Pepsin Activity Research Articles

Weikangling capsules combined with omeprazole ameliorates ethanol-induced chronic gastritis by regulating gut microbiota and EGF-EGFR-ERK pathway

AimsWeikangling capsules (WKLCs) have been widely used in the treatment of chronic gastritis. Whether used alone or combined with omeprazole (OME), it shows a significant effect. However, the mechanisms haven't been established. The study aimed to explore the mechanisms of WKLCs and its combination with OME on chronic gastritis. Main methodsThe components of WKLCs and EA (the ethyl acetate extraction extracted from WKLCs) fraction were analyzed. Then chronic gastritis model rats were induced by 56 % ethanol and treated with OME, low dose of WKLCs (WKL), high dose of WKLCs (WKH), WKLCs combined with OME (WO), and EA fraction (EA) to evaluate the mechanisms of WKLCs, drug combination and EA fraction. Key findingsA total of 22 components of WKLCs were quantified, among them 18 were enriched in EA fraction. WKLCs alleviated the morphology and inflammation of gastric mucosa and downregulated the levels of inflammatory factors (IL-1β, TNF-α, IL-6) and epidermal growth factor (EGF) in serum by inhibiting the EGF-EGFR-ERK pathway, regulating gut microbiota composition and SCFAs contents in feces. WKLCs plus OME was better than OME. EA fraction improved digestive function by increasing pepsin activity and decreasing gastrointestinal hormones (GAS and VIP) compared with WKLCs. SignificanceThis study elucidated that the effect of WKLCs and its combination with OME in the treatment of chronic gastritis was attributed to regulating the composition of the gut microbiota and inhibiting the EGF-EGFR-ERK pathway. The EA fraction is an inseparable effective substance of WKLCs. This study provides scientific evidence for clinical application.

Effects of dietary plant protein sources intake on growth, digestive enzyme activity, edible tissue nutritional status and intestinal health of the omnivorous Redclaw crayfish, Cherax quadricarinatus.

For the omnivorous Cherax quadricarinatus crayfish, plant raw materials can be good alternatives to dietary fish meal (FM). A 56-d feeding trial was conducted in C. quadricarinatus (11·70 (se 0·13) g). Diet with 100 % FM as the protein source was the control. Seven experimental diets were formulated by replacing 75 or 100 % of FM with soyabean meal (SM75, SM100) or cottonseed meal (CM75 and CM100), and a mixture of SM and CM (protein content is 1:1) replacing 50, 75 or 100 % of FM (SC50, SC75 and SC100). Crayfish fed the CM100 and SC100 showed significantly lower weight gain (WG), specific growth rate, trypsin and pepsin activities compared with the control diet. Crayfish in CM100 group showed significantly higher GPx, alanine aminotransferase, aspartate aminotransferase activities and malondialdehyde content than the control. SM100 and CM100 diets can cause slight separation of the peritrophic membrane from the intestinal folds. The pepsin activity of crayfish in SC50 was significantly higher than those in other experimental diets. The highest WG and muscle arginine content were also found in crayfish fed SC50. The relative abundance of Proteobacteria, Unclassified Enterobacteriaceae and Candidatus Bacilloplasma was significantly higher, but Actinobacteriota was significantly lower in SM100, CM100 and SC100 than in control. Microbiota functional prediction indicated that the relative abundance of 'cell motility' pathway in crayfish fed CM100 was significantly decreased compared with the control. In conclusion, only half of the FM can be effectively substituted with a mixture of SM and CM (protein content is 1:1) for C. quadricarinatus.

Vitamin C modulates adrenaline-augmented gastric injury via cardiac troponin/creatine kinase pathway in Wistar rats.

