Origanum and E. coli

[Guest guest]

Beddows CG, Jagait C, Kelly MJ

School of Health Science, Leeds Metropolitan University, UK.

 

The ability of some commercially available herb and spice extracts to

preserve alpha-tocopherol in sunflower oil during heating at 85-105

degrees C was assessed using sunflower oil as a model system. The

Rancimat was evaluated for the heating stage and was used throughout as

it was shown to be viable: alpha-tocopherol did not evaporate under the

test conditions. The delay in the onset of rancidity was found to be

directly related to the initial alpha-tocopherol concentration (P <

0.01). Rosemary, thyme, turmeric, sage, oregano and cumin extracts (2000

mg.kg-1) delayed rancidity (P < 0.01) and preserved alpha-tocopherol (P

< 0.01). Some preservation was observed with clove extract but coriander

and cardamom extracts were pro-oxidants. With thyme extract, the log of

the induction time (as an indicator of the delay in rancidity) was

directly proportional to the temperature (85-100 degrees C). The ethyl

acetate, hexane and methanol extracts of fresh sage were effective for

preserving alpha-tocopherol (P < 0.01). With thyme, rosemary and sage

extracts, the increase in the preservation of alpha-tocopherol was

directly related to the concentration of the herb extract (P < 0.01) and

was quite effective even at 100 mg.kg-1. The increased delay in the

onset of rancidity was due directly to the improved preservation of

alpha-tocopherol (P < 0.01). In further experiments, the preservative

effect of turmeric was shown not to be due to its reported major

antioxidant, curcumin, even though it delayed rancidity. When herb/spice

extracts were examined mixed with thyme, bay and turmeric showed

synergism (P < 0.01) whereas bay alone was

 

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

their fungitoxicity 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 Origanumdictamus

(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.

 

Inhibition of enteric parasites by emulsified oil of oregano in vivo.

 

Force M, Sparks WS, Ronzio RA

 

Health Explorations Trust, Scottsdale, AZ, USA (M.F.) and Biotics

Research Corporation, P.O. Box 36888, Houston, Texas 77236, USA.

 

Oil of Mediterranean oregano Oreganum vulgare was orally administered to

14 adult patients whose stools tested positive for enteric parasites,

Blastocystis hominis, Entamoeba hartmanni and Endolimax nana. After 6

weeks of supplementation with 600 mg emulsified oil of oregano daily,

there was complete disappearance of Entamoeba hartmanni (four cases),

Endolimax nana (one case), and Blastocystis hominis in eight cases.

Also, Blastocystis hominis scores declined in three additional cases.

Gastrointestinal symptoms improved in seven of the 11 patients who had

tested positive for Blastocystis hominis.

 

Antimicrobial agents from plants: antibacterial activity of plant

volatile oils.

 

Dorman HJ, Deans SG

 

Aromatic and Medicinal Plant Group, Scottish Agricultural College,

Auchincruive, South Ayrshire, UK.

 

The volatile oils of black pepper [Piper nigrum L. (Piperaceae)], clove

[syzygium aromaticum (L.) Merr. & Perry (Myrtaceae)], geranium

[Pelargonium graveolens L'Herit (Geraniaceae)], nutmeg [Myristica

fragrans Houtt. (Myristicaceae), oregano [Origanum vulgare ssp. hirtum

(Link) Letsw. (Lamiaceae)] and thyme [Thymus vulgaris L. (Lamiaceae)]

were assessed for antibacterial activity against 25 different genera of

bacteria. These included animal and plant pathogens, food poisoning and

spoilage bacteria. The volatile oils exhibited considerable inhibitory

effects against all the organisms under test while their major

components demonstrated various degrees of growth inhibition.

 

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. khammer

 

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.

 

A predictive model for the non-thermal inactivation of Salmonella

enteritidis in a food model system supplemented with a natural

antimicrobial.

