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The International Agency for Research on Cancer (IARC) placed the most widely used herbicide glyphosate (GLY) into the category 2A (probably carcinogenic to humans), a classification questioned by experts from academia and industry. This article critically appraised the epidemiological and experimental data that led the IARC working group (WG) to consider GLY a probable human carcinogen and the ensuing controversy. An association of GLY with non-Hodgkin lymphoma was suggested by some observational studies. A non-causal explanation for this weak association, however, cannot be excluded. Contrary to WG's view, long-term rodent assays yielded no convincing evidence that GLY is carcinogenic. The mechanistic evidence remains elusive as well. Bacterial reverse mutation tests (including tester strains sensitive to oxidative mutagens) were clearly negative, and so were rodent genotoxicity assays by oral route. Tests with mammalian cells in vitro yielded conflicting results at high (cytotoxic) concentrations of GLY-based formulations. Conflicting results were also obtained when high doses of GLY-based herbicides were administered to rodents by the intraperitoneal route. Such high doses are unlikely to be attained in realistic scenarios of exposure. Finally, the IARC classification is based on a conjectural hazard, and rational public health interventions must be based on estimated risks.

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Dragon ́s blood root (Jatropha dioica) underwent a phytochemical screening showing the presence of flavonoids and terpenes responsible for the antioxidant potential observed in DPPH model for the decoction, aqueous and methanolic extracts. The chemoprotective effect of the root decoction was evaluated in liver, kidney and bone marrow cells of mice using the comet assay. Mutagens were administered via IP: cyclophosphamide (CCF) 50 mg/kg, daunorubicin (DAU) 10 mg/kg, and metyl metanesulfonate (MMS) 40 mg/kg, were co-administered with three doses of decoction 3.72 ml/kg, 10.71 ml/kg, and 21.42 ml/kg orally. Animals were sacrificed at 3, 9, 15 and 21 h after inoculation. The chemoprotective effect decreased DNA breaks at 3 hours in all organs, and longer against CCF and DAU, this effect probably being related to the antioxidant capacity of the decoction.

La raíz de Sangre de Drago (Jatropha dioica) se sometió a un tamizaje fitoquímico destacando la presencia de flavonoides y terpenos, posibles responsables del efecto antioxidante observado en el modelo de DPPH para la decocción, extracto acuoso y metanólico de la raíz. El efecto quimioprotector de la decocción, se evaluó en células hepáticas, renales y de médula ósea de ratón, mediante el ensayo cometa. Los mutágenos administrados vía I.P.: ciclofosfamida (CCF) 50 mg/kg, daunorrubicina (DAU) 10 mg/kg y metilmetanosulfonato (MMS) 40 mg/kg, se co-administraron con tres dosis de decocción 3,72 ml/kg, 10,71 ml/kg y 21,42 ml/kg, vía oral. Los animales fueron sacrificados a las 3, 9, 15 y 21 h posteriores a la aplicación. El efecto quimioprotector disminuyó las rupturas del DNA a las 3 horas en todos los órganos con los tres mutágenos, y permaneció por más tiempo frente a CCF y DAU, dicho efecto está relacionado con la capacidad antioxidante de la decocción.

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PURPOSE: To evaluate the genotoxicity of propolis and L-lysine, as well as their effects on the possible cellular damage in erythroblasts (bone marrow) and leukocytes (peripheral blood) caused by the carcinogen BBN (n - butyl - n {4 - hydroxybutyl} nitrosamine) in rats subjected to bladder carcinogenesis and treated with green propolis and L-lysine. METHODS: One hundred and twenty five rats were distributed into the following groups: I, IIA, IIB, III, K, L M N, X, XI, XII and XIII. Groups I to X received BBN in drinking water for 14 weeks (wks). Group I was treated with intragastric (ig) propolis at 150 mg/kg body weight, for 44 wks, beginning 30 days before start of BBN. Groups IIA and III were treated with propolis (150 mg/kg), for 40 wks, subcutaneous (sc) and ig, respectively, beginning simultaneously with BBN. On the 32nd wk, the animals of groups L, M and N were treated ig with L-lysine (300 mg/kg), celecoxib (30 mg/kg) and propolis (300 mg/kg), respectively, up to the 40th wk. The groups that received only BBN (IIB and K) were treated with water, sc and orally, respectively, for 40 wks. Groups XI, XII and XIII received respectively propolis (150 mg/kg), L-lysine (150 mg/kg) and water ig for 40 wks. After 40 wks, the surviving animals were anesthetized and subjected to femoral bone marrow aspiration and blood collection from the aorta, for CA and MNT, respectively, for investigation of genotoxicity. RESULTS: Groups IIB and K, which received only BBN and water, showed the greatest DNA damage in peripheral leukocytes (CA) and largest number of micronuclei in bone marrow erythrocytes (MNT) in relation to all other groups that received BBN and lysine and/or propolis (p<0.001). CONCLUSIONS: Both propolis and L-lysine are effective in protecting against genotoxicity, as well not being genotoxic themselves toward the cells evaluated, at the doses and times administered and according to the two tests utilized. (AU)

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