Assessment of the phenolic content, mutagenicity and genotoxicity of ethanolic extracts of stem bark and leaves from Strychnos pseudoquina A. St.-hil.

Strychnos pseudoquina is a plant species whose stem bark is used as bitter tonic beverage. The phytochemical analysis, as well as quantification of phenolic constituents and antioxidant activity of ethanolic extracts from S. pseudoquina stem bark, and leaves were conducted. The extracts were tested for mutagenicity (Ames test) and DNA-damaging activity (Plasmid Cleavage test). Leaves recorded the largest amount of flavonoids. The performed high-performance liquid chromatography (HPLC) showed flavonoids such as isorhamnetin and strychnobiflavone (phytochemical markers of the investigated species) in stem barks, but not in leaves. The proanthocyanidin content and antioxidant activity were significantly higher in stem barks than in leaves. Stem bark and leaf extracts presented mutagenic activity against TA98 and TA100 strains with, and without, metabolic activation (S9). The Plasmid Cleavage test did not indicate DNA-damaging activity. Our results suggest that extracts deriving from S. pseudoquina should be used with extreme caution, mainly the stem bark extract, which is widely used in folk medicine.

Avaliação do potencial genotóxico de extratos etanólicos de cascas e folhas de Bathysa cuspidata (A. St-Hil) Hook / Evaluation of the genotoxic potential of ethanolic extracts of stem bark and leaves of Bathysa cuspidata (A. St-Hil) Hook

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.

The mutagenic, DNA-damaging and antioxidative properties of bark and leaf extracts from Coutarea hexandra (Jacq.) K. Schum.

Coutarea hexandra is a species commonly known in Brazil as quina, and its bark is used in folk medicine. In this study, we assess the mutagenic and DNA-damaging effects of ethanol extracts from C. hexandra stem bark (SCH) and leaves (LCH) by employing the Ames test on the TA98 and TA100 strains of Salmonella typhimurium in addition to a plasmid treatment test. Furthermore, we performed a phytochemical analysis by TLC and HPLC, a quantification of the phenolic constituents and an assessment of the antioxidative activity. SCH and LCH showed mutagenic action in the Ames test for TA98 strains after metabolic activation. LCH also showed mutagenicity for the TA100 strain after metabolic activation. The findings from the plasmid treatment test did not indicate any DNA-damaging activity for either of the extracts with the tested dosages. SCH showed greater flavonoid content and greater antioxidative potential in relation to LCH. This study suggests that caution is advisable in the use of this plant. However, in vivo studies should be conducted to confirm these data.