Antiulcerative properties of bovine α-lactalbumin

Role of whey protein in vascular function: a systematic review and meta-analysis of human intervention studies

Whey protein (WP) has been heavily appreciated as a rich source of bioactive peptides, with potential benefits for cardiovascular health. This study constitutes a systematic review and meta-analysis summarising the effects of WP consumption on vascular reactivity, arterial stiffness and circulatory biomarkers of vascular function. We searched electronic databases, including PubMed, SCOPUS and Web of science for relevant articles from inception to July 2020. Original clinical trials published in English-language journals that investigated the effects of WP on vascular function were eligible. A total of 720 records were identified in the initial search; from these, sixteen were included in our systematic review and thirteen in meta-analysis. The pooled analysis of six studies showed a significant increase in flow-mediated dilation (FMD) after WP consumption (weighted mean differences (WMD): 1·09 %, 95 % CI: 0·17, 2·01, P= 0·01). Meta-analysis of available data did not show any significant reduction in arterial stiffness measures including augmentation index (effect sizes: 7, WMD: -0·29 %, 95 % CI: -1·58, 0·98, P= 0·64) and pulse wave velocity (effect sizes: 4, WMD: -0·72 m/s, 95 % CI: -1·47, 0·03, P= 0·06). Moreover, the pooled analysis of six effect sizes showed no significant effects on plasma levels of nitric oxide following WP supplementation (WMD: 0·42 μmol/l, 95 % CI: -0·52, 1·36, P= 0·38). The overall results provided evidence supporting a protective effect of WP on endothelial function measured by FMD, but not for arterial stiffness measures and circulatory biomarker of vascular function. Further research is required to substantiate the benefits of WP on vascular function.

α-Lactalbumin, Amazing Calcium-Binding Protein

α-Lactalbumin (α-LA) is a small (Mr 14,200), acidic (pI 4–5), Ca²⁺-binding protein. α-LA is a regulatory component of lactose synthase enzyme system functioning in the lactating mammary gland. The protein possesses a single strong Ca²⁺-binding site, which can also bind Mg²⁺, Mn²⁺, Na⁺, K⁺, and some other metal cations. It contains several distinct Zn²⁺-binding sites. Physical properties of α-LA strongly depend on the occupation of its metal binding sites by metal ions. In the absence of bound metal ions, α-LA is in the molten globule-like state. The binding of metal ions, and especially of Ca²⁺, increases stability of α-LA against the action of heat, various denaturing agents and proteases, while the binding of Zn²⁺ to the Ca²⁺-loaded protein decreases its stability and causes its aggregation. At pH 2, the protein is in the classical molten globule state. α-LA can associate with membranes at neutral or slightly acidic pH at physiological temperatures. Depending on external conditions, α-LA can form amyloid fibrils, amorphous aggregates, nanoparticles, and nanotubes. Some of these aggregated states of α-LA can be used in practical applications such as drug delivery to tissues and organs. α-LA and some of its fragments possess bactericidal and antiviral activities. Complexes of partially unfolded α-LA with oleic acid are cytotoxic to various tumor and bacterial cells. α-LA in the cytotoxic complexes plays a role of a delivery carrier of cytotoxic fatty acid molecules into tumor and bacterial cells across the cell membrane. Perhaps in the future the complexes of α-LA with oleic acid will be used for development of new anti-cancer drugs.

Antiulcer and antiproliferative properties of spent brewer's yeast peptide extracts for incorporation into foods

The main objective was to study the antiulcer and antiproliferative potential of yeast peptide extract for further incorporation into functional foods.