Vitamin C has anti-oxidant benefits in the gastrointestinal tract and heart. This study investigated the effect of vitamin C on some gastric parameters in myocardial injury in rats. Thirty Wistar rats were divided into five groups (n = 6). Group 1 was the control and Group 2 (ADR) received 1 mg/kg of adrenaline subcutaneously on days 13 and 14. Group 3 received vitamin C (200 mg/kg) orally for 14 days. Group 4 received adrenaline (1 mg/kg) on days 1 and 2 and vitamin C from days 1 to 14. Group 5 received vitamin C till day 14 and adrenaline on days 13 and 14. All animals were sacrificed after 2 hr of pyloric ligation. Gastric secretion parameters were assessed while a blood sample was obtained for biochemical analysis. Gastric juice volume, total gastric acidity, pepsin activity, cardiac troponin 1, creatine kinase-MB, and lactate dehydrogenase levels increased (P<0.05) in ADR only group relative to the control. Pre- and post-vitamin C treatment reduced (P<0.05) these markers to near normal. However, treatment with vitamin C reduced (P<0.05) ulcer score, and increased (P<0.05) pepsin activity, mucus weight, and serum vitamin C levels when compared with the ADR-only group. Pre-treatment with vitamin C resulted in a marked decrease (P<0.05) in gastric juice volume, pepsin activity, and total gastric acidity compared with post-treatment in the adrenaline-induced injury group. Vitamin C pretreatment reduces excessive gastric secretions, ulcer scores, and attenuates cardio-inflammatory responses in adrenaline-augmented myocardial injury in rats.

Exploration of binding mechanism of apigenin to pepsin: Spectroscopic analysis, molecular docking, enzyme activity and antioxidant assays

Pepsin plays an important role in nutrient metabolism. Apigenin (AP) is a beneficial polyphenol to human health. To enhance the bioavailability of AP and elucidate the inhibitory effect of AP on pepsin, the interaction mechanism of AP with pepsin was investigated using spectroscopic analysis and molecular docking, and the activity of pepsin and antioxidant activity of AP was also evaluated. Specifically, AP performed static quenching of pepsin and had only one binding site on pepsin. More interestingly, the interaction between AP and pepsin was spontaneous, while hydrogen bonds and van der Waals forces were the main binding forces. Generally, synchronous and three-dimensional fluorescence confirmed that AP induced the conformational changes of pepsin, and molecular docking proved the above results and illustrated the specific binding patterns. Specifically, AP inhibited the activity of pepsin, while pepsin decreased the antioxidant activity of AP. These results provided useful information for elucidating the interactions between AP and pepsin.

A bovine serum albumin and squaraine dye assembly fluorescent probe for pepsin detection

Gastroesophageal reflux disease (GERD) is a highly prevalent condition. Screening for GERD remains a great challenge due to the non-specific nature of the symptoms. Now, salivary pepsin detection has become an effective tool for diagnosing GERD due to its non-invasive and highly specific advantages. However, the diagnosis of GERD by detecting pepsin in saliva still has factors such as long reaction time, poor selectivity, and low detection sensitivity, which need to be improved. In this work, bovine serum albumin (BSA) and a squaraine dye (SQ) were employed to build a BSA-SQ assembly with a fluorescent “on-off” change for rapid and sensitive detection of pepsin. In a Gly-HCl (pH = 2.6) buffer system, SQ had a significant aggregation caused-quenching (ACQ) effect. As SQ was embedded in the cavity of BSA, this improved its dispersion and inhibited the ACQ effect of SQ, resulting in enhanced fluorescence of the system. At this stage, pepsin catalyzed the hydrolysis of BSA, leading to the aggregation of SQ and the quenching of the fluorescence of BSA-SQ. The high catalytic activity of pepsin makes BSA-SQ suitable for the qualitative and quantitative detection of pepsin, showing a good linear relationship in the range of 0.5–40 μg/mL with a detection limit of 97 ng/mL. Finally, the use of this fluorescent probe method to detect pepsin in human saliva showed results consistent with conventional ELISA methods with relative errors between 0.4 and 5.5 %, confirming the great potential of BSA-SQ for the rapid diagnosis of GERD.

Ulcero-Protective Potential of Ethyl Acetate Fractions of Persea americana Seed and Bryophyllum pinnatum Leaf Binary Combinations in Indomethacin Induced Gastric Ulcer

