Table 1.
Overview of crude essential oils and their identified target sites and modes of action.
| Common name of plant from which essential oil is derived | Species of plant from which essential oil is derived | Major constituents of essential oil | Model organisms and measured MIC | Mechanism | Reference |
|---|---|---|---|---|---|
| African basil | Ocimum gratissimum | Thymol (53.2%), γ-terpinene (25.7%), eugenol (12.7%), p-cymene (7.3%) |
E. coli (6 μg/mL) Klebsiella sp. (6 μg/mL) L. innocua L. monocytogenes Proteus mirabilis (12 μg/mL) Pseudomonas aeruginosa (≥24 μg/mL) Salmonella enteritidis (3 μg/mL) Shigella flexneri (3 μg/mL) Staphylococcus aureus (0.75 μg/mL) |
Permeabilized membrane | Nakamura et al. (1999), Cimanga et al. (2002), Nguefack et al. (2004b) |
| Bishop’s weed | Trachyspermum ammi L. | Thymol (49.6%), β-cymene (16.3%), eugenol (3%), β-pinene (2.5%) | Three Gram-positive strains (12.5–175 μg/mL) Six Gram-negative strains (12.5–462.5 μg/mL) |
Potassium and ATP leakage; cell lysis | Paul (2011) |
| Cinnamon | Cinnamomum verum | E-cinnamaldehyde (73.35%), β-caryophyllene (4.09%), linalool (3.55%), cinnamyl acetate (2.96%), eugenol (2.68%) |
Campylobacter jejuni (0.05% v/v) Enterobacter aerogenes E. coli (0.05% v/v) Listeria monocytogenes (0.03% v/v) P. aeruginosa (0.125% v/v) S. enteritidis (0.05% v/v) S. aureus (0.04–0.125% v/v) |
Inhibited histidine decarboxylase P. aeruginosa: depolarized and permeabilized membranes; leakage and coagulation of cytoplasmic content; inhibited respiration activity S. aureus: entered a viable but non-cultivable state, and lost membrane integrity |
Wendakoon and Morihiko (1995), Smith-Palmer et al. (1998), Bouhdid et al. (2010) |
| Cinnamomum cassia | Cinnamaldehyde (75.3%), coumarin (10.6%), cinnamic alcohol (3%) |
B. cereus (339 μg/mL) E. coli (2640 μg/mL) L. monocytogenes (2640 μg/mL) Salmonella infantis (2640 μg/mL) S. aureus (1320 μg/mL) |
Released cellular content; reduced intracellular pH; affected membrane integrity | Alzoreky and Nakahara (2003), Oussalah et al. (2006) | |
| Coriander | Coriandrum sativum | Linalool (25.9–64.4%), (E)-2-decenal (0–20.2%), decanol (0.14–8.4%), (E)-2-decen-1-ol (0–7.9%) |
Candida species (0.05–0.4% v/v) L. monocytogenes (0.018–0.074% v/v) |
Damage cytoplasmic membrane; released cellular content | De et al. (1999), Gill et al. (2002), Silva et al. (2011) |
| Cloves | Syzygium aromaticum | Eugenol (64%), eugenyl acetate (16.3%), caryophyllene (14.5%) |
C. jejuni (0.05% v/v) E. aerogenes E. coli (0.04% v/v) L. monocytogenes (0.03% v/v) S. enteritidis (0.04% v/v) S. aureus (0.04% v/v) |
Inhibited histidine decarboxylase (E. aerogenes) | Wendakoon and Morihiko (1995), Smith-Palmer et al. (1998) |
| Cumin | Cuminum cyminum L. (seed) | Cumin aldehyde (29%), α-terpinen-7-al (20.7%), γ-terpinene (12.9%), p-cymene (8.6%) |
B. cereus (0.05 μL/mL) B. subtilis (0.05 μL/mL or 1000 μg/mL) |
Mild changes in cytoplasm; cell envelope intact | De et al. (1999), Pajohi (2011) |
| Garlic | Allium sativum | Allicin (70%) |
Candida albicans (470–940 μg/mL) E. coli (15–15000 μg/mL or 3.95% v/v) L. monocytogenes (8.8% v/v) Salmonella typhi (7% v/v) S. aureus (12–15000 μg/mL or 5% v/v) |
Induced leakage from E. coli cells | Hughes and Lawson (1991), Kumar and Berwal (1998), Ankri and Mirelman (1999), Perry et al. (2009) |
| Kaffir lime | Citrus hystrix | Citronellol (10.7%), limonene (7.3%), linalool (5.8%) |
Aspergillus flavus (560 μg/mL) Aspergillus parasiticus (1130 μg/mL) |
Reduced aflatoxin production | Rammanee and Hongpattarakere (2011) |
| Lemon grass | Cymbopogon citratus | Geranial (45.7%), myrcene (3.9%), 6-methylhept-5-en-2-one (2.7%) |
L. innocua L. monocytogenes S. aureus |
Permeabilized membrane | Baratta et al. (1998), Nguefack et al. (2004b) |
| Lime | Citrus aurantifolia | Limonene (69.1%), p-cymene (12.8%) |
A. flavus (560 μg/mL) A. parasiticus (1130 μg/mL) |
Reduced aflatoxin production; extra- and intracellular damages to cells | Rammanee and Hongpattarakere (2011) |
| Mustard oil |
