Variations in the Composition, Antibacterial and Haemolytic Activities of Peel Essential Oils from Unripe and Ripened Citrus limon (L.) Osbeck Fruit

This research work was carried out to assess the variations in the chemical composition, yield, antibacterial and haemolytic activities of hydro-distilled peel essential oils from unripe and ripened limon [Citrus limon(L.) Osbeck] fruit. The extracted essential oil yield from unripe fruit peel (1.79 %) is slightly lower as compared to the ripened fruit peel oil (1.81 %). By GC/MS analysis, 14 compounds were identified in unripe while 11 components in ripened lemon peel essential oil (LPEO). The major components identified in unripe lemon peel essential oil were caryophyllene oxide (16.791 %) followed by 3-cyclohexene-1-methanol (11.463 %), 2-isoprpenyl-5-metyhlhex-4-enal (10.174 %), limonene (9.649 %) and beta-citral (8.323 %) whereas ripened LPEO contained alpha-Terpineol as major compound (38.497 %) followed by 2,6-octadienal-3,7-dimethyl (9.981 %) and limonene (9.195 %). Both the isolated lemon peel essential oils (LPEOs) exhibited considerable antibacterial activity against E. coli, Bacillus subtilis, Salmonella typhimurium and Staphylococcus aureus with no cytotoxic effects. Overall, a significant variation in the yield, volatiles composition and biological activities of LPEOs were observed that can be linked to lemon fruit ripening stages.