Lauraceae plants are recognized as a good source of bioactive metabolites. Ethanolic extracts of Nectandra amazonum heartwood, leaf and bark were screened for antifungal activity against Fusarium oxysporum by bioautography detection. This test allowed identifying the antifungal properties of N. amazonum heartwood extract and the non-properties of the resting extracts. In order to establish the antifungal potential of N. amazonum heartwood extract, F. oxysporum was subjected to “the drop-test” (an antifungal, micro-scale MU Nueva Granada outline methodology to test inhibition on fungal mycelium) where the hormesis response this extract generates on F. oxysporum was determined. This response is characterized by the inhibition of the pathogen growth from up to 24% at low amounts and the promotion at high amounts (53%). In the search of bioactive compounds, a direct bioautography-thin-layer chromatography test was carried out for all N.amazonum-derived extracts leading to the identification of a bioactive compound from N. amazonum bark extract. This active compound was then isolated by chromatography techniques. Once obtained, by NMR and LC-MS, the compound was structurally elucidated as a sesquiterpene-related compound (mw 234 g/mol) known as costic acid. The antifungal activity of this sesquiterpene was also evaluated using the test developed by us exhibiting a reasonable growth inhibition against F. oxysporum. Further structure-activity studies and biological analyses are currently in course in order to clarify the underlying mechanism and to draw unambiguous conclusions for the antifungal-inhibition of this sesquiterpene.
