Antimicrobial and Antivirulence Action of Eugenia brejoensis Essential Oil in vitro and in vivo Invertebrate Models

Abstract

Eugenia brejoensis L. (Myrtaceae) is an endemic plant from caatinga ecosystem (brazilian semi-arid) which have an E. brejoensis essential oil (EbEO) with reported antimicrobial activity. In this work, in vitro and in vivo models were used to characterize the inhibitory effects of EbEO in relation to Staphylococcus aureus. EbEO inhibited the growth of all tested S. aureus strains (including multidrug resistance isolates) with values ranging from 8 to 516 µg/mL. EbEO also synergistically increased the action of ampicillim, chloramphenicol, and kanamycin. The treatment with subinhibitory concentrations (Sub-MIC) of EbEO decreased S. aureus hemolytic activity and its ability to survive in human blood. EbEO strongly reduced the levels of staphyloxanthin (STX), an effect related to increased susceptibility of S. aureus to hydrogen peroxide. The efficacy of EbEO against S. aureus was further demonstrated using Caenorhabditis elegans and Galleria mellonella. EbEO increased the lifespan of both organisms infected by S. aureus, reducing the bacterial load. In addition, EbEO reduced the severity of S. aureus infection in G. mellonella, as shown by lower levels of melanin production in those larvae. In summary, our data suggest that EbEO is a potential source of lead molecules for development of new therapeutic alternatives against S. aureus.

Galleria mellonella as a Suitable Model of Bacterial Infection: Past, Present and Future

“…For example, Eugeria brejoensis essential oil inhibits Staphyloxanthin production in S. aureus and acts synergistically with conventional antibiotics ( Bezerra Filho et al., 2020 ) and Myricetin downregulates multiple S. aureus virulence factors involved in adhesion, biofilm formation or hemolysis ( Silva et al., 2017 ). Numerous plant-derived products have been evaluated in the G. mellonella model, in particular to target S. aureus , whether they are phenolic or flavonoid compounds (myricetin, epigallocatechin gallate) or molecules derived from plant oils (cinnamon oil, Eugeria brejoensis essential oil) ( Ferro et al., 2016 ; Silva et al., 2017 ; Knidel et al., 2019 ; Bezerra Filho et al., 2020 ). All showed reduced larvae mortality with no toxicological effect when infected by S. aureus , so they might be promising substances to treat S. aureus infection including Methicillin-resistant strains.…”

Cuminum cyminum L. Essential Oil: A Promising Antibacterial and Antivirulence Agent Against Multidrug-Resistant Staphylococcus aureus

“…Infectious diseases are known as the second leading cause of death in the world. One of the most important causes of infectious diseases is Staphylococcus aureus , which has the ability to cause various diseases from minor skin and soft tissue infections to life-threatening diseases such as pneumonia, severe sepsis, and fatal infections ( Bezerra Filho et al, 2020 ; Guo et al, 2020 ). Today, the resistance rates of S. aureus infection and emergence of multidrug-resistant (MDR) strains are increasing, making the S. aureus infections treatment more difficult.…”

Staphyloxanthin as a Potential Novel Target for Deciphering Promising Anti-Staphylococcus aureus Agents

“…Furthermore, it reduced the hemolytic activity of S. aureus, thus interfering with its ability to survive in human blood. In vivo studies on Caenorhabditis elegans and G. mellonella infected with S. aureus further confirmed the ability of EbEo treatment to markedly decrease the bacterial load and infection severity in the models [42].…”