Fig. 7. A signaling pathway responsible for barrier-promoting effect of quercetin and myricetin in cells. Two flavonols act on IEC-6 cells to cause the suppression of RhoA/ROCK. This suppression prevents the separation of GDP from the Rho GTPase, reduces enzyme activity, and causes the suppression of ROCK. Afterwards, phosphorylation of myosin light chain phosphatase (MLCP) is reduced while phosphorylation of myosin light chain (MLC) is suppressed, which leads to contractility inhibition of the actinomyosin. Subsequently, ZO-1 protein will highly interact with occludin and claudins proteins to form tight junctions, causing enhanced barrier function.