Evaluation of the antimicrobial properties of unripe banana (Musa sapientum L.), lemon grass (Cymbopogon citratus S.) and turmeric (Curcuma longa L.) on pathogens

Abstract

The investigation on the potency of unripe banana (Musa sapientum L.), lemon grass (Cymbopogon citratus S.) and turmeric (Curcuma longa L.) was carried out against pathogens. The formulations were
in the powder form as used locally. The antimicrobial activity of these plants was examined using different solvents and efficacy was compared. The solvents were ethanol (70%, v/v) and water.
Antimicrobial activity was carried out by the agar well diffusion method. The clinical isolates include aerobic, facultative bacteria namely: Stapyhlococcus aureus ATCC 25921, S. aureus, Salmonella
paratyphi, Shigella flexnerii, Escherichia coli ATCC 25922, E. coli, Klebsiella pneumoniae, Bacillus subtilis and Pseudomonas aeruginosa. Crude extracts of the solvents varied in zones of inhibition. All
the Gram-positive bacteria (S. aureus, S. aureus ATCC 25921 and B. subtilis) and all Gram-negative bacteria (E. coli ATCC 25922, E. coli, P. aeruginosa, S. paratyphi, S. flexneri and K. pneumonia) were
susceptible to ethanolic extracts of unripe banana, lemon grass and turmeric while some namely E. coli ATCC 25922, E. coli, P. aeruginosa and S. flexneri were not susceptible to aqueous extracts of the three
medicinal plants. The minimum inhibition concentration (MIC) ranged from 4 – 512 mg/ml while the minimum bactericidal concentration (MBC) ranged from 32 – 512 mg/ml depending on isolates and
extracting solvent. Ethanolic extracts showed greater antimicrobial activity than aqueous extracts. The killing rate of the extracts varied. Unripe banana had less than 2 h killing time for S. aureus ATCC
25921, turmeric less than 3 h for E. coli while lemon grass had more than 3 h killing time for S. paratyphi.