Background: The large scale growing and harvesting of Calamus aromaticus, a medicinally
important weed, is rampant in Asia due to its well-known medicinal importance. The gigantic antimicrobial
potential of C. aromaticus, however, is not reflected in the absolute sense by the efforts devoted
to this purpose so far.
Methods: The role of Gallic acid in the determination of antibacterial potency was established by first
assessing the biological activity of different solvent extracted samples from the commercially available
rhizome of C. aromaticus through disc diffusion assay. The different extracts were then quantified for
the presence of Gallic acid using HPLC.
Results: Staphylococcus aureus and Citrobacter freundii were more susceptible to crude methanol extract
at 2000 µg.disc-1 (31.6% and 32.1% respectively) while Bacillus subtilis, Klebsiella pneumoniae,
Pseudomonas aeruginosa, Escherichia coli and Xanthomonas campestris were more susceptible to ethyl
acetate fraction at the same concentration (40.6%, 31.5%, 39.8%, 41.7% and 48.3% respectively). S. aureus
was most susceptible gram positive bacterium and B. subtilis was comparatively more resistant.
Among Gram negative bacteria, P. aeruginosa showed maximum susceptibility while K. pneumoniae
revealed more resistivity in comparison to others. HPLC analysis of the extracts confirmed the hypothesis
about the role of Gallic acid, with ethyl acetate fraction revealing the highest amount of the phenolic
Conclusions: Organic solvents were found to be the solvents of choice for the extraction of Gallic acid
and the results also pointed towards the potential of Gallic acid as a broad spectrum antibacterial agent.