Composição química, atividade acaricida, propriedade antioxidante, inibição da acetilcolinesterase e toxicidade do óleo essencial das folhas de Sparattanthelium botocudorum

Abstract

Sparattanthelium botocudorum is a species endemic to Brazil, commonly known as “Canela-brava”, this shrub is distributed on the coast of Paraíba and in the state of Pernambuco. Due to the scarcity of chemical and biological studies on this plant, the research aimed to determine the chemical composition of the essential oil of the leaves as well as the evaluation of the acaricidal, antioxidant and toxicity properties against Artemia salina. The essential oil, extracted from fresh leaves, through the hydrodistillation technique with the aid of a Clevenger-type device, had a yield of 0.40% m/m and its chemical characterization, through Gas Chromatography coupled to the Mass Spectrometer (CG-MS), emerged as the majority constituents were the sesquiterpenes Germanecrene D with (38.28 %), E-Nerolidol (18.95 %), [beta]-Caryophyllene (14.49 %) and Biciclogermacrene (14.18 %) and the single monoterpene Z-[beta]-Ocimene identified in the OE with a percentage of 0.37%. Residual contact bioassays were carried out, with the aim of identifying the effects of the oil on the two-spotted mite, and showed promising toxicity. The residual contact bioassay, in which the mites are arranged on already treated leaves, showed LC50 = 16.5 μL/mL. Furthermore, the oil also demonstrated ovicidal properties with an estimated LC50 of 1.20 μL/mL. And regarding repellency activity, the oil showed a better potential with the LC30 concentration 8.8 μL/mL. After evaluating the inhibition activity of the acetylcholinesterase enzyme, the essential oil from the leaves of S. botocudorum inhibited the enzyme, since the LC50 resulted was 2.9 μg/mL below the LC50 of the positive control, which is 5.95 μg/mL. mL. Furthermore, OE presented antioxidant properties for the free radical DPPH˙, estimating an EC50 = 110.3 μg/mL, while for the free radical ABTS˙+ it was EC50 = 49.23 μg/mL. Finally, the oil exhibited a toxicity concentration of 700 μg/mL for the toxicity test against A. salina, which compared to what described in the literature had no toxicity. Therefore, the study showed that the essential oil presented similar and promising effects compared to already commercialized acaricides, and that the bioassays presented different routes of action, therefore acting with different mechanisms on the pest and presenting a biological property of antioxidant activity.