 

Koutsoumanis K, Lambropoulou K, Nychas GJ

 

Agricultural University of Athens, Department of Food Science and

Technology, Greece. gjn

 

Home-made taramasalad, a traditional Greek appetizer, was inoculated

with Salmonella enteritidis supplemented with different concentrations

of oregano essential oil (0.0, 0.5, 1.0, 2.0% v/w) and stored at

different temperatures (5, 10, 15, 20 degrees C). The product's pH was

adjusted from 4.3 to 5.3 with lemon juice. At each combination of the

environmental factors, the bacterial counts were modelled as a function

of time in order to estimate the kinetic parameters of the pathogen. For

comparison, two different models were used. A reduction of Salmonella

enteritidis was observed in all cases and its death rate depended on the

pH, the storage temperature and the essential oil concentration. Death

responses as a function of pH, storage temperature and concentration of

oregano essential oil were described using a quadratic function which

was then used to predict the death of Salmonella enteritidis in

home-made taramasalad of different compositions.

 

Mechanisms of action of carvacrol on the food-borne pathogen Bacillus

cereus.

 

Ultee A, Kets EP, Smid EJ

 

Agrotechnological Research Institute, 6700 AA Wageningen, The

Netherlands. A.Ultee

 

Carvacrol, a naturally occurring compound mainly present in the

essential oil fraction of oregano and thyme, was studied for its effect

on bioenergetic parameters of vegetative cells of the food-borne

pathogen Bacillus cereus. Incubation for 30 min in the presence of 1 to

3 mM carvacrol reduced the viable cell numbers exponentially. Carvacrol

(2 mM) significantly depleted the intracellular ATP pool to values close

to 0 within 7 min. No proportional increase of the extracellular ATP

pool was observed. Depletion of the internal ATP pool was associated

with a change of the membrane potential (Deltapsi). At concentrations of

0.01 mM carvacrol and above, a significant reduction of Deltapsi was

observed, leading to full dissipation of Deltapsi at concentrations of

0.15 mM and higher. Finally, an increase of the permeability of the

cytoplasmic membrane for protons and potassium ions was observed (at

0.25 and 1 mM carvacrol, respectively). From this study, it could be

concluded that carvacrol interacts with the membranes of B. cereus by

changing its permeability for cations like H(+) and K(+). The

dissipation of ion gradients leads to impairment of essential processes

in the cell and finally to cell death.

 

Inhibitory effects of some spice essential oils on Aspergillus ochraceus

NRRL 3174 growth and ochratoxin A production.

 

Basilico MZ, Basilico JC

 

Dpto. Biotechnologia, Facultad Ingenieria Quimica, Universidad Nacional

del Litoral, Santiago del Estero, Santa Fe, Argentina.

 

Inhibitory effects of essential oils of oregano (Origanum vulgare), mint

(Menta arvensis), basil (Ocimum basilicum), sage (Salvia officinalis)

and coriander (Coriandrum sativum), on the mycelial growth and

ochratoxin A production by Aspergillus ochraceus NRRL 3174 were studied.

Cultures were incubated on yeast extract-sucrose (YES) broth, at

concentrations of 0, 500, 750 and 1000 p.p.m. of essential oils during

7, 14 and 21 d at 25 degrees C. At 1000 p.p.m., oregano and mint

completely inhibited the fungal growth and ochratoxin A production up to

21 d, while basil was only effective up to 7 d. At 750 p.p.m., oregano

was completely effective up to 14 d, whereas mint allowed fungal growth

but no ocratoxin A production up to 14 d. At 500 p.p.m., no evident

inhibition could be in observed with any of the essential oils under

analysis. Sage and coriander showed no important effect at any of the

concentrations studied. These inhibitory effects are interesting in

connection with the prevention of mycotoxin contamination in many foods

and they could be used instead of synthetic antifungal products.

 

Estrogen and progestin bioactivity of foods, herbs, and spices.

 

Zava DT, Dollbaum CM, Blen M

 

Aeron Biotechnology, San Leandro, California 94577, USA.

