Scientific Studies proving Anti-Microbial properties of Essential Oils

[Guest guest]

just thought y'all might be interrested in this LONG series of

findings.

*smile*

chris

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http://www.bth.co.uk/EssentialOils.htm

 

These substances [essential oils] are known to be: Anti-Bacterial,

Anti-Viral, Anti-Fungal, Antiseptic, Anti-Microbial, Anti-Infectious

and Immune-Stimulating.

 

Recent research has also shown that many of the so called " super

bugs " that has modern medicine so concerned (such as the

dreadful " MRSA " : methicillin-resistant Staphylococcus aureus),

cannot survive in the presence of essential oils...Nor has there been

any pathogen known to resist EO's by mutating. This factor may very

weel be due to the fact that bacteria are able to develop genetic

mutation and consequent resistance only versus a strictly specific

drug - such as methicillin - but their genetic system seems not to be

able to develop defensive mutations versus many natural anti-

bacterial terpenic substances, such as those contained in EO's. In

fact, there can be several hundreds of different terpenic substances

present in just one Essential oil and their concentration may vary in

relationship with the climatic conditions, harvesting time, humidity,

sun exposition, etc. All such variances make impossible the

triggering of those genetic mechanisms which on the contrary are

successful when they are " shot " by one and only one specific chemical.

 

Many people nowadays diffuse the oils into the atmosphere of their

homes, creating a virus free and pleasant environment.

 

Scientific Study of properties of Essential Oils

 

Very extensive research and study has been accomplished on the

antibacterial and antifungal properties of essential oils.

 

A recent study has demonstrated that Tea tree oil for instance was

very effective not only against bacteria and moulds but even against

dust mites: 0.05% of Tea tree oil was found as effective as 0.5%

Benzyl benzoate over a 30 minute period. It was further revealed that

at shorter exposure times Tea tree oil was more effective, killing

79% of the mites in 10 minutes.

 

Paolo Rovesti, who was considered internationally one of the top

leading scientist expert in essential oils, wrote in 1980:

 

" …it is indispensable to explain thoroughly the chemical,

physical

and biochemical properties of essential oils, which may briefly be

summed up as follows:

 

a) The considerable bactericidal power of the whole or the oxygenated

part of the essences, hence their use in disinfectant and antiseptic

preparations of every kind. Each chemical function of the different

constituent parts of the essential oils has a conspicuous

bactericidal predilection. Thus, for example, phenol hydroxyl for

staphylococcus and for choleric parasites, the aldehyde group for

typhus and cholera, etc. The double bonds of the aliphatic chains of

terpenic molecules amplify these microbicidal functions and if they

are specially treated with certain natural gases, the microbicidal

action is further increased… "

 

(Paolo Rovesti, " In search of lost perfumes " , Blow-up, 1980)

 

In-vitro antimicrobial activity and chemical composition of Sardinian

Thymus essential oils.

 

Cosentino S, Tuberoso CI, Pisano B, Satta M, Mascia V, Arzedi E,

Palmas F

 

Department of Experimental Biology, University of Cagliari, Sardinia,

Italy.

 

" Essential oils and their components are becoming increasingly

popular as naturally occurring antimicrobial agents. In this work the

chemical composition and the antimicrobial properties of Thymus

essential oils and of their main components were determined. Three

essential oils obtained from different species of Thymus growing wild

in Sardinia and a commercial sample of Thymus capitatus oil were

analysed. The essential oil components were identified by GC/MS

analysis. The antimicrobial activity of the oils and components was

determined against a panel of standard reference strains and multiple

strains of food-derived spoilage and pathogenic bacteria, using a

broth microdilution method. The GC/MS analysis showed that the major

constituents of the oils were monoterpene hydrocarbons and phenolic

monoterpenes, but the concentration of these compounds varied greatly

among the oils examined. The results of the antimicrobial assay

showed that essential oils extracted from Sardinian Thymus species

have an antimicrobial activity comparable to the one observed in

other thyme oils. It seems also confirmed that the antimicrobial

properties of thyme essential oils are mainly related to their high

phenolic content. Among the single compounds tested carvacrol and

thymol turned out to be the most efficient against both reference

strains and food-derived bacteria. The results of this study

confirmed the possibility of using thyme essential oils or some of

their components in food systems to prevent the growth of foodborne

bacteria and extend the shelf-life of processed foods. "

 

Antimicrobial activity of clove oil dispersed in a concentrated sugar

solution.

 

Briozzo J, Nunez L, Chirife J, Herszage L, D'Aquino M

 

Departamento de Industrias, Facultad de Ciencias Exactas y Naturales,

 

Universidad de Buenos Aires, Republica Argentina.

 

Essential oil of clove, dispersed (0.4% v/v) in a concentrated sugar

solution, had a marked germicidal effect against various bacteria and

Candida albicans. Staphylococcus aureus (five strains), Klebsiella

pneumoniae, Pseudomonas aeruginosa, Clostridium perfringens, and

Escherichia coli inoculated at a level of 10(7) cfu/ml, and C.

albicans (inoculum 4.0 x 10(5) cfu/ml) were killed (greater than

99.999%) after 2-7 min in a laboratory broth supplemented with 63%

(v/w) of sugar, and containing 0.4% (v/w) of essential oil of clove.

