Peptides with Charged Amino Acids Mitigate nZnO-Induced Growth Inhibition of Lactobacillus rhamnosus LRa05.

Growing concern is about the potential side effects of nanomaterials from food packaging, notably zinc oxide nanoparticles (nZnO). Previous research revealed that walnut-derived peptides could mitigate this inhibitory effect, but the mechanism involved is unclear. Here, we found that not all peptides have such an effect. Based on the growth inhibition model of Lactobacillus rhamnosus LRa05 induced by nZnO, we assessed the protective effects of various peptides. Notably, four peptides containing charged amino acids (PPKNW, WPPKN, ADIYTE, and WEREEQE) were found to effectively alleviate the growth inhibition phenomenon. We hypothesize that the peptide-nZnO interaction modifies this effect, as confirmed through infrared, Raman, and fluorescence spectroscopy. Our results highlight amide bonds, amino groups, carboxyl groups, and benzene rings as key peptide binding sites on nZnO, with static quenching primarily due to hydrogen bonds and van der Waals forces. This study elucidates peptide characteristics in nZnO interactions, facilitating a deeper exploration of food matrix-nanocomposite interactions.

The therapeutic potential for senescence-associated diabetes of green alga Enteromorpha prolifera polysaccharide.

DEAE-52 and Sephadex G-100 columns were used to isolate Enteromorpha prolifera polysaccharide (EPP), which contains α-L-Rhap-(1 â†’ 4)-α-L-Arap-(1 â†’ 2)-α-L-Rhap-(1 â†’ 3)-ß-D-Galp-(1 â†’ structural fragment, along with α-L-Rhap-(1 â†’ and →2)-α-L-Rhap-(1 â†’ 3)-ß-D-GlcpA-(1 â†’ side bonds that connect to →3,6)-ß-D-Galp-(1→. The anti-ageing and hypoglycemic activities of EPP were assessed using an ageing diabetic mice model, and the revealed that EPP could improve glucose metabolism-associated parameters and inhibit the expression of ageing associated genes, including p16INK4a, p38 MAPK, NOX-1, VEGF, and AGER, thus preventing liver damage. Moreover, gut microbiota profiling revealed that EPP significantly increased the abundances of o_Lactobacillaceae, c_Bacilli, f_Lactobacillaceae, g_Lactobacillus, and p_Firmicutes, showing that EPP has a probiotic effect on enhancing the beneficial microbiota in ageing diabetic mice. In summary, EPP might serve as a potential bioactive compound to alleviate hyperglycaemia and ageing in diabetic in mice and further clinical studies are required to verify these effects.

Green Alga Enteromorpha prolifera Oligosaccharide Ameliorates Ageing and Hyperglycemia through Gut-Brain Axis in Age-Matched Diabetic Mice.

SCOPE: To investigate the anti-ageing and anti-diabetic effects of Enteromorpha prolifera oligosaccharide (EPO) in age-matched streptozocin-induced diabetic mice. METHODS AND RESULTS: LC-MS metabolomics and 16S rRNA sequencing is used to identify the brain metabolites and gut microbiota, respectively. EPO could significantly improve glucose metabolism and activity of total superoxide dismutase in serum. It also could regulate the tricarboxylic acid cycle, arginine, and inosine-related metabolic pathways in the brain of aged diabetic mice. Inosine is found to enhance the relative expressions of daf-2, daf-16, and skn-1 in insulin-resistant Caenorhabditis elegans. Additionally, EPO could alter the composition and diversity of gut microbiota in mice. It could upregulate the Signal Transducer and Activator of Transcription 3/Forkhead Box O1 (FOXO1)/B cell lymphoma 6 (Bcl-6) pathways in the brain and the c-Jun N-terminal Kinase (JNK)/FOXO1/Bcl-6 signaling axis in the intestine to regulate glucose metabolite status and ageing in mice. EPO could also improve the levels of glucagon-like peptide type 1 (GLP1) expression in the gut, thereby inducing high expression of GLP1 receptor in the brain to control glucose metabolites through the brain-gut axis. Enterococcus is negatively correlated with AMP in the brain and could be a potential hallmark species in age-related diabetes. CONCLUSIONS: These results suggest that EPO could be a potential novel natural drug for the treatment of diabetes in the elderly.

Hypoglycaemic and anti-ageing activities of green alga Ulva lactuca polysaccharide via gut microbiota in ageing-associated diabetic mice.

