Chemical composition, anticancer, and antioxidant activities of essential oil obtained from lemon (Citrus limon) by-product

Abstract

The by-product of lemon (Citrus limon) is more than 0.8 million metric tons in 2020/2021 which consist mostly of the peel. This is a problem for management, pollution, and the environment due to microbial spoilage. Lemon peel is a good source of essential oil. Utilization of lemon essential oil (LEO) can provide an efficient and environmentally friendly material for many uses. LEO has GRAS (generally recognized as safe) status, which has generated considerable appeal from the food sector. However, in its implementation, it has to face many problems related to the volatility and variability of the composition. This study was carried out to extract LEO from lemon peel by steam distillation, to determine its composition, to evaluate its antioxidant and anticancer activities, and to analyze the encapsulation effect of LEO in whey protein-pectin complex on these parameters. The LEO yield was 1.2 % (d.m). The main component in LEO was D-limonene (59.8 %) followed by ß-pinene (15.3 %), γ-terpinene (8.4 %), and α-pinene (3.0 %). Encapsulation of LEO in whey protein pectin-complex changed the composition of volatile compounds with an increase in D-limonene and γ-terpinene, and a decrease in ß-pinene and α-pinene. The LEO and LEO nanocapsules (LEONCs) showed a positive effect on the inhibition of colon-26 cells proliferation with IC50 of 105.9 μg/mL and 2.3 mg /mL, respectively