Abstract
Biological and chemical investigations were carried out to evaluate the antimicrobial potential of Callistemon comboynensis and C. citrinus leaf oils for herbal medicines. Disk diffusion and micro broth dilution methods were used for the evaluation of the antimicrobial activity of the essential oils against selected strains of bacteria (Staphylococcus aureus, S. epidermidis, Streptococcus mutans, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter aerogenes and Escherichia coli) and fungi (Candida albicans, Cryptococcus neoformans, Trichophyton rubrum, Aspergillus flavus, A. niger and Sporothrix schenckii). Analysis of the leaf essential oils of C. comboynensis and C. citrinus using GC and GC-MS resulted in the identification of thirty and twenty eight compounds, respectively. 1,8-Cineole (58.5% and 58.0%), α-pinene (22.7% and 24.1%), and (E)-β-terpineol (6.4% and 1.8%), were the major constituents. The isolated essential oils could be of use for the future development of antimicrobial agents.