AVALIAÇÃO DO POTENCIAL BIOHERCIDA DO ÓLEO ESSENCIAL DAS FOLHAS DE Eugenia dysenterica (Mart.) DC

Abstract

Weed control represents a critical challenge in agriculture, accounting for estimated losses of about 34% in global productivity. Although the use of synthetic herbicides remains the predominant strategy, increasing environmental concerns and the emergence of resistance in invasive plants have driven the search for bioherbicides based on natural metabolites. In this context, essential oils emerge as promising sources of phytotoxic compounds capable of interfering with vital processes such as photosynthesis. The present study evaluated the bioherbicidal potential of the essential oil from the leaves of Eugenia dysenterica (Mart.) DC, a species native to the Brazilian Cerrado with recognized ecological and phytochemical relevance. The plant material was collected in Rianápolis, Goiás, Brazil, and the oil was extracted by hydrodistillation. Chemical characterization was performed using GC/MS and revealed the predominance of (E)- caryophyllene, myrcene, α-humulene, β-selinene, and (E)-β-ocimene. Phytotoxic activity was analyzed through chlorophyll a fluorescence assays in leaf discs of Spinacia oleracea. The results demonstrated that the essential oil of E. dysenterica causes severe damage to the photosynthetic apparatus in a dose-dependent manner, through a drastic reduction in performance indices (PIABS and PICSo) and in electron transport flux (ET0/CS0), as well as through the deactivation of reaction centers (RC/CS0). At concentrations above 100 mg L-1, its efficacy was comparable to the commercial herbicide DCMU. The inhibitory effects suggest direct interference with Photosystem II (PSII), possibly through blockage of electron transport at the quinone acceptor site. Therefore, it is concluded that the essential oil of E. dysenterica has significant potential for the development of bioinputs aimed at the sustainable management of weeds, combining biological efficiency with reduced environmental impacts.