Aims: This study was aimed at investigating the protective potential of ethyl acetate fractions of Persea americana (PA) seed and Bryophyllum pinnatum (BP) leaf binary combinations against indomethacin-induced gastric ulcers.&#x0D; Methodology: Fifty (50) male Wistar rats were used in this study; they were assigned into 10 groups of five animals each and respective groups received a standard rat diet and drinking water ad libitum. The groups were group 1 (normal control group (NC)), group 2 (ulcer control (UC)), group 3 (Omeprazole, 20mgkg-1 (OMEP)), group 4 (PA) and group 5 (BP). Groups receiving binary combinations were group 6 (PA + BP, 1:1), group 7 (PA + BP, 1:2), group 8 (PA + BP, 1:3), group 9 (PA + BP, 2:1), group 10 (PA + BP, 3:1) each group was pre-treated with 400 mgKg-1 body weight/day of respective fraction or binary mixture by intubation for 21 days. On the 22nd day after overnight fasting, a gastric ulcer was induced with indomethacin (30mg/kg body weight) by intubation in a single dose. Ulcer markers and histopathology of stomach tissues were measured using standard methods.&#x0D; Results: The present study revealed that the ethyl acetate fraction of the plants PA seeds and BP leaf showed potent gastric tissue protective effects. Analysis of gastric changes indicated a significant (P&lt;0.05) reduction in ulcer index, gastric acid output, gastric mucus content and pepsin activity of ulcerated rats pretreated with PA and BP fractions. The effect of the binary combinations was significantly (p&lt;0.05) higher than single plant fractions. The protective effect of the fractions was in the order OMEP &gt; PA+BP (3:1) &gt; PA+BP (2:1) &gt; PA+BP (1:1), &gt; PA+BP (1:2) &gt; PA+BP (1:3) &gt; PA &gt; BP. The observed ulcero-protective effect of the binary combinations of P. americana seed and B. pinnatum leaf may be attributed to the synergy of the phytochemicals contained in the fractions.&#x0D; Conclusion: These findings suggest that P. americana and B. pinnatum ethyl acetate fraction combination favorably protect against indomethacin-induced gastric mucosal oxidative damage, reducing ulcer index, gastric acid output, gastric mucus content and pepsin activity. The ethyl acetate fractions exhibited a dose-dependent inhibition of ulcer formation in indomethacin gastric ulcer model.

A comprehensive insight into the effects of caffeic acid (CA) on pepsin: Multi-spectroscopy and MD simulations methods

The interaction between caffeic acid (CA) and pepsin was investigated using multi-spectroscopy approaches and molecular dynamic simulations (MDS). The effects of CA on the structure, stability, and activity of pepsin were studied. Fluorescence emission spectra and UV–vis absorption peaks all represented the static quenching mechanism of pepsin by CA. Moreover, the fluorescence spectra displayed that the interaction of CA exposed the tryptophan chromophores of pepsin to a more hydrophilic micro-environment. Consistent with the simulation results, thermodynamic parameters revealed that CA was bound to pepsin with a high binding affinity. The Van der Waals force and Hydrogen bond interaction were the dominant driving forces during the binding process. The circular dichroism (CD) spectroscopy analysis showed that the CA binding to pepsin decreased the contents of α-Helix and Random Coil but increased the content of β-sheet in the pepsin structure. Accordingly, MD simulations confirmed all the experimental results. As a result, CA is considered an inhibitor with adverse effects on pepsin activity.

Growth, Muscle Nutrition Composition, and Digestive Enzyme Activities of the Juvenile and Adult Siniperca chuatsi Fed on Live Baits and a Formulated Diet

The present study aimed to evaluate the feasibility of a formulated diet to replace live baits as feed for Siniperca chuatsi. A 2 × 2 factorial design with three replicates was used to investigate the effects of conventional live baits (LB) and a formulated diet (FD) on the growth, muscle nutrition composition, and digestive enzyme activities of S. chuatsi at two growth stages. The results showed that the feed conversion ratio (FCR) in the FD group was significantly lower than that in the LB group. The final body weight (FBW) and weight gain (WG) were not significantly different between the two feeding modes. However, at the juvenile stage, the specific growth rate (SGR) in the FD group was significantly lower than that in the LB group. Muscle moisture, crude protein, and crude lipid contents were not influenced by dietary treatments. There were no significant differences in ∑EAA, ∑NEAA, and ∑AA compositions of the juvenile and adult stages fed the two kinds of diets. At the juvenile stage, histidine (His) content in the FD group was significantly higher than that in the LB group; at the adult stage, cysteine (Cys) content in the FD group was significantly higher than that in the LB group; at both growth stages, Met content in the FD group was significantly lower than that in the LB group. The FD group showed higher levels of ∑SFA, ∑HUFA, ∑n-3PUFA, n-3/n-6, EPA, and DHA than the LB group did, whilst the opposite occurred in the MUFA levels. In addition, fish fed with LB had significantly higher values of pepsin and intestinal trypsin activities in the juvenile fish compared to the FD group, but the activities were not significantly different between the two feeding modes at the adult stage. The activities of stomach and intestine amylase in the FD group were significantly higher than those in the LB group. Overall, these results showed that under long-term feeding conditions, S. chuatsi fed with the artificial diet had no significant difference in muscle crude protein, crude lipid, amino acid composition, and digestive capacity, but showed superiority in the composition of fatty acids such as EPA and DHA levels compared to the live baits group. Therefore, the artificially formulated diet might be a more appropriate feeding approach for sustainable development of the S. chuatsi industry.

