Investigação da toxicidade e do potencial bioinseticida do extrato hidroalcoólico de folhas de croton campestris a. St.-Hill em modelo de drosophila melanogaster

Abstract

Brazil has a vast territory and a large number of plant species. Despite this, there are few studies focusing on biotecnological potential of its biodiversity. Plants have secondary metabolites, substances with known biological properties, which may serve as a defense, or as attractive to organisms. Croton campestris, pop. Velame do campo is a shrub found in the Northeast and Southeast regions of the country, popularly used for therapeutic purposes, but research describing the in vivo toxicity of this plant are scarce. Therefore, the present study was aimed to investigate the toxicity and possible bioinsecticide activity of the hydroalcoholic extract of leaves of C. campestris in Drosophila melanogaster. D. melanogaster, known as the fruit fly, is an ideal biensaios because of its numerous advantages in biological research model. For the experiments, adult flies of both sexes were treated as follows: control (1% sucrose), 0.1 1 10 and 50mg/mL of extract diluted in 1% sucrose for 07 days (mortality) and 72h (locomotor activity and other biochemical assays). To estimate survival, dead flies were counted daily until the end of treatment. Locomotor activity was evaluated using the Negative Geotaxis assay and other biochemical tests involved: analysis of cell viability assay by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and fluorescence reduction of Resazurin; analysis of oxidative stress by oxidation of 2´,7´-dichlorofluorescein diacetate (DCF-DA); determination of thiols; activity of antioxidant enzymes catalase, glutathione S-transferase, superoxide dismutase, and enzyme acetylcholinesterase; phosphorylation of MAPK, ERK, JNK and p38 proteins, in vitro antioxidant activity through DPPH assays, FRAP and ABTS+, and subsequently the effect of C. campestris in combination with herbicide Paraquat. Thus, our results demonstrated that after 07 days of treatment C. campestris caused significant mortality of flies, and 72 hours after treatment decreased locomotor activity, reduced cell viability, there was also an increase in the general index of oxidative stress, and activity of antioxidant enzymes, increased phosphorylation of p38 and inhibition of JNK2. In addition, C. campestris potentiated the effect of Paraquat, inducing locomotor deficits and causing mortality in Drosophila melanogaster. Therefore, the data obtained from this study demonstrate for the first time, the toxicity of C. campestris and its potential biopesticide and biotechnology.