A tetrapeptide from maize combined with probiotics exerted strong anti-inflammatory effects and modulated gut microbiota in DSS-induced colitis mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by recurrent gastrointestinal inflammation caused by abnormal immune response, and patients usually have intestinal flora imbalance. At present, the pathogenesis of UC is not well understood, and it appears that there is chronic activation of the immune and inflammatory cascade in genetically susceptible individuals. Some food supplements such as specific peptides and probiotics have been investigated and shown the potential for the treatment of UC. The purpose of this study is to investigate the therapeutic effect and potential mechanism of tetrapeptide from maize (TPM) and probiotic treatment on dextran sulfate sodium (DSS)-induced UC in C57BL/6J mice. Our results indicated that the therapeutic effects of TPM and probiotics are positively associated with a reduction in pro-inflammatory cytokine levels and restoration of the gut microbiota. Treatment with TPM or probiotics effectively alleviated the adverse effects of UC, including weight loss, shortened colon length, and colon and kidney tissue damage in mice. Additionally, both TPM and probiotics significantly reduced pro-inflammatory cytokine levels and oxidative stress in UC mice, and the effect was more pronounced when both were used together. Moreover, co-treatment with TPM and probiotics increased the diversity of gut microbes in UC mice, reduced the ratio of Firmicutes to Bacteroidetes (F/B) and increased the abundance of bacterial species, including Muribaculaceae, Alistipes, Ligilactobacillus and Lactobacillus, and has been shown to be beneficial for a variety of pathological conditions.

Neuroprotective Effect of Ginseng Fibrous Root Enzymatic Hydrolysate against Oxidative Stress

Oxidative stress is one of the potential causes of nervous system disease. Ginseng extract possesses excellent antioxidant activity; however, little research on the function of the ginseng fibrous root. This study aimed to investigate the neuroprotective effects of ginseng fibrous root to alleviate the pathogenesis of Alzheimer's disease (AD) against oxidative stress. Ginseng fibrous root enzymatic hydrolysate (GFREH) was first prepared by digesting ginseng fibrous roots with alkaline protease. In vitro, the GFREH showed antioxidant activities in free radical scavenging mechanisms. With a cellular model of AD, GFREH inhibited the increase in Ca²⁺ levels and intracellular ROS content, maintained the balance of mitochondrial membrane potential, and relieved L-glutamic acid-induced neurotoxicity. In vivo, GFREH improved the survival rate of Caenorhabditis elegans (C. elegans) under oxidative stress, upregulated SOD-3 expression, and reduced reactive oxygen species (ROS) content. Therefore, our findings provide evidence for the alleviation effect of GFREH against oxidative stress in neuroprotection, which may accelerate the development of anti-Alzheimer's drugs and treatments in the future.

Caenorhabditis elegans as an in vivo model for food bioactives: A review

Caenorhabditis elegans (C. elegans) is being widely explored as an in vivo model to study the effects of food bioactives. These nematodes are largely advantageous over other in vivo models as they are relatively inexpensive, have a short generation time, and have a completely sequenced genome, among other advantages. C. elegans is a commonly used model to study diseases such as Alzheimer's and Parkinson's disease; however, researchers are finding they can also give insight into the health promoting effect of food-derived bioactive compounds. As consumers become more aware of the health benefits of the foods that they consume, the study of bioactive properties of foods and food constituents is becoming an important source of information. This review focuses on the advantages of using C. elegans as a model such as their short lifespans, high level of gene conservation relative to humans, and large number of progenies per reproductive cycle. They are also easily manipulated in order to perform controlled experiments on synchronous populations. Through review of recent literature, it is clear that C. elegans can be used to study a range of food derived compounds such as bioactive peptides, phenolic compounds, carbohydrates, and lipids. This review also provides information on potential challenges associated with working with this nematode. These challenges include the need for a sterile environment, potential inaccuracy when determining if the nematodes are dead, and the simplicity of the organism making it not suitable for all studies.

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Caenorhabditis elegans is an advantageous in vivo model over other organisms.

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Bioactivity of food compounds can be determined using Caenorhabditis elegans.

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Food bioactive compounds can decrease the risk of human disease.

