Antioxidant and Antimicrobial Activities of Essential Oil of Lemon (Citrus limon) Peel in Vitro and in a Food Model

Background: Citrus fruits have some antioxidant and antimicrobial properties. The aim of this study was to determine the chemical compounds, antioxidant, and antimicrobial activities of Essential Oil (EO) of lemon (Citrus limon) peel in vitro and in a food model. Methods: The analysis of the lemon peel EO was carried out using gas chromatographymass spectrometry. Total phenolic and flavonoid content was determined using standard protocols. The antioxidant activity of the EO was also evaluated using 2, 2-diphenyl-1- picrylhydrazyl (DPPH) radical scavenging assay. Antimicrobial properties of the EO were assessed against Staphylococcus aureus using the broth microdilution method. Also, barely soup was chosen as food model. Data were analyzed using SPSS Inc. software version 22.0. Results: The total phenol content was 81.82±8.02 mg gallic acid equivalent/g of the EO. Also, the total amount of flavonoids in the EO of lemon peel was 11.72±1.82 mg/g rutin equivalent. Lemon peel EO showed 55.09% inhibition of DPPH, showing significant difference with control group (p<0.05). The MIC and MBC value of EO against S. aureus was 1.25 and 5%, respectively having significant difference (p<0.05) with control group. A dose-dependent manner was seen in food model revealed significantly lower (p<0.05) bacterial number in EO containing barley soup groups than the control one. Conclusion: The EO of lemon peel showed considerable antioxidant and antimicrobial properties both in vitro and barley soup as food model.