Avaliação do potencial do óleo essencial e hidrolato de Varronia curassavica Jacq. no controle in vitro de Fusarium oxysporum f. sp. cubense

Abstract

In the search for new substances that can act in the management of phytopathogens, this work aimed to evaluate the in vitro potential of the essential oil (EO) and hydrosol of Varronia curassavica Jacq. as a control of Fusarium oxysporum f. sp. cubense, the causal agent of Fusarium wilt in banana plants; to evaluate the chemical profile of these extracts; and to quantify the phenolic compounds, flavonoids, and their antioxidant activity. The EO was tested at concentrations of 0, 1, 10, and 100 µL.mL-¹, and the hydrosol at 0 and 30% (v.v-¹). The major compounds identified in the EO (GC-MS) were: 2-trans, 6-trans-methyl-farnesoate and trans-caryophyllene. The EO exerted a fungistatic effect, delaying fungal development by up to 33.4% at the highest concentration. In contrast, the hydrosol was not effective, but the presence of phenolic compounds, flavonoids, and DPPH and ABTS radical scavenging activity was confirmed. The hydrosol profiles (HPLC-UV) proved to be relatively complex, with a predominance of up to 3 major compounds and a variety of other peaks at different retention times and intensities. It was also observed that the hydrosol samples that showed greater intensity or number of peaks up to 20 min. also exhibited higher levels of total phenolics, DPPH, and ABTS, suggesting a direct relationship between chemical complexity and the levels of phenolics and antioxidants. Therefore, even without the structural identification of the compounds, the chromatographic profile provides evidence that allows us to infer their chemical composition.