficiency of synthetic antioxidants has been recognized, both consumers and manufacturers are looking for more innovative, healthy and quality products while rejecting synthetic additives due to their concern about safety, along with their environmental impact issues. In this context, plant biomass, which have shown to be rich in compounds, have raised interest for the isolation of novel naturally occurring antioxidants. Among their myriad of molecules, bioactive peptides, which are biologically active sequence of amino acid residues of proteins, seem to be of a great interest. Therefore, the number of identified amino acids sequences of bioactive peptides from plant biomass with potential antioxidant action is progressively increasing. Thus, this review provides a description of 129 works that have been made to produce bioactive peptides (hydrolysate, fraction and/or isolate peptide) from 55 plant biomass, along with the procedure to examine their antioxidant capacity (until 2019 included). The protein name, the process, and the method to concentrate or isolate antioxidant bioactive peptides, along with their identification and/or specificity were described. Considering the complex, dynamic and multifactorial physico-chemical mechanisms of the lipid oxidation, an appropriate in-vitro methodology should be better performed to efficiently probe the antioxidant potential of bioactive peptides. Therefore, the results were discussed, and perspective for antioxidant applications of bioactive peptides from plant biomass was argued.

Protective effects of crimson snapper scales peptides against oxidative stress on Drosophila melanogaster and the action mechanism

Peptides derived from crimson snapper scales (CSSPs) were reported to possess excellent free radical scavenging activities in vitro. In present study, the anti-aging and anti-oxidative stress effects of CSSPs were evaluated in Drosophila melanogaster models. Results showed that the addition of CSSPs in the diets of normal Drosophila could effectively extend their lifespan and improve the motor ability of aged Drosophila. Moreover, CSSPs could protect Drosophila from oxidative damage induced by H₂O₂, paraquat and UV irradiation. The extension of lifespan was found to be associated with the effects of CSSPs in improving the antioxidant defense system of Drosophila, manifesting as the reduction of oxidation products MDA and PCO, the elevated activities of T-SOD, CAT and GSH-Px, and the upregulated expression of antioxidant related genes after CSSPs supplemented. Furthermore, CSSPs at 6 mg/mL significantly downregulated mTOR signaling pathway and activated autophagy in aged male Drosophila, and the inhibition on mTOR activation was probably mediated by the antioxidant effects of CSSPs. Our findings suggest that CSSPs have the potential in making dietary supplements against natural aging and oxidative stress in organisms.

Use of Alcalase in the production of bioactive peptides: A review

This review aims to cover the uses of the commercially available protease Alcalase in the production of biologically active peptides since 2010. Immobilization of Alcalase has also been reviewed, as immobilization of the enzyme may improve the final reaction design enabling the use of more drastic conditions and the reuse of the biocatalyst. That way, this review presents the production, via Alcalase hydrolysis of different proteins, of peptides with antioxidant, angiotensin I-converting enzyme inhibitory, metal binding, antidiabetic, anti-inflammatory and antimicrobial activities (among other bioactivities) and peptides that improve the functional, sensory and nutritional properties of foods. Alcalase has proved to be among the most efficient proteases for this goal, using different protein sources, being especially interesting the use of the protein residues from food industry as feedstock, as this also solves nature pollution problems. Very interestingly, the bioactivities of the protein hydrolysates further improved when Alcalase is used in a combined way with other proteases both in a sequential way or in a simultaneous hydrolysis (something that could be related to the concept of combi-enzymes), as the combination of proteases with different selectivities and specificities enable the production of a larger amount of peptides and of a smaller size.

Physicochemical properties and hepatoprotective effects of glycated Snapper fish scale peptides conjugated with xylose via maillard reaction

The physicochemical properties and hepatoprotective effects of fish scales peptides (FSP) and the glycated peptides conjugated with xylose via Maillard reaction (FSP-MRPs) were investigated. Results showed that the FSP was rich in oligopeptides within 2-10 amino acids, the degree of grafting of FSP-MRPs was 52.97 ± 1.58% and the antioxidant activities in vitro of FSP were improved through Maillard reaction. In order to investigate the antioxidant activities of FSP-MRPs after digestion, the simulated gastrointestinal digestion experiments of FSP and FSP-MRPs in vitro were conducted. Results indicated that the antioxidant activities of FSP and FSP-MRPs remained as stronger as before even under the digestive conditions. Furthermore, FSP-MRPs could significantly reduce the elevated activities of serum aspartate aminotransferase and alanine aminotransferase, decrease the elevated the levels of hepatic malondialdehyde and triglyceride, and inhibit the decrease of hepatic superoxide dismutase, catalase and glutathione peroxidase caused by alcohol-induced liver damage. These findings suggest that the glycated peptides formed by FSP and xylose via Maillard reaction may be potential to be exploited as a potential functional ingredient in food industry.