Effects of Glutamine on Rumen Digestive Enzymes and the Barrier Function of the Ruminal Epithelium in Hu Lambs Fed a High-Concentrate Finishing Diet.

The present experiment aimed to research the effects of glutamine (Gln) on the digestive and barrier function of the ruminal epithelium in Hu lambs fed a high-concentrate finishing diet containing some soybean meal and cottonseed meal. Thirty healthy 3-month-old male Hu lambs were randomly divided into three treatments. Lambs were fed a high-concentrate diet and supplemented with 0, 0.5, and 1% Gln on diet for 60 days. The experimental results show that the Gln treatment group had lower pepsin and cellulase enzyme activity, propionate acid concentration, and IL-6, TNF-α, claudin-1, and ZO-1 mRNA expression in the ruminal epithelium (p < 0.05); as well as increases in lipase enzyme activity, the ratio of propionic acid to acetic acid, the IL-10 content in the plasma, and the mRNA expression of IL-2 and IL-10 in the ruminal epithelium, in contrast to the CON (control group) treatment (p < 0.05). Taken together, the findings of this present study support the addition of Gln to improve digestive enzyme activity, the ruminal epithelium’s barrier, and fermentation and immune function by supplying energy to the mononuclear cells, improving the ruminal epithelium’s morphology and integrity, and mediating the mRNA expression of tight junction proteins (TJs) and cytokines.

In vitro evaluation of the gastrointestinal delivery of acid-sensitive pancrelipase in a next generation enteric capsule using an exocrine pancreatic insufficiency disease model

The dissolution characteristics of five capsules (Next Generation Enteric [NGE], Vcaps® Enteric [VCE], VCE DUOCAP® [VCE/VCE] system, Hard Gelatin Capsule [HGC] as negative control, and Creon® 10,000 U as market reference) were evaluated using an in vitro simulation of the stomach and upper intestinal tract with an acidic duodenal incubation (pH 4.5 for the first 10 min, pH 6 for the remaining 17 min) to simulate exocrine pancreatic insufficiency. Caffeine was a marker of capsule dissolution, and tributyrin to butyrate conversion measured pancrelipase activity. All capsules were filled with pancrelipase; the NGE, VCE, VCE/VCE, and HGC capsules also contained 50 mg caffeine. Caffeine was released first from the HGC capsule, followed by the VCE, NGE, and VCE/VCE capsules. Pancrelipase activity followed this trend and demonstrated a similar activity level over time for the NGE, VCE/VCE, and Creon® capsules. The HGC formulation confirmed gastric degradation of unprotected pancrelipase. NGE capsules provided similar protection to the simple fill formulation as observed for the complex formulation of the Creon® capsule in a setting with increased pepsin activity and may hasten the time needed to go from formula development to first-in-human studies for pH sensitive drugs or those requiring small intestine targeting.

The impact of the soluble protein fraction and kernel hardness on wheat flour starch digestibility

Wheat is the staple crop for 35% of the world’s population, providing a major source of calories, mainly in the form of starch. The digestibility of wheat starch varies between different flours and products. Wheat products that are rapidly digested elicit large post-prandial glucose peaks associated with metabolic disorders. We investigated the impact of protein on starch digestion in three commercial flours with different grain hardness. A soluble extract of wheat proteins reduced starch digestion, even following gastric proteolysis. This extract was enriched in proteinaceous α-amylase inhibitors which were partially degraded during gastric proteolysis. Starch digestion kinetic analysis was carried out for flour samples pre-treated with different pepsin activities. The rate of starch digestion was altered following pepsin pre-digestion, and the extent of starch digestion increased in response to pepsin pre-digestion. We conclude that soluble proteinaceous alpha-amylase inhibitors present in wheat can escape gastric digestion and significantly contribute to reducing starch digestion in the small intestine.

