The DPPH radical scavenging assay for essential oils was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The DPPH is a stable free radical with a violet color that, under the action of proton-donating compounds, is reduced to a light yellow color, and this change can be monitored at 517 nm [71]. Concentrations of the methanolic solution between 0.156 and 20 mg/mL were tested.