In vitroantioxidant and protective effects of corn peptides on ethanol-induced damage in HepG2 cells

Diesel exhaust particulate matter induces GC-1 spg cells oxidative stress by KEAP1-NRF2 pathway and inhibition of ATP5α1 S-sulfhydration

Diesel exhaust particle (DEP) exposure induces a variety of toxicological effects through oxidative stress and inflammation responses. This research investigated the mechanisms underlying DEP-induced GC-1spg cells oxidative stress by examining ROS accumulation, antioxidant defense systems activation, mitochondrial dysfunction, and the Nrf2/Keap1/HO-1 pathway response. Subsequently, we further evaluated the ATP levels, ATP5α synthase activity and ATP5α synthase S-sulfhydrated modification in DEP-exposed GC-1 spg cells. The results showed that DEP exposure significantly inhibited cell proliferation and viability, increased intracellular ROS production, decreased MMP, down-regulated antioxidant capacity, activated the Nrf2/Keap1/HO-1 pathway. However, DEP-induced oxidative stress was partially alleviated by GSH and exogenous H2S. In addition, DEP exposure induced ATP depletion and ATP5α synthase inactivity in GC-1 spg cells, accompanied by ATP5α synthase S-sulfhydrated modification. In conclusion, our research showed that DEP may incapacitate mitochondria through oxidative stress injury, leading to GC-1 spg cells oxidative stress. This process may be associated with the reduction of ATP5α1 S-sulfhydrated modification. It provides a new perspective for the research of the mechanism related to male reproductive toxicity due to air pollution.

The antioxidant peptides from walnut protein hydrolysates and their protective activity against alcoholic injury

In this study, walnut protein was hydrolyzed, separated by ultrafiltration, purified by RP-HPLC, identified by LC-MS/MS, and screened by molecular docking to finally obtain three novel antioxidant peptides HGEPGQQQR (1189.584 Da), VAPFPEVFGK (1089.586 Da) and HNVADPQR (949.473 Da). These three peptides exhibited excellent cellular antioxidant activity (CAA) with EC50 values of 0.0120 mg mL-1, 0.0068 mg mL-1, and 0.0069 mg mL-1, respectively, which were superior to that of the positive control GSH (EC50: 0.0122 mg mL-1). In the ethanol injury model, three antioxidant peptides enhanced the survival of cells treated with ethanol from 47.36% to 62.69%, 57.06% and 71.64%, respectively. Molecular docking results showed that the three antioxidant peptides could effectively bind to Keap1, CYP2E1 and TLR4 proteins. These results suggested that walnut-derived antioxidant peptides could be potential antioxidants and hepatoprotective agents for application in functional foods.

Impact of In Vitro Digestion on the Digestibility, Amino Acid Release, and Antioxidant Activity of Amaranth (Amaranthus cruentus L.) and Cañihua (Chenopodium pallidicaule Aellen) Proteins in Caco-2 and HepG2 Cells

This study evaluated the impact of in vitro gastrointestinal digestion on the digestibility, amino acid release, and antioxidant activity of proteins from amaranth (Amarantus cruentus L.) and cañihua (Chenopodium pallidicaule Aellen). Antioxidant activity was assessed using ORAC, ABTS, DPPH, and cellular antioxidant activity (CAA) assays in human intestinal Caco-2 and hepatic Hep-G2 cell lines. The results showed that amaranth had higher protein digestibility (79.19%) than cañihua (71.22%). In addition, intestinal digestion promoted the release of essential amino acids, such as leucine, lysine, and phenylalanine, in both protein concentrates. Concentrations of amaranth and cañihua proteins, ranging from 0.125 to 1.0 mg mL-1, were non-cytotoxic in both cell lines. At a concentration of 0.750 mg mL-1, simulated gastrointestinal digestion enhanced cellular antioxidant activity. Intestinal digest fractions containing peptides >5 kDa were the principal contributors to CAA in both cell lines. Notably, cañihua proteins exhibited high CAA, reaching values of 85.55% and 82.57% in Caco-2 and HepG2 cells, respectively, compared to amaranth proteins, which reached 84.68% in Caco-2 and 81.06% in HepG2 cells. In conclusion, both amaranth and cañihua proteins, after simulated gastrointestinal digestion, showcased high digestibility and released peptides and amino acids with potent antioxidant properties, underscoring their potential health benefits.

