**4. Impact of phenolic compounds on the gut health and its relationship with human health**

The gut microbiota plays an important role in food digestion, immunity, and other metabolic functions; its composition is influenced by endogenous and environmental factors such as age, diet, lifestyle, antibiotic intake, and xenobiotics. Optimal gut health depends on the microbial community structure, a balanced composition of gut microbiota, an epithelial barrier, and an intact host mucosa; therefore, a disorder of these components can lead to the development of intestinal diseases such as obesity, inflammatory bowel disease, and colon cancer [1–3, 6, 7, 21, 22, 24, 49, 61].

Legumes are composed of bioactive compounds, such as phenolic compounds, capable of modifying the physiological basal function within the intestinal microenvironment affecting the microbiota and epithelial barrier, improving metabolic and gastrointestinal health, enhancing resistance to colonization by pathogens, and exerting an impact on the gut microbiota. These actions lead to decrease the severity of diseases associated with the intestine due to their chemopreventive effects. However, not all polyphenols support gastrointestinal integrity equally, and their benefits depend on chemical structure and phenolic concentration [12, 21, 31, 49, 62]. Isoflavones, such as biochanin A, have been reported to improve gut health by exerting antioxidant and anti-inflammatory effects [12, 20, 21]. On the other hand, the effect of formononetin in an acute colitis model in mice induced by dextran sulfate sodium has been evaluated, observing an attenuation of colitis. This effect may be due to the inhibition of the NLRP3 immamasome pathway by the action of formononetin [9].

Bian et al. [2] suggest that kaempferol has a protective effect on the secretion of interleukin-8 (IL-8) and the barrier dysfunction of the Caco-2 monolayer in the lipopolysaccharide-induced epithelial-endothelial co-culture model. This effect is due to the inhibition of the nuclear factor-kappa B (NF-κB) signaling pathway,

#### *Phenolic Compounds in Legumes: Composition, Processing and Gut Health DOI: http://dx.doi.org/10.5772/intechopen.98202*

which allows the reduction of inflammatory bowel disease. Also, caffeic acid reduces the secretion of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-), and IFN, and colonic infiltration of CD3+ T cells, CD177+ neutrophils, and F4/80+ macrophages by inhibiting the activation of the NF-B signaling pathway [63]. Naringin is a flavonoid that has a beneficial effect on intestinal disorders. Liu et al. [64] showed that naringin (50 μM) protects the integrity of rat intestinal microvascular endothelial cell monolayer barriers against TNF-*α*-induced disruption, preventing TNF-*α*-induced apoptosis and suppressing cell migration, and avoiding gut-vascular barrier disruption. Moreover, the proanthocyanidins or condensed tannins have been reported to have bioactive properties like anti-inflammatory and antimicrobial, causing a reduction in intestinal inflammation and promoting the growth of *Lactobacillus* spp. and *Bifidobacteria* spp. [1, 62].

Recent animal studies have shown that chickpeas consumption improves gut health by inhibiting the proliferation of cancer cells, attenuating inflammation, modulating the composition and activity of the microbiome, promoting epithelial barrier integrity, mucus production, and antimicrobial defenses [49, 65]. In addition, the quantitative structure–activity relationship on the cytotoxic effect of

#### **Figure 2.**

*The potential prebiotic effect of anthocyanins on gut microbiota and obesity. SCFA: Short-chain fatty acids; FIAF: Fasting-induced adipose factor; LPS: Lipopolysaccharide; ZO-1: Zonula occludens-1; IR: Insulin resistance. Anthocyanins and metabolites formed in the intestine change the composition of the gut microbiota. This is associated with restored tight-junction protein (ZO-1 and occludin) distribution, and localization. Hence, the gut permeability is decreased, and plasma lipopolysaccharide (LPS) levels (metabolic endotoxemia) are lowered, improving low-grade inflammation and obesity-related comorbidities. Anthocyanins decrease transcription factor NF-kB activity in the cell nucleus by decreasing gene expression of inflammatory cytokines, exerting their anti-inflammatory action. Anthocyanins have the ability to promote the growth of*  Bifidobacterium *spp., which increases the intestinal production of FIAF that inhibits fat storage in the host.*  Bifidobacterium *spp. degrade SCFA; propionate stimulates mucus secretion and contributes to thickening of the mucus layer. At the same time, reduced mucus layer thickness favors microbiota encroachment. The figure is taken from [15].*

*Legumes Research - Volume 2*

phenolic compounds have been studied. The *p*-hydroxybenzoic acid present in *P. sativum* exhibits strong cytotoxic activity in the colon carcinoma (HCT116) cell line [33]. Additional clinical evidence suggests that bean intake may reduce the incidence of developing advanced colorectal adenoma in humans [66]. Chen et al. [67] noted that cyanidin-3-*O*-glucoside protects against intestinal mucosal damage caused by 3-chloro-1, 2-propanediol (3-MCPD), a food contaminant. **Figure 2** shows the prebiotic effect of anthocyanins on the gut microbiota.
