2.4.4. ABTs Radical-Scavenging Activity

The ABTs scavenging assay of 0.5 g/mL of LEO and LEO-NEs (stored for 7 days) was performed following the kit instructions. The change in absorbance was measured at 734 nm by the microplate reader. The percentage inhibition of ABTs was calculated with the following formula:

ABTs scavenging activity (Inhibition%) = [(Acontrol − Asample + Ablank)/Acontrol] × 100 (2)

## *2.5. Data Analysis*

The results of the single-factor experiments were analyzed by Graphpad Prism version 8 software. The statistical analysis of the results of the response surface test was performed by Design-Expert version 13 software. All of the components, as well as their probable interactions, were examined using statistical parameters for analyses of variance (ANOVAs), such as degrees of freedom, F-ratios, and *p*-values. The model with a good fit to the data was selected (*p* < 0.05).
