The consumption of organic tomatoes (ORTs) reduces the risk of harmful effects to humans and the environment caused by exposure to toxic agrochemicals. In this study, we used the somatic mutation and recombination test (SMART) of wing spots in Drosophila melanogaster to evaluate the genotoxicity of ORT and the effect of cotreatment with ORT on the genotoxicity of Doxorubicin® (DXR, a cancer chemotherapeutic agent) that is mediated by free radical formation. Standard (ST) cross larvae were treated chronically with solutions containing 25%, 50% or 100% of an aqueous extract of ORT, in the absence and presence of DXR (0.125 mg/mL), and the number of mutant spots on the wings of emergent flies was counted. ORT alone was not genotoxic but enhanced the toxicity of DXR when administered concomitantly with DXR. The ORT-enhanced frequency of spots induced by DXR may have resulted from the interaction of ORT with the enzymatic systems that catalyze the metabolic detoxification of this drug.

beta-carotene (BC), pro-vitamin A, is an efficient antioxidant, effective in the neutralization of oxygen reactive species, which cause serious damage to DNA. Various studies have been conducted on the effectiveness of BC for chemoprevention of cancer and heart disease. Doxorubicin is a chemotherapeutic agent used for cancer treatment that generates free radicals. We examined the effects of BC (1, 2 and 4 mg/mL) on the genotoxicity of doxorubicin (0.125 mg/mL), using the wing spot test in Drosophila melanogaster (somatic mutation and recombination test). The BC alone had no significant effect on the frequency of mutant spots. However, it significantly reduced the number of spots caused by doxorubicin. We concluded that BC is not genotoxic and that it exerts protective effects against the genotoxic action of the chemotherapeutic free-radical generator doxorubicin.

ABStRACt. Caryocar brasiliense Camb. is a tree popularly known in Central Brazil as pequi. Its fruit contains carotenes, retinols, vitamin C, and polyphenols. These compounds possess antioxidant properties preventing excessive free radical formation and modulating the genotoxicity of physical and chemical agents in the body. However, at high concentrations these compounds can have recombinogenic and mutagenic effects, because they can act as prooxidants. We examined the genotoxic effects of aqueous extracts of pequi pulp on wing spots of Drosophila melanogaster using the somatic mutation and recombination test (SMART). SMART was applied to a standard cross and to a high bioactivation cross. Two types of descendants were obtained from these crosses: markedheterozygous (mwh + / + flr 3 ) and balancer-heterozygous (mwh + / + TM3, Bds). Seventy-two-hour larvae from both crosses were treated with pequi pulp extract at 1, 5 and 10%. The extract increased significantly the frequency of mutant spots when compared with the negative control. Recombinogenic effects were also observed in the mwh/TM3 descendants.