Phycobiliproteins (derived from Arthrospira platensis) bioactive peptide extracts (PPE) possess multiple pharmacological effects in the mitigation of human metabolic disorders. The role of PPE in the treatment of diet-induced obesity and the understanding of the underlying mechanism between the gut microbiome and metabolic blood circulation for obese patients remains poorly understood. In this study, we showed that PPE attenuated obesity by reducing body weight, and ameliorated glucose and lipid indexes in serum. In particular, PPE is postulated to mitigate liver steatosis and insulin resistance. On the other hand, dietary treatment with PPE was found to “reconfigure” the gut microbiota in the way that the abundances were elevated for Akkermansia_muciniphila, beneficial Lactobacillus and Romboutsia, SCFA-producing species Faecalibacterium prausnitzii, Lachnospiraceae_bacterium, Clostridiales_bacterium, probiotics Clostridium sp., Enterococcus faecium, and Lactobacillus_johnsonii, while the abundance of Firmicutes was reduced and that of Bacteroidetes was increased to reverse the imbalance of Firmicutes/Bacteroidetes ratio. Finally, the metabolomics of circulating serum using UHPLC-MS/MS illustrated that PPE supplementation indeed promoted lipid metabolism in obese rats. As summary, it was seen that PPE reprogrammed the cell metabolism to prevent the aggravation of obesity. Our findings strongly support that PPE can be regarded as a potential therapeutic dietary supplement for obesity.

Arthrospira platensis phycobiliprotein peptide extracts (PPEs) exhibit potential mitigative effects on hepatic steatosis. However, the precise role of PPEs in addressing high-fat-induced nonalcoholic fatty liver disease (NAFLD), as well as the underlying mechanism, remains to be elucidated. In this study, NAFLD was induced in rats through a high-fat diet (HFD), and the rats were subsequently treated with PPEs for a duration of 10 weeks. The outcomes of this investigation demonstrate that PPE supplementation leads to a reduction in body weight gain, a decrease in the accumulation of lipid droplets within the liver tissues, alterations in hepatic lipid profile, regulation of lipolysis-related gene expression within white adipose tissues and modulation of intestinal metabolites. Notably, PPE supplementation exhibits a potential to alleviate liver damage by manipulating neutral lipid metabolism and phospholipid metabolism. Additionally, PPEs appear to enhance fat mobilization by up-regulating the gene expression levels of key factors such as HSL, TGL, UCP1 and UCP2. Furthermore, PPEs impact intestinal metabolites by reducing the levels of long-chain fatty acids while concurrently increasing the levels of short-chain fatty acids. The findings from this study unveil the potential of PPE intervention in ameliorating NAFLD through the modulation of hepatic lipid profile and the reinforcement of the fat mobilization of intestinal metabolites. Thus, PPEs exhibit noteworthy therapeutic effects in the context of NAFLD.

Almond (Prunus dulcis) is a tree nut with high nutritional value that is widely cultivated and consumed globally. Prudu6, an 11S globulin, is one of the main allergens in almond, which can trigger a series of severe allergic reactions. To our knowledge, its correlation with Glym6, another 11S globulin, in terms of allergenicity has not yet been studied. In this study, natural Prudu6 was obtained by the optimized column chromatography method. Its structure was studied by the CD spectra, ultraviolet spectra and bioinformatics method. Then, WB and ELISA were performed to analyze the cross-reactivity. Prudu6 of high purity (>85%) was obtained by one-step chromatography. Strong cross-reactivity was found between Prudu6 and Glym6, which were also the main actors in the cross-reactivity between almond and soybean. For IgE in sera from almond-allergic patients, Glym6 demonstrated considerable affinity compared with Prudu6, while Prudu6 could hardly inhibit Glym6 in the soybean group. Three groups of epitope structures were found to be common in both proteins. These similar epitopes were regarded as the core structures causing the cross-reactivity between Prudu6 and Glym6.

Pru du 8 is a 31 kDa antibacterial protein and officially recognized almond allergen, but its native form in mature almonds has not been characterized, and no effective extraction method has been established. In this study, we successfully isolated a high-purity (>95%) 15 kDa protein from almond extract using a one-step chromatographic approach. Mass spectrometry identified this protein as a fragment of Pru du 8. The purified 15 kDa fragment exhibited strong IgE-binding activity with sera from almond-allergic patients, and its IgE-binding specificity was confirmed by negative reactivity with non-atopic control blood serum. Structural characterization by circular dichroism and ultraviolet spectroscopy revealed that the fragment adopts a predominantly α-helical, compact fold. Furthermore, computational epitope prediction identified key B-cell epitopes on this naturally occurring fragment. This study provides the isolation method for a native Pru du 8 fragment and confirms its allergenic potential, offering a valuable tool for future research on almond allergy.