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 around the world. In Brazil, due to its large territory and its immense diversity of plant species, the use of medicinal plants is a traditional practice. This traditional use often implies that drugs of plant origin pose no risk of toxicity. In this context, the aerial parts of Baccharis aliena (Spreng) Joch. Müll (synonymy Heterothalamus alienus), known as alecrim, are widely used in southern Rio Grande do Sul. Infusion of its leaves is administered to animals, especially dogs, for the treatment of snake bites, while alcoholmacerated leaves are used in humans for “bulging”, ie. they are rubbed over the skin to treat allergies, minor injuries, aches and muscular and rheumatic pains. However, studies on the species are scarce and do not allow confirmation of the indication of popular use. Thus, the objective of this work was to evaluate the chemical composition of the aqueous extract of B. aliena (ExBA), preliminary toxicity and antioxidant potential, besides verifying the protective capacity of the extract against the venom of Philodryas patagoniensis (papapinto). For this, ExBA was prepared by decoction, simulating the method of popular use. Phytochemical analysis was performed by high performance liquid chromatography coupled with diode array detector (CLAE/DAD) and pointed to the presence of the major compounds rutin, quercetin and ferulic acid. To analyze the toxicological potential of B.aliena extract, the assay was prepared with Artemia salina, which estimated the DL50 of the aqueous extract in 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 remained around 0,70 ±0,09 mg. g-1 of quercetin equivalents. The antioxidant activity of ExBA was evaluated by determination of the toral antioxidant capacity against DPPH and ABTS free radicals and by the thiobarbituric acid assay (TBARS). ExBA extract was able to significantly inhibit lipid peroxidation in brain and hepatic tissues at concentration,up to100μg/mL. ExBA showed IC50 de 5.61 ± 1.19 μg/ mL in the TAC test while in the tests DPPH• and ABTS•+, the IC50 found were from 628.7 ± 48.2 and 31.25 ± 5.96 μg/ mL. Antiophidic activity was evaluated by performing cell and comet viability tests. It was observed that ExBA showed no toxicological potential at the tested concentration of 10 μg/mL, but was able to inhibit venom-induced genotoxicity of P. patagoniensis.