Milk proteins, peptides, and oligosaccharides: effects against the 21st century disorders

Milk is the most complete food for mammals, as it supplies all the energy and nutrients needed for the proper growth and development of the neonate. Milk is a source of many bioactive components, which not only help meeting the nutritional requirements of the consumers, but also play a relevant role in preventing various disorders. Milk-derived proteins and peptides have the potential to act as coadjuvants in conventional therapies, addressing cardiovascular diseases, metabolic disorders, intestinal health, and chemopreventive properties. In addition to being a source of proteins and peptides, milk contains complex oligosaccharides that possess important functions related to the newborn's development and health. Some of the health benefits attributed to milk oligosaccharides include prebiotic probifidogenic effects, antiadherence of pathogenic bacteria, and immunomodulation. This review focuses on recent findings demonstrating the biological activities of milk peptides, proteins, and oligosaccharides towards the prevention of diseases of the 21st century. Processing challenges hindering large-scale production and commercialization of those bioactive compounds have been also addressed.

Gastroprotective effects of goniothalamin against ethanol and indomethacin-induced gastric lesions in rats: Role of prostaglandins, nitric oxide and sulfhydryl compounds

Goniothalamin (GTN), a styryl-lactone, is a secondary metabolite naturally found in its enantiomeric form (R) in plants of the genus Goniothalamus (Annonaceae). The antiproliferative activity against human tumor cell lines reported in several studies suggest that the α,β-unsaturated δ-lactone moiety emerges as a key Michael acceptor for cysteine residues or other nucleophilic biological molecules. Our group reported on the in vivo activity of (R)- and (S)-GTN as well as its racemic form (rac-GTN) in both Ehrlich solid tumor and carrageenan-induced paw edema in mice, without side effects in the effective doses. Despite the rich body of data on the in vitro GTN biological activity, much less is known about its in vivo pharmacological action. Herein we describe the gastroprotective activity of rac-GTN on chemical-induced gastric ulcers models in rats. GTN has a potent gastroprotective effect on ethanol-induced ulcers (effective dose50=18mg/kg) and this activity is dependent on sulfhydryl compounds and prostaglandins generation, but independent of nitric oxide (NO), gastric secretion and mucus production. We hypothesize that goniothalamin may act as a mild irritant, inducing the production of sulfhydryl compounds and prostaglandins, in a process known as adaptive cytoprotection. This hypothesis is supported by the fact that Michael acceptors are the most potent inducers of antioxidant response (as activation of Nrf2 pathway) through generation of mild oxidative stress and that gastroprotective activity of goniothalamin is inhibited after pre-treatment with NEM (N-ethylmaleimide) and NSAID (non-steroidal anti-inflammatory drugs), highlighting the importance of sulfhydryl compounds and prostaglandins on GTN activity.

Mechanisms involved in the gastroprotective activity of Celtis iguanaea (Jacq.) Sargent on gastric lesions in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Celtis iguanaea (Canabaceae) is popularly known as esporão-de-galo, stands out among the medicinal plants used for treatment of gastric ulcers. In Brazil, the leaves they are used traditionally in infusion forms as an analgesic, antiasthmatic, digestive and diuretic.

AIM OF THE STUDY

The present study was aimed to investigate the antiulcer mechanisms of hexane extract Celtis iguanaea leaves (HE) in several induced-gastric ulcer and characterize its chemical composition.

MATERIALS AND METHODS

The HE was obtained by exhaustive extraction in Soxhlet apparatus. The chemical characterization of HE was performed by Electrospray Fourier transform ion cyclotron mass spectrometry (ESI FT-ICR MS) analysis. Mice were used for the evaluation of the gastroprotective activity. HE was analyzed in the HCl/ethanol, hypothermic restraint stress ulcer and acetic acid. In the investigation of the gastroprotective mechanisms of HE, were performed the amount of adhered gastric mucus, participation of the α2-adrenoceptor, nitric oxide (NO) and prostaglandins (PGs) using the HCl/ethanol-induced gastric mucosa lesion model.

RESULTS

ESI FT-ICR MS analysis of HE suggest the presence of compounds as lipids, sterol lipids, steroids glycosides and polyphenol glycosides. The oral administration of HE at doses of 100 mg/kg or 200 mg/kg was able to protect the gastric mucosa against HCl/ethanol (10 mL/kg p.o.), and HE at dose of 100mg/kg protected against hypothermic-restraint stress and acetic -induced gastric lesions. The pretreatment with Yoimbine (2mg/kg, s.c.), an antagonist α2-adrenergic, L-NAME (20mg/kg, s.c.), an inhibitor of nitric oxide synthesis or indomethacin (10mg/kg, s.c.), an inhibitor of prostaglandin production, reversed the gastroprotective activity of HE (100mg/kg, p.o.).