Hepatoprotective Effect of Albumin Peptide Fractions from Corn Germ Meal against Alcohol-Induced Acute Liver Injury in Mice

Acute alcoholic liver disease can cause serious liver damage. This study reports on the hepatoprotective effect of albumin peptide fractions from corn germ meal (MW < 1 kDa) (APF4) on acute alcohol hepatic damage in mice. In the mice model, the results indicated that APF4 at a dose of 800 mg/kg/bw could markedly boost alcohol metabolism, which was shown in the reduced duration of the loss of the righting reflex; the reduced level of blood alcohol concentration (BAC), cytochrome P450 2E1 (CYP2E1), alanine aminotransferase (ALT), aminotransferase (AST), triglycerides (TG), and malondialdehyde (MDA) (p < 0.01); the enhanced activity of aldehyde dehydrogenase (ALDH); and the superoxide dismutase (SOD) and glutathione (GSH) levels being increased by up to 84.02% and 193.22% (p < 0.01) compared to the control group. The antioxidant capability and lipid peroxidation inhibition activity of APF4 may be responsible for its protective effect against liver damage induced by alcohol. The findings suggested that APF4 had the hepatoprotective property against liver damage induced by alcohol.

Serum metabolic effects of corn oligopeptides with 7-day supplementation on early post-surgery primary liver cancer patients: a double-blind randomized controlled trial

BACKGROUND

Liver cancer as the main leading cancer has caused heavy burdens globally. The prognosis of liver cancer is closely related with postoperative nutrition support. Corn oligopeptides (COPs) are protein hydrolysates produced by enzymatic treatments, which have shown potential bioactivities, such as inhibiting angiotensin I-converting enzyme, resisting lipid peroxidation and anti-oxidant. However, the correlation between COPs and liver cancer patients is still unknown and the potential mechanism of COPs on liver cancer is unclear as well. The aim of this study was to assess effects of 7-day intervention of COPs after surgery on liver function and serum metabolic profiles of liver cancer patients.

METHODS

Patients were assigned into COPs intervention group (n=50) and control group (n=91) for 7 days. Investigations were scheduled at 1st day and 7th day after liver resection surgery respectively, mainly including anthropometric, biochemical indexes and liquid chromatography-mass spectrometry (LC/MS) analysis.

RESULTS

Seven-day supplementation of COPs on early post-surgery liver cancer patients down-regulated levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin, direct bilirubin and up-regulated prothrombin time activity and prealbumin levels. LC/MS analysis revealed metabolic signatures including regulation of 16 metabolites, which was closely related with two metabolic pathways (nicotinate and nicotinamide metabolism, fatty acid metabolism).

CONCLUSIONS

COPs supplementation has displayed the potentials on alleviating the injury of liver function and it may be due to regulation of fatty acid metabolism, nicotinate and nicotinamide metabolism, lipid peroxidation and anti-inflammatory action. More researches are warranted in future to confirm the exact mechanisms.

The Protective Effects of Corn Oligopeptides on Acute Alcoholic Liver Disease by Inhibiting the Activation of Kupffer Cells NF-κB/AMPK Signal Pathway

Alcohol can cause injury and lead to an inflammatory response in the liver. The NF-κB/AMPK signaling pathway plays a vital role in regulating intracellular inflammatory cytokine levels. In this study, corn oligopeptides (CPs), as the research objects, were obtained from corn gluten meal, and their regulation of the activation of the Kupffer cell NF-κB/AMPK signal pathway induced by LPS was investigated. Results showed that ALT, AST, and inflammatory cytokines in mice serum after the administration of CPs at 0.2, 0.4, and 0.8 g/kg of body weight displayed a distinct (p < 0.05) reduction. On the other hand, the CPs also inhibited the expression of recognized receptor CD14 and TLR4, down-regulated P-JNK, P-ERK, and P-p-38, and thus inhibited inflammatory cytokine levels in Kupffer cells (KCs). Furthermore, four kinds of dipeptides with a leucine residue at the C-terminus that might exhibit down-regulated inflammatory cytokines in the NF-κB/AMPK signaling pathway functions were detected using HPLC-MS/MS. These results indicated that CPs have a potential application value in acute alcoholic liver disease.

