Efeito antioxidante do extrato hidroetanólico de Passovia ovata e sua ação sobre a toxicidade e produção de nitrito em macrófagos RAW 264.7

Abstract

Several families are explored for pharmacological purposes, we can highlight Loranthaceae, composed of hemiparasites of fruit trees, better known as mistletoe. Considering the distribution and identification of Passovia ovata among the mistletoes popularly used for a series of purposes, it is necessary to study and standardize its extract, emphasizing the analysis of its composition, pharmacological action and its viability. The aim of the study was to evaluate the antioxidant effect of the hydroethanolic extract of P. ovata, its cytotoxic action and to quantify nitrite production in RAW 264.7 macrophages stimulated with lipopolysaccharide (LPS). Passovia ovata leaves were collected at the school farm of the State University of Maranhão- UEMA, located in the city of São Luís- MA. The 70% hydroethanolic extract (EHE) of P.ovata was obtained by maceration during a period of twelve days. From 750g of ground plant material, 200g of dry P. ovata EHE could be obtained, which gave it a percentage yield of 26.6%. In qualitative photochemical assays, anthraquinones, tannins, catechins, flavanones and flavonols were found. The total flavonoid content was 4.44 mgEQ/g. In the determination of antioxidant activity by DPPH and ABTS, IC50 values were 15.38 µg/mL and 62.72 µg/mL, respectively. In the determination by FRAP, a reducing power of 3488.24 μmolET/g was obtained. When evaluating the cytotoxicity at the different concentrations tested after an incubation period of 24 and 48 hours, it was not possible to observe a significant difference between untreated and treated cells. In the nitrite dosage of the groups treated with 125 and 250µg/mL of P. ovata EHE there was no statistical difference when compared to the group stimulated by LPS, but not treated. The group treated with a concentration of 500µg/mL of the extract showed a statistical difference when compared to the positive control group, only stimulated by LPS. Thus, the results indicate that EHE from P. ovata has antioxidant activity, low cytotoxicity on RAW 264.7 macrophages, and was able to inhibit the production of nitric oxide in these cells when stimulated with LPS.