CONCLUSIONS

Our results suggest that the Celtis iguanaea HE exhibits gastroprotective activity in different gastric ulcer models. The mechanism of gastroprotective effect of Celtis iguanaea HE suggests the participation of mucus as well as the involvement of α2-adrenergic receptors, NO and prostaglandins. The hydroxyl-linolenic acid, linoleic acids and conjugated oxo-linoleic acids are among the phytoconstituents that were identified in the Celtis iguanaea HE.

Efficacy of fermented milk and whey proteins in Helicobacter pylori eradication: A review

Helicobacter pylori (H. pylori) eradication is considered a necessary step in the management of peptic ulcer disease, chronic gastritis, gastric adenocarcinoma and mucosa associated lymphoid tissue lymphoma. Standard triple therapy eradication regimens are inconvenient and achieve unpredictable and often poor results. Eradication rates are decreasing over time with increase in antibiotic resistance. Fermented milk and several of its component whey proteins have emerged as candidates for complementary therapy. In this context the current review seeks to summarize the current evidence available on their role in H. pylori eradication. Pertinent narrative/systematic reviews, clinical trials and laboratory studies on individual components including fermented milk, yogurt, whey proteins, lactoferrin, α-lactalbumin (α-LA), glycomacropeptide and immunoglobulin were comprehensively searched and retrieved from Medline, Embase, Scopus, Cochrane Controlled Trials Register and abstracts/proceedings of conferences up to May 2013. A preponderance of the evidence available on fermented milk-based probiotic preparations and bovine lactoferrin suggests a beneficial effect in Helicobacter eradication. Evidence for α-LA and immunoglobulins is promising while that for glycomacropeptide is preliminary and requires substantiation. The magnitude of the potential benefit documented so far is small and the precise clinical settings are ill defined. This restricts the potential use of this group as a complementary therapy in a nutraceutical setting hinging on better patient acceptability/compliance. Further work is necessary to identify the optimal substrate, fermentation process, dose and the ideal clinical setting (prevention/treatment, first line therapy/recurrence, symptomatic/asymptomatic, gastritis/ulcer diseases etc.). The potential of this group in high antibiotic resistance or treatment failure settings presents interesting possibilities and deserves further exploration.

Food-derived peptides stimulate mucin secretion and gene expression in intestinal cells

In this study, the hypothesis that food-derived opioid peptides besides β-casomorphin 7 might modulate the production of mucin via a direct action on epithelial goblet cells was investigated in HT29-MTX cells used as a model of human colonic epithelium. Seven milk whey or casein peptides, a human milk peptide, and a wheat gluten-derived peptide with proved or probable ability to bind μ- or δ-opioid receptors were tested on the cell culture. Significantly increased secretion of mucins was found after exposure to six of the assayed peptides, besides the previously described β-casomorphin 7, as measured by an enzyme-linked lectin assay (ELLA). Human β-casomorphin 5 and α-lactorphin were selected to study the expression of mucin 5AC gene (MUC5AC), the HT29-MTX major secreted mucin gene. α-Lactorphin showed increased expression of MUC5AC from 4 to 24 h (up to 1.6-fold over basal level expression), although differences were statistically different only after 24 h of exposure. However, this increased expression of MUC5AC did not reach significance after cell treatment with human β-casomorphin 5. In conclusion, six food-derived peptides have been identifed with described or probable opioid activity that induce mucin secretion in HT29-MTX cells. Concretely, α-lactorphin is able to up-regulate the expression of the major secreted mucin gene encoded by these cells.

