Origanums - Some Studies on Fungus and Yeast

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Hi y'all,

 

We gotta keep in mind that in-vivo or in-vitro tests are conducted using

controlled conditions .. in a sterile environment (save the presence of

the critter being tested) and can not necessarily be expected to work on

a walking, talking human critter just because it zapped life in a petri

dish. However, we should also keep in mind that the fact that we should

not necessarily expect results from such tests .. does not .. indicate

that we should disregard the potential. Lack of proof that something is

not is also lack of proof that something is .. except for skeptics. ;-)

 

Below are a few of many test results I have collected over the years.

 

Y'all keep smiling. :-) Butch http://www.AV-AT.com

 

 

Study: GC-MS analysis of essential oils from some Greek aromatic plants

and their fungi toxicity on Penicillium digitatum.

 

Daferera DJ, Ziogas BN, Polissiou MG

Laboratory of General Chemistry and Laboratory of Phytopathology,

Agricultural University of Athens, Greece.

 

The isolated essential oils from seven air-dried plant species were

analyzed by gas chromatography-mass spectrometry (GC-MS). Thymus

vulgaris (thyme), Origanum vulgare (oregano), and Origanum dictamus

(dictamus) essential oils were found to be rich in phenolic compounds

representing 65.8, 71.1, and 78.0% of the total oil, respectively.

Origanum majorana (marjoram) oil was constituted of hydrocarbons

(42.1%), alcohols (24.3%), and phenols (14.2%). The essential oil from

Lavandula angustifolia Mill. (lavender) was characterized by the

presence of alcohols (58.8%) and esters (32.7%). Ethers predominated in

Rosmarinus officinalis (rosemary) and Salvia fruticosa (sage) essential

oils, constituting 88.9 and 78.0%, respectively. The radial growth,

conidial germination, and production of Penicillium digitatum were

inhibited completely by oregano, thyme, dictamus, and marjoram essential

oils at relatively low concentrations (250-400 mgr;g/mL). Lavender,

rosemary, and sage essential oils presented less inhibitory effect on

the radial growth and conidial germination of P. digitatum. Conidial

production of P. digitatum was not affected by the above oils at

concentrations up to 1000 mgr;g/mL. Apart from oregano oil, all

essential oils were more effective in the inhibition of conidial

germination than of radial growth. The monoterpene components, which

participate in essential oils in different compositions, seem to have

more than an additive effect in fungal inhibition.

 

Study: Inhibitory effects of selected Turkish spices and oregano

components on some food borne fungi.

 

Akgul A, Kivanc M

Ziraat Fak., TUT Bol, Erzurum, Turkey.

 

The inhibitory effects of 10 selected Turkish spices, oregano essential

oil, thymol and carvacrol towards growth of 9 food borne fungi were

investigated in culture media with pH 3.5 and 5.5. The antifungal

effects of sodium chloride, sorbic acid and sodium benzoate and the

combined use of oregano with sodium chloride were also tested under the

same conditions for comparison. Of the spices tested, only sodium

chloride were also tested under the same conditions for comparison. Of

the spices tested, only oregano at 1.0, 1.5, 2.0% (w/v) levels showed

effect on all fungi. 8% (w/v) sodium chloride was less effective than

oregano. Oregano essential oil, thymol or carvacrol at concentrations of

0.025% and 0.05% completely inhibited the growth of all fungi, showing

greater inhibition than sorbic acid at the same concentrations. The

combined use of oregano and sodium chloride exhibited a synergistic

antifungal effect.

 

Study: Sensitivity of heat-stressed yeasts to essential oils of plants.

Conner DE, Beuchat LR

 

Eight strains of yeasts (Candida lipolytica, Debaryomyces hansenii,

Hansenula anomala, Kloeckera apiculata, Lodderomyces elongisporus,

Rhodotorula rubra, Saccharomyces cerevisiae, and Torulopsis glabrata)

were examined for changes in sensitivity to eight essential oils of

plants (allspice, cinnamon, clove, garlic, onion, oregano, savory, and

thyme) after being sub lethally heat stressed. With the exception of

garlic oil for all test yeasts, onion oil for S. cerevisiae, and oregano

oil for R. rubra, the essential oils at concentrations of up to 200 ppm

in recovery media did not interfere with colony formation by unheated

cells. However, some oils, at concentrations as low as 25 ppm in

recovery media, reduced populations of sub lethally heat-stressed cells

compared to populations recovered in media containing no test oils. This

demonstrates that the yeasts were either metabolically or structurally

damaged as a result of being exposed to elevated temperatures and that

essential oils prohibited repair of injury. The size (diameter) of

colonies produced on oil-supplemented recovery agar by heat-stressed

cells was reduced compared to that observed on unsupplemented agar.

Pigment production by heated R. rubra was inhibited by oils of oregano,

savory, and thyme, but enhanced by garlic and onion oils. The influence

of essential oils on survival of yeasts in thermally processed foods and

in the enumeration of stressed cells in these foods should not be

minimized.

 

Study: Antifungal properties of essential oils and their main

components upon Cryptococcus neoformans.

 

Viollon C, Chaumont JP

Laboratory of Botany, Faculty of Medicine and Pharmacy, Besancon,

France.

 

Cryptococcus neoformans opportunistic fungus met in the last phasis of

AIDS is inhibited in vitro by several essential oils on natural volatile

compounds. The minimal inhibitory concentration may reach 100

microliters/l and minimal fungicidal concentration 200 microliters/l

with Palmarosa or Cinnamon oils. Among phenolic compounds, thymol and

carvacrol are most fungi toxic. Terpenoids, citral, geraniol, and

citronellol show best activities.

 

Study: Inhibitory effects of essential oil components on growth of

food contaminating fungi.

Pauli A, Knobloch K

 

The antifungal activity of several components of essential oils were

evaluated using a paper disk method. The substances investigated are

structurally related to eugenol. Equimolar amounts were tested on more

than ten fungal strains known to contaminate food. Iso-eugenol,

cinnamaldehyde, carvacrol, eugenol and thymol revealed the strongest

antifungal activity. The most resistant strain appeared to be

Penicillium verrucosum var. cyclopium, and the most sensitive was P.

viridicatum. Some of the structural effects were considered, including a

free hydroxyl group in connection with an alkyl substituent which seemed

to represent an especially active configuration of phenolic compounds

and which rendered antimicrobial activity.