Evaluation of cytotoxity and antioxidant activity of aqueous extract of Eugenia astringes cambess leaves

Resumo

The genus Eugenia belongs to the Myrtaceae family, being one of the most important families due to its wide distribution throughout the Brazilian territory. Some species have antioxidant, antifungal, antiviral, bactericidal, and lowering triglyceride and cholesterol levels. In addition to terpenoids, phenolic substances such as tannins and flavonoids have been described in the genus Eugenia. It is worth mentioning that in recent decades, it has been observed that there is a growing interest in polyphenolic substances, as most of them protect biological systems against the negative effects of processes or reactions that lead to the oxidation of molecules or cellular structures. In view of the above, the objective of this work was to evaluate the in vitro antioxidant capacity using the ABTS radical capture method of aqueous extracts of Eugenia astringens leaves, obtain the LD50 through the bioassay with Artemia salina Leach, determine the action of the isolated and combined aqueous extract with antibiotics against cultures of Escherichia coli BW9091 and AB 1157, evaluate the biological effects of the extract on the survival of cultures of the mutant Escherichia coli BW9091 against the action of oxidizing agents (SnCl2 and H2O2) and compare with the wild species (Escherichia coli AB 1157), which has all efficient genetic DNA repair mechanisms. We can conclude that the preliminary analysis of the aqueous extract obtained a positive result for the presence of polyphenolic compounds, among which tannins stand out, which have several pharmacological activities already described in the literature; the bioassay with Artemia salina revealed that the extract presented high toxicity with LD50 of 32.3 µg mL-1 determined by linear regression analysis, with a correlation coefficient (R2) equal to 0.9745 and straight line equation y = 0 .0125x+77.5926; the aqueous extract showed antioxidant activity, with a TEAC value of 3746.50 ± 210.71 µM trolox /g, determined by linear regression analysis with a correlation coefficient (R2) equal to 0.9982, equation of the straight line y = 0.0002X + 0.0009, with a relative standard deviation of 5.62% between measures; the extract did not exhibit microbicidal action; the associations of the extract with antibiotics revealed an increase in the size of the halos and differences between them in the E. coli AB 1157 and BW9091 strains, however, these differences were not significant by the Tukey test; the aqueous extract in E. coli BW 9091, inhibited the oxidative capacity of stannous chloride and increased the oxidative capacity of hydrogen peroxide and in E. coli AB 11577, the extract promoted an increase in oxidative capacity, when associated with stannous chloride and oxygen peroxide.