Antioxidant and antimicrobial activities of essential oils extracted from peels of limes by using emzyme-assisted vacuum distillation

Abstract

Essential oils are natural compounds containing an amount of complex mixtures of volatile compounds. This study was carried out to determine the antioxidant and antimicrobial activities of essential oils extracted from peels of different lime varieties. Essential oils of Long An lime, Da Lat lime, Dao lime peels were extracted by using three different methods: hydro-distillation method, vacuum distillation method, and enzyme-assisted vacuum distillation method. The antimicrobial activities were tested by diffusion method and dilution method. Essential oil of Long An lime peel was the strongest antimicrobial activities with big zones of inhibition and low minimum inhibitory concentration against Staphylococcus aureus, Samonella typhimurium and Bacillus cereus. On the other hand, essential oil of Dao lime peel was considered as the weakest one because of lowest inhibition against Salmonella typhi. The antioxidant activities of these essential oils were determined by 2,2-diphenyl–1-picrylhydrazyl (DPPH) assay. The antioxidant activities of essential oil of Long An lime peel, in contrast to antimicrobial activities, were reported to be the weakest among all (with 8.10 ± 0.20mg/ml of half inhibition concentration). Essential oil of Da Lat lime peels was found to be the strongest in antioxidant activities (with 23.70 ± 0.59mg/ml of half inhibition concentration). According to the results, essential oils extracted from peels of different lime varieties may have different antimicrobial and antioxidant activities. Keywords: essential oil, peels, lime, hydro-distillation, vacuum distillation, antimicrobial activities, antioxidant activities.