ABSTRACT
INTRODUCTION: Due to Plasmodium resistance to antimalarial drugs, it is important to find new therapeutic alternatives for malaria treatment and control. Based on the knowledge of Colombian indigenous communities, we collected extracts of plants with potential antimalarial effects from the middle Vaupés region. OBJECTIVE: To evaluate the mutagenic and genotoxic effects, as well as the gene expression of Rad51C, Xiap, P53 and Nrf2 induced by four ethanolic extracts with antimalarial activity (R001, T002, T015 and T028). MATERIALS AND METHODS: We evaluated four ethanolic extracts with antimalarial activity using the Ames test to assess mutagenicity, and the comet assay on HepG2 cells to determine the genotoxicicity. We also evaluated the expression of Rad51C, Xiap, P53 and Nrf2 from HepG2 cells stimulated with the four extracts. RESULTS: None of the four extracts was mutagenic in Salmonella typhimurium TA98 strain in the presence and absence of S9 metabolic activity. Extracts R001, T015 and T028 were weakly mutagenic on the TA100 strain in the presence of S9, with mutagenic indexes (MI) of 1.58, 1.53 and 1.61, respectively. The T015 strain showed the same behavior without S9 with an MI of 1.36. The results of the comet assay showed that the four extracts produced category 1 or 2 damage, with comets between 36.7 and 51.48 µm in length. However, the genetic damage index suggested that most of the cells were affected by the treatments. Regarding gene expression, extracts R001 and T028 induced an overexpression of genes Xiap and P53 with an 1.84 to 3.99 fold-change compared with untreated cells. CONCLUSIONS: These results revealed that the T002 extract was the safest as it had antimalarial activity and was not cytotoxic on HepG2 cells. Moreover, it was not mutagenic and it only produced category 1 damage on the DNA. Also, the extract did not induce a change in the expression of the tested genes.
Subject(s)
Antimalarials/pharmacology , DNA-Binding Proteins/biosynthesis , Gene Expression Regulation/drug effects , NF-E2-Related Factor 2/biosynthesis , Plant Extracts/pharmacology , Plants, Medicinal/chemistry , Tumor Suppressor Protein p53/biosynthesis , X-Linked Inhibitor of Apoptosis Protein/biosynthesis , Activation, Metabolic , Antimalarials/isolation & purification , Colombia , Comet Assay , DNA-Binding Proteins/genetics , Drug Evaluation, Preclinical , Ethanol , Genes, Bacterial/drug effects , Hep G2 Cells , Humans , Mutagenicity Tests , NF-E2-Related Factor 2/genetics , Plant Extracts/isolation & purification , Plasmodium falciparum/drug effects , Salmonella typhimurium/drug effects , Salmonella typhimurium/genetics , Solvents , Tumor Suppressor Protein p53/genetics , X-Linked Inhibitor of Apoptosis Protein/geneticsABSTRACT
Resumen Introducción. Dada la resistencia de Plasmodium a los medicamentos antipalúdicos, es necesario encontrar nuevas alternativas terapéuticas para su tratamiento y control. Con base en el saber indígena colombiano, se recopilaron extractos de plantas del Vaupés medio con potencial efecto antipalúdico. Objetivo. Evaluar el efecto mutagénico y genotóxico, y la expresión de los genes Rad51C, Xiap, P53 yNrf2, inducidos por cuatro extractos etanólicos con actividad anti-Plasmodium(R001, T002, T015 y T028). Materiales y métodos. Se evaluó el potencial mutagénico de cuatro extractos etanólicos con efecto antiplasmódico utilizando el test de Ames y el efecto genotóxico, con un ensayo del cometa; asimismo, se analizó la expresión de los genes Rad51C, Xiap, P53 y Nrf2 en células HepG2. Resultados. Los extractos no fueron mutágenos en la cepa TA98 de Salmonella typhimurium en presencia y ausencia de actividad metabólica de la fracción S9. En la cepa TA100, los extractos R001, T015 y T028 se comportaron como mutágenos débiles en presencia de S9, con índices mutagénicos de 1,58; 1,38; 1,53 y 1,61, respectivamente; T015 tuvo el mismo comportamiento en ausencia de S9, con un índice mutagénico de 1,36. En el ensayo del cometa, todos los extractos provocaron daño de categorías 1 o 2, con colas de cometas entre 36,7 y 51,48 µm de longitud; sin embargo, el índice dedaño genético sugirió que los tratamientos afectaron la mayoría de las células. En los genes en estudio, los extractos R001 y T028 indujeron una sobreexpresiónde 1,84 a 3,99 frente a las células sin tratar de los genes Xiap y P53. Conclusiones. Los resultados evidenciaron que el extracto T002 fue el más seguro, ya que presentó actividad anti-Plasmodium, no fue citotóxico en las células HepG2, no fue mutágeno, causó daño de categoría 1 en el ADN y no modificó la expresión de los genes evaluados.
