Essential oil antimicrobial activity

The focus of the work of many of the articles published in the last 10 years by researchers in the field of essential oil biological activity is on the activity to inhibit microorganisms. Over a third (out of 220) of the articles obtained from a recent literature search dealt with antimicrobial activity, either against bacteria or fungi or both. Essential oil activity for the inhibition of bacteria and/or fungi was determined, usually followed by an investigation of the activity of the individual components. Sometimes the activities associated with the essential oils from various plant varieties, with different amounts of constituents, were compared. 

Lopez, P Sanchez, C. BatUe, R. Nerin, C. Development of flexible antimicrobial fihns using essential oils as active agents. Journal of Agricultural and Food Chemistry, 2007a, 55(21), 8814-8824. 

Lis-BALCHIN M, HART s, SIMPSON E (2001) Buchu (Aguthosmu betuUna and. crenulata, Rutaceae) essential oils their pharmacological action on guinea-pig ileum and antimicrobial activity on microorganisms. J Pharm Pharmacol. S3 579-82. 

Cold-pressed essential oils from the peel are some of the most important by-products recovered during the processing of Citrus fruits. The presence of limonene in the aqueous discharges, with its antimicrobial activity [1], decreases the effectiveness of the waste treatment system and increases the time necessary for the biological breakdown of the organic matter produced in the peel oil recovery system [2,3]. Additional recovery of essential oils from waste water would increase industry s returns and reduce the pollution problems associated with the disposal of waste water [4,5]. Several methods for reducing the levels of residual essential oils in the aqueous effluent have been developed over the years [6-11]. 

About 120 chemical constituents have been identified in chamomile as secondary metabolites, including 28 terpenoids, 36 flavonoids and 52 additional compounds [4]. A substantial part of drag effects are determined by the essential oil content. Oil is collected from flower heads, either by steam distillation or solvent extraction, for yields of 0.24-1.90% of fresh or dry plant tissue. Among the essential oil constituents the most active are /-/-a-bisabolol and chamazulene. /-/-a-bisabolol has demonstrated anti-inflammatory, antispasmodic, antimicrobial, antiulcer, sedative and CNS activity. Chamazulene is also anti-inflammatory. Topical applications of chamomile preparation have shown benefit in the treatment of eczema, dermatitis and ulceration [5]. 

Biond, D., Ciand, P., Geraci, C. Antimicrobial activity and chemical composition of essential oil from Sicilian aromatic plants. Flavor Fragrance 1993 8 331-337. 

Secondary metabolites include essential oils, used in the flavour and fragrance industries. Essential oils are found in over 50 plant families and represent terpenoids and other aromatic compounds accumulating typically at relatively low concentrations (usually <1% of fresh weight, but can be up to 20%), but which have useful antimicrobial activity (Biavati el a/., 2003). Production of essential oils by plants is affected by many factors influencing plant growth. 

Clove bud oil has various biological activities such as antibacterial, antifungal, antioxidant and insecticidal properties. The high level of eugenol present in the essential oil imparts strong biological and antimicrobial activity. 

Clove exhibits potent antimicrobial activity against Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae (De et al., 1999). Essential oils from clove and eugenol show various degrees of inhibition against... 

Lopez, P., Sanchez, C., Batle, B. and Nerin, C. (2005) Solid and vapour phase antimicrobial activities of six essential oils susceptibility of selected foodborne bacterial and fungal strains. Journal of Agriculture and Food Chemistry 53, 6338-6346. 

Meena, M.R. and Sethi, V. (1 994) Antimicrobial activity of essential oils from spices. Journal of Food Science and Technology 31 (1), 68-70. 

Baratta, M.T., Dorman, H.J.D., Deans, S.G., Biondi, D.M. and Ruberto, G. (1998) Chemical composition, antimicrobial and antioxidative activity of laurel, sage, rosemary, oregano and coriander essential oils. Journal of Essential Oil Research 1 0(6), 61 8-627. 

Elgayyar, M., Draughon, F.A., Golden, D.A. and Mount, J.R. (2001) Antimicrobial activity of essential oils from plants against selected pathogenic and saprophytic microorganisms. Journal of Food Protection 64(7), 1019-1 024. 