 

In this study we report on the content and bioactivity of plant (phyto)

estrogens and progestins in various foods, herbs, and spices, before and

after human consumption. Over 150 herbs traditionally used by herbalists

for treating a variety of health problems were extracted and tested for

their relative capacity to compete with estradiol and progesterone

binding to intracellular receptors for progesterone (PR) and estradiol

(ER) in intact human breast cancer cells. The six highest ER-binding

herbs that are commonly consumed were soy, licorice, red clover, thyme,

tumeric, hops, and verbena. The six highest PR-binding herbs and spices

commonly consumed were oregano, verbena, tumeric, thyme, red clover and

damiana. Some of the herbs and spices found to contain high

phytoestrogens and phytoprogestins were further tested for bioactivity

based on their ability to regulate cell growth rate in ER (+) and ER (-)

breast cancer cell lines and to induce or inhibit the synthesis of

alkaline phosphatase, an end product of progesterone action, in PR (+)

cells. In general, we found that ER-binding herbal extracts were

agonists, much like estradiol, whereas PR-binding extracts, were neutral

or antagonists. The bioavailability of phytoestrogens and

phytoprogestins in vivo were studied by quantitating the ER-binding and

PR-binding capacity of saliva following consumption of soy milk,

exogenous progesterone, medroxyprogesterone acetate, or wild mexican yam

products containing diosgenin. Soy milk caused a dramatic increase in

saliva ER-binding components without a concomitant rise in estradiol.

Consumption of PR-binding herbs increased the progestin activity of

saliva, but there were marked differences in bioactivity. In summary, we

have demonstrated that many of the commonly consumed foods, herbs, and

spices contain phytoestrogens and phytoprogestins that act as agonists

and antagonists in vivo.

 

Bactericidal activity of carvacrol towards the food-borne pathogen

Bacillus cereus.

 

Ultee A, Gorris LG, Smid EJ

 

Agrotechnological Research Institute (ATO-DLO), Wageningen, The

Netherlands. A.Utec.

 

Carvacrol, a natural plant constituent occurring in oregano and thyme,

was investigated for its bactericidal effect towards the food-borne

pathogen Bacillus cereus. Carvacrol showed a dose-related growth

inhibition of B. cereus. At concentration of 0.75 mmol l-1 and above,

total inhibition of the growth was observed. Below this concentration,

carvacrol extended the lag-phase, reduced the specific growth rate and

reduced the maximum population density. Incubation for 40 min in the

presence of 0.75-3 mmol l-1 carvacrol decreased the number of viable

cells of B. cereus exponentially. Spores were found to be approximately

2-3 fold less sensitive to carvacrol than vegetative cells. Bacillus

cereus cells showed reduced susceptibility towards carvacrol at pH 7.0

compared with different values between pH 4.5 and 8.5. The culture and

exposure temperatures had a significant influence on the survival of

vegetative cells. The highest death rate of cells was observed at an

exposure temperature of 30 degrees C. Membrane fluidity was found to be

an important factor influencing the bactericidal activity of carvacrol.

 

Development and Evaluation of a Model Predicting the Survival of

Escherichia coli O157:H7 NCTC 12900 in Homemade Eggplant Salad at

Various Temperatures, pHs, and Oregano Essential Oil Concentrations

 

Panagiotis N. Skandamis and George-John E. Nychas*

 

Department of Food Science and Technology, Laboratory of Microbiology

and Biotechnology of Foods, Agricultural University of Athens, Athens

11855, Greece

Received 9 August 1999/Accepted 27 January 2000

Homemade eggplant salad, a traditional Greek appetizer, was inoculated

with Escherichia coli O157:H7 NCTC 12900 supplemented with different

concentrations of oregano essential oil (0.0, 0.7, 1.4, and 2.1%

[vol/wt]) and stored at different temperatures (0, 5, 10, and 15°C). The

product's pH was adjusted to 4.0, 4.5, or 5.0 with lemon juice. For each

combination of the environmental factors, the bacterial counts were

modeled, using the Baranyi model, as a function of time to estimate the

kinetic parameters of the pathogen. A reduction of more than 1 log unit

in E. coli O157:H7 counts was observed in all cases, and the death rate

depended on the pH, the storage temperature, and the essential oil

concentration. Separate quadratic models were developed with natural

logarithms of the shoulder period and death rate as estimated by the

growth model, as a function of temperature, pH, and oregano essential

oil concentrations. These were further used to predict the population of

E. coli O157:H7 NCTC 12900 from other inoculated eggplant salads at

random conditions of temperature, pH, and oregano oil concentration. The

predicted values were compared with viable-count measurements for

validation.