Partial chemical and functional characterization of milk whey products obtained by different processes

Whey protein samples (S-1 to S-5) were tested in vivo and in vitro for nutritional properties and selected bioactivities. Weanling male Wistar rats fed modified AIN-93G (12 g protein.100 g-1) diets for 21 days were used the in vivo studies. The nutritional parameters did not differ among the protein diets tested. Erythrocyte glutathione content was considered high and was higher for S-3, but liver glutathione was the same for all dietary groups. For S-3, cytokine secretion (IL-10 and TNF-α) by human peripheral blood mononuclear cells (in RPMI-1640 medium) was higher in the absence of antigen than in the presence of BCG antigen. Interleukin-4 secretion was repressed in all treatments. The IC50, whey protein concentration required to inhibit 50% of the melanoma cell proliferation, was 2.68 mg.mL-1 of culture medium for the S-3 sample and 3.66 mg.mL-1 for the S-2 sample. Based on these results, it was concluded that S-3 (whey protein concentrate enriched with TGF-β and lactoferrin) produced better nutritional and immunological responses than the other products tested.

Caracterização químico-nutricional de um isolado protéico de soro de leite, um hidrolisado de colágeno bovino e misturas dos dois produtos

OBJETIVO:Estudar química e nutricionalmente um isolado protéico de soro de leite bovino, um hidrolisado de colágeno bovino e misturas dos dois produtos visando elevado valor nutritivo e funcional. MÉTODOS: Realizaram-se análises da composição centesimal e do perfil de aminoácidos dos dois materiais protéicos, para cálculo da melhor adequação dos aminoácidos essenciais, com base no perfil recomendado pela Organização Mundial de Saúde. Os índices de valor nutritivo para o isolado de soro de leite, o hidrolisado de colágeno e as misturas foram determinados em ratos, a partir de ensaios de crescimento e de balanço de nitrogênio. Os resultados dos parâmetros nutricionais foram submetidos à análise de variância e ao teste de Tukey para a verificação de diferenças entre médias (p<0,05). RESULTADOS: O isolado protéico de soro de leite mostrou-se completo quanto aos aminoácidos essenciais pelo padrão de referência da Organização Mundial de Saúde enquanto que o hidrolisado de colágeno bovino mostrou-se deficiente em todos os aminoácidos essenciais, com agravante de completa ausência de triptofano. A caseína mostrou-se mais eficaz que o isolado de soro e as misturas quanto ao poder de promover crescimento em ratos. Não houve diferença estatística no crescimento dos ratos entre o isolado protéico de soro e a mistura 60% isolado de soro e 40% hidrolisado de colágeno. Nos demais índices de valor protéico a mistura 60% isolado de soro: 40% hidrolisado de colágeno mostrou-se igual ou superior à caseína e ao isolado (100%). CONCLUSÃO: A mistura 60% isolado de soro mais 40% hidrolisado de colágeno bovino apresentou elevado valor nutritivo e alto índice de solubilidade em água, mostrando-se promissora como ingrediente na formulação de alimentos dietéticos para idosos, inclusive pelas propriedades funcionais já descritas para essas proteínas.

Beneficial health effects of milk and fermented dairy products--review

Milk is a complex physiological liquid that simultaneously provides nutrients and bioactive components that facilitate the successful postnatal adaptation of the newborn infant by stimulating cellular growth and digestive maturation, the establishment of symbiotic microflora, and the development of gut-associated lymphoid tissues. The number, the potency, and the importance of bioactive compounds in milk and especially in fermented milk products are probably greater than previously thought. They include certain vitamins, specific proteins, bioactive peptides, oligosaccharides, organic (including fatty) acids. Some of them are normal milk components, others emerge during digestive or fermentation processes. Fermented dairy products and probiotic bacteria decrease the absorption of cholesterol. Whey proteins, medium-chain fatty acids and in particular calcium and other minerals may contribute to the beneficial effect of dairy food on body fat and body mass. There has been growing evidence of the role that dairy proteins play in the regulation of satiety, food intake and obesity-related metabolic disorders. Milk proteins, peptides, probiotic lactic acid bacteria, calcium and other minerals can significantly reduce blood pressure. Milk fat contains a number of components having functional properties. Sphingolipids and their active metabolites may exert antimicrobial effects either directly or upon digestion.