In vitro antimicrobial status of methanolic extract of Citrus sinensis Linn. fruit peel

Aim : The present investigation evaluated the antimicrobial potential of methanolic extract of Citrus sinensis Linn. (Rutaceae) fruit peel. There is a basis for the traditional use of this plant for local health remedies. Materials and Methods: The antimicrobial activity of methanolic extract of C. sinensis fruit peel was tested against three bacterial and two fungal strains. Turbidimetric or tube dilution method and paper disc diffusion method were followed. Results are expressed as mean ± standard deviation. Results: The C. sinensis fruit peel methanolic extract exhibited antibacterial activity against Escherichia coli with minimum inhibitory concentration of 0.78 μg/ ml and minimum bactericidal concentration of 6.25 μg/ml, and appreciable antifungal activity with minimum inhibitory concentration of 12.5 μg/ml. The phytochemistry of C. sinensis fruit peel methanolic extract revealed the presence of carbohydrates (reducing sugars, hexose sugars, non-reducing polysaccharides, gums, and mucilages), flavonoid glycosides, coumarin glycosides, volatile oils, organic acids, fats and fixed oils. Conclusion: Most of the organic chemical constituents reported are aromatic phenolic compounds, which are known for their wide spectra of antimicrobial activity. Therefore, the bacteriostatic and fungistatic action of the tested extract may be attributed to the presence of polyphenolic compounds. In short, C. sinensis fruit peel methanolic extract is a potential source of natural antimicrobials.