ABSTRACT
Extratos vegetais possuem metabólitos secundários que podem atuar como bioherbicidas com a vantagem de promoverem menores riscos ao ambiente. Mikania laevigata pertence à família Asteraceae e possui a cumarina 1,2-benzopirona como marcador químico, capaz de inibir ou estimular a germinação e crescimento de plantas adjacentes. Diante do exposto, objetivou-se avaliar a fitotoxicidade dos extratos aquoso e etanólico de M. laevigata sobre Lactuca sativa (alface) e Bidens pilosa (picão preto). Foram testadas cinco concentrações (0,1; 1,0; 1,5; 2,0 e 3,0 mg.mL-1) dos extratos, aquoso e etanólico, em experimentos separados, e água destilada como controle. Para isso, foram avaliados a porcentagem de germinação, o índice de velocidade de germinação, o crescimento inicial e os teores de peróxido de hidrogênio (H2O2) e do malonaldeido (MDA). Na presença do extrato etanólico, as espécies (alface e picão preto) reduziram 85 e 90% da germinação, respectivamente. O comprimento da radícula, na menor concentração dos extratos, não foi afetado. Entretanto, na concentração de 2,0 mg.mL-1, as reduções foram de 85%, para alface, e 65%, para picão preto. O aumento do teor de H2O2 foi dose dependente, ou seja, conforme o aumento da concentração dos extratos maior a produção de peróxido, seguido do aumento do MDA para alface e picão preto. As plântulas cultivadas na concentração de 3 mg.mL-1 do extrato etanólico sofreram necrose, impossibilitando as análises subsequentes. Os extratos da M. laeviagata nas concentrações 2,0 e 3,0 mg.mL-1 demonstraram fitointoxicação com aumento do estresse oxidativo nas espécies alface e picão preto.
Plant extracts have secondary metabolites that can act as bioherbicides, with the advantage of being more environmentally friendly. Mikania laevigata belongs to the family Asteraceae and has coumarin 1,2-benzopyrone as a chemical marker, which is capable of inhibiting or stimulating the germination and growth of adjacent plants. Thus, the objective of this work was to evaluate the phytotoxicity of aqueous and ethanolic extracts of M. laevigata on Lactuca sativa (lettuce) and Bidens pilosa (beggarticks). Five concentrations (0.1, 1.0, 1.5, 2.0 and 3.0 mg.mL-1) of aqueous and ethanolic extracts were tested in separate experiments, with distilled water as the control. Germination percentage, germination speed index, initial growth and the content of hydrogen peroxide (H2O2) and malonaldehyde (MDA) were evaluated. In the presence of the ethanolic extract, germination of the species (lettuce and beggarticks) was reduced by 85% and 90%, respectively. Radicle length, for the lowest concentration of the extracts, was not affected. However, at a concentration of 2.0 mg.mL-1 the reductions were 85% for lettuce and 65% for beggarticks. The increase of H2O2 content depended on the dose, where the greater the concentration of the extracts, the greater the production of peroxide, followed by an increase in MDA for lettuce and beggarticks. Seedlings grown in a concentration of 3.0 mg.mL-1 of the ethanolic extract were subjected to necrosis, making subsequent analyses impossible. The M. laeviagata extracts at concentrations of 2.0 and 3.0 mg.mL-1 demonstrated phytotoxicity, with increased oxidative stress in lettuce and beggarticks.
