Chemical Composition and Antioxidant Potential of Essential Oils from Peels of Four Citrus Species

Abstract

Essential oils were isolated from the dried peels of Citrus limon, Citrus sinensis, Citrus auratifolia and Citrus reticulata using hydrodistillation method and were characterized using Gas Chromatography-Mass Spectrometry, while DPPH scavenging analysis was used to determine the antioxidant potentials of the oils. The hydrodistillation of the peels afforded oil in the yield of 0.61, 0.42, 0.72 and 0.52 (% w/w) for C. limon, C. auratifolia, C. sinensis and C. reticulate respectively. Analyses of the oils revealed the presence of monoterpenoids, sesquiterpenoids and non-terpenes. A total of 19, 25, 16 and 21 compounds were identified in the peels essential oils C. limon, C. auratifolia, C. sinensis and C. reticulata respectively. D-limonene, with the percentage composition of 84.9%, 44.6%, 91.8% and 82.4% in C. limon, C. auratifolia, C. sinensis and C. reticulata respectively was the most predominant compound. All the citrus species peels essential oils showed antioxidant activity of scavenging DPPH with IC₅₀ of 27.29, 28.67, 32.0 and 33.0 μg/ml for C. limon, C. auratifolia, C. sinensis and C. reticulata respectively. The oils were of d-limonene chemotype and can thus be candidates for antioxidant drugs.