Effect of water temperature on embryonic development of Protunus trituberculatus in an off-season breeding mode

Portunus trituberculatus (swimming crab) is an important breeding crab in China. The current breeding mode of swimming crab is still the traditional “spring seedling and winter harvest” breeding mode. In recent years, researchers have begun to explore a new off-season breeding mode through autumn seedling. In this study, the rate of embryonic development, embryo antioxidant ability and hatching rate of swimming crab in different water temperatures in an off-season breeding mode (breeding in early autumn) and digestive enzyme activity of newly hatched larvae were compared. The results showed that the duration of each development stage of swimming crab embryos was gradually reduced with increasing water temperature. The total development time was 9.43 d at 27°C and only 6.88 d at 33°C. These effects were accompanied by an increase in the development rate from 0.11 d-1 to 0.15 d-1. The total effective accumulated temperature under the 4 temperature conditions was basically maintained at about 150°C·d (147.08 ∼ 153.62°C·d), and there was no significant difference between different groups. The development of embryos at 27°C and 29°C was very synchronous, and no abnormal embryos were observed. Conversely, at 31°C, the later stage of development exhibited asynchrony, and diapause and death were noted in some embryos. At 33°C, more embryos died. The embryo hatching rate was approximately 70% at 27°C and 29°C, and the rate was significantly reduced at 31°C and 33°C. Specifically, the rate was only 13.89% at 33°C. As the water temperature increased, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) as well as the total antioxidant capacity (T-AOC) and malondialdehyde (MDA) levels of embryos increased first and then decreased, reaching the highest value at 31°C. Catalase (CAT) activity exhibited the opposite trend which was the lowest at 29 °C with a value of only 0.17 U/mg prot and the highest at 33°C with a value of up to 0.51 U/mg prot. At temperatures of 27°C, 29°C and 31°C, the differences in various digestive enzymes of newly hatched larvae primarily manifested as the high activities of pepsin (PEP) and α-amylase (AMS) at 31°C, and other differences were not obvious. At 33°C during embryonic development, the activities of various digestive enzymes were relatively low, especially the activities of trypsin (TPS) and cellulase (CL), which were significantly lower than those of the other three temperature groups. Therefore, judging from the antioxidant index of embryos and the digestive enzyme activity of newly hatched larvae, the embryonic development was still good when the water temperature was 31°C, accompanied by water temperatures above 31°C that seriously affected enzyme activity. Overall, a temperature below 31°C represents the appropriate temperature for embryonic development in autumn in swimming crabs.

Achillea millefolium Essential Oil Mitigates Peptic Ulcer in Rats through Nrf2/HO-1 Pathway.

Extreme ethanol ingestion is associated with developing gastric ulcers. Achillea millefolium (yarrow) is one of the most commonly used herbs with numerous proven pharmacological actions. The goal of the hereby investigation is to explore the gastroprotective action of yarrow essential oil against ethanol-induced gastric ulcers and to reveal the unexplored mechanisms. Rats were distributed into five groups (n = 6); the control group administered 10% Tween 20, orally, for two weeks; the ethanol group administered absolute ethanol (5 mL/kg) to prompt gastric ulcer on the last day of the experiment. Yarrow essential oil 100 or 200 mg/kg + ethanol groups pretreated with yarrow oil (100 or 200 mg/kg, respectively), orally, for two weeks prior to gastric ulcer induction by absolute ethanol. Lanso + ethanol group administered 20 mg/kg lansoprazole, orally, for two weeks prior to gastric ulcer induction by ethanol. Results of the current study showed that ethanol caused several macroscopic and microscopic alterations, amplified lipid peroxidation, pro-inflammatory cytokines, and apoptotic markers, as well as diminished PGE2, NO, and antioxidant enzyme activities. On the other hand, animals pretreated with yarrow essential oil exhibited fewer macroscopic and microscopic modifications, reduced ulcer surface, and increased Alcian blue binding capacity, pH, and pepsin activity. In addition, yarrow essential oil groups exhibited reduced pro-inflammatory cytokines, apoptotic markers, and MDA, restored the PGE2 and NO levels, and recovered the antioxidant enzyme activities. Ethanol escalated Nrf2 and HO-1 expressions, whereas pretreatment of yarrow essential oil caused further intensification in Nrf2 and HO-1. To conclude, the current study suggested yarrow essential oil as a gastroprotective agent against ethanol-induced gastric lesions. This gastroprotective effect could be related to the antioxidant, anti-inflammatory, and anti-apoptotic actions of the essential oil through the instigation of the Nrf2/HO-1 pathway.

