Effect of Essential Oils on Pathogenic Bacteria

Abstract

The increasing resistance of microorganisms to conventional chemicals and drugs is a serious and evident worldwide problem that has prompted research into the identification of new biocides with broad activity. Plants and their derivatives, such as essential oils, are often used in folk medicine. In nature, essential oils play an important role in the protection of plants. Essential oils contain a wide variety of secondary metabolites that are capable of inhibiting or slowing the growth of bacteria, yeasts and moulds. Essential oils and their components have activity against a variety of targets, particularly the membrane and cytoplasm, and in some cases, they completely change the morphology of the cells. This brief review describes the activity of essential oils against pathogenic bacteria.

Using Essential Oils to Combat the Threat of Multi-Drug Resistant Bacteria, Pseudomonas Aeruginosa

“…It is then that medicinal oils extracted from a variety of plants were first recorded as the treatment for various human maladies [1,2]. Today, antibiotics, synthetically produced or naturally occurring chemicals, are amongst the most commonly prescribed drugs in the world, effective in treating pathogenic bacterial infections.…”

“…aeruginosa infections are most effectively treated with aminoglycosides including amikacin, gentamicin, streptomycin, tobramycin and neomycin which interfere with the 30S subunit during protein synthesis in the bacterium. However, P. aeruginosa has shown an increase in resistance to these once most effective antibiotics [1,6,8,10]. Physicians are running out of antibiotics to treat these serious multi-drug resistant bacterial infections, particularly those caused by gram-negative bacteria like P. aeruginosa [3,8].…”

“…The outer membrane contains various proteins as well as lipopolysaccharides (LPS). The LPS, which is composed of a lipid, a core polysaccharide, and a highly variable Oantigen, forms an extra barrier in gram-negative bacteria to make them more resistant to growth inhibitors [1]. Of the most threatening gram-negative pathogens, P. aeruginosa ranks second, with a 58% mortality rate [10].…”

“…The antimicrobial activity of essential oils and their components is likely due to their ability to inhibit or interact with multiple targets of the cell, including their membranes and cytoplasmic structures [2]. Their hydrophobic properties facilitate their penetration into cell membranes causing the alteration to the structure of membranes as well as leakage of cell contents and sometimes completely change the morphology of the organism's cells [1,2].…”

Chemical Composition, Antioxidant and In vitro Antibacterial Activities of Essential Oils of Mentha spicata Leaf from Tiaret Area (Algeria)

“…The mechanism of antibacterial activity of carvone is not completely understood in great detail. It has been demonstrated that the mechanism of action of carvone on the growth of microorganisms includes the destabilization of the phospholipid bilayer structure, interaction with membrane enzymes and proteins, 6 it act as a proton exchanger reducing the pH gradient across the membrane 6,37 and probably it could act by disrupting the metabolic energy state of the cells. In contrast, another study found that carvone was ineffective against the outer membrane of E. coli and S. typhimurium and did not affect their intracellular ATP pool.…”