Commercial Essential Oils as Potential Antimicrobials to Treat Skin Diseases

Table 10

Essential oil studies demonstrating synergistic interactions in combination with conventional antimicrobials.

Antimicrobial	Essential oil	Microbial species studied			Reference
Amoxicillin	Origanum vulgare (oregano)	E. coli	0.75	A	[324]
	Elettaria cardamomum (cardamom)	S. aureus (ATCC 25923)	1.06–2.00	I	[325]
		MRSA (clinical isolate)	0.56–1.11	A-I
			0.61–1.50
Amphotericin B	Melaleuca alternifolia (tea tree)	C. albicans (NRRL y-12983, ATCC 14053, NRRL y-869, NRRL y-22077, ATCC 10231)	0.13–1.75	S	[249]
	Origanum vulgare (oregano)		0.03–0.35
	Pelargonium graveolens (geranium)		0.04–0.18
	Thymus broussonetii (thyme)	C. albicans (CCMM L4)	0.37	S	[259]
	Thymus maroccanus (thyme)		0.49
	Thymus vulgaris (thyme)	C. albicans (ATCC 90029)	n.m.		[326]
Ampicillin	Cinnamomum verum (cinnamon)	E. coli	0.75	A	[327]
	Lavandula angustifolia (lavender)		2	I
	Melaleuca alternifolia (tea tree)		0.75	A
	Mentha piperita (peppermint)	E. coli	1	A	[328]
	Origanum majorana (marjoram)		0.63		[327]
Carbenicillin	Cinnamomum verum (cinnamon)	E. coli	2	I	[327]
	Lavandula angustifolia (lavender)
	Melaleuca alternifolia (tea tree)	E. coli	0.56	A	[327]
	Mentha piperita (peppermint)		0.75
	Origanum majorana (marjoram)	E. coli	1.06	I	[327]
Cefazolin	Cinnamomum verum (cinnamon)	E. coli	0.63	A	[327]
	Lavandula angustifolia (lavender)	E. coli	2	I	[327]
	Melaleuca alternifolia (tea tree)	E. coli	1.5
	Mentha piperita (peppermint)	E. coli	2	I	[327]
	Origanum majorana (marjoram)	E. coli
Cefixime	Thymus broussonetii (thyme)	E. coli	0.5	S	[329]
		P. aeruginosa
		S. aureus
	Thymus maroccanus (thyme)	E. coli	0.5	S	[329]
		P. aeruginosa	0.75	A
		S. aureus	0.18	S
Ceftazidime	Cinnamomum verum (cinnamon)	E. coli (J53 pMG321)	2	I	[327]
	Lavandula angustifolia (lavender)	E. coli (J53 pMG321)	1	A	[327]
	Melaleuca alternifolia (tea tree)
	Mentha piperita (peppermint)	E. coli (J53 pMG321)	2	I	[327]
	Origanum majorana (marjoram)
Ceftiofur	Origanum vulgare (oregano)	E. coli	0.63	A	[324]
Ceftriaxone
Cefuroxime	Cinnamomum verum (cinnamon)	E. coli	2	I	[327]
	Lavandula angustifolia (lavender)		0.53	A
	Melaleuca alternifolia (tea tree)		1.5	I
	Mentha piperita (peppermint)		0.56	A
	Origanum majorana (marjoram)		0.63
Chlorhexidine	Cinnamomum burmannii (cinnamon)	S. epidermidis (clinical isolate)	0.3	S	[211]
		S. epidermidis (clinical isolate 64)	0.35
		S. epidermidis (clinical isolate)	0.3
		S. epidermidis strains (ATCC 35984)	0.15
		S. epidermidis (ATCC 12228)	0.45
Chlorhexidine digluconate	Eucalyptus globulus (eucalyptus)	S. epidermidis (RP62A)	2	I	[213]
		S. epidermidis (clinical isolate)
	Melaleuca alternifolia (tea tree)	S. epidermidis (RP62A)
	Melaleuca alternifolia (tea tree)	S. epidermidis (clinical isolate TK1)
Ciprofloxacin	Melaleuca alternifolia (tea tree)	S. aureus	1.58–7.70	I-An	[304]
	Mentha piperita (peppermint)		0.75–1.40	A-I
	Pelargonium graveolens (geranium)	S. aureus (ST2)	0.38	S	[330]
	Rosmarinus officinalis (rosemary)	S. aureus	1.03–1.30	I	[304]
	Thymus broussonetii (thyme)	E. coli	0.37	S	[329]
		P. aeruginosa	0.14
		S. aureus	0.5
	Thymus maroccanus (thyme)	E. coli	0.12	S	[329]
		P. aeruginosa	0.15
		S. aureus	0.26
	Thymus vulgaris (thyme)	S. aureus	0.80–2.59	A-I	[304]
	Elettaria cardamomum (cardamom)	S. aureus (ATCC 25923)	0.62–1.12	A-I	[325]
		MRSA (clinical isolate)	1.01–2	I
			1.01–1.50
	Salvia officinalis (sage)	E. coli (ATCC 25922)	1.03	I	[176]
Doxycycline	Origanum vulgare (oregano)	E. coli	0.38	S	[324]
Erythromycin	Mentha piperita (peppermint)	E. coli	1	A	[328]