Ultrasonic treatment of foam for the prevention of foam-induced pepsin inactivation

The phenomenon of foam-induced inactivation is a common challenge during foam fractionation of proteins. In this work, we attempted to use ultrasound to treat foam out of the foam fractionation column with the aim of minimizing the foam-induced protein inactivation using pepsin as a model protein. Firstly, the mechanisms by which ultrasound prevented the foam-induced pepsin inactivation during defoaming were explored. The results showed that ultrasound promoted the refolding of unfolded pepsin molecules at the gas-liquid interface to restore their activities during the desorption process from the interface and before dissolving into the foamate. Subsequently, the effects of ultrasonic power on the pepsin renaturation were analyzed, which revealed that the unfolding degree of pepsin in the foamate gradually decreased and then increased as the ultrasonic power increased. Correspondingly, the specific activity of pepsin in the foamate increased and then decreased. Finally, we explored the effects of defoaming efficiency, type of gas and pH. The results indicated that the decrease in defoaming efficiency and gas solubility in water facilitated the ultrasound-assisted pepsin renaturation in the pH range from 1.0 to 2.5. When air was applied in the foaming process, the specific activity of pepsin in the foamate with ultrasonic treatment was not significantly different from that in the feed solution at ultrasonic power of 400 W and pH 2.0. Collectively, these results indicate the ultrasonic treatment of foam effectively prevented the foam-induced pepsin inactivation.

Characteristics of basal gastric juice in Helicobacter pylori-associated gastritis before and after eradication therapy

Purpose: To evaluate the characteristics of basal gastric juice in Helicobacter pylori-positive patients before and after Helicobacter pylori eradication therapy. &#x0D; Methods: This was a cross-sectional descriptive study on 150 gastritis patients admitted at the Hospital of Can Tho University of Medicine and Pharmacy. The patients were divided into 2 groups: study group (Helicobacter pylori gastritis patients) and control group (non-Helicobacter pylori gastritis patients). The pH, HCO3- concentration, and activities and concentrations of pepsin, lipase, and amylase were determined before and after treatment in study group. &#x0D; Results: Patients with abnormal gastric juice comprised 76 % of the study population. Mean gastric potential of hydrogen (pH) was 2.31 (range: 1.64 - 7.68), while median concentration of HCO3- was 4.06 mmol/L (range: 0 - 73.04 mmol/L). The concentrations of pepsin, lipase, and amylase were 8.93, 0.93 and 1.38 ppm, respectively. Activities of pepsin, lipase, and amylase were 2.23, 0.28 and 0.04 U/mL, respectively. After the successful eradication of Helicobacter pylori, pH and HCO3- levels decreased, and there were significant differences in activities of pepsin and lipase before and after treatment (p &lt; 0.05). Moreover, the levels of these parameters differed between patients in whom successful eradication was achieved and those in whom eradication failed (p &lt; 0.05). The concentrations and activities of pepsin and lipase were statistically different between pre-treatment and post-treatment stages in both successful and failed Helicobacter pylori eradication categories (p &lt; 0.05). &#x0D; Conclusion: Basal gastric juice differs significantly between Helicobacter pylori-positive and Helicobacter pylori-negative patients. Intragastric ammonia produced by H. pylori may have a role in the increased pH of gastric juice.

Dietary Cinnamaldehyde Enhances Growth Performance, Digestion, Immunity, and Lipid Metabolism in Juvenile Fat Greenling (Hexagrammos otakii).

