Synergistic Effect of the Methanolic Extract of Lemongrass and Some Antibiotics to Treat Urinary Tract Bacteria

Abstract

Some medicinal plants are used traditionally in Saudi Arabia to treat many bacterial infections. Three plants, lemongrass (Oymbopogon citrates), lantana (Lantana camara), and wild olive leaves (Olea europaea) were collected, identified, extracted with either hot water or organic solvents (methanol, diethyl ether, ethyl acetate and n-butanol) to investigate their antibacterial activities against E. coli. The methanol extracts of lemongrass, lantana and olive showed the highest activities against Esherichia coil while aqueous extract exhibited the lowest activities. Thus, the antibacterial activities of the methanolic extract of the three tested plants were determined using agar well diffusion method against some bacterial pathogens, isolated from urine samples. The highest antibacterial activity was recorded for themethanolic extract of lemongrass against all tested bacteria, E. coli, K. pneumoniae, P. aeuroginosa, P. mirabilis, E. faecalis and S. aureus. The tested bacteria differed with regard to their susceptibility to plant extracts. Lemongrass was the most active extract followed by lantana and wild olive extracts. Minimal inhibitory concentrations (MICs) of the methanolic extract of Lemongrass and some used antibiotics, Erythromycin, Tetracycline, Amoxicillin, Ciprofloxacin and Chloramphenicol were determined usingfluorescein diacetate method. Synergistic effect of the methanolic extract of lemongrass with the previous antibiotics against the tested clinical bacterial isolates was determined and the Fractional inhibitory concentrations (FIC) of different combination of the extract and the antibiotics were determined. FIC index (FICI) was calculated and it was ranged from 0.08 -0.98. The interaction between the tested plant extract and the tested antibiotics was either synergistic or additive effects and no antagonistic effect was recorded. In conclusion, methanolic extract of lemongrass singly or in combination with some antibiotics can be used to treat pathogenic bacteria that cause urinary tract infections.

Combination therapy: synergism among three plant extracts against selected pathogens

“…The FICI is based on the Loewe additivity zero interaction theory [ 7 – 9 ]. A FICI of ≤ 0.5 indicates synergism, > 0.5 to 1 indicates additive effects, > 1 to ≤ 4 indifference, and > 4 is considered to be antagonism [ 10 , 11 ].…”

Comprehensive Review of Olea europaea: A Holistic Exploration into Its Botanical Marvels, Phytochemical Riches, Therapeutic Potentials, and Safety Profile

“…Vural et al [115] found that the essential oil extracted from olive leaves displayed a highly intriguing volatile composition, showcasing potent antibacterial activity [115]. Vegetal extract Ø = 13-18.5 mg/mL MIC = 12.5-25 mg/mL MBC = 25-50 mg/mL [102,105] Leaves Essential oil Ø = 9-29 mm MIC = 0.625-5 mg/mL [6,96,115,117] Vegetal extract Ø = 1-20 mm MIC = 0.60-25 mg/mL MBC = 0.70-12.5 mg/mL [109,110,[118][119][120][121][122][123][124][125][126][127] Ø = zone of inhibition; MIC = minimum inhibition concentration; MBC = minimum bactericidal concentration; GN = Gram negative; GP = Gram positive.…”