Chemical composition of Lippia spp. essential oil and antimicrobial activity against Aeromonas hydrophila

Abstract

Phytotherapy can replace antibiotic administration as an alternative to control Aeromonas hydrophila, one of the main bacteria involved in the aetiology of farmed fish diseases. Given that plants of the Lippia spp. genus show biological potential for antimicrobial activity, this study evaluated the chemical composition of essential oils extracted from Lippia alba, Lippia origanoides and Lippia sidoides and their activity against A. hydrophila. The oils were obtained by steam distillation in a Clevenger‐type apparatus and their composition determined by gas chromatography and mass spectrometry (CG/MS). Antibacterial activity was assessed by calculating the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using broth microdilution method. The main compounds identified were geranial (25.4%) and neral (16.6%) in L. alba oil, carvacrol (40.4%) and p‐cymene (11.4%) in L. origanoides oil and thymol (76.6%) and ortho‐cymene (6.3%) in L. sidoides oil. The three Lippia species showed bacteriostatic and bactericidal action against A. hydrophila, with MICs and MBCs ranging from 1250 to 5000 μg mL−1. Of the species tested, the best performance was obtained with essential oil of L. sidoides.

Plant essential oils against bacteria isolated from fish: an in vitro screening and in vivo efficacy of Lippia origanoides

“…It is thought that the bactericidal action is due to the bacterial membrane being disrupted by the lipophilic constituents of the EO (ALVIANO & ALVIANO, 2009). Recently it has been demonstrated that an L. origanoides EO, with a similar composition to what was used in the present study, showed MIC and MBC values of 2.5 mg mL -1 against A. hydrophila (MAJOLO et al, 2017). It was suggested that the mechanism may be associated to the rupture of the cell membrane and the subsequent release of liposaccharide, leading to an increase permeability to adenosine triphosphate.…”

The effects of essential oils and their major compounds on fish bacterial pathogens – a review

“…hydrophila in vitro (Majolo et al . ), and the EO of Lippia nobilis against several Gram‐positive and Gram‐negative bacterial species isolated from fish and shellfish products (Snuossi et al . ; Table ).…”

Antibacterial potential of phytochemicals alone or in combination with antimicrobials against fish pathogenic bacteria

“…The O. vulgare EO (carvacrol rich) has been reported to be effective in the treatment of channel catfish (Ictalurus punctatus) bacteriosis caused by A. hydrophila, probably because it disrupts bacterial membranes (Zheng et al 2009;Sousa et al 2015). This phytochemical has bacteriostatic and bactericidal activity against A. hydrophila (Majolo et al 2016). This phytochemical has bacteriostatic and bactericidal activity against A. hydrophila (Majolo et al 2016).…”

“…Thymol is a colourless aromatic monoterpene and a major component of the Thymus vulgaris, O. vulgare and Lippia sidoides EOs (Poulose and Croteau 1978;Lambert et al 2001;Botelho et al 2007). This phytochemical has bacteriostatic and bactericidal activity against A. hydrophila (Majolo et al 2016). Linalool is a monoterpene and the major component of several plant EOs, such as those of Ocimum basilicum, Aniba rosaeodora and L. alba EOs; it has antibacterial properties against A. hydrophila (Dorman and Deans 2000;Sampaio et al 2012;Avetisyan et al 2017;Souza et al 2017).…”