Tight Junction in the Intestinal Epithelium: Its Association with Diseases and Regulation by Phytochemicals

Table 2

The effects of phytochemicals on the tight junction barrier function.

Treatment	Conc.	System	Stimuli	Tight junction protein affected	Potential targeting pathways	Ref.
Quercetin	200 μM	Caco-2	None	↑ claudin-4	↓ protein kinase A (PKA) or PKG	[50]
	100 μM	Caco-2	None	↑ ZO-2, occludin, claudin-1 and -4	↓ PKCδ	[51]
Berberine	100 μM	Caco-2	None	Not studied	Not studied	[55]
	100 μM	Caco-2	TNF-α, IFNγ	↑ occludin	Not studied	[56]
	200 mg/kg	Mouse	LPS	↑ occludin, ZO-1, claudin-1 and -4	↓ myosin light chain kinase, ↓ nuclear factor-κB (NF-κB)	[53]
	375 mg/kg/day	Rat	Streptozotocin	↑ occludin, ZO-1, claudin-1	↓ TLR4/MyD88/NF-κB signaling pathways	[54]
Genistein	300 μM	Caco-2	None	Not studied	Localization of filamentous actin in the perijunctional area	[59]
Kaempferol	100 μM	Caco-2	None	↑ occludin, claudin-1 and -3, and ZO-1; ↑ ZO-2 and claudin-4; phosphorylation of occludin	Not studied	[63]
Curcumin	5 μM	Caco-2	TNF-α	↑ ZO-1	↓ NF-κB	[17]
	5 μM	Caco-2	TNF-α	Not studied	↓ myosin light chain kinase, ↓ NF-κB	[19]
	5 μM	Caco-2	IL-1β	Not studied	↓ NF-κB	[20]
	30 μM	Caco-2 BBe	Leptin	↑ ZO-3, claudin-5, occludin	↓ leptin signaling pathway	[67]