Phytochemical analysis and assessment of the in vitro antibacterial and antioxidant potential of Citrus × aurantiifolia (Christm.) Swingle fruit peel

This study investigates the bioactive compounds in Citrus × aurantiifolia (Christm.) Swingle (CA) fruit peel using qualitative phytochemical tests, UV-visible spectroscopy, FT-IR and GC-MS techniques. The hydroalcoholic extract was obtained through preparation using aqueous ethanol (Distilled water: Ethanol, 3:1) through maceration, yielding secondary metabolites amounting to approximately 32% of the initial dry weight of the plant material. Phytochemical screening confirmed the occurrence of alkaloids, flavonoids, carbohydrates, glycosides, phenolic compounds, proteins, steroids, terpenoids and tannins. The total phenolic content (TPC) was determined to be 81.72 ± 0.126 mg/g, while the total flavonoid content (TFC) was recorded at 4.71 ± 0.052 mg/g, highlighting their phytochemical richness. The extract demonstrated moderate antibacterial activity against uropathogens, including Acinetobacter sp., Enterobacter sp., Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis. The antimicrobial activity is attributed to the presence of phenolic compounds, flavonoids and alkaloids, which are known to disrupt microbial cell walls, interfere with enzyme activity and inhibit nucleic acid synthesis. Terpenoids and tannins further enhance this effect by disrupting the microbial membranes’ integrity, leading to cell lysis. Additionally, the methanolic extract demonstrated significant antioxidant potential. Elemental analysis through ICP-MS identified essential minerals, reinforcing their medicinal potential. This study highlights the potential of CA fruit peel, typically considered agricultural waste, in sustainable resource utilization by transforming waste into valuable bioactive products, thereby reducing environmental impact and supporting waste valorization. The integration of antibacterial and antioxidant properties and its rich phytochemical and mineral profile suggests its potential use in herbal medicine and the discovery of novel antibiotics and drugs. Utilizing such by-products aligns with sustainable practices, supporting pharmaceutical advancements while reducing environmental impact.