Figure 3.

Luciferase activity versus concentration of two nutritional supplements.

Notes: Both of the tested nutritional supplements Protandim® (Lifevantage, Inc, Sandy, UT, USA) – reported by the manufacturer to be an Nrf2 activator – and Supercritical Antioxidants™ (New Chapter, Inc, Brattleboro, VT, USA), not reported by the manufacturer to be an Nrf2 activator – upregulated the Nrf2-driven luciferase reporter gene expression in the AREc32 cell line, depicted as relative light units. Briefly, AREc32 cells were grown by standard methods, then trypsinized, counted and seeded at 20,000 cells/well on 24-well plates. After 24 hours the cells were reattached and growing, and were treated with varied concentrations of the test material extracts in duplicate. Protandim® was obtained by BG as a gift from Professor Joe McCord; Supercritical Antioxidants™ was obtained by retail purchase. The agents were extracted overnight with 95% ethanol in 15 mL tubes on a rocking table. The extract was obtained by centrifugation and then added to the wells in an appropriate concentration range by dilution into phosphate buffer solution, with final volumes added to culture wells ranging from 1 to 10 μL/well. An ethanol blank at the highest 10 μL/well level was used as the zero control. The cells were incubated for 24 hours, then washed and lysed, after which the lysate was assayed for luciferase activity by measuring luciferin-dependent chemiluminescence, reported as relative light units for the contents of each well. Each assay was performed in duplicate. Luciferase activity correlates directly in this case with Nrf2 activation.

Abbreviations: Nrf2, nuclear factor (erythroid-derived 2)-like 2; ARE, antioxidant response element.