 

Nutrient antioxidants in oregano.

 

Lagouri V, Boskou D

 

Laboratory of Food Chemistry and Technology, Faculty of Chemistry,

Aristotle University, Thessaloniki, Greece.

 

Oregano and its various extracts have been studied as inhibitors of

autoxidation but so far the research work has focused mainly on the

polar non nutrient compounds. Very little is known about the non polar

fraction extracted by hexane which is also antioxidant and has been

reported to suppress the mutagenicity of Trp-P-2, a dietary carcinogen.

In this work four different species of oregano, Origanum vulgare subsp.

hirtum, Satureja thymbra, Origanum dictamnus and Origanum onites, were

extracted with hexane. The extracts were saponified and in the

unsaponifiable fraction thin layer chromatography and high performance

liquid chromatography were applied for the isolation, detection and

determination of tocopherols. The four known homologues of tocopherol,

alpha-, beta-, gamma- and delta-, were found to be present in all the

samples but the concentration of the gamma-homologue was significantly

higher. Total tocopherol content ranged from 288 ppm to 672 ppm.

 

Labiatae allergy: systemic reactions due to ingestion of oregano and

thyme.

 

Benito M, Jorro G, Morales C, Pelaez A, Fernandez A

 

Servicio de Alergia, Hospital Clinic Universitari, Valencia, Spain.

 

BACKGROUND: There are no cases described in the medical literature of

systemic allergic reactions due to oregano (Origanum vulgare) or thyme

(Thymus vulgaris). These herbs belong to the Lamiaceae (Labiatae) family

which comprises other plants such as hyssop (Hyssopus officinalis),

basil (Ocimum basilicum), marjoram (Origanum majorana), mint (Mentha

piperita), sage (Salvia officinalis) and lavender (Lavandula

officinalis). OBJECTIVE: We describe three systemic allergic reactions

caused by oregano and thyme in the same patient. METHODS: Skin tests

with inhalant allergens and plants of the Labiatae family were done. We

used the prick by prick technique with dried commercial plants and prick

tests with extracts prepared with the Frugoni method in our patient and

in ten control patients. Total serum IgE was determined by Phadezym IgE

PRIST (Pharmacia). Specific IgE was measured by two methods: CAP system

(Pharmacia) and Phadezym RAST (Pharmacia Diagnostics, Uppsala, Sweden)

with activated discs of the allergenic extracts that were prepared in

our laboratory. RESULTS: Skin tests with inhalants were positive to

grasses. Skin tests with plants of the Labiatae family were positive in

all cases when the skin prick technique was used; tests were negative

with basil and lavender, and positive with all the others when we used

the prick by prick technique. We did not detect any positive skin tests

nor specific IgE to plants of the Labiatae family in control patients.

Total serum IgE was 406 U/mL. Specific IgE was detected to all herbs

tested; higher levels were obtained with the CAP system. CONCLUSIONS:

Plants belonging to the Labiatae family seem to show cross-sensitivity

on the basis of clinical history and in vitro and in vivo test results.

 

[Factors which modify the nutritional state of iron: tannin content of

herbal teas].

 

Pizarro F, Olivares M, Hertrampf E, Walter T

 

Unidad de Hematologia, Universidad de Chile, Santiago.

 

Tannins are natural compounds that abound in herbs, wood and fruits.

Their numerous hydroxyl radicals confer them a strong avidity for metals

such as Fe, Zn and Cu. This property makes them strong inhibitors for

the gastrointestinal absorption of these metals. Our purpose was to

determine the tannin content of herbal infusions commonly consumed in

Chile and other Latino American countries. The determination was

performed from dessicated herbs with the Folin-Denis technique. Yerba

mate, tea and oregano had the highest tannin content (117, 100 and 84 mg

of tannic acid/g dry herb respectively). An intermediate level (between

20 and 40 of tannic acid/g) was for coca, matico, boldo, palto, laurel,

orange and binojo. The lowest level of tannin for paico, cedron, apio

and manzanilla (< 10 mg/g). We conclude that the consumption of herbal

teas at or around meals may inhibit the absorption of metals such as Fe,

Zn, or Cu by decreasing their bioavailability.