The essential oil of cumin exhibits strong antimicrobial activity against Escherichia coli, Staphylococcus aureus and Listeria monocytogenes. Complete death time on exposure to cumin oil was 20, 180 and 90 min for E. coli, S. aureus and L. monocytogenes, respectively (Gachkar et al., 2007). 

Among the 60 constituents of the cumin oil identified by GC, GC-MS and olfactometry as essential volatiles, cuminaldehyde (36%), /3-pinene (19.3%), p-cymene (18.4%) and y-terpinene (15.3%) are the principal components showing high antimicrobial activity against the mould A. niger, the Gram-positive bacteria, Bacillus subtilis and S. epidermidis, as well as the yeasts, Saccharomyces cerevisiae and Candida albicans (Jirovetz et al., 2005). 

Jirovetz, L., Buchbauer, G., Stoyanova, A.S., Georgiev, E.V. and Damianova, S.T. (2005) Composition, quality control and antimicrobial activity of the essential oil of cumin (Cuminum cyminum F.) seeds from Bulgaria that had been stored for up to 36 years. Flavour and Fragrance journal 21 (1), 186-1 91. 

Bouzouita, N., Kachouri, F., Hamdi, M. and Chaabouni, M.M. (2003) Antimicrobial activity of essential oils from Tunisian aromatic plants. Flavour and Fragrance journal 18(5), 380-383. 

Antimicrobial activity of the essential oils from T parthenium [166], T. vulgare [207], T. corymbosum [162], T. macrophyllum [91] and T. cilicium [161], and the n-hexane extract and the a,P-unsaturated ddehyde constituents from T. balsamita [208] have studied and characterized as antimicrobial agents. 

Antimicrobial Activity T. parthenium Parthenolide Ethanol extracts Essential oils 203,204 202 166... 

Volatile or essential oils, as their name implies, are volatile in steam and are generally complex mixtures of hydrocarbons and oxygenated compounds derived from these hydrocarbons. The odour and taste of volatile oils is mainly determined by these oxygenated constituents. In chemical structure, most essential oils are terpenoids in origin. Testing and evaluation of the antimicrobial activity of essential oils is difficult because of their volatility, their water insolubility and their complexity. However, in recent years a large number of studies have been conducted on the antimicrobial activity of essential oils from the Anthemideae tribe. These reports concerned mainly the genera Achillea and Artemisia. 

The essential oil from another Achillea species, Achillea sintenisii, was assayed for its antimicrobial activities against 12 bacteria and 2 yeasts [26]. The oil was found to be active against some of the test microorganisms studied. The analysis of the oil revealed that the main components, e.g., camphor. Fig. (1) and eucalyptol, possessed appreciable activity against Candida albicans and Clostridium perfringens. The antimicrobial activities of the essential oils of Achillea setacea W. K. and Achillea teretifolia Willd. were individually evaluated against 14... 

Karamenderes et al. [67] reported the composition and antimicrobial activity of the essential oils obtained from Achillea millefolium L. subsp. pannonica (Scheele) Hayek, Achillea millefolium subsp. millefolium, Achillea arithmifolia Waldst Kitt and Achillea kotschyi Boiss. subsp. kotschyi, four Achillea species from Turkey. 1,8-cineole, Fig. (2), artemisia alcohol and ascaridole were identified as major components. The essential oils showed antibacterial and antifungal effects even with low concentrations. The essential oil of the flowering tops of another Achillea species, Achillea fragantissimum (Forsk.) Sch. Bip growing in Sinai, was analyzed [68]. Santolina alcohol, a- and P-thujone, Fig. (5) and artemisia ketone account for approximately 80% of the oil. The oil showed marked antimicrobial activities against Escherichia coli. Bacillus subtilis and Staphylococcus aureus. 

More recently, Cha et al. [82] investigated the chemical composition and antimicrobial activity of the essential oils of Artemisia scoparia and Artemisia capillaris Thunb. The essential oil from Artemisia scoparia was rich in camphor. Fig. (1), 1,8-cineole, Fig. (2) and (3-caryophyllene. Fig. (3) as the major compounds, whereas Artemisia capillaris oil was rich in 3-pinene. Fig. (6), P-caryophyllene, Fig. (3) and capillene. The essential oils and some of their major compounds were tested for their antimicrobial activity against 15 different genera of oral bacteria. The essential oils exhibited considerable inhibitory effect against all the oral bacteria tested, while the major components demonstrated various degrees of growth inhibition. 

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