Surfactin effectively improves bioavailability of curcumin by formation of nano-capsulation

To improve the bioavailability of curcumin, surfactin was used to prepare curcumin-loaded nanoemulsions (Cur-NEs). Moreover, the physicochemical properties, digestive characteristics, as well as inhibition activity to Caco-2 cells of Cur-NEs were measured. Furthermore, the morphological analysis revealed that Cur-NEs with 320 mg/L surfactin appeared spherical nanoparticale (23.23 ± 2.86 nm) and uniform distribution. The encapsulation efficiency of Cur-NEs with 320 mg/L surfactin was 97.25 ± 1.28%. Simulated gastrointestinal digestion results indicated that surfactin elevated the sustained-release characteristics and higher bioaccessibility (40.92 ± 2.84%) of curcumin. Besides, Cur-NEs with 320 mg/L surfactin exhibited excellent stability in different temperature, pH and light irradiation. In addition, the inhibition of Cur-NEs with 320 mg/L surfactin to Caco-2 cells was 71.29%. Biochemical analysis showed that Cur-NEs enhanced the activity of lactate dehydrogenase, superoxide dismutase, catalase and glutathione peroxidase, as well as the reactive oxygen species content. RT-PCR and ELISA results also revealed that Cur-NEs inhibited Caco-2 cells through the activated mitochondria-mediated pathway. This study provided a strategy to encapsulate curcumin in nanoparticles with surfactin for improving bioavailability.

Hepatoprotective effect of Trigonella foenum graecum against ethanol-induced cell death in human liver cells (HepG2 and Huh7)

BACKGROUND

The plant Trigonella foenum graecum, also known as fenugreek, has been shown to have anticancer, antidiabetic, anti-inflammatory, and antioxidant properties. In this study, the hepatoprotective effect of fenugreek seed extract (FSE) against ethanol-induced cell death was investigated in human liver cells (HepG2 and Huh7).

METHODS AND RESULTS

The cytotoxic effect of FSE and ethanol on cells was evaluated by exposing the cells at different concentrations. Following that, the cells were pre-incubated with 5-25 μg/ml FSE, followed by a cytotoxic concentration (0.5 mM) of ethanol. MTT and neutral red uptake assays were performed in treated cells to assess the ability of FSE to protect cells from the cytotoxic effects of ethanol. When compared to controls, ethanol treatment significantly reduced the viability of HepG2 and Huh7 cells and altered the cell morphology, whereas treatment with FSE significantly increased cell viability and reversed ethanol-induced morphological changes. Furthermore, pretreatment with FSE dose-dependently reduced lactate dehydrogenate (LDH) leakage, lipid peroxidation (LPO) level, and catalase activities while increasing glutathione (GSH) level induced by ethanol. Pretreatment with FSE also reduced the generation of reactive oxygen species (ROS), caspase enzyme activities, and protein expression of caspase-3 and -9. In HepG2 cells, ethanol-induced apoptosis was observed, whereas FSE treatment reduced apoptosis by downregulating the expression of pro-apoptotic marker genes and upregulating the antiapoptotic gene.

CONCLUSIONS

In conclusion, this study reports on the mechanistic details of the hepatoprotective potential of FSE. The results also suggest that fenugreek seeds may be useful in preventing liver diseases caused by toxicants such as ethanol.

Protective Effect and Potential Antioxidant Role of Kakadu Plum Extracts on Alcohol-Induced Oxidative Damage in HepG2 Cells

Serial alcohol consumption causes alcoholic liver disease (ALD), which can lead to fatty liver, hepatitis, and cirrhosis. Terminalia ferdinandiana (Kakadu plum) is an indigenous fruit of Australia, which is utilized as a functional food. It is a commercially important antioxidant as it contains a more eloquent level of ascorbic acid than other oranges. In this study, we analyzed the chemical constituents of vitamin C, gallic acid, ellagic acid, and daidzin via High-performance liquid chromatography (HPLC) in the Kakadu plum from two different regions including the Northern Territory (NT) and Western Australia (WA), and compared their biochemical properties. The vitamin C content was much higher (almost 70%) in Kakadu plum (KKD) from the NT than WA. Moreover, ROS generation was inhibited significantly in HepG2 (human hepatoma) cells with the KKD-NT extract treatment when compared to the KKD-WA extract treatment. The cytotoxicity produced by ethanol was significantly suppressed in response to the treatment with both of the samples. In addition, our samples (KKD-NT and KKD-WA) increased the activity of two key enzymes involving alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) that metabolize ethanol. These results show the biochemical confirmation of the mechanism by which KKD exhibits its biological functions including relief from alcohol hangovers as well as protection of the liver cells by the suppression of ROS production and toxic insults.

