ABSTRACT
ABSTRACTThe aim of this study was to investigate the effect of the bark extractBathysa cuspidata on chemically induced preneoplastic colorectal lesions in Wistar rats. Forty male rats were randomly divided into four groups (n = 10 each): saline (control group, oral administration of saline solution 0.9%); dimethylsulfoxide (DMSO, vehicle control), B200 (treated with 200 mg/kg bark extract ofB. cuspidata), and B400 (treated with 400 mg/kg bark extract ofB. cuspidata). Administration of treatments was carried out by the gavage. The animals received four subcutaneous injections of 1,2-dimethylhydrazine (DMH, 40 mg/kg) in the initial two weeks of the experiment to induce preneoplastic colorectal lesions. After 15 weeks, the animals were euthanized and the presence of aberrant crypt foci (ACF), body weight, biochemical analyses, and oxidative stress markers were measured. The extract ofB. cuspidata decreased the levels of superoxide dismutase (SOD), but did not influence the levels of catalase (CAT), malondialdehyde (MDA), nitric oxide or protein carbonyl, compared with the saline group. The animals supplemented with a more concentratedB. cuspidata extract (B400) showed a significant reduction in the number of ACF in all the portions of the intestinal mucosa. The study demonstrated that the bark extract ofB. cuspidata at 400 mg/kg reduced the preneoplastic colorectal lesions in an animal model of colon cancer and that the effect could be dose-dependent.
ABSTRACT
Bathysa cuspidata (A.St.-Hil.) Hook. is a native tree of the Brazilian Atlantic Forest biome, widely used in Brazilian herbal medicine. Despite its widespread use, there is no report as yet regarding the toxicology of this plant. In this study, the mutagenic and genotoxic effects of ethanolic extracts of B. cuspidata stem bark (SBC) and leaves (LBC) were assessed. The mutagenicity of the extracts was estimated by performing the Ames test on strains TA98 and TA100 of Salmonella typhimurium, in the absence and presence of metabolic activation. The direct action of the extracts on DNA was assessed through plasmid treatment. Phytochemical screening was conducted to compare the secondary metabolite composition of the extracts. No mutagenic activity was found in LBC when tested on strain TA98 or TA100, without or with metabolic activation. However, SBC did show mutagenic activity. Plasmid tests did not indicate genotoxic action for either SBC or LBC. Differences in the composition of secondary metabolites present in the bark and leaves, detected by phytochemical analysis, appear to be a deciding factor in differences in mutagenicity between SBC and LBC. The findings in this study suggest caution in the use of B. cuspidata bark.
Bathysa cuspidata (A.St.-Hil.) Hook. é uma árvore nativa do bioma Mata Atlântica largamente utilizada na medicina popular brasileira. Apesar do amplo uso, ainda não existe relato sobre a toxicologia dos compostos obtidos dessa espécie vegetal. O presente estudo avaliou efeitos mutagênicos e genotóxicos de extratos etanólicos de B. cuspidata obtidos das cascas do caule (SBC) e das folhas (LBC). A mutagenicidade dos extratos foi avaliada utilizando o teste de Ames nas linhagens TA98 e TA100 de Salmonella typhimurium, na ausência e presença de ativação metabólica. Os efeitos dos extratos diretamente sobre o DNA foram avaliados por clivagem plasmidial. Análises fitoquímicas foram realizadas para comparar a composição de metabólitos secundários dos extratos. Não foi encontrada atividade mutagênica para LBC quando avaliados utilizando as cepas TA98 e TA100, sem ou com ativação metabólica. No entanto, SBC apresentou atividade mutagênica. Clivagem plasmidial não indicou ação genotóxica tanto para SBC quanto para LBC. Diferenças na composição dos metabólitos secundários presentes nos cascas e folhas, detectadas pelas análises fitoquímicas, devem ser determinantes para a variação do efeito mutagênico entre SBC e LBC. Os resultados sugerem cautela no emprego de cascas de B. cuspidata.