Fruit peels that unlock curative potential: Determination of biomedical application and bioactive compounds

Abstract

• DMSO fruit peel extract of Citrus aurantium possess excellent antimicrobial activity. • This is the first study to report the MIC,MBC/MFC antimicrobial activities of Citrus aurantium . • Flavonoids, tannins, and phenolic compounds were present only in DMSO fruit peel extract of Citrus aurantium . • Eleven main peaks in HPLC and twelve compounds in GC–MS were detected. Control of multi drug resistant bacteria and their infection rate is a threat for biomedical and clinical research. Citrus fruits have proven effective against incurable bacterial infections suggesting alternate therapeutics to replace antibiotics in the near future. The antimicrobial potential of bitter orange ( Citrus aurantium ), citron ( Citrus medica ), and wood apple ( Limonia acidissima ) fruit peel extracts against pathogenic microorganisms was focused in this study. The antimicrobial activities and minimum inhibitory concentrations (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) values were determined using the agar well diffusion and micro dilution method respectively against Gram-positive bacteria ( Staphylococcus aureus and Staphylococcus epidermis), Gram-negative bacteria ( Pseudomonas aeruginosa and Klebsiella pneumoniae ), as well fungi ( Candida albicans and Aspergillus niger ). HPLC, GC-MS, and FT-IR analyses were used to identify phytochemicals and functional groups in addition to cytotoxicity investigations using MTT assay. DMSO peel extract of C. aurantium has shown superior antimicrobial activity against the studied pathogens, particularly S. aureus (33 mm), followed by C. medica (DMSO extract – inhibition zone of 26 mm) against S. aureus . While the methanolic extract of C. aurantium had the lowest inhibitory zone against S. epidermis (12 mm). The MIC varied from 0.39 µg/mL to 6.24 µg/mL, while the MBC/MFC ranged from 0.78 µg/mL to 12.5 µg/mL.In all samples of studied fruit peel extracts, the phytochemical analysis revealed the presence of alkaloids, steroids, saponins, flavonoids, tannins, terpenes, phenolics, and cardiac glycoside. Only the DMSO extract of C. aurantium contained flavonoids, tannins, and phenolic compounds. The DMSO peel extract of C. aurantium exhibited eleven main peaks in HPLC and GC-MS analysis, revealing twelve chemicals in total. The FT-IR spectrum was used to determine the chemical composition of the peel extract. The DMSO peel extract of C. aurantium outperformed other extracts and even conventional medications in terms of antimicrobial activity. The results prove that this plant may be evaluated further to uncover active biomolecules in the development of antimicrobial therapeutics.