Hepatoprotective action of papain-hydrolyzed buffalo milk protein on carbon tetrachloride oxidative stressed albino rats

Buffalo skim milk retentate was hydrolyzed with papain for 4 h (enzyme:substrate, 1:200), resulting in a retentate hydrolysate (RH) with a degree of hydrolysis of 23%. We then investigated the potential hepatoprotective activity of RH at 250 and 500 mg/kg of body weight per day on carbon tetrachloride (CCl₄)-induced oxidative stress in albino rats. Liver biomarkers (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase), kidney biomarkers (urea, creatinine), and serum lipid profile (total lipids and triglycerides) were measured, in addition to histopathological status. Injection of CCl₄ significantly increased all liver and kidney biomarkers compared with the negative control. In contrast, CCl₄ injection significantly reduced hepatic antioxidant enzyme activities; that is, glutathione peroxidase and superoxide dismutase. Oral administration of RH for 28 d effectively maintained a physiologically normal range of liver and kidney biomarkers compared with the positive control. Furthermore, RH administration significantly increased activities of glutathione peroxidase and superoxide dismutase. Histopathological sections of CCl₄-stressed rats treated with RH were different from that of the positive control and were similar to those of the negative control, in a concentration-dependent manner. Our results demonstrated the antihepatotoxic activities of buffalo milk RH and demonstrated that the higher RH concentration (500 mg/kg of body weight per day) could maintain the healthy biological status of the CCl₄-injected rats.

Water-dispersible astaxanthin-rich nanopowder: preparation, oral safety and antioxidant activity in vivo

In this research, astaxanthin-rich nanopowder was prepared by nanoencapsulation and freeze-drying techniques with enhanced bioavailability and antioxidant activities. The nanopowder showed a maximum solubility of 230 mg mL-1 with an astaxanthin content as high as 2.9%. Compared with free astaxanthin, the astaxanthin-loaded nanopowder exhibited a more efficient antioxidant effect: an oral dose of 0.9 mg per kg BW significantly reduced the malondialdehyde and protein carbonyl contents, and increased the glutathione content as well as the superoxide dismutase activities in alcohol-induced acute hepatic injured mice, and maintained these oxidative stress indicators at a normal level for a longer period when treated with nanoencapsulated-astaxanthin than free astaxanthin. Simulated gastrointestinal tract studies demonstrated that the nanopowder with pH and DNase I-dependent dissociation properties delivered astaxanthin efficiently to the small intestine. Astaxanthin-rich nanopowder with a dose as high as 2.4 mg per kg BW (equivalent to astaxanthin) showed no chronic toxicity to mice in terms of hematology and pathological histology, indicating its impressive biocompatibility for biomedical applications. Pharmacokinetics and relative bioavailability (207%) of the nanopowder further proved that DNA/chitosan nanocarriers significantly improved the delivery efficiency of astaxanthin. With enhanced bioavailability and antioxidant activities, this novel type of astaxanthin-loaded nanopowder is expected to find broad application in the food and drug industry.

Organic selenium derived from chelation of soybean peptide-selenium and its functional properties in vitro and in vivo

Organic selenium has been widely explored as an important source of selenium (Se) supplement due to its low toxicity and easy absorption. In the present study, a new type of organic selenium was fabricated by chelating Se with soybean protein isolate peptides (SPIPs), and its physio-chemical properties, structural characteristics, and antioxidant activities were investigated. Results indicated that the structure of the SPIP molecule was folded and aggregated during the chelation process. SPIP-Se exhibited stronger hydroxyl radical scavenging activity and reducing power than SPIP in vitro. In addition, SPIP-Se could repair the H2O2-induced oxidative damage of Caco-2 cells by enhancing the activities of antioxidant enzymes. The in vivo assay showed that SPIP-Se showed much less toxicity than inorganic Se supplements, and exhibited a more positive effect on the activities of key enzymes including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and aspartate aminotransferase (AST). These findings suggest that SPIP-Se could be developed as an effective dietary Se supplement in the food or pharmaceutical field in the future.

