Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/24/2004
Publication Date: 3/24/2004
Citation: Keck, A.S., Finley, J.W. 2004. Selenium from selenium-enriched broccoli is more effective than selenite or broccoli alone for the reduction of h2o2-induced dna strand breaks in hepa 1c1c7 cells. Meeting Abstract.
Technical Abstract: Selenium (Se) protects against certain cancers and Se from broccoli has been reported to be especially protective. Sulforaphane (Sf) from broccoli also protects against cancer by activation of Phase II enzymes. To determine whether cancer protection by Se and broccoli is mediated through decreased oxidative stress, we measured DNA damage in mouse hepatoma Hepa 1c1c7 cells exposed to as much as 2.5 µM Se or 2 µM SF, or to broccoli extracts that contained up to 0.7 µM Se and 0.5 µM SF. Cells were exposed to Se/SF for 4 or 24h and then challenged with 50 µM H2O2; DNA damage was assessed by the COMET assay. Incubation of cells with Se, Sf or broccoli extracts for 4h did not provide any protection. Incubation for 24h with extracts of broccoli that were highest in Se completely inhibited DNA damage; however, incubation with low-Se broccoli extracts inhibited damage by only 60%. Complete inhibition of DNA damage was observed with 0.35 µM Se from high-Se broccoli, whereas 1 µM Se as selenite was needed for the same protection. Also, 2 µM pure SF inhibited DNA damage by 60%, whereas 0.5 µM SF from low-Se broccoli provided the same protection. These results demonstrate that Se is effective for reducing DNA strand breaks in vitro, and that Se as high-Se broccoli is more protective than Se as selenite. Sulforaphane and low-Se broccoli also protect against DNA strand breaks, but are not as protective as Se or high-Se broccoli.