In vitro Study on Antibacterial Efficacy of Essential Oil and Major Compounds from Rhizomes of Curcuma aromatica Salisb. Against Two Virulent Aeromonads of Farmed Channa punctata

Abstract

Essential oils (EOs) extracted from plants and their parts can be a promising therapeutic approach to control microbial infections. Analysis of Curcuma aromatica (wild turmeric) EO through gas chromatography and mass spectrometry (GC/MS) revealed the presence of camphene (7.24%), eucalyptol (7.05%), camphor (10.21%), β-elemenone (15.83%), epicurzerenone (16.04%) and ar-turmerone and (9.41%) as the major compounds. Members of the Gram-negative bacterial genus, Aeromonas have a wide range of distribution in the aquatic environment and are primarily responsible for causing diseases in fishes. Therefore, the present study was carried out to evaluate the antibacterial efficacy of the crude EO and its major compounds in vitro against two bacterial pathogens, Aeromonas veronii and Aeromonas hydrophila, isolated from diseased, farmed Channa punctata. The antibacterial efficacy was tested following disc diffusion and broth dilution methods. Results of disc diffusion of both EO and major compounds showed that A. hydrophila is comparatively more sensitive (maximum diameter of zone of inhibition: 43.27 ± 0.04 mm) than A. veronii (40.21 ± 0.15 mm) against the EO and major compounds. Though antibiotics can prevent or control bacterial infections, the resultant antibiotic resistance and possibility of residual effects in aquaculture systems are major drawbacks. Thus, the present study can aid as baseline data for using part of C. aromatica against bacterial infections in aquaculture and promote the use of traditional plants and their EOs as suitable alternative medicine.