Abstracts Introduction: Due to Plasmodium resistance to antimalarial drugs, it is important to find new therapeutic alternatives for malaria treatment and control. Based on the knowledge of Colombian indigenous communities, we collected extracts of plants with potential antimalarial effects from the middle Vaupés region. Objective: To evaluate the mutagenic and genotoxic effects, as well as the gene expression of Rad51C, Xiap, P53 and Nrf2 induced by four ethanolic extracts with antimalarial activity (R001, T002, T015 and T028). Materials and methods: We evaluated four ethanolic extracts with antimalarial activity using the Ames test to assess mutagenicity, and the comet assay on HepG2 cells to determine the genotoxicicity. We also evaluated the expression of Rad51C, Xiap, P53 and Nrf2 from HepG2 cells stimulated with the four extracts. Results: None of the four extracts was mutagenic in Salmonella typhimurium TA98 strain in the presence and absence of S9 metabolic activity. Extracts R001, T015 and T028 were weakly mutagenic on the TA100 strain in the presence of S9, with mutagenic indexes (MI) of 1.58, 1.53 and 1.61, respectively. The T015 strain showed the same behavior without S9 with an MI of 1.36. The results of the comet assay showed that the four extracts produced category 1 or 2 damage, with comets between 36.7 and 51.48 µm in length. However, the genetic damage index suggested that most of the cells were affected by the treatments. Regarding gene expression, extracts R001 and T028 induced an overexpression of genes Xiap and P53 with an 1.84 to 3.99 fold-change compared with untreated cells. Conclusions: These results revealed that the T002 extract was the safest as it had antimalarial activity and was not cytotoxic on HepG2 cells. Moreover, it was not mutagenic and it only produced category 1 damage on the DNA. Also, the extract did not induce a change in the expression of the tested genes.
Subject(s)
Humans , Plants, Medicinal/chemistry , Plant Extracts/pharmacology , Gene Expression Regulation/drug effects , Tumor Suppressor Protein p53/biosynthesis , DNA-Binding Proteins/biosynthesis , X-Linked Inhibitor of Apoptosis Protein/biosynthesis , NF-E2-Related Factor 2/biosynthesis , Antimalarials/pharmacology , Plasmodium falciparum/drug effects , Salmonella typhimurium/drug effects , Salmonella typhimurium/genetics , Solvents , Plant Extracts/isolation & purification , Tumor Suppressor Protein p53/genetics , Colombia , Comet Assay , Ethanol , DNA-Binding Proteins/genetics , Drug Evaluation, Preclinical , X-Linked Inhibitor of Apoptosis Protein/genetics , NF-E2-Related Factor 2/genetics , Hep G2 Cells , Activation, Metabolic , Genes, Bacterial/drug effects , Mutagenicity Tests , Antimalarials/isolation & purificationABSTRACT
Increased expression of COX-2 has been linked to inflammation and carcinogenesis. Constitutive expression of COX-2 protects hepatocytes from several pro-apoptotic stimuli. Increased hepatic apoptosis has been observed in experimental models of diabetes. Our present aim was to analyze the role of COX-2 as a regulator of apoptosis in diabetic mouse liver. Mice of C57BL/6 strain wild type (Wt) and transgenic in COX-2 (hCOX-2 Tg) were separated into Control (vehicle) and SID (streptozotocin induced diabetes, 200 mg/kg body weight, i.p.). Seven days post-injection, Wt diabetic animals showed a decrease in PI3K activity and P-Akt levels, an increase of P-JNK, P-p38, pro-apoptotic Bad and Bax, release of cytochrome c and activities of caspases-3 and -9, leading to an increased apoptotic index. This situation was improved in diabetic COX-2 Tg. In addition, SID COX-2 Tg showed increased expression of anti-apoptotic Mcl-1 and XIAP. Pro-apoptotic state in the liver of diabetic animals was improved by over-expression of COX-2. We also analyzed the roles of high glucose-induced apoptosis and hCOX-2 in vitro. Non-transfected and hCOX-2-transfected cells were cultured at 5 and 25 mM of glucose by 72 h. At 25 mM there was an increase in apoptosis in non-transfected cells versus those exposed to 5 mM. This increase was partly prevented in transfected cells at 25 mM. Moreover, the protective effect observed in hCOX-2-transfected cells was suppressed by addition of DFU (COX-2 selective inhibitor), and mimicked by addition of PGE(2) in non-transfected cells. Taken together, these results demonstrate that hyperglycemia-induced hepatic apoptosis is protected by hCOX-2 expression.