Chemical composition and antibacterial activity of melaleuca bracteata essential oil from India: A natural source of methyl eugenol

Abstract

The aim of this study was to investigate the chemical composition and antibacterial activity of the essential oil of Melaleuca bracteata F. Muell from India. The hydrodistilled essential oils of M. bracteata in spring, summer, rainy, autumn and winter seasons were analyzed using GC-FID and GC-MS. Altogether, 25 constituents, comprising 97.3-99.7% of the total oil were identified with methyl eugenol (87.2-89.5%), (E)-methyl cinnamate (2.8-5.4%), methyl chavicol (0.2-0.5%), and elemicin (0.2-0.4%) as major constituents. The antibacterial efficacy of the essential oil was evaluated against nine pathogenic bacterial strains. Zone of inhibition and MIC of the essential oil ranged from 5-10 mm and 500-1000 μg/mL against the tested pathogens, respectively. Results showed that essential oil of M. bracteata from Indian origin possessed good activity against Salmonella typhimurium, Staphylococcus epidermidis, and moderate activity against Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumonia, and Streptococcus mutans. Results of the present seasonal variation study clearly indicated that M. bracteata grown in foothills of Uttarakhand, India could be classified as seasonally stable 'methyl eugenol' chemotype (>85.0%), hence may be considered as a novel natural resource for methyl eugenol rich essential oil for flavor, fragrance and pharmaceutical applications.