Disulfide-Rich Cyclic Peptides from Clitoria ternatea Protect against β-Amyloid Toxicity and Oxidative Stress in Transgenic Caenorhabditis elegans

Neurotoxic aggregation of β-amyloid (Aβ) peptides is a hallmark of Alzheimer's disease and increased reactive oxygen species (ROS) is an associated process. In the present study, we report the neuroprotective effects of disulfide-rich, circular peptides from Clitoria ternatea (C. ternatea) (butterfly pea) on Aβ-induced toxicity in transgenic Caenorhabditis elegans. Cyclotides (∼30 amino acids long) are a special class of cyclic cysteine knot peptides. We show that cyclotide-rich fractions from different plant tissues delay Aβ-induced paralysis in the transgenic CL4176 strain expressing the human muscle-specific Aβ_1-42 gene. They also improved Aβ-induced chemotaxis defects in CL2355 strain expressing Aβ_1-42 in the neuronal cells. ROS assay suggests that this protection is likely mediated by the inhibition of Aβ oligomerization. Furthermore, Aβ deposits were reduced in the CL2006 strain treated with the fractions. The study shows that cyclotides from C. ternatea could be a source of a novel pharmacophore scaffold against neurodegenerative diseases.

A Novel Peroxidase Mimics and Ameliorates Alzheimer's Disease-Related Pathology and Cognitive Decline in Mice

Alzheimer's disease (AD) is the most common neurodegenerative disorder in the elderly, which is characterized by the accumulation of amyloid β (Aβ) plaques, oxidative stress, and neuronal loss. Therefore, clearing Aβ aggregates and reducing oxidative stress could be an effective therapeutic strategy for AD. Deuterohemin-AlaHisThrValGluLys (DhHP-6), a novel deuterohemin-containing peptide mimetic of the natural microperoxidase-11 (MP-11), shows higher antioxidant activity and stability compared to the natural microperoxidases. DhHP-6 possesses the ability of extending lifespan and alleviating paralysis in the Aβ1-42 transgenic Caenorhabditis elegans CL4176 model of AD, as shown in our previous study. Therefore, this study was aimed at exploring the neuroprotective effect of DhHP-6 in the APPswe/PSEN1dE9 transgenic mouse model of AD. DhHP-6 reduced the diameter and fiber structure of Aβ1-42 aggregation in vitro, as shown by dynamic light scattering and transmission electron microscope. DhHP-6 exerted its neuroprotective effect by inhibiting Aβ aggregation and plaque formation, and by reducing Aβ1-42 oligomers-induced neurotoxicity on HT22 (mouse hippocampal neuronal) and SH-SY5Y (human neuroblastoma) cells. In the AD mouse model, DhHP-6 significantly ameliorated cognitive decline and improved spatial learning ability in behavioral tests including the Morris water maze, Y-maze, novel object recognition, open field, and nest-building test. Moreover, DhHP-6 reduced the deposition of Aβ plaques in the cerebral cortex and hippocampus. More importantly, DhHP-6 restored the morphology of astrocytes and microglia, and significantly reduced the levels of pro-inflammatory cytokines. Our findings provide a basis for considering the non-toxic, peroxidase mimetic DhHP-6 as a new candidate drug against AD.

Tryptophan-Containing Dual Neuroprotective Peptides: Prolyl Endopeptidase Inhibition and Caenorhabditis elegans Protection from β-Amyloid Peptide Toxicity

Neuroprotective peptides represent an attractive pharmacological strategy for the prevention or treatment of age-related diseases, for which there are currently few effective therapies. Lactoferrin (LF)-derived peptides (PKHs) and a set of six rationally-designed tryptophan (W)-containing heptapeptides (PACEIs) were characterized as prolyl endopeptidase (PEP) inhibitors, and their effect on β-amyloid peptide (Aβ) toxicity in a Caenorhabditis elegans model of Alzheimer's disease (AD) was evaluated. Two LF-derived sequences, PKH8 and PKH11, sharing a W at the C-terminal end, and the six PACEI heptapeptides (PACEI48L to PACEI53L) exhibited significant in vitro PEP inhibition. The inhibitory peptides PKH11 and PACEI50L also alleviated Aβ-induced paralysis in the in vivo C. elegans model of AD. Partial or total loss of the inhibitory effect on PEP was achieved by the substitution of W residues in PKH11 and PACEI50L and correlated with the loss of protection against Aβ toxicity, pointing out the relevance of W on the neuroprotective activity. Further experiments suggest that C. elegans protection might not be mediated by an antioxidant mechanism but rather by inhibition of Aβ oligomerization and thus, amyloid deposition. In conclusion, novel natural and rationally-designed W-containing peptides are suitable starting leads to design effective neuroprotective agents.

Anti-Cancer Activity of Maize Bioactive Peptides

Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derivative food products has been associated with a reduced risk of various types of cancer. The main biomolecules in cereals include proteins, peptides, and amino acids, all of which are present in different quantities within the grain. Some of these peptides possess nutraceutical properties and exert biological effects that promote health and prevent cancer. In this review, we report the current status and advances in knowledge regarding the bioactive properties of maize peptides, such as antioxidant, antihypertensive, hepatoprotective, and anti-tumor activities. We also highlight the potential biological mechanisms through which maize bioactive peptides exert anti-cancer activity. Finally, we analyze and emphasize the potential applications of maize peptides.