Investigação da composição química, capacidade antioxidante e antiofídica do extrato aquoso das folhas de Baccharis aliena (spreng) Joch.Müll

Abstract

The use of medicinal plants as a therapeutic base is known and applied in different cultures worldwide. In Brazil, due to its large territory and its immense diversity of plant species, the use of medicinal plants is a traditional practice and due to its origin it is understood that they do not present toxicity risks. In this context, the aerial parts of Baccharis alienate (Spreng) Joch. Müll (synonym Heterothalamus alienus), known as rosemary, are widely used in the southern region of Rio Grande do Sul. The decoction is administered to animals, mainly dogs, for the treatment of snake bites, while leaves macerated in alcohol are used in humans for “affectionation”, that is, they are rubbed on the skin in the treatment of allergies, minor injuries, muscular and rheumatic pains. However, studies on the species are scarce and do not allow confirmation of the indication for popular use. Thus, the objective of this work was to evaluate the chemical composition of the aqueous extract of B. aliena (ExBA), its preliminary toxicity and its antioxidant potential, in addition to verifying the protective capacity of the extract against the venom of Philodryas patagoniensis (papa-pinto) . For this, ExBA was prepared by decoction, simulating the method of popular use. The phytochemical analysis was performed by high performance liquid chromatography coupled to a diode array detector and pointed out the presence of the major compounds rutin, quercetin and ferulic acid. To analyze the toxicological potential of the B.aliena extract, the assay with Artemia salina was prepared, which estimated the LD50 of the aqueous extract at 5140 μg / mL (R2 = 0.9982), characterizing it as non-toxic. EXBA presented a significant level for total polyphenols, 266.09 ± 8.88 mg / g -1 of gallic acid equivalents, while for flavonoids it remained around 0.70 ± 0.09 mg / g -1 of quercetin equivalents. The antioxidant activity of ExBA was evaluated by determining the total antioxidant capacity against DPPH and ABTS free radicals and by the thiobarbituric acid (TBARS) assay. ExBA was able to significantly inhibit lipid peroxidation in brain and liver tissues, from a concentration of 100μg / mL. The ExBA presented an IC50 of 5.61 ± 1.19 μg / mL in the TAC test, while in the tests with the radicals DPPH • and ABTS, the IC50 found were 628.7 ± 48.2 and 31.25 ± 5.96 μg / mL. The antiophidic activity was assessed by carrying out the cell and comet viability tests. It was possible to observe that the ExBA did not demonstrate any toxicological potential at the tested concentration of 10 μg / mL, but was able to inhibit the genotoxicity induced by the venom of P. patagoniensis.