Drug Delivery Systems Utilizing Essential Oils and Their Compounds--A Promising Approach to Fight Pathogens  
[PERSON]  
1 Department of Diagnostic Immunology, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland; [EMAIL_ADDRESS] (K.H. ); [EMAIL_ADDRESS] (M.S. ); [EMAIL_ADDRESS] (A.W. ); [EMAIL_ADDRESS] (I.W.-K.)  
[PERSON]  
1 Department of Diagnostic Immunology, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland; [EMAIL_ADDRESS] (K.H. ); [EMAIL_ADDRESS] (M.S. ); [EMAIL_ADDRESS] (A.W. ); [EMAIL_ADDRESS] (I.W.-K.)  
[PERSON]  
1 Department of Diagnostic Immunology, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland; [EMAIL_ADDRESS] (K.H. ); [EMAIL_ADDRESS] (M.S. ); [EMAIL_ADDRESS] (A.W. ); [EMAIL_ADDRESS] (I.W.-K.)  
[PERSON]  
2 Department of Genetics and Pathology, International Hereditary Cancer Center, Pomeranian Medical University in Szczecin, 71-25 Szczecin, Poland; [EMAIL_ADDRESS] (I.W.-K.)  
[PERSON]  
1  
Footnote 1: email: {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19  
bacteria, enables the EOs' compounds (EOCs) to penetrate the cell wall more effectively [4]. In the case of Gram-negative bacteria, their outer membrane may act protectively against the EO mode of action. Despite this, studies on Gram-negative bacteria like _Escherichia coli_ demonstrated that they are not immune to them. However, most of the research on this topic concerns food spoilage prevention and not clinical settings [4]. EOCs usually show various mechanisms of antibacterial action; the most common one is the interference with cell membrane permeability or modification of its properties. It causes the bacterial cell components (like ions or adenosine-5\({}^{\prime}\)-triphosphate) to spill out. Other common effects of EOCs include protein denaturation, inhibition of cell walls, and fatty acid synthesis [4]. This multivariate mode of action slows down the potential bacterial tolerance and improves bacteriostatic or bactericidal activity thanks to targeting various microbial cell elements. Despite this, compared to traditional antibiotics, their minimum inhibitory/bactericidal concentration (MIC/MBC) values are substantially higher, which may hinder their broad utilization in modern medicine, albeit their MIC values still fall in the range of effective concentrations [7]. Additionally, EOs are not broadly used as antimicrobials in medical settings due to their properties, which include vulnerability to environmental conditions (light, temperature, oxygen) and hydrophobic structure, making it more challenging to create formulas easily absorbed and utilized by the organism. The selected physicochemical and biological properties of the most common EOCs are summarized in Table 1. Moreover, despite them being considered safe substances, relatively few studies assess their cytotoxicity [6; 8; 9; 10]. The new trend that emerged to counter these issues is the utilization of EOs in combination with different carriers or other antimicrobials. Several studies assessed the synergism of EOCs with other substances. One of such compositions is adding silver nanoparticles (SNP) in the context of bactericidal properties. [PERSON] et al. [11] have shown that cinnamaldehyde, in combination with SNP, has a high synergistic effect against _Bacillus cereus_ and _Clostridium perfringens_. Additionally, the synergism of both SNP and cinnamaldehyde was within the range of safe chronic exposure to these compounds, which is important since SNPs are known to be highly toxic to water ecosystems, and their cytotoxicity on humans is not fully known [12]. Other studies combined EOs with various antibiotics, which produced varying results. So far, the studies have reported synergism [13; 14; 15; 16; 17], indifference, and antagonisms [8]. This combination may be critical due to the growing antibiotic tolerance, where the multivariate mode of action with EOCs can be helpful.