Citrus fruit wastes contain a high concentration of plant secondary bioactive compounds with multifunctional properties. The purpose of this study was to investigate the antioxidant and antimicrobial properties of lemon and lime essential oils and extracts. Antimicrobial properties of the extracts and essential oils were determined using the agar-well diffusion method, while antioxidant potentials were determined using the 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging activity assay. The samples were screened for their antibacterial activities, and all tested bacterial isolates were susceptible to all lemon seed extracts. The most sensitive bacterial isolate was Klebsiella pneumoniae (28 mm) to ethanol extract of lime peel, while the majority of the bacterial isolates were susceptible to lime pomace. None of the bacterial isolates tested positive for sensitivity to lime seed ethanol extract. Pseudomonas aeruginosa was found to be resistant to all lime extracts. Furthermore, all of the extracts demonstrated a significant (p < 0.05) increase in their inhibitory activities against DPPH free radicals in a concentration-dependent manner. The gas chromatography-mass spectroscopy analysis on the extracts and essential oils revealed the presence of tetradecanoic acid, 1,4-butanediol, 2-(1-ethoxy ethoxy)-3-methyl-, n-hexadecanoic acid, 1,2-benzene dicarboxylic acid, diisooctyl ester, stigmasterol, and spathulenol. Therefore, the findings of this study revealed that extracts and essential oils of lemon and lime could be explored for possible bioactivities and health benefits.
Key words: Antimicrobial, antioxidant, bioactive components, citrus fruit wastes, extracts, phytochemical
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