E. coli (0.2% v/v) S. typhi (0.2% v/v) |
Affected membrane integrity; released cell content; decreased intracellular ATP and pH, while external ATP increased | Turgis et al. (2009) | ||
| Menthol | Mentha longifolia | Menthol (32.5%), menthone (20.7%), pulegone (17.8%), 1,8-cineole (5.6%), terpineol-4 (4.9%) |
Salmonella typhimurium (1560 μg/mL) E. coli (780 μg/mL) Micrococcus luteus (190 μg/mL) S. aureus (780 μg/mL) |
Damaged cell wall | Hafedh et al. (2010) |
| Oregano | Origanum compactum | Carvacrol (36.5%), thymol (29.7%), p-cymene (24.3%), γ-terpinene (1.1%) |
P. aeruginosa (1% v/v) S. aureus (0.031% v/v) |
Dissipated potassium gradient; depolarized membranes; permeabilized membranes; inhibited cell respiration; affected cell structure: coagulated cytoplasmic material; liberation of membrane vesicles; mesosome-like structures | Bouhdid et al. (2009), Babili et al. (2011) |
| Origanum vulgare | Carvacrol (68.1%), p-cymene (15.9%), α-pinene (2.6%), myrcene (2%) |
E. coli (0.625 μL/mL) P. aeruginosa (1648 μg/mL) S. aureus (0.6 μL/mL or 575 μg/mL) Six bacteria (20–40 μL/mL) Three Candida spp. (10–20 μL/mL) |
Suppressed enterotoxin production; released cellular content; cell morphological changes; permeabilized membranes; leaked potassium and phosphate; dissipated pH gradients | Lambert et al. (2001), Burt and Reinders (2003), De Souza et al. (2008, 2010) | |
| Rosemary | Rosmarinus officinalis | Carnosic acid, carnosol, rosmadial, genkwanin, rosmarinic acid | Model membranes C. albicans (10 μg/mL) Saccharomyces cerevisiae (5 μg/mL) B. subtilis (10 μg/mL) E. coli (0.1% v/v or 40 μg/mL) S. aureus (0.1% v/v or 20 μg/mL) |
Membrane-rigidifying effects; affected lipid polymorphism | Panizzi et al. (1993), Smith-Palmer et al. (1998), Pérez-Fons et al. (2006) |
| Savory | Satureja montana | Thymol (29%), p-cymene (12%), linalool (11%), carvacrol (10.7%) |
C. albicans (5 μg/mL) S. cerevisiae (5 μg/mL) E. coli (0.05% v/v or 40 μg/mL) L. monocytogenes (0.05% v/v) S. aureus (0.013% v/v or 5 μg/mL) S. Typhimurium (0.05% v/v) Clostridium perfringens (1.56% v/v) |
Increased extracellular ATP; reduced intracellular pH; affected membrane integrity; structural damages; and cell lysis | Panizzi et al. (1993), Oussalah et al. (2006, 2007), De Oliveira et al. (2011) |
| Spanish oregano | Coridothymus capitatus |
E. coli (0.025% v/v) L. monocytogenes (0.025% v/v) S. aureus (0.013% v/v) S. Typhimurium (0.025% v/v) |
Increased extracellular ATP; released cellular content; reduced intracellular pH; affected membrane integrity | Oussalah et al. (2006, 2007) | |
| Thyme | Thymus eriocalyx | Thymol (63.8%), α-phellandrene (13.3%), cis-sabinene hydroxide (8.1%) | L. monocytogenes (125 μg/mL) | Damaged cell envelope | Rasooli et al. (2006) |
| Thymus vulgaris | Thymol (31.4%), p-cymene (17%), carvacrol (12.4%), γ-terpinene (11.1%) |
C. albicans (1 μg/mL) S. cerevisiae (2 μg/mL) B. subtilis (2 μg/mL) C. jejuni (0.04% v/v) Erwinia amylovora (1600 μg/mL) Erwinia carotovora (1600 μg/mL) E. coli (0.05% v/v or 2 μg/mL) L. innocua L. monocytogenes (0.02% v/v) S. aureus (0.02% v/v or 5 μg/mL) S. enteritidis (0.04% v/v) |
Permeabilized membrane; caused changes in outer membrane protein profile of Erwinia strains | Panizzi et al. (1993), Smith-Palmer et al. (1998), Nguefack et al. (2004b), Horváth et al. (2009) | |
| Thymus x-porlock | α-Phellandrene (38.7%), thymol (31.7%), cis-sabinene hydroxide (9.6%) | L. monocytogenes (125 μg/mL) | Damaged cell envelope; clumping of intracellular material | Rasooli et al. (2006) | |
| Gnaphalium affine | Eugenol (18.2%), linalool (10.6%), trans-caryophyllene (8.9%), α-terpineol (6%), p-cymene (5.8%) | Six bacteria (0.39–1.56 μg/mL) Five fungi (0.2 μg/mL) |
Disrupted cell walls and membranes | Zeng et al. (2011) | |
| Sphallerocarpus gracilis | α-Asarone (33.1%), γ-terpinene (25,6%), p-cymene (17.4%) | Eight Gram-positive bacteria (160–640 μg/mL) Four Gram-negative bacteria (80–320 μg/mL) One fungus (no MIC) |
Altered cell morphology | Gao et al. (2011) |