Table 2.

Comparison of antibacterial properties of EO.

EOs	Source	Major Compounds	Pathogen Strains	Dosage/MIC (minimum inhibitory concentration)	Mechanism of anti-bacteria	Effects on biofilms/MBIC (minimal biofilms inhibitory concentration)	Mechanism of anti-biofilms	Safety	Refs.
–	Clinopodium nepeta, Origanum vulgare and Foeniculum vulgare	piperitone oxide, estragole, and p-thymol, respectively	E. coli JM109, and its derived antibiotic-resistant cells	0.3–0.966 μL/mL	methylation at both cytosine and adenine residues	–	–	–	[70]
Cedar EO	Cedar wood	e δ-cadinene (36.35%), (Z)-β-farnesene (13.8%), β-himachalene (9.4%),	M. luteus	MIC 90: 8.99 μL/mL	–	–	–	–	[71]
Cinnamon EO	–	cinnamaldehyde	Y. enterocolitica	0.625 mg/mL	altering bacteria cell membrane structure, stability, and osmotic function	0.078 mg/mL	interfering with the QS system by inhibiting AHL production	–	[72]
Clove essential oil (CEO) and Oregano essential oil (OEO)	–	eugenol and carvacrol, respectively	S. Derby	0.8 mg/mL and 0.2 mg/mL, respectively	–	At 1/8 MIC, the inhibition rate of CEO and OEO on the biofilms formation was 90.29% and 48.79%.	suppressing the metabolic activity and the production of the extracellular polysaccharide	–	[73]
Composite EO	–	cinnamaldehyde, carvacrol, and eugenol	E. coli and S. aureus	7.94 μL/mL	destroying bacteria cell wall and cell membrane integrity, and retarding the respiratory chain	The biofilms of S. aureus decreased by 11.19%, 15.32%, and 18.09%, and that of E. coli decreased by 14.25%, 21.72%, and 22.37% after exposure (0 h) to EOs at 0.5 MIC, 1 MIC, and 2 MIC, respectively.	–	–	[74]
J. intigrimma, J. roseae and J. gossypifolia EO	leaves of Jatropha	diterpenes	E. coli	5 mg/mL, 5 mg/mL, and 2.5 mg/mL, respectively	–	31.25 μg/mL, 250 and above 1000 μg/mL, respectively	disturbing adhesion proteins FimH	–	[75]
Propolis essential oil (PEO)	complex material that honey bees collect from resinous and balsamic material	β-himachalene (13.94%), α-curcumene (11.28%), α-bergamotene (4.5%)	S. mutans	0.625 μL/mL	–	1/4 MIC or above can significantly reduce the biofilms biomasses compared to the control group (p < 0.05).	membrane permeability, releasing lactic dehydrogenase (LDH) and calcium ions; inhibiting bacterial proliferation; suppressing the activity of glucosyltransferases (GTFs) to reduce the production of extracellular polysaccharides and alleviate bacterial adherence	IC10 value of PEO on HOECs was 1.299 μL/mL, which was significantly higher than double the MIC.	[76]
Thymus x citriodorus EO	Thyme species	monoterpenes (72.6%), being geraniol (27.5%), 1,8-cineole (16.3%), and thymol (9.2%);	C. acnes and S. epidermidis	0.06%	–	0.12%–0.24%	–	affecting cellular viability in a dose-dependent manner.	[77]
Thymus zygis subsp. gracilis EO	Lamiaceae	p-cymene (25.98 ± 0.07%), thymol (22.64 ± 0.06%), carvacrol (21.28 ± 0.06%), and γ-terpinene (11.01 ± 0.03%)	L. monocytogenes	0.02% (v/v)	–	0.02% (v/v)	–	–	[78]