Evaluation of in vitro antimicrobial potential and phytochemical analysis of spruce, cajeput and jamrosa essential oil against clinical isolates

Abstract

Objective: To investigate the phytochemical constituents and thin-layer chromatography (TLC) bioautography of Picea abies (spruce), Melaleuca spp. (cajeput), and Cymbopogon khasans (jamrosa) essential oils. The in vitro antimicrobial potential was also determined against fungal isolates and Gram-positive and Gram-negative bacterial strains isolated from human infections. Materials and Methods: A preliminary phytochemical analysis was performed. The antimicrobial potential of essential oil from spruce, cajeput and jamrosa was evaluated by agar well diffusion method against clinical isolates. The antibacterial effect was investigated using the TLC-bioautographic method. Results: Phytoconstituents analysis demonstrated the presence of few phytochemicals including steroids, reducing sugars and cardiac glycosides in all the tested samples. The essential oils were further investigated for its antimicrobial activity against 11 bacterial clinical isolates and 4 fungi, respectively. The oils showed broad antimicrobial activity against Gram-positive and Gram-negative bacteria and fungal isolates including Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Acinetobacter spp., and Aspergillus niger. The highest in vitro inhibitory activity was observed for S. aureus with a maximum zone of inhibition (27 ± 0.05 mm in diameter) for cajeput essential oil followed by 23 ± 0.07 mm for jamrosa oil against Acinetobacter spp. Among fungal isolates tested, the growth of only A. niger and Aspergillus spp. was inhibited. TLC bioautography assay demonstrated two big spot and one small spot observed at Rf values 0.083 and 0.33 (active spots) and 0.47 (inactive spot) against S. aureus 3 and S. aureus 1. Conclusions: It can be concluded that the essential oils from cajeput and jamrosa possessing antimicrobial potential against clinical isolates can be used in the treatment of various microbial infections.