Fat greenling (Hexagrammos otakii) is a kind of economic fish that is widely consumed by human, and its intensive farming technology is making important progress. However, high-density farming may cause the occurrence of diseases in H. otakii. Cinnamaldehyde (CNE) is a new feed additive for aquatic animals and has a positive effect on disease resistance. In the study, dietary CNE was evaluated on the growth performance, digestion, immune response, and lipid metabolism of juvenile H. otakii (6.21 ± 0.19 g). Six experimental diets were formulated containing CNE at levels of 0, 200, 400, 600, 800, and 1000 mg/kg for 8 weeks. The percent weight gain (PWG), specific growth rate (SGR), survival (SR), and feeding rate (FR) were significantly increased by including CNE in fish diets regardless of the inclusion level (P < 0.05). The feed conversion ratio (FCR) was significantly decreased among the groups fed CNE supplemented diets (P < 0.05). A significant decrease in hepatosomatic index (HSI) was observed in fish fed 400 mg/kg-1000 mg/kg CNE compared to the control diet (P < 0.05). Fish-fed diets containing 400 mg/kg and 600 mg/kg CNE had a higher level of crude protein in muscles than the control diet (P < 0.05). Moreover, the activities of lipase (LPS) and pepsin (PEP) in the intestinal were markedly increased in juvenile H. otakii-fed dietary CNE (P < 0.05). Apparent digestibility coefficient (ADC) of dry matter, protein, and lipid was significantly increased with CNE supplement (P < 0.05). The activities of catalase (CAT) and acid phosphatase (ACP) in the liver were markedly enhanced by including CNE in juvenile H. otakii diets compared with the control (P < 0.05). The activities of superoxide dismutase (SOD) and alkaline phosphatase (AKP) in the liver were markedly enhanced in juvenile H. otakii treated with CNE supplements 400 mg/kg-1000 mg/kg (P < 0.05). Additionally, the levels of total protein (TP) in the serum were markedly increased by including CNE in juvenile H. otakii diets compared with the control (P < 0.05). In the CNE200, CNE400, and CNE600 groups, albumin (ALB) levels in the serum were markedly higher compared with that in the control (P < 0.05). In the CNE200 and CNE400 groups, the levels of immunoglobulin G (IgG) in the serum were significantly increased compared with that the control group (P < 0.05). The juvenile H. otakii-fed dietary CNE had lower triglycerides (TG) and total cholesterol (TCHO) levels in the serum than fish-fed CNE-free diets (P < 0.05). The gene expression of peroxisome proliferator-activated receptor alpha (PPAR-α), hormone-sensitive lipase (HSL), and carnitine O-palmitoyltransferase 1 (CPT1) in the liver was significantly increased by including CNE in fish diets regardless of the inclusion level (P < 0.05). However, fatty acid synthase (FAS), peroxisome proliferator-activated receptor gamma (PPAR-γ), and acetyl-CoA carboxylase alpha (ACCα) in the liver were markedly decreased with CNE supplements 400 mg/kg-1000 mg/kg (P < 0.05). The glucose-6-phosphate1-dehydrogenase (G6PD) gene expression levels in the liver were markedly decreased compared with the control (P < 0.05). The optimal supplementation level of CNE was shown by curve equation analysis to be 590.90 mg/kg.

Evaluation of mechanism(s) of action underlying the antioxidant and antiulcer activity of Sesamum indicum leaves extract in experimental rats.

The current study aimed to estimate phytochemical screening, in vitro antioxidant activity, and gastroprotective activity of Sesamum indicum Linn ethanolic extract. The current study was held out by ulceration induced by pylorus ligation and indomethacin-induced ulcer screening models in Wister albino rats. The screening of antiulcer activity of ethanolic extract of S. indicum leaves (EESIL) at the different amounts (100, 200, and 400 mg/kg; per orally for 7 days) was compared with omeprazole as a usual antiulcer drug. Additional parameters such as gastric content, pH, total acidity, pepsin activity ulcer score, free acidity, ulcer index (UI), % inhibition of ulcers, mean mucin, pepsin content, and total protein content were observed. In the pylorus ligation model, the pepsin activity free acidity, pepsin content, UI, total acidity, ulcer score, total protein content, and percentage ulcer inhibition were considerably decreased (P < 0.05 and P < 0.01), and mean mucin and gastric content pH extensively elevated (P < 0.05 and P < 0.01) in EESIL tested groups in the comparison of the control group. Doses (100, 200, and 400 mg/kg p.o.) of EESIL showed dose-reliant gastro protective outcomes, a considerable (P < 0.05 and P < 0.01) decrease in gastric parameters as UI and ulcer score and induction in gastric pH and percentage inhibition of ulcer compared with the control group. Antioxidant, anti-Ulcer, EESIL, and EESIL show antioxidant activity at different concentration. The fallout of the study indicated that the EESIL had improved antiulcer potential due to the decrease in offensive factors and increase in defensive factors.

Impact of Pulsed Electric Fields and pH on Enzyme Inactivation and Bioactivities of Peptic Hydrolysates Produced from Bovine and Porcine Hemoglobin.

