Food allergy (FA) is an increasing public health concern, highlighting the urgent need for safe, bioactive-based preventive strategies. This study evaluated genistein, a plant-derived isoflavone, in an ovalbumin (OVA)-induced murine FA model. Genistein was administered before sensitization and throughout allergy induction. Clinical symptoms, rectal temperature, diarrhea, OVA-specific antibodies, mast cell responses, intestinal barrier markers, gut microbiota, short-chain fatty acids (SCFAs), and fecal metabolites were assessed using immunological, histological, microbiome, and metabolomic analyses. Genistein pretreatment prevented OVA-induced clinical symptom scores, rectal temperature decline, diarrhea occurrence, OVA-specific antibody responses, and mast cell responses. These changes were accompanied by preservation of jejunal tight junction-related markers and modulation of T-cell-associated immune responses. In vitro, genistein modulated antigen uptake, maturation-associated features of bone marrow-derived dendritic cells (BMDCs), and BMDC-driven CD4⁺ T-cell polarization. In parallel, genistein-pretreated mice showed altered gut microbial structure, higher relative abundances of selected SCFA-associated taxa, increased fecal butyrate, and fecal metabolomic alterations involving purine metabolism, bile-acid-related metabolism, and tryptophan-related microbial metabolites. Consistently, correlation analyses indicated associations among microbial taxa, metabolites, immune indicators, and intestinal barrier markers. Together, these findings provide preliminary mechanistic insight into genistein in experimental FA and support further investigation of genistein as a dietary bioactive candidate for FA prevention.

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.