Essential Oils and Their Components as Modulators of Antibiotic Activity against Gram-Negative Bacteria

Abstract

Gram-negative bacteria cause infections that are difficult to treat due to the emergence of multidrug resistance. This review summarizes the current status of the studies investigating the capacity of essential oils and their components to modulate antibiotic activity against Gram-negative bacteria. Synergistic interactions are particularly discussed with reference to possible mechanisms by which essential oil constituents interact with antibiotics. Special emphasis is given to essential oils and volatile compounds that inhibit efflux pumps, thus reversing drug resistance in Gram-negative bacteria. In addition, indifference and antagonism between essential oils/volatile compounds and conventional antibiotics have also been reported. Overall, this literature review reveals that essential oils and their purified components enhance the efficacy of antibiotics against Gram-negative bacteria, being promising candidates for the development of new effective formulations against Gram-negative bacteria.

Chemical Composition and Antimicrobial Activity of Essential Oils from the Aerial Parts of Asteriscus graveolens (Forssk.) Less. and Pulicaria incisa (Lam.) DC.: Two Asteraceae Herbs Growing Wild in the Hoggar

“…[30] This activity may be due either to the main constituents or to the synergistic effect between the major and some minor compounds. [4] [31] According to our study, the difference in the chemical profile of the two hydrodistilled oils was remarkable, even if both are composed for more than 75% by terpenes (Tables 1 and 2).…”

“…demonstrated to be effective against several MRSA, Streptococcus and Candida strains . This activity may be due either to the main constituents or to the synergistic effect between the major and some minor compounds …”

“…Antimicrobial activities of these natural plant materials have been intensively explored in recent years. Even today, essential oils are attracting substantial interest from scientists because of their use in the treatment of certain infectious diseases for which synthetic antibiotics are becoming less active …”

“…Even today, essential oils are attracting substantial interest from scientists because of their use in the treatment of certain infectious diseases for which synthetic antibiotics are becoming less active. [1][3] [4] Asteraceae, formerly known as Compositae, is one of the largest families of flowering plants comprising about 1535 genera and about 23 000 species, cosmopolitan. It represents approximately 10% of all world flora.…”

Antimicrobial activity oftrans-cinnamic acid and commonly used antibiotics against important fish pathogens and nonpathogenic isolates

“…; Aelenei et al . ). Accordingly, great number of Gram‐negative bacterial strains was examined in our study, including Aeromonas species that are known to create a variety of diseases in humans and animals (Praveen et al .…”