A comparative analysis of the antioxidant and antibacterial potential of sweet lime and orange peel extracts against pathogenic bacteria

Background: Agro-industrial wastes from the citrus juice processing industry are of main concern. The presence of volatile oils and phenolic compounds in the orange and sweet lime peels exhibited various biological activities. Aim: Comparative evaluation of sweet lime and orange peel extracts against urinary tract infection causing bacteria and their antioxidant potential. Methods: Mature sweet lime and sweet orange were purchased from the local market. Peel of the samples were dried and powdered, and the alcoholic and hydro-alcoholic extracts were prepared. Samples were analyzed for total phenolic content and total flavonoid content. Further, the antioxidant activity of samples was analyzed using the DDPH scavenging activity method. The antibacterial activity of extracts against Gram-positive E. faecalis, S. saprophyticus, and Gram-negative P. mirabilis and K. pneumoniae was analyzed using the disc diffusion method. Results: The alcoholic extracts of these peels also showed high phenols, i.e., 13.20 ± 0.105 mg/ml for Sweet Lime Peel Extract (SLPE) and 7.64 ± 0.04 for Orange Peel Extract (OPE), flavonoid content of 1.659 ± 0.06 mg QE/ml for SLPE and 2.14 ± 0.09 mg QE/ml for OPE. This contributed to antioxidant activities, which showed DPPH scavenging activity of 85.95 ± 0.099 % for OPE and 89.31 ± 0.126 % for SLPE. The sample extracts showed inhibitory activities against tested bacteria. The K. pneumonia was comparatively more susceptible to OPE and S. saprophyticus to SLPE. Conclusion: Citrus peels showed promising antibacterial and antioxidant activity; therefore, these can be a potential alternative to synthetic antioxidant and antibacterial agents.