 

[in vitro effect against Giardia of 14 plant extracts].

 

Ponce-Macotela M, Navarro-Alegria I, Martinez-Gordillo MN,

Alvarez-Chacon R

 

Laboratorio de Investigacion en Parasitologia, Instituto Nacional de

Pediatia SSA. Mexico, D.F.

 

OBJECTIVE. To investigate antigiardiasic activity in plants used in

Mexico as antidiarrheics and/or antiparasitics. MATERIALS AND METHODS.

Fourteen species were evaluated. The antigiardiasic activity was

measured in vitro in a blinded fashion using trophozoites of Giardia

duodenalis incubated with plant extracts. The viability of trophozoites

was ascertained using MTT (3-[4,5-dimethylthiazol-2-il]-2, 5-diphenyl

tetrazolium bromide) which is reduced to MTT-formazan by the activity of

live trophozoites. The reduced MTT was extracted with an acidified

alcohol (2-propanol with HCI 0.04 M) and measured in a spectrophotometer

at 570 nm. Negative (trophozoites without extract) and positive controls

(incubated with tinadazol) were included. RESULTS. The scientific and

trivial names of the plants are given (trivials in Spanish marked by an

asterisk). They had the following trophozoite mortality (mean +/- SD in

percent): Justicia spicigera (muicle*) = 91 +/- 0.5; Lipia beriandieri

(oregano) = 90 +/- 0.6; Psidium guajava (guava) = 87 +/- 1.0; positive

control of tinidazol = 79 +/- 1.9; Punica granutus (granado*) = 78 +/-

1.3; Magnifera indica (mango) = 77 +/- 1.0; Plantago major (lante*) = 76

+/- 1.2; Cupressus semperbirens (cipres) = 73 +/- 1.2; Castella

tormentosa (chaparro amargoso*) = 70 +/- 0.7; Hematoxilon campechanum

(palo de Campeche*) = 67 +/- 1.2. Without or with a low mean activity

were Prosopis juliflora (mesquite*) and Rizophora mangle (mangle*) with

0%, Oriza sativa (rice) with 5%, Capsicum annum (pimiento*) with 21% and

Persea americana (avocado) with 23%. There were no associations of the

antigiardiasic effect with concentration or osmolality of the extracts.

CONCLUSIONS. A clear in vitro antigiardiasic effects was seen in nine

species. Three of them were superior to tinidazol which is a drug of

common use in the treatment of giardiasis.

 

Inhibition of growth and aflatoxin production in Aspergillus parasiticus

by essential oils of selected plant materials.

 

Tantaoui-Elaraki A, Beraoud L

 

Department of Food Microbiology and Biotechnology, Hassan II Institute

for Agriculture and Veterinary Medicine, Rabat-Instituts, Morocco.

 

We studied the effect of 13 chemically different essential oils (EO) on

the mycelial growth of and aflatoxin synthesis by Aspergillus

parasiticus. Cinnamon, thyme, oregano, and cumin EO were able to stop

mycelial growth at only 0.1% in the medium, while curcumin, ginger,

lemon, and orange EO were unable to inhibit totally the growth even at

1% concentration. Coriander, black pepper, mugwort, bay, and rosemary EO

caused the growth to stop at concentrations between 0.2 and 1%. The EO

most active upon mycelial growth were also the most active against

aflatoxinogenesis. However, aflatoxin synthesis was inhibited by all the

EO at higher extent than the mycelial growth.

 

Spice allergy evaluated by results of patch tests.

 

Futrell JM, Rietschel RL

 

Department of Dermatology, Ochsner Clinic, New Orleans, Louisiana 70121.

 

Allergic contact dermatitis caused by spices is well documented;

however, commercial patch tests are unavailable. Between October, 1991,

and August, 1992, a series of fifty-five patients with suspected contact

dermatitis were tested at Ochsner Clinic for sensitivity to a group of

spices at concentrations of 10 percent and 25 percent in petrolatum.

