Fungicidal properties and insights on the mechanisms of the action of volatile oils from Amazonian Aniba trees

The Amazonian Aniba species are world-renowned for their essential oils (EOs). The molecules derived from EOs have been intensively investigated in regards to their potential for disease control in plants. The aim of this study was to investigate the antifungal properties of Aniba canelilla EO (ACEO) and Aniba parviflora EO (APEO) when used against eight phytopathogenic fungi. Gas chromatography-mass spectrometry (GC-MS) analysis of oils showed that 1-nitro-2-phenylethane (similar to 80%) and linalool (similar to 40%) are the major compounds in ACED and APEO, respectively. The ACE) and APEO treatments displayed remarkable antifungal effects against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Pusarium solani, Alternaria alternata, Colletotrichum gloeosporioides, Colletotrichum musae and Colletotrichum guaranicola, for which the IC50 values ranged from 0.05 to 0.28 mu L mL(-1) and 0.17 to 0.63 mu L mL(-1), respectively. Furthermore, the oil caused the inhibition of conidial germination by at least 83% for ACEO and 78% for APEO. The ACED and APEO at 5 mu L mL(-1) induced leakage of nucleic acids and protein, suggesting that inhibition could be linked to the breakdown of membrane integrity of the conidia. In addition, the detection of fluorescent dye propidium iodide (PI) on F. solani conidia treated with ACED and APEO indicates damage on the conidia cytoplasmic membrane. The findings of this study may be of biotechnological interest for the development of new plant protection products, with the advantage of being less harmful than the agrochemicals currently available.