Embriotoxicidade e atividades antioxidantes e anti-inflamatórias dos extratos de Eryngium foetidum em zebrafish

Abstract

Plant extracts are a mixture of several bioactive compounds, with variable chemical properties and polarities, making it necessary, therefore, to use different tests to assess the antioxidant activity of an extract and especially to select the correct method. The first work of this thesis consists of a systematic review of in vitro and in vivo methods to evaluate the antioxidant activity of plant extracts, addressing the frequency of use of different methods, animal models used and extraction methods. Scopus and Science Direct were searched, resulting in 310 articles, using keywords (plant extract + antioxidant + in vitro + in vivo), and articles published from January to July 2020 were accepted for analysis. , there are 17 in vitro and 13 in vivo methods, with the most used for the respective measurements, DPH and LPO. Among the means of extraction, methanol is the most used. Furthermore, few studies performed in vitro and in vivo tests simultaneously (25%) and, when in vivo tests are used (16%), rodents are the most used models. The objective of the second work was to evaluate the effect and concentration of different extracts of E. foetidum on the development of zebrafish (Danio rerio) embryos. To investigate the impact of aqueous extract (EA), ethanolic (EE) and methanolic (EM), embryos were exposed to 0.625; 1.25; 2.5; 5 and 10 mg mL-1 up to 120 hpf (hours after fertilization) for evaluation of toxicity in embryonic development and then to 0.039; 0.078; 0.156; 0.312 and 0.625 mg mL-1 for antioxidant responses of the enzymes superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and cellular apoptosis. The results showed that, depending on the extraction solvent, concentrations used and exposure times, E. foetidum extracts cause mortality, alter the hatching time and promote differences in enzymatic activities. Delays in the development and increased activity of GST were found in all treatments. Apoptosis was not observed in any of the treatments. The antioxidant and anti-inflammatory activities of E. foetidum extracts were addressed in the third work. To determine the antioxidant activity, embryos were exposed to the medium containing the extracts (0; 0.039; 0.078; 0.156; 0.312 and 0.625 mg mL-1) added with hydrogen peroxide (H2O2) and subsequently measured by the enzymes SOD, CAT and GST and cell apoptosis. The anti-inflammatory activity was analyzed through the number of neutrophils migrated to the wound site in the caudal fin in zebrafish larvae after treatment with the extracts. Larvae exposed to H2O2 showed high activities of SOD and CAT enzymes. However, significant reductions occurred in the activity of these enzymes when the larvae were exposed to the extracts. For the GST enzyme, an increase in activity was verified for larvae exposed to EA and EM. Apoptosis induced by H2O2 was reduced by the extracts in a concentration-dependent manner. Regarding the anti-inflammatory activity, a reduction in the number of neutrophils migrating to the injured region of the tail was verified in larvae treated with the ethanol extract.