Ageing-related type 2 diabetes is a significant public health problem. Particularly, the number of cases and fatality rates of ageing-associated diabetes increase with population ageing. This study aimed to investigate the structural characterisation of Ulva lactuca polysaccharide (ULP) and the hypoglycaemic effect on ageing-associated diabetic mice using gut microbiota variation. Sugar residuals analysis showed that the purified ULP (ULP-1) comprised ß-D-Xylp-(1→3)-ß-D-Arap-(1→6)-ß-D-Galp-(1→6)-ß-D-Glcp linked to [→α-L-Rhap-(1→4)-ß-D-GlcpA→]n and α-D-Manp-(1→4)-α-L-Rhap(2SO3-)-(1→2)-α-L-Rhap(4SO3-)-(1→2)-α-L-Arap-(1→2)-α-L-Rhap-(1→ as its side chains at ß-D-Glcp. Moreover, ULP modulated the expression levels of p16Ink4a, MMP2, FoxO1, GLP-1/GLP-1R, STAT3, and GLUT4 to improve the status of ageing and diabetes, which was concurrent with the increased abundance of Dubosiella, Enterococcus, Romboutsia, Bifidobacterium, Kurthia, Clostridium_sensu_stricto_1, Corynebacterium, Faecalibaculum, Aerococcus and Vibrio. Notably, Dubosiella, Romboutsia, Bifidobacterium, Turicibacter and Clostridium_sensu_stricto_1 could serve as important intermediates for delaying ageing and diabetes. Additionally, the ULP-1 structure is strongly binding interaction with the target protein through hydrogen bonding and Van der Waals force, especially for GLP-1 (-10.34 kcal/mol), p16Ink4a (-10.51 kcal/mol) and GLP-1R (-8.57 kcal/mol). Moreover, the average length of the hydrogen bond was observed to be 2.36 MPa, which is smaller than that of the traditional hydrogen bond. Therefore, ULP has the potential to function as a nutraceutical to delay or prevent the development of ageing-related type 2 diabetes.

Nutraceutical potentials of algal ulvan for healthy aging.

Several theories for aging are constantly put forth to explain the underlying mechanisms. Oxidative stress, DNA dysfunction, inflammation, and mitochondrial dysfunction, along with the release of cytochrome c are some of these theories. Diseases such as type 2 diabetes mellitus, intestinal dysfunction, cardiovascular diseases, hepatic injury, and even cancer develop with age and eventually cause death. Ulva polysaccharides, owing to their special structures and various functions, have emerged as desirable materials for keeping healthy. These polysaccharide structures are found to be closely related to the extraction methods, seaweed strains, and culture conditions. Ulvan is a promising bioactive substance, a potential functional food, which can regulate immune cells to augment inflammation, control the activity of aging-related genes, promote tumor senescence, enhance mitochondrial function, maintain liver balance, and protect the gut microbiome from inflammatory attacks. Given the desirable physiochemical and gelling properties of ulvan, it would serve to improve the quality and shelf-life of food.

Cancer-fighting potentials of algal polysaccharides as nutraceuticals.

Cancer has been listed as one of the world's five incurable diseases by the World Health Organization and causes tens of thousands of deaths every year. Unfortunately, anticancer agents either show limited efficacy or show serious side effects. The algae possess high nutritional value and their polysaccharides have a variety of biological activities, especially anti-cancer and immunomodulatory properties. Algal polysaccharides exert anti-cancer effects by inducing apoptosis, cell cycle arrest, anti-angiogenesis, and regulating intestinal flora and immune function. Algal polysaccharides can be combined with nanoparticles and other drugs to reduce the side effects caused by chemotherapy and increase the anticancer effects. This review shows the signal pathways related to the anti-cancer mechanisms of algal polysaccharides, including their influence on intestinal flora and immune regulation, the application of nanoparticles, and the effects on combination therapy and clinical trials of cancer treatments.

Characterization of the structure and analysis of the anti-oxidant effect of microalga Spirulina platensis polysaccharide on Caenorhabditis elegans mediated by modulating microRNAs and gut microbiota.

The antioxidant activity of Spirulina platensis polysaccharide (SPP) was investigated in Caenorhabditis elegans. Nuclear magnetic resonance, Fourier-transform infrared, multi-angle laser light scattering, and GC-MS were used to identify the structural characteristics of SPP. It was composed of the →2)-α-L-Rhap-(1→, →4)-ß-D-Manp-(1→, →6)-ß-D-Glcp-(1→, →4)-ß-Xylp-(1→, →3)-ß-L-Araf-(1→, and →2)-ß-L-Fucp-(1→, respectively. The modulation of gut microbiota in C. elegans was determined using 16S rRNA gene high-throughput sequencing. The malondialdehyde (MDA) content was significantly decreased, while the total superoxide dismutase (T-SOD) and reactive oxygen species (ROS) levels were improved after SPP supplementation. The cellular mitochondrial content and apoptosis were significantly down-regulated. The obvious increased levels of the DAF-16 and SKN-1 mRNAs were observed in the SPP-treated group, while the levels of miR-48 and miR-51 were significantly reduced. Moreover, SPP administration significantly increased the abundance of Flavobacterium, Achromobacter, Empedobacter, Anaerolinea, and Pseudoalteromonas of the intestinal flora. Based on these results, S. platensis polysaccharides may be used as a functional food to ameliorate diseases related to oxidative stress.