Ageratum conyzoides, an invasive species with antioxidant and antifungal potential

This study aimed to evaluate the chemical composition and the antioxidant and antifungal activities of the essential oil (EO) extracted from the aerial parts (leaves and flowers) of Ageratum conyzoides (Asteraceae). The EO was extracted by the hydrodistillation process (3h), and the compounds were identified by gas chromatography coupled to mass spectrometry (GC-MS). Antioxidant activity was performed by the β-carotene/linoleic acid co-oxidation system and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging and the iron reduction method (FRAP). The antifungal activity was performed by the broth microdilution (MIC) method using the strains Rhizopus oryzae ATCC 7560; Aspergillus flavus ATCC 1217; Aspergillus ochraceus ATCC 6787 and Penicillium verrucosum ATCC 7680. The results indicated a yield of 0.82 mg/kg. Sesquiterpenes hydrocarbons (33.28%) were the major class, and precocene I (48.19%), precocene II (7.38%) and β-caryophyllene (19.66%) were the major constituents. The co-oxidation system of β-carotene/linoleic acid showed 52.18% inhibition of oxidation in the concentration of 1.0 mg/mL. Of the four fungi evaluated, only Aspergillus ochraceus showed results, with a MIC of 1250 μL/mL, and the importance of finding activity on this fungus lies in the fact that it is a producer of ochratoxin A, infesting mainly green coffee beans. The results found open up new perspectives in valuing a species considered invasive.