Antioxidant activity of SSeCAHK in HepG2 cells: a selenopeptide identified from selenium-enriched soybean protein hydrolysates

This paper is aimed at purifying and identifying selenium (Se)-containing antioxidative peptides from Se-enriched soybean peptides (SSP). In this work, the SSP was separated into five fractions (F1 to F5). Fraction F4, displaying the highest antioxidative activity, was further separated, and sub-fractions F4-1 to F4-5 were selected for antioxidative activity evaluation using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzo-thiazoline-6-sulphonic acid)diammonium salt (ABTS), and OH- radical scavenging assays. The Se-containing antioxidative peptides with sequence Ser-SeC-Ala-His-Lys (SSeCAHK) were identified in sub-fraction F4-1 and chemically synthesized. This Se-containing pentapeptide showed a preventive effect against hydrogen peroxide (H2O2)-induced oxidative stress in HepG2 cells. Pretreating the cells for 2 h with SSeCAHK (0.13-0.50 mg mL-1) induced strong intracellular, reactive oxygen species (ROS) scavenging activity while preventing a decrease in reduced glutathione (GSH) and an increase in malondialdehyde (MDA). Therefore, SSeCAHK treatment improved H2O2-induced oxidative stress in HepG2 cells, demonstrating the significant potential of SSeCAHK as a natural antioxidative functional material for dietary supplementation.

Isolation, purification, and characterization of antioxidant peptides from fresh mare's milk

In this study, the whey protein of fresh mare's milk was used as raw material. The antioxidant peptide liquid XMNDT was extracted from fresh mare's milk solution and purified. The peptide had a molecular weight of 1594.89 kDa and was mainly composed of VAPFPQPVVPYPQR. Antioxidant peptide XMNDT could inhibit the proliferation of A549 lung cancer cells in the G1 phase, accelerate cell apoptosis, increase the activity of SOD and the amount of GSH, and reduce the secretion of MDA. It also exhibited certain antioxidant capacity and free radical scavenging. These data can provide a basis for research on new antioxidant properties by reducing the inflammation caused by aging.

Anti-intoxication and protective effects of a recombinant serine protease inhibitor from Lentinula edodes against acute alcohol-induced liver injury in mice

Serine protease inhibitors (serpins) are involved in inflammation, coagulation, fibrinolysis, tumor suppression, molecular chaperone, chromatin densification, and hormone transport. However, their anti-intoxication activity has not been determined. Here, we heterologously expressed the serpin gene from Lentinula edodes in Escherichia coli and purified the recombinant serpin protein from L. edodes (rLeSPI). Then, we administered alcohol and active protein or Haiwangjinzun as a positive control to mice via gavage to evaluate the anti-intoxication activities of rLeSPI in vivo. We also investigated the protective effects of rLeSPI on acute alcohol-induced liver injury in mice by physiological and biochemical assays. The assay results for the anti-intoxication activity revealed that pretreating mice with 5 mg/kg rLeSPI for 0.5 h before gavage with Erguotou liquor (56%V EtOH, 0.15 ml/10 g) significantly prolonged the tolerance time and shortened the intoxication time relative to the results of the control group, thereby proving its anti-intoxication activities. The biochemical analysis showed that rLeSPI improved glutathione peroxidase activity, which was evidently reduced by ethanol. Additionally, rLeSPI significantly improved the activity of aldehyde dehydrogenase, which is important in alcohol metabolism, and reduced the intracellular malondialdehyde content, aspartate amino transferase, and alanine amino transferase activity. We concluded that LeSPI displayed anti-intoxication activity and exerted protective effects against acute alcohol-induced liver injury, providing new insight into the prevention of alcoholism and alcohol-related diseases.Key Points• Anti-intoxication activity of a recombinant serpin protein rLeSPI was assessed.• LeSPI displayed anti-intoxication activity in mice.• LeSPI exerted protective effects against acute alcohol-induced liver injury in mice.

