Diallylsulfide attenuates asbestos-induced genotoxicity.

It is well known that asbestos fibers induced genotoxicity is mediated by reactive oxygen species (ROS) and insufficient endogenous antioxidant protection. Asbestos exposure can result in ROS generation in two different ways: (a) by catalyzation of Fe(2+), which is present in asbestos fibers, and (b) via oxidative bursts during phagocytosis of the fibers. On the other hand, it has been discussed that the physical presence of the fibres may mechanically influence the normal segregation of chromosomes during mitosis resulting in the induction of micronuclei in late ana/telophase, and aneuploidy. Glutathione and the glutathione redox system protect cells from the oxidative damage after exposure to xenobiotics. Glutathione depletion occurs during oxidative stress conditions and it is observed that supplementation of a precursor of glutathione and other sulphur containing compounds results in reduced toxicity. In the present study, diallyl sulfide (DAS), a lipid soluble allyl sulphur compound present in fresh extracts of garlic was evaluated for its protective effects. The micronucleus (MN) assay was performed in human mesothelial cells (HMC) exposed to 1 microg/cm(2) of crocidolite and chrysotile. Simultaneously, the cells were treated with 5 and 10 microM DAS, incubated for 48 and 66 h. Asbestos fibers induced significant genetic damage in HMC. The assay revealed a significant reduction in MN induction after treatment of cells with 5 microM but not with 10 microM DAS in mesothelial cells. The study revealed that at appropriate concentrations DAS protects mesothlelial cells against asbestos induced genotoxicity.