Avaliação do potencial toxicológico da quercetina em teleóginas de Rhipicephalus (Boophilus) Microplus

Abstract

The cattle raising in Brazil has weaknesses due to several factors that cause losses in the herd productivity. Among the agents that cause damage to production in cattle is Rhipicephalus (Boophilus) microplus, known as tick, that among the various damages caused by mites are apparent change in milk production, changes in the leather transmission disease and changes in meat. The control of Rhipicephalus (Boophilus) microplus is based on acaricides application mostly erroneously. Thus, the emergence of resistance to many active principles used commercially has been accelerated. Alternative methods using herbal medicines and biological control with fungi has been proposed in an attempt to control. There are natural flavonoids with scientific and therapeutic interest being studied highlighting the antioxidant and antimutagenic potential. Quercetin, flavonoid found in vegetables such as apples, teas and medicinal plants, has pharmacological properties, antioxidants and antimutagências. In contrast, studies related to quercetin substance present in Araucaria angustifolia carried out in kind of cheap Phoetalia pallida demonstrating that its extract is a natural insecticide found through irreversible neuromuscular blockade in the animal. This toxicity may be related to the presence of quercetin on your statement. Thus, the main objective of this study was to evaluate the toxicological potential of quercetin in engorged females of Rhipicephalus (Boophilus) microplus. For this, we used a total of 440 engorged females manually collected from infected animals, transported and stored in refrigeration (around 15 hours) until the time of handling. Concentrations were used in 0,1 μg ml, 1 μg/ml, 2 μg/ml quercetin and the control group (0,0 μg/ml), all in 20% DMSO. Solutions were made with ethyl alcohol in concentrations of 10%, 50%, and absolute control group, all in distilled water. Then, the groups of 20 ticks per concentration were submitted to soaking for ten (10) minutes in the solutions quercetin and kept in petri dishes lined with filter paper. 50 ticks were used for each concentration of ethyl alcohol and also subjected to soaking. The ticks were kept at room temperature and evaluated daily for their viability and mortality for 7 (seven) days. The tests were done in triplicate and the statistical analysis performed by ANOVA test. It was observed that at concentrations of 2 μg/ml quercetin average mortality was 5% and concentrations of 1μg/ml the average percentage mortality was 10%. Since the concentration of 0,1μg/ml averaged high percentage of death, approximately 42%. The control group (0,0 μg/ml) was assessed percentage of death by 35%. The results with respect to ethyl alcohol in had a mortality rate 30%, as 50% and equating to the control group was obtained 4% mortality. In other concentrations no significant mortality rates within 7 days of analysis. The egg-laying was not influenced by the use of quercetin. The results show that the quercetin in concentrations of 2 μg/ml and 1μg/ml eventually preventing the death of ticks.