Evaluation of Chemical Composition and Antioxidant Traits of Essential Oils from Selected Citrus Varieties

Abstract

The peels of the four selected citrus varieties, Citrus sinensis, Citrus limon, Citrus aurantium and Citrus reticulata were used to evaluate the chemical composition and antioxidant capacity of the essential oils of these four citrus varieties. Hydro distillation was used to obtain the volatile compounds of the essential oils and then the analysis was done through gas chromatography-mass spectrometry (GC-MS). The most predominant constituent in all the species was d-limonene and its contents varied between 52.4 in C. reticulata and 87.3 in C. aurantium with other minor constituents including b-myrcene, a-pinene, linalool and g-terpinene varying in the species. The antioxidant activity was determined using the DPPH, ABTS, FRAP, and b-carotene/linoleic acid bleaching. It was found out that C. aurantium essential oil had the greatest antioxidant ability with C. limon coming in second, and C. reticulata in the third place. The correlation analysis of the result revealed that small oxygenated monoterpenes also significantly contributed to the activity of antioxidants, which reveals the effect of synergistic control of major and minor components of each other. These findings show that the chemical composition is vital to determine the bioactivity of citrus essential oils as well as reveal their possible uses which render them convenient natural antioxidants in food, cosmetic and pharmaceutical industries.