Added organic matter (i.e. human or bovine serum) did not impair its

antimicrobial activity. Sugar was not necessary for the antimicrobial

activity of clove oil, but the concentrated sugar solution provided a

good vehicle for obtaining an oil dispersion that is relatively

stable for certain practical applications.

 

Antimicrobial activity of essential oils and other plant extracts.

 

Hammer KA, Carson CF, Riley TV

 

Department of Microbiology, The University of Western Australia,

Nedlands,Western Australia.

 

The antimicrobial activity of plant oils and extracts has been

recognized for many years. However, few investigations have compared

large numbers of oils and extracts using methods that are directly

comparable. In the present study, 52 plant oils and extracts were

investigated for activity against Acinetobacter baumanii, Aeromonas

veronii biogroup sobria, Candida albicans, Enterococcus faecalis,

Escherichia col, Klebsiella pneumoniae, Pseudomonas aeruginosa,

Salmonella enterica subsp. enterica serotype typhimurium, Serratia

marcescens and Staphylococcus aureus, using an agar dilution method.

Lemongrass, oregano and bay inhibited all organisms at concentrations

of < or = 2.0% (v/v). Six oils did not inhibit any organisms at the

highest concentration, which was 2.0% (v/v) oil for apricot kernel,

evening primrose, macadamia, pumpkin, sage and sweet almond. Variable

activity was recorded for the remaining oils. Twenty of the plant

oils and extracts were investigated, using a broth microdilution

method, for activity against C. albicans, Staph. aureus and E. coli.

The lowest minimum inhibitory concentrations were 0.03% (v/v) thyme

oil against C. albicans and E. coli and 0.008% (v/v) vetiver oil

against Staph. aureus. These results support the notion that plant

essential oils and extracts may have a role as pharmaceuticals and

preservatives.

 

Antimicrobial properties of plant essential oils and essences against

five important food-borne pathogens.

 

Smith-Palmer A, Stewart J, Fyfe L Department of Dietetics and

Nutrition, Queen Margaret College, University of Edinburgh Medial

School, UK.

 

The antimicrobial properties of 21 plant essential oils and two

essences were investigated against five important food-borne

pathogens, Campylobacter jejuni, Salmonella enteritidis, Escherichia

coli, Staphylococcus aureus and Listeria monocytogenes. The oils of

bay, cinnamon, clove and thyme were the most inhibitory, each having

a bacteriostatic concentration of 0.075% or less against all five

pathogens. In general, Gram-positive bacteria were more sensitive to

inhibition by plant essential oils than the Gram-negative bacteria.

Campylobacter jejuni was the most resistant of the bacteria

investigated to plant essential oils, with only the oils of bay and

thyme having a bactericidal concentration of less than 1%. At 35

degrees C, L. monocytogenes was extremely sensitive to the oil of

nutmeg. A concentration of less than 0.01% was bacteriostatic and

0.05% was bacteriocidal, but when the temperature was reduced to 4

degrees, the bacteriostatic concentration was increased to 0.5% and

the bacteriocidal concentration to greater than 1%.

 

Antibacterial and antifungal activity of ten essential oils in vitro.

 

Pattnaik S, Subramanyam VR, Kole C.

 

Regional Medical Research Centre, (Indian Council of Medical

Research), Bhubaneswar, India.

 

The essential oils of aegle, ageratum, citronella, eucalyptus,

geranium, lemongrass, orange, palmarosa, patchouli and peppermint,

were tested for antibacterial activity against 22 bacteria, including

Gram-positive cocci and rods and Gram-negative rods, and twelve fungi

(3 yeast-like and 9 filamentous) by the disc diffusion method.

Lemongrass, eucalyptus, peppermint and orange oils were effective

against all the 22 bacterial strains. Aegle and palmarosa oils

inhibited 21 bacteria; patchouli and ageratum oils inhibited 20

bacteria and citronella and geranium oils were inhibitory to 15 and

12 bacterial strains, respectively. All twelve fungi were inhibited

by seven oils (aegle, citronella, geranium, lemongrass, orange,

palmarosa and patchouli). Eucalyptus and peppermint oils were

effective against eleven fungi. Ageratum oil was inhibitory to only

four fungi tested. The MIC of eucalyptus, lemongrass, palmarosa and

peppermint oils ranged from 0.16 to > 20 microliters ml-1 for

eighteen bacteria and from 0.25 to 10 microliters ml-1 for twelve

fungi.

 

Antibacterial activity of essential oil components.

 

Moleyar V, Narasimham P

 

Area of Fruit and Vegetable Technology, Central Food Technological

Research Institute, Mysore, India.

 

Antibacterial activity of fifteen essential oil components towards

food borne Staphylococcus sp., Micrococcus sp., Bacillus sp. and

Enterobacter sp. was studied by an agar plate technique. Cinnamic

aldehyde was the most active compound followed by citral, geraniol,

eugenol and menthol. At 500 micrograms/ml, cinnamic aldehyde

completely inhibited the bacterial growth for more than 30 days at 30

degrees C that was comparable to 200 micrograms/ml of butylated

hydroxy anisole (BHA). At lower temperatures, 25 and 20 degrees C,

antibacterial activity of the five essential oil components

increased. Addition of sodium chloride at 4% level (w/v) in the

medium had no effect on the inhibitory activity of cinnamic aldehyde.

In mixtures of cinnamic aldehyde and eugenol or BHA an additive

effect was observed.