Formation of reactive oxygen species and of 8-hydroxydeoxyguanosine in DNA in vitro with betel quid ingredients |
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| Authors: | U J Nair R A Floyd J Nair V Bussachini M Friesen H Bartsch |
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| Institution: | Unit of Environmental Carcinogens and Host Factors, International Agency for Research on Cancer, Lyon, France. |
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| Abstract: | The formation of reactive oxygen species (ROS) from betel quid ingredients, namely areca nut, catechu and tobacco, was studied using a chemiluminescence (CL) technique. Aqueous extracts of areca nut and catechu were capable of generating superoxide anion and hydrogen peroxide at pH greater than 9.5. The formation of O2 was enhanced by Fe2+, Fe3+ and Cu2+ but inhibited by Mn2+. Tobacco extract failed to generate ROS under similar conditions. Saliva was found to inhibit both O2 and H2O2 formation from betel quid ingredients. Upon incubation of DNA at alkaline pH with areca nut extract and Fe3+ or catechu, 8-hydroxydeoxyguanosine was formed as quantified by high performance liquid chromatography (HPLC)/electrochemical detection. The data suggest a possible role of reactive oxygen species in the etiology of oral cancer in betel quid chewers. |
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