Antibacterial effect of some wild medicinal plants in Palestine against multidrug resistant Escherichia coli clinical isolate

Due to the emergence of antibiotic resistant pathogens, plants are being an excellent alternate to fight the further spread of multidrug resistant microorganisms. In this study, six plant species grown wildly in Palestine were used to determine their efficacy against multidrug resistant clinical isolate of Escherichia coli. The dried areal parts of Calamintha incana, Lupins pilosus, Parietaria judica, Satureja thymbra, Thymbra spicata and Verbascum fruticulosum were extracted with water, ethanol and methanol solvents. All extracts were screened for their antibacterial activity using micro-dilution method. Plant extraction with alcohol solvents provided stronger antibacterial effect compared to the aqueous ones. All alcoholic extracts have an inhibitory effect against E. coli except the ethanol extract of L. pilosus and the methanol extracts of V. fruticulosum and C. incana. Moreover, C. incana aqueous extract was the only aqueous extract with bacteriostatic activity. Among the studied plant species, ethanol extract of T. spicata was the most potent one with MBC value 12.5 mg/mL. However, P. judica ethanol extract which exhibited the best MIC effect (6.25 mg/mL) killed E. coli isolate at a 25 mg/mL. In conclusion, obtained results confirmed the efficacy of using some plant extracts as natural antibacterial alternatives. Therefore, it suggests the possibility of using them as drugs for the treatment of other multidrug resistant bacterial isolates.