FIG. 1.

Phytonutrients differentially stimulate NQO1 activity. Hepa1c1c7 cell cultures were treated with increasing concentrations of phytonutrients for 24 h, before assay of NQO1 activity. SUL, CMN, QRN, and RES each stimulated NQO1 activity over a range of concentrations, with SUL being most efficacious at concentrations ≤1 μM (A). SUL triggered significant (P < .05) NQO1 activation at concentrations as low as 0.05 μM (B). Values are mean ± SEM, n = 5. Arrows indicate the lowest respective phytonutrient concentrations stimulating NQO1 activity, P < .05 (A). Means lacking a common letter differ, P < .05 (B). CMN, curcumin; NQO1, NAD(P)H:quinone oxidoreductase; QRN, quercetin; RES, resveratrol; SUL, sulforaphane.