Journal of Microbial & Biochemical Technology

Abstract

In Vitro Antibacterial Activity of four Saudi Medicinal Plants

Alothyqi N, Almalki M, Albqa'ai M, Alsamiri H, Alrashdi SM, Ibraheem F and Osman GHE

In the current study, we tested, evaluated and compared the antibacterial activity of twenty-four extracts prepared from four traditional Saudi medicinal plants (Jatropha pelargoniifolia, Euphorbia inaequilatera, Cadaba glandulosa and Cadaba rotundifolia).The plant materials were extracted in six organic solvents with different polarity by two different extraction methods. The activity of these plant extracts was tested against three Gram-positive bacteria (Staphylococcus aureus, Bacillus megaterium and Bacillus cereus) and four Gram-Negative bacteria (Klebsiella pneumonia, Pseudomonas aeruginosa, Escherichia coli and Salmonella enteritidis. Minimum inhibitory concentrations (MICs) of the extracts were determined using the agar dilution method. Our results indicated that most of the tested extracts exhibited a significant broad-spectrum antibacterial activity against both Gram-Positive and Gram-Negative bacteria. The Euphorbia inaequilatera extracts were active against all tested bacterial strains whereas the other plant extracts showed selective activity at the level of both organic solvent and bacterial strain. The use of different extraction solvents resulted in substantial differences in the potency of the antibacterial activity of the extracts with acetone being the most effective solvent in the extraction of bioactive compounds from the tested plant species. In addition, a number of the tested plant extracts successfully recovered more than 70% of the Ciprofloxacin antibacterial activity. Cadaba glandulosa extracts showed the most potent antimicrobial activity against B. megatherium (MIC of 16 and 32 mg/l). Different organic solvents, as well as different extraction methods, can be effectively employed to mine plants' phytochemical profiles and consequently illustrate their antibacterial activity against antibiotic-resistant bacterial strains.