Subject(s)
Lactuca/toxicity , Bidens/toxicity , Mikania/toxicity , Plant Extracts , PhytochemicalsABSTRACT
Embora seja notável o avanço no uso popular de plantas com finalidade terapêutica, estudos são necessários para demonstrar seus potenciais tóxicos, já que grande parte dos usuários de fitoterápicos os considera inócuos. Durante a gestação, a maioria das alterações no feto é decorrente da exposição da mãe a agentes químicos, podendo ocorrer efeitos abortivos, teratogênicos e citotóxicos. A relevância deste trabalho se deve a escassez de estudos sobre os efeitos tóxicos do extrato de Mikania glomerata, popularmente conhecida como guaco, durante o período gestacional. Foram estudadas ratas Wistar prenhes (normotensas e espontaneamente hipertensas) sob tratamento com extrato seco de M. glomerata (2mL) e avaliada a morfologia do fígado dos fetos. Todos os grupos apresentaram fetos vivos sem alterações macroscópicas, perda pré-implantação e reabsorção fetal normal. Não houve alterações anatômicas nos fígados, apenas presença de monócitos e linfócitos nas veias-centrolobulares. Conclui-se que o extrato, na concentração e formulação estudadas, não apresentou toxicidade aos fetos.(AU)
Although remarkable advances in the use of herbal medicine were observed, studies are needed to demonstrate the toxic potential of their compounds, since most of their users consider them effective and safe. During pregnancy, most of the abnormal changes in the fetus is mainly due to the mother's exposure to chemicals, resulting in abortion or teratogenic and cytotoxic effects to the mother and neonate. The relevance of this research is due to the lack of studies on the toxic effects of Mikania glomerata. popularly known as "guaco" - extract administration during the gestational period. Experimental groups of normotensive and spontaneously hypertensive pregnant Wistar rats were studied. The animals were treated with M. glomerata extract (2 ml) and the morphology of fetal liver was evaluated to evaluate the possible toxic effects of M. glomerata to fetuses. In all groups the live fetuses were without macroscopic changes and the pre-implantation loss or normal fetal reabsorption were physiologically normal (data not shown). There were no anatomical or histological changes in the livers of fetuses studied, which showed centrilobular veins with the presence of monocytes and lymphocytes. The results lead the conclusion that M. glomerata extract, at the tested concentration, did not show toxicity to rats' fetuses.(AU)
Subject(s)
Animals , Female , Pregnancy , Fetal Development , Mikania/toxicity , Hypertension , Liver/pathology , Models, Animal , Phytotherapy/adverse effects , Rats, WistarABSTRACT
Teas of Bidens pilosa and Mikania glomerata are popularly consumed to medicinal ends. The capacity to induce DNA damages and mutagenic effects of these teas were evaluated, in vitro, on HTC cells, with comet assay and micronucleus test. The teas tested at various doses were prepared differently: infusion of Mikania glomerata (IM) and Bidens pilosa (IB), macerate of Mikania glomerata in 80% ethanol (MM80) and decoction of Bidens pilosa (DB). In IM and MM80, the quantity of coumarin was determined by high-performance liquid chromatography (HPLC) with UV detection. Methylmethanesulfonate was utilized as positive control, phosphate-buffered saline as negative control, 80% ethanol as solvent control and 2-aminoanthracene as drug metabolism control. The comet assay demonstrated genotoxic effects for both plants. The genotoxic potential of IB was upper than DB, showing dose-response. In the MN test, excepting IM 40 microL/mL, all treatments was not mutagenic. The effects did not show direct relation with cumarin quantity present in IM and MM80. The results demonstrated DNA damages at the highest concentrations of alcoholic macerate (10 and 20 microL/mL) and infusion of Mikania glomerata (20 and 40 microL/mL) and of Bidens pilosa infusion (40 microL/mL). Thus, both dose and preparation-form suggest caution in the phytotherapeutic use of these plants.
Subject(s)
Bidens/toxicity , Mikania/toxicity , Mutagens/toxicity , Tea/toxicity , Animals , Bidens/chemistry , Cell Line, Tumor , Chromatography, High Pressure Liquid , Comet Assay/methods , Coumarins/administration & dosage , Coumarins/isolation & purification , Coumarins/toxicity , Dose-Response Relationship, Drug , Liver Neoplasms/metabolism , Micronucleus Tests/methods , Mikania/chemistry , Mutagens/administration & dosage , Mutagens/isolation & purification , Rats , Tea/chemistryABSTRACT
Mikania glomerata (guaco) is a plant well known in Brazil for its therapeutic properties, especially in the treatament of respiratory diseases. Coumarin and flavonoids are active compounds of M. glomerata leaves and have been reported to cause adverse effects on the organism, including antifertility activity in famale rat and male dog respectively. This work analyzes the effect of short-term administration of M.glomerata hydroalcoholic extract on vital organs, of the reproductive system and sperm concentration of mature male wistar rats. Treated animals received 1 ml of the extract at a dose of 1.1 g/kg of body weight for live days. Body and organs weights, sperm production and food consumption were evaluated. No body weigth reduction and no toxic effect on the organs, gamete production or food intake were detected in any of the groups analyzed, given the experimental protocol used.