The production of bioactive peptides from hemoglobin via peptic hydrolysis is a promising alternative to valorizing slaughterhouse blood proteins. Nevertheless, it has some limitations such as low yield, high cost of enzymes, and the use of chemical reagents. The latter is aggravated by the pH increase to inactivate the enzyme, which can affect the bioactivity of the peptides. Thus, this study aimed to evaluate the effect of pulsed electric fields (PEF) on the pepsin inactivation and biological activities (antimicrobial and antioxidant) of hemoglobin hydrolysates. Bovine (Hb-B) and porcine (Hb-P) hemoglobin were hydrolyzed with pepsin for 3 h and treated with PEFs to inactivate the enzyme. The degree of hydrolysis (DH) did not show significant changes after PEF inactivation, whereas peptide population analysis showed some changes in PEF-treated hydrolysates over time, suggesting residual pepsin activity. PEF treatments showed no significant positive or negative impact on antimicrobial and antioxidant activities. Additionally, the impact of pH (3, 7, and 10) on bioactivity was studied. Higher pH fostered stronger anti-yeast activity and DPPH-scavenging capacity, whereas pH 7 fostered antifungal activity. Thus, the use of hemoglobin from the meat industry combined with PEF treatments could fit the circular economy concept since bioactive peptides can be produced more eco-efficiently and recycled to reduce the spoilage of meat products. Nevertheless, further studies on PEF conditions must be carried out to achieve complete inactivation of pepsin and the potential enhancement of peptides' bioactivity.

Surface chemistry of graphene tailoring the activity of digestive enzymes by modulating interfacial molecular interactions

As a kind of novel functional material, graphene-related nanomaterials (GRMs) have great potentials in industrial and biomedical applications. Meanwhile, the production and wide application of GRMs will increase the risk of unintended or intentional oral exposure to human beings, attracting safety concerns about their biological fates and toxicological effects. The normal enzymatic activity of digestive enzymes is essential for the proper functioning of the gastrointestinal tract system. However, whether and how orally entered GRMs and their surface groups affect digestive enzymes’ activity are still scarce. In this paper, we systematically studied the effects of graphene oxide (GO), graphene modified with hydroxyl groups (OH-G), carboxyl groups (COOH-G), and amino groups (NH2-G) on enzymatic activity of three typical digestive enzymes (pepsin, trypsin, and α-pancreatic amylase). The results showed that the activity of trypsin and α-pancreatic amylase could be greatly changed after GRMs incubation in a surface chemistry dependent manner, while the activity of pepsin was not affected. To elucidate the mechanisms at the molecular level, the interactions between trypsin and GRMs were studied by spectrometry, thermophoresis, and computational simulation approaches, and the key roles of surface chemistry of GRMs in tailoring the activity of trypsin were finally figured out. GO allosterically inhibited trypsin’s activity in the non-competitive manner because of the conformation transition induced by the intensive interactions. COOH-G could effectively hamper enzymatic activity of trypsin in the competitive manner by blocking the active catalytic pocket. As for NH2-G and OH-G, they had little impact on the activity of trypsin due to the weak binding affinity or limited conformational change. Our findings not only indicate surface chemistry plays an important role in tailoring the effects of GRMs on the activity of digestive enzymes but also provide new insights for understanding the oral safety of nanomaterials from daily products and the environment.

Multiple effects driven by pulsed electric field to enhance the catalytic efficiency of the mussel-inspired proteolytic membrane in protein hydrolysis

Although the immobilization of enzymes on the membrane is an effective method to improve enzyme stability and reusability, the immobilized enzyme also causes low activity and reduces substrate accessibility. In order to overcome these shortcomings and provide a viable proteolytic membrane with increasing enzyme activity and substrate accessibility, a pulsed electric field (PEF)-assisted proteolytic membrane (PAPM) was constructed by immobilizing PEF-treated pepsin on PDA and PEI co-deposited ultrafiltration membrane. The PEF-treated pepsin endowed high activity (165.33 ± 2.31 %) and charge amount (−3.95 mV), with stable and uniform particle size (39 nm). These phenomena were attributed to the multiple effects driven by PEF, including the diffusion effect, electrolysis reactions, and microstructural regulation. Specifically, PAPM retained 80 % of original pepsin activity and enhanced 25 % pepsin activity compared to the conventional proteolytic membrane (PM). Such improvement can be ascribed to two factors: Firstly, PEF regulated pepsin microstructure to an optimal structure (4.6 % increase of the α-helix and 4.0 % reduction of the random coil) for pepsin immobilization. Secondly, PEF changed pepsin charge properties from positive (+1.62 mV) to negative (−3.95 mV), while substrate charges were positive. Heterogeneous charge interactions between pepsin and substrates increased the accessibility of the substrate to immobilized pepsin, effectively promoting enzymatic reactions. This study offers a feasible method to prepare the proteolytic membrane in protein hydrolysis.