To be or not to be a carcinogen; delving into the glyphosate classification controversy

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.

Análisis fitoquímico de Jatropha dioica y determinación de su efectoantioxidante y quimioprotector sobre el potencial genotóxico deciclofosfamida, daunorrubicina y metilmetanosulfonato evaluadomediante el ensayo cometa / Phytochemical analysis of Jatropha dioica and determination of its antioxidant and chemopreventive effect on the genotoxic potential of cyclophosphamide, daunorubicin and methyl methane-sulfonate evaluated by the comet assay

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.