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

Abstract

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 β-citral (8.323 %) whereas ripened LPEO contained α-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.