S-allyl-l-cysteine (SAC) protects hepatocytes from alcohol-induced apoptosis

Hepatocyte apoptosis is frequently observed in alcohol‐related liver disease (ARLD), which ranks among the 30 leading causes of death worldwide. In the current study, we explored the impact of S‐allyl‐l‐cysteine (SAC), an organosulfur component of garlic, on hepatocyte apoptosis induced by alcohol. Rat liver (BRL‐3A) cells were challenged by ethanol with or without SAC treatment. Cell death/viability, reactive oxygen species (ROS) generation, mitochondrial Cytochrome C release, and caspase 3 activity were then examined. We found that ethanol remarkably induced apoptosis of hepatocytes, while SAC treatment rescued ethanol‐induced hepatocyte injury, as demonstrated by cell counting kit‐8 (CCK8) assay, TUNEL assay, and annexin V/PI staining assay. Ethanol evoked ROS generation in BRL‐3A cells, and this was abated by SAC pretreatment, as indicated by 2′,7′‐dichlorofluorescin diacetate (DCFDA) staining assay. Moreover, ethanol suppressed cellular anti‐apoptotic protein B‐cell lymphoma‐2 (Bcl‐2) expression, increased pro‐apoptotic protein Bcl‐2‐associated X protein (Bax) expression, induced mitochondrial Cytochrome C release, and activated the caspase 3‐dependent apoptosis pathway in BRL‐3A cells. SAC was sufficient to abolish all these changes induced by ethanol, thereby revealing the molecular mechanisms underlying its protective effects. In conclusion, SAC protects hepatocytes from ethanol‐induced apoptosis and may be suitable for use as a novel anti‐apoptotic agent for treating ARLD.

Protective properties of Huperzine A through activation Nrf2/ARE-mediated transcriptional response in X-rays radiation-induced NIH3T3 cells

Huperzine A (HupA), derived from Huperzia Serrata, has exhibited a variety of biological actions, in particular neuroprotective effect. However, the protective activities of HupA on murine embryonic fibroblast NIH3T3 cells after X-rays radiation have not been fully elucidated. Herein, HupA treatment dramatically promoted cell viability, abated a G0/G1 peak accumulation, and ameliorated increase of cell apoptosis in NIH3T3 cells after X-rays radiation. Simultaneously, HupA notably enhanced activities of anti-oxidant enzymes, inhibited activity of lipid peroxide, and efficiently eliminated production of reactive oxygen species in NIH3T3 cells after X-rays radiation. Dose-dependent increase of antioxidant genes by HupA were associated with up-regulated Nrf2 and down-regulated Keap-1 expression, which was confirmed by increasing nuclear accumulation, and inhibiting of degradation of Nrf2. Notably, augmented luciferase activity of ARE may explained Nrf2/ARE-mediated signaling pathways behind HupA protective properties. Moreover, expression of Nrf2 HupA-mediated was significant attenuated by AKT inhibitor (LY294002), p38 MAPK inhibitor (SB202190) and ERK inhibitor (PD98059). Besides, HupA-mediated cell viability, and ROS production were dramatically bated by LY294002, SB202190, and PD98059. Taken together, HupA effectively ameliorated X-rays radiation-induced damage Nrf2-ARE-mediated transcriptional response via activation AKT, p38, and ERK signaling in NIH3T3 cells.

Lipid (per) oxidation in mitochondria: an emerging target in the ageing process?

Lipids are essential for physiological processes such as maintaining membrane integrity, providing a source of energy and acting as signalling molecules to control processes including cell proliferation, metabolism, inflammation and apoptosis. Disruption of lipid homeostasis can promote pathological changes that contribute towards biological ageing and age-related diseases. Several age-related diseases have been associated with altered lipid metabolism and an elevation in highly damaging lipid peroxidation products; the latter has been ascribed, at least in part, to mitochondrial dysfunction and elevated ROS formation. In addition, senescent cells, which are known to contribute significantly to age-related pathologies, are also associated with impaired mitochondrial function and changes in lipid metabolism. Therapeutic targeting of dysfunctional mitochondrial and pathological lipid metabolism is an emerging strategy for alleviating their negative impact during ageing and the progression to age-related diseases. Such therapies could include the use of drugs that prevent mitochondrial uncoupling, inhibit inflammatory lipid synthesis, modulate lipid transport or storage, reduce mitochondrial oxidative stress and eliminate senescent cells from tissues. In this review, we provide an overview of lipid structure and function, with emphasis on mitochondrial lipids and their potential for therapeutic targeting during ageing and age-related disease.