Interaction of the aryl hydrocarbon receptor with several constituents from spinach and komatsuna extracts determined using in vitro bioassay

As a part of our study to clarify the interaction of food ingredients with the aryl hydrocarbon receptor (AhR), we studied the interaction of 10 constituents (phytol, p-coumaric acid, 5 flavonol glycosides, adenosine, guanosine and uridine), isolated from aqueous alcohol extracts of spinach and komatsuna, with the AhR by applying the AhR-based bioassay for dioxins, the Ah-Immunoassay and the AhR-dependent luciferase reporter gene assay. Among them, flavonol glycosides and phytol had slight inhibitory effects on AhR activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at high concentrations, however the effects were not comparable with those produced by kaempferol, regarded as one of the main antagonists of AhR. Also, flavonol glycosides showed weak luciferase inductions at high concentrations.