Selenium-chelating corn oligopeptide as a potential antioxidant supplement: investigation of the protein conformational changes and identification of the antioxidant fragment composition

A selenium-chelating corn oligopeptide (Se-COP) with high protein and low molecular weight was prepared as a selenium supplement. We utilized infrared (IR), ultraviolet (UV), and circular dichroism (CD) spectroscopy, 1-anilinonaphthalene-8-sulfonate (ANS)-binding fluorescence spectra, and isothermal titration calorimetry (ITC) to analyze and describe Se-COP and its reactions. It was concluded that the chelation reaction was a spontaneous process driven by enthalpy and entropy, with ΔH=3.79 × 104 ± 4075 cal/mol, ΔS = 146 cal/mol, ΔG = –23356.30 ± 126.94 cal/mol, binding constant Ka = 1.18 × 104 ± 855 M–1, and binding site number n = 0.13 ± 0.0126, and described as coordination bonds forming and hydrophobic interaction, as well as protein conformational changes including secondary and tertiary hydrophobic structure. Se-COP had strong antioxidant capacity, and mass spectrometry (MS) was used to identify the antioxidant peptide fragment, which was characterized as LLPPY and quantified at 428.95 ng/mg. This study indicated that Se-COP prepared by chelation may be a Se supplement with antioxidant capacity that can be applied in functional foods or ingredients.

Effect of soybean peptides against hydrogen peroxide induced oxidative stress in HepG2 cells via Nrf2 signaling

The aim of this study was to determine the effects of soybean protein hydrolysates against intracellular antioxidant activity.

Protective effect of Letinous edodes foot peptides against ethanol‑induced liver injury in L02 cells

The aim of the present study was to evaluate the protective effect and mechanism of Letinous edodes foot peptides on ethanol‑induced L02 cells. A cell model of ethanol‑induced damage was established in vitro to study the effects of the Letinous edodes foot peptides on human L02 hepatocytes. The expression and activity of superoxide dismutase (SOD), malondialdehyde (MDA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH), following treatment were examined to determine the anti‑alcoholism and hepatoprotective functions of Letinous edodes foot peptides. Taking Letinous edodes foot peptides prior to ethanol exposure was more beneficial, which significantly increased SOD activity and the mRNA expression of ADH and ALDH suppressed by ethanol. In addition, the intracellular MDA content, and AST and ALT activity decreased in ethanol‑induced L02 cells pretreated with the peptides, when compared with the control. Furthermore, Letinous edodes foot peptides inhibited the ethanol‑induced activation of the proinflammatory cytokines, interleukin‑6 and tumor necrosis factor‑α, and promoted the metabolic regulation factors, AMP‑activated protein kinase‑α2 and peroxisome proliferator‑activated receptor‑α.

Structural Characterization of a Tetrapeptide from Sesame Flavor-Type Baijiu and Its Preventive Effects against AAPH-Induced Oxidative Stress in HepG2 Cells

Peptides are rarely reported from Chinese Baijiu (Chinese liquor) because they are often present in very low concentrations in the complex matrix. A tetrapeptide, Ala-Lys-Arg-Ala (AKRA), was recently identified by high-performance liquid chromatography and quadrupole-time-of-flight-mass spectrometry (HPLC-Q-TOF-MS) from sesame flavor-type Baijiu at a concentration of 8.497 ± 0.753 μg/L (P > 0.05), and this tetrapeptide showed preventive effects against 2,2'-azobis(2-methylpropanimidamidine) dihydrochloride (AAPH)-induced oxidative stress in HepG2 cells. The cellular antioxidant activity assay results showed that AKRA protected AAPH-induced oxidative stress in HepG2 cells in a concentration-dependent manner. Pretreatment of the cells for 2 h with AKRA (0.38-1.50 mg/mL) caused strong intracellular reactive oxygen species (ROS) scavenging activities and prevented a decrease in reduced glutathione (GSH) and increases in oxidized glutathione (GSSG) and malondialdehyde (MDA). In addition, AKRA treatment prevented significant decreases in glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) induced by AAPH. Thus, AKRA treatment ameliorated AAPH-induced oxidative stress in HepG2 cells. This study will be important for the design and regulation of functional Baijiu production.