Finding Novel Antibiotic Substances from Medicinal Plants – Antimicrobial Properties of Nigella Sativa Directed against Multidrug-resistant Bacteria

The progressive rise in multidrug-resistant (MDR) bacterial strains poses serious problems in the treatment of infectious diseases. While the number of newly developed antimicrobial compounds has greatly fallen, the resistance of pathogens against commonly prescribed drugs is further increasing. This rise in resistance illustrates the need for developing novel therapeutic and preventive antimicrobial options. The medicinal herb Nigella sativa and its derivatives constitute promising candidates. In a comprehensive literature survey (using the PubMed data base), we searched for publications on the antimicrobial effects of N. sativa particularly directed against MDR bacterial strains. In vitro studies published between 2000 and 2015 revealed that N. sativa exerted potent antibacterial effects against both Gram-positive and Gram-negative species including resistant strains. For instance, N. sativa inhibited the growth of bacteria causing significant gastrointestinal morbidity such as Salmonella, Helicobacter pylori, and Escherichia coli. However, Listeria monocytogenes and Pseudomonas aeruginosa displayed resistance against black cumin seed extracts. In conclusion, our literature survey revealed potent antimicrobial properties of N. sativa against MDR strains in vitro that should be further investigated in order to develop novel therapeutic perspectives for combating infectious diseases particularly caused by MDR strains.