In-Vitro Evaluation of Crocus Sativus L. Petals and Stamens as Natural Antibacterial Agents Against Food-Borne Bacterial Strains

Abstract

Growing interest to use natural preservatives and spices with antimicrobial effects and large amounts of floral bio-residues (92.6 g per 100 g) generated and wasted in the production of saffron spice guided this study to evaluate the opportunity to expand the uses of <em>C. sativus</em> flowers (petals and stamens), beyond the spice (dried stigmas). The antibacterial potential of total extracts and different sub-fractions of floral bio-residues of saffron production (petals and stamens) were primarily evaluated against five bacterial strains potentially causing food-borne disease (<em>Bacillus cereus, Staphylococcus aureus, Salmonella enterica</em>,<em> Escherichia coli </em>and<em> Shigella dysenteriae</em>) using well diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined by macrodilution method. Methanol extract of petals had shown more antibacterial activity against <em>S. aureus, S. enteric, </em>and <em>S. dysenteriae</em> compared to stigma. Methanol extract and ethyl acetate sub-fraction of stamens showed more antimicrobial effect against <em>B. cereus</em> and <em>E. coli</em>. The petals total extract showed the most antibacterial activity against <em>Shigella dysenteriae </em>(MIC 15.6mg/ml) while the ethyl acetate and chloroform sub fractions showed the maximum effect against<em> Bacillus cereus</em>(MIC 62.5mg/ml). Stamen methanol total extract and aqueous sub fraction have the maximum effect against<em> Staphylococcus aureus </em>and<em> Bacillus cereus</em> (MIC 62.5mg/ml) while the ethyl acetate sub fraction has the best effect against <em>Shigella dysenteriae</em> (MIC 15.6mg/ml). Results showed that both petals and stamens could act as new and natural sources of antibacterial agents with food industrial applications.