Concordant patch test results (positive at concentrations of 10 percent

and 25 percent) were most common with ginger (seven), nutmeg(five), and

oregano (four); the remaining spices produced zero or one positive

responses. Patients exhibiting positive reactions at only one

concentration were more likely to do so at 25 percent: nutmeg (five),

ginger and cayenne (four), curry, cumin, and cinnamon (three), turmeric,

coriander, and sage (two), oregano (one), and basil and clove (zero).

Solo responses at this level may represent a threshold for detecting

true allergy or, as an alternative, a marginal irritant reaction. Those

responding to only 10 percent concentrations generally did so weakly.

Three patients were deemed to have relevant patch test responses to

spices.

 

Inhibition of antibacterial activity of essential oils by tween 80 and

ethanol in liquid medium.

 

Remmal A, Bouchikhi T, Tantaoui-Elaraki A, Ettayebi M

 

Biotechnology Laboratory, Faculty of Sciences, Fes Morocco.

 

The emulsifying agents used to disperse essential oils in culture media

can interfere in the estimation of essential oils antimicrobial

activity; we showed in this study that 0.2% Agar suspension was

sufficient to obtain a stable dispersion of oregano and clove essential

oils in liquid media comparable to the dispersions obtained with tween

80 (0.25%) or ethanol (0.2%). The dispersion with agar was as homogenous

as a true solution in absolute ethanol. Furthermore, minimal inhibitory

concentration and minimal lethal concentration for different bacterial

species in presence of agar were significantly lower than those observed

in presence of tween 80 or ethanol. This demonstrates the fact that

solvents and detergents often used in antimicrobial studies

significantly decreases the antibacterial activity of essential oils.

 

Inhibitory and stimulatory effects of cumin, oregano and their essential

oils on growth and acid production of Lactobacillus plantarum and

Leuconostoc mesenteroides.

 

Kivanc M, Akgul A, Dogan A

 

Biology Department, Faculty of Sciences and Arts, Anadolu University,

Eskisehir, Turkey.

 

Cumin at concentrations of 0.5, 1.0 and 2.0% (w/w) stimulated growth and

acid production of Lactobacillus plantarum and Leuconostoc mesenteroides

in a liquid medium. Essential oil from cumin at high concentrations (300

and 600 ppm) inhibited growth and acid production of Lactobacillus

plantarum. After a certain period, growth of Leuconostoc mesenteroides

was observed at all concentrations (150, 300 and 600 ppm) and its acid

production was stimulated at 600 ppm. Oregano and its essential oil at

all concentrations inhibited growth of both cultures. Acid production by

Lactobacillus plantarum was stimulated by oregano spice.

 

Iron absorption and phenolic compounds: importance of different phenolic

structures.

 

Brune M, Rossander L, Hallberg L

 

Department of Medicine II, University of Goteborg, Sweden.

 

The phenolic compounds (phenolic monomers, polyphenols, tannins) are

considered to interfere with iron absorption by complex formation with

iron in the gastro-intestinal lumen, making the iron less available for

absorption. Very little is known about the extent to which different

types of phenolic compounds of different size and chemical structure

inhibit iron absorption. The relationship between iron absorption and

the amount and type of phenolic compounds was studied by the extrinsic

tag method. The aims of the studies were as follows: (i) To study the

effect of small phenolic compounds with different hydroxylation patterns

(gallic acid, catechin, chlorogenic acid) on iron absorption, (ii) To

study the effect of different amounts of a hydrolysable tannin

containing ten gallic acid residues (tannic acid) on iron absorption.

(iii) To study the degree of inhibition of iron absorption by some foods

and beverages (oregano, spinach, coffee and tea) in relation to their

respective content of iron-binding phenolic groups, measured by a newly

developed method. The inhibition of iron absorption by tannic acid was

strongly dose-related. The smallest amount (5 mg) inhibited absorption

by 20 per cent, 25 mg by 67 per cent and 100 mg by 88 per cent. Gallic

acid inhibited iron absorption to the same extent as tannic acid, per

mol galloyl groups, whereas no inhibition was observed when catechin was

added to the test meal. Chlorogenic acid inhibited iron absorption to a

lesser extent. Oregano and tea inhibited iron absorption in proportion

to their respective content of galloyl groups, whereas the inhibitory

effect of spinach was less marked. The inhibiