Influence of Fruit Maturation on Phenolic Composition and Antibacterial Efficacy of Citrus Sinensis Peels

Abstract

The peel of Citrus sinensis was investigated as a potential source for the development of new antibacterial agents, addressing the growing global health concern posed by bacterial infections—a leading cause of mortality worldwide. This study aimed to evaluate the impact of fruit maturation on the total phenolic content and antibacterial potential of C. sinensis peel. Phenolic compounds, known for their antimicrobial properties, were the focus of this investigation. The peels of the selected plant were shade-dried for one week, ground into a fine powder, and subjected to both methanolic and aqueous extraction. Standard protocols were followed to carry out qualitative and quantitative analyses of phenolic content. The antibacterial activity of the extracts against Escherichia coli was evaluated using the agar well diffusion method and minimum inhibitory concentration (MIC) analysis. Among all samples, the third-week matured peels yielded the highest phenolic content (0.093 ± 0.08), while the first-week samples recorded the lowest (0.044 ± 0.02). The methanolic extract at a concentration of 1.5 mg/mL showed the largest zone of inhibition, whereas the aqueous extract at 1.0 mg/mL showed the smallest. Notably, the methanolic extract from the third-week peel exhibited the highest MIC values, achieving 80–100% inhibition of E. coli and significantly outperforming its aqueous counterpart. These results underscore the strong antibacterial potential of phenolic compounds in Citrus sinensis peel, particularly at the third week of maturation. The results support the use of plant-derived phenolics in the formulation of safe, effective, and natural antibacterial agents, potentially offering a valuable alternative to synthetic drugs with fewer adverse effects on human health.