Florfenicol	Origanum vulgare (oregano)	E. coli	0.38	S	[324]
Fluconazole	Ocimum sanctum (holy basil)	C. albicans (29 clinical isolates)	0.24–0.50	S	[255]
		C. albicans (3 clinical isolates)	0.63–0.93	A
		C. albicans (ATCC 90028)	0.48	S	[255]
		C. albicans (ATCC 10261)	0.47
		C. albicans (ATCC 44829)	0.48
	Thymus broussonetii (thyme)	C. albicans (CCMM L4)	0.3	S	[259]
	Thymus maroccanus (thyme)		0.27
	Thymus vulgaris (thyme)	T. rubrum (clinical isolate)	0.25		[271]
Gentamicin	Cinnamomum burmannii (cinnamon)	S. epidermidis (clinical isolate 46)	1.5	I	[211]
		S. epidermidis (clinical isolate 64)	0.23	S
		S. epidermidis (clinical isolate 236)	0.15
		S. epidermidis (ATCC 35984)	1.1	I
		S. epidermidis (ATCC 12228)	1.2
	Melaleuca alternifolia (tea tree)	MRSA (2 clinical isolates)	n.m.	I	[144]
	Mentha piperita (peppermint)	E. coli	1.25		[328]
	Thymus broussonetii (thyme)	E. coli	0.37	S	[329]
		P. aeruginosa	0.28
		S. aureus	0.5
	Thymus maroccanus (thyme)	E. coli	0.28	S	[329]
		P. aeruginosa	0.18
		S. aureus	0.5
Kanamycin	Origanum vulgare (oregano)	E. coli	1.5	I	[324]
Ketoconazole	Pelargonium graveolens (geranium)	T. erinacei (KCCM 60411)	0.56	A	[264]
		T. schoenleinii (KCCM 60477)	0.31	S	[264]
		T. soudanense (KCCM 60448)	0.18
	Ocimum sanctum (holy basil)	C. albicans (26 clinical isolates)	0.25–0.50	S	[255]
		C. albicans (6 clinical isolates)	0.52–0.71	A
		C. albicans (ATCC 90028)	0.42	S	[255]
		C. albicans (ATCC 10261)	0.41
		C. albicans (ATCC 44829)	0.5
	Thymus magnus (thyme)	T. rubrum (ATCC 6345)	0.37	S	[260]
	Thymus quinquecostatus (thyme)		0.35
Levofloxacin	Origanum vulgare (oregano)	E. coli	0.5	S	[324]
Lincomycin			0.75	A
Lysostaphin	Melaleuca alternifolia (tea tree)	MRSA (2 clinical isolates)	n.m.	I	[144]
Maquindox	Origanum vulgare (oregano)	E. coli	0.5	S	[324]
Meropenem	Cinnamomum verum (cinnamon)	E. coli (clinical isolate)	0.75	A	[327]
	Lavandula angustifolia (lavender)		1.5	I
	Melaleuca alternifolia (tea tree)		1	A
	Mentha piperita (peppermint)		0.26	S
	Origanum majorana (marjoram)		1	A
Mupirocin	Melaleuca alternifolia (tea tree)	MRSA (2 clinical isolates)	n.m.	I	[144]
Norfloxacin	Pelargonium graveolens (geranium)	E. coli (ATCC 35218)	0.57	A	[157]
		S. aureus (ATCC 6538)	0.37	S	[157]
		S. aureus (ATCC 29213)	0.38
Nystatin	Melaleuca alternifolia (tea tree)	C. albicans (ATCC 14053)	>0.5	A	[61]
	Origanum vulgare (oregano)	C. albicans (ATCC 14053)	0.04	S	[61]
			0.04–0.35
	Pelargonium graveolens (geranium)		0.01–0.06
Oxytetracycline	Mentha piperita (peppermint)	E. coli	0.5	S	[328]
Piperacillin	Cinnamomum verum (cinnamon)	E. coli (J53 R1)	0.5	S	[327]
	Lavandula angustifolia (lavender)		0.26
	Melaleuca alternifolia (tea tree)	E. coli (J53 R1)	0.56	A	[327]
	Mentha piperita (peppermint)		0.31	S
	Origanum majorana (marjoram)		0.75	A
Polymycin	Origanum vulgare (oregano)	E. coli	0.75	A	[324]
Pristinamycin	Thymus broussonetii (thyme)	E. coli	0.37	S	[329]
		P. aeruginosa	0.75	A
		S. aureus	0.5	S	[329]
		E. coli
		P. aeruginosa	0.75	A	[329]
		S. aureus	0.62
Sarafloxacin	Origanum vulgare (oregano)	E. coli	0.38	S	[324]
Tobramycin	Melaleuca alternifolia (tea tree)	E. coli (ATCC 25922)	0.37	S	[97]
		S. aureus (ATCC 29213)	0.62	A
Triclosan	Cinnamomum burmannii (cinnamon)	S. epidermidis (clinical isolate 46)	1.2	I	[211]
		S. epidermidis (clinical isolate 64)	1.5
		S. epidermidis (clinical isolate 236)	1.2
		S. epidermidis (ATCC 35984)	0.03	S	[211]
		S. epidermidis (ATCC 12228)	0.06
Vancomycin	Melaleuca alternifolia (tea tree)	MRSA (2 clinical isolates)	>0.50	A	[144]

.: not mentioned.
: synergy; A: additive; I: indifference; An: antagonism.