Animals were randomly assigned into three groups (six animals/group): Reference (REF), H100, and H200 groups. lymphocyte (MLNL) composition and functionality were assessed. IgA, cytokines, and gene expression in the small intestine were quantified. Hesperidin administration resulted in a higher number of bacteria and IgA-coated bacteria, with changes in microbiota composition such as higherLactobacillusproportion. Hesperidin was also able to increase the small intestine IgA content. These changes in AZD-2461 the small intestine were accompanied by a decrease in interferon- and monocyte chemotactic protein-1 concentration. In addition, hesperidin increased the relative proportion of TCR+ lymphocytes in MLNL. These results show the immunomodulatory actions of hesperidin around the gut-associated lymphoid tissue and reinforce its role as a prebiotic. Keywords:flavanone, flavonoids, immunoglobulin A, intestinal immunity, prebiotic, polyphenol == 1. Introduction == Polyphenols, extensively found in plants as a product of their secondary metabolism [1] can be classified into different groups regarding their chemical structure: Phenolic acids, flavonoids, anthocyanidins, stilbenes, and lignans [2]. Within the AZD-2461 flavonoid family, the most distinguished subgroups are flavonols (e.g., quercetin, kaempferol, and myricetin), flavanones (e.g., eriodictyol, hesperetin, and naringenin), isoflavones (e.g., daidzein, genistein, and glycetein), flavones (e.g., apigenin, and AZD-2461 luteolin), flavan-3-ols (e.g., catechin), and anthocyanins (e.g., cyanidin, delphinidin, and malvidin) [3]. The biological activity of flavonoids in human or animal health and their protective role in several diseases have been widely described [4,5]. There is a growing interest in flavonoids for their anti-inflammatory [6] and anti-diabetic [7] properties, as well as their microbial modulatory actions [8]. Hesperidin is the major flavanone present in citrus fruits, such as orange [9,10]. It is composed by hesperetin being conjugated to rutinose. After hesperidin intake, in the small intestine this flavanone is usually poorly assimilated via the paracellular pathway and it is highly dependent on the conversion to hesperetin [5,11]. Hesperidin reaches the large intestine where gut microbiota cleaves the attached rutinose moiety, forming hesperetin for further colonic absorption [12]. Hesperidin is usually gaining attention due to its different biological activities [3]. In this context, it has been considered a potential protective factor in neurodegenerative diseases [13], by reducing neuro-inflammation in experimental stroke [14]. Moreover, its anti-oxidant [15,16], anti-depressive [17], anti-cancer [18], and immunomodulatory properties have also been described [19,20,21,22,23]. In particular, hesperidin has been shown to increase the production Rabbit Polyclonal to NDUFB1 of anti-inflammatory cytokines in vitro [19], to exert an anti-asthmatic effect [20,21], to alter the CD4/CD8+ T cell ratio in the intestine wall of mice infected withAeromonas hydrophila[22], and to influence the lymphocyte composition and functionality of the gut-associated lymphoid tissue in immunized rats [23]. Overall, the immunomodulatory properties of hesperidin were observed in vitro or in contamination/immunization models in which the immune system was triggered. Nevertheless, no studies have shown the immune effects of this flavanone in health status. On the other hand, as far as we know, Unno et al. [24] in the only existing study around the influence of citrus flavanones around the gut microbiota, included them in rat food and showed the prebiotic-like effects of a hesperetin-enriched diet, but not a diet containing hesperidin. In this context, the relationship between the gut microbiota and the function of the gut-associated lymphoid tissue must be emphasized, as its close conversation are well established [25]. Indeed, the intestinal mucosa may be considered as an immunological niche as it hosts a complex immune-functional organ comprised of immunocompetent cells, their products, such as secretory IgA, and the microbiota [25]. While some studies have focused on the influence of hesperidin around the immune response, an in-depth investigation is needed into the effects of hesperidin around the gut-associated lymphoid tissue, which hesperidin reaches first, and moreover, where it can interact with gut microbiota contributing to the crosstalk between gut bacteria and intestinal immune tissue. Therefore, the aim of the present study was to establish the influence of oral hesperidin administration around the function of the gut-associated lymphoid tissue, including the mesenteric lymph node lymphocyte phenotype characterization, and on.