Quercetin inhibits transcriptional up-regulation of histamine H1 receptor via suppressing protein kinase C-δ/extracellular signal-regulated kinase/poly(ADP-ribose) polymerase-1 signaling pathway in HeLa cells

This study investigated quercetin's ability to modulate histamine H1 receptor (H1R) gene expression in HeLa cells and its effects on allergy-like symptoms in TDI-sensitized rats. Quercetin suppressed histamine- and PMA-induced up-regulation of H1R by inhibiting PKC-δ activation and its translocation, reducing allergy-like symptoms in rats. In vivo, it also decreased