Antibacterial Activity of Crude Extract and Solvent Fractions of Crocus sativus L. Against Selected Gram-Positive and Gram-Negative Bacteria

Abstract

The rapid development of the multidrug-resistant (MDR) bacterial pathogens has exacerbated the worldwide quest to obtain alternative antimicrobial agents derived naturally. Saffron (Crocus sativus L. (Iridaceae) is a medicinal plant that contains bioactive phytochemicals such crocin, crocetin, safranal and flavonoids. The current research was conducted to determine the antibacterial activity of crude extract and subsequent solvent fractions (n-hexane, chloroform, ethyl acetate, and n-butanol) of C. sativus against selected Gram-positive and Gram-negative bacterial isolates using the agar well diffusion technique. The n-butanol fraction of the tested fractions displayed the best antibacterial effect and was active against Bacillus stearothermophilus (29.15 ± 1.43 mm) and Escherichia coli (26.00 ± 1.98 mm), which is close to streptomycin (30.44 ± 0.40 mm). The chloroform fraction was found to be also active against E. coli (25.23 ± 0.87 mm). Conversely, the n-hexane fraction exhibited relatively weak anti-bacterial activities. The findings show that the apparently antibacterial activity is probably due to moderately polar phytoconstituents. The results suggest that C. sativus can be further used as a natural source of antibacterial agents and need to be investigated as a source of bioactive compounds and mechanisms of action.