TABLE 2.

Influence of phytocompounds (quercetin, kaempferol, and sulforaphane) on gut barrier function.

Phytocompounds	Experimental subject	Effect on gut barrier function	References
Quercetin	Caco-2 cell line	TER, claudin-4 expression ↑	Amasheh et al. (2008)
Quercetin	Caco-2 cell line	TER, claudin-4 expression, assembly of ZO-2, occludin, and claudin-1 ↑	Suzuki and Hara (2009)
Quercetin	Villus epithelium	TER, claudin-4 protein level ↑; claudin-2 protein level ↓	Cornelius et al. (2024)
Kaempferol	Caco-2 cell line	TER, assembly of ZO-1, ZO-2, occludin, claudin-1, claudin-3, and claudin-4 ↑	Suzuki et al. (2011)
Kaempferol	LPS-induced epithelial-endothelial cells co-culture	TER, occludin, claudin-2 and ZO-1 expression ↑; IL-8 ↓	Bian et al. (2020)
Kaempferol	C57black/6 mice fed a high-fat diet	Gut microbiota dysbiosis, TNF-α protein level, intestinal permeability ↓	Bian et al. (2022)
Sulforaphane	LPS-induced Caco-2 cell line	TER, SOD, GPx, CAT activities ↑; IL-1β, IL-6, IL-8 і TNF-α levels ↓	Zhang and Wu (2021)
Sulforaphane	C57black/6 mice with bladder cancer	Gut microbiota dysbiosis, pathological signs in colon ↓; claudin-1 expression ↑	He et al. (2018)
Sulforaphane	C57black/6 mice fed a high-fat and high-fructose diet	ZO-1, claudin-4 expression ↑; TLR4, Myd88, NF-κB expression ↓	Xu et al. (2023)
Sulforaphane	C57black/6 mice with ulcerative colitis	Gut microbiota dysbiosis, damage scores of colon ↓	Zhang et al. (2020)

↑, increased; ↓, decreased. Abbreviations: Caco-2, cancer coli (human colorectal adenocarcinoma cells); TER, transepithelial resistance; ZO, zonula occludens; LPS, lipopolysaccharides; IL, interleukin; TNF-α, tumor necrosis factor α; SOD, superoxide dismutase; GPx, glutathione peroxidase; CAT, catalase; TLR4, Toll-like receptor 4; Myd88, myeloid differentiation factor 88; NF-κB, nuclear factor κB.