Caracterização e investigação da atividade anti-oomiceto de óleos essenciais de Alpinia speciosa, Eremanthus erythropappus, Schinus lentiscifolius, Hesperozygis ringens e Ocimum americanum frente à Saprolegnia parasitica

Abstract

This study aimed to characterize the essential oils of Alpinia speciosa (EOAS), Eremanthus erythropappus (EOEE), Schinus lentiscifolius (EOSL), Hesperozygis ringens (EOHR) and Ocimum americanum (EOOA), and to investigate the in vitro antimicrobial activity against Saprolegnia parasitica zoospores (strain CBS 223.65). Composition of the oils was analyzed by gas chromatography/mass spectrometry (GC/MS) using flame ionization detector for GC. Evaluation of the antimicrobial activity was performed through an adaptation of the method according to the CLSI M38-A2. The main chemical compounds identified were: eucalyptol (30.58%) and terpinen-4-ol (20.04%) in EOAS; α-bisabolol (71.47%) in EOEE; 3-carene (55.51%) and α-thujene (11.03%) in EOSL; pulegone (88.31%) in EOHR; and linalol (28.96%), eucalyptol (17.83%) and eugenol (16.22%) in EOOA. The minimum inhibitory concentration was >300 μg/mL for EOAS, EOHR and EOOA; 320 μg/mL for EOEE; and 160 μg/mL for EOSL. Evaluation of the minimum oomyceticidal concentration identified values of >320 μg/mL for EOAS, EOEE, EOHR and EOOA, while 300 μg/mL was found as the lowest lethal concentration of EOSL against Saprolegnia parasitica. The present findings indicate the susceptibility of Saprolegnia parasitica CBS 223.65 to the tested essential oils. This is the first report on the antioomycotic property of EOAS, EOEE, EOSL, EOHR and EOOA against Saprolegnia parasitica CBS 223.65, indicating that this class of natural products could be a feasible alternative for preventing and/or treating Saprolegnia parasitica caused saprolegniosis. Nonetheless, further studies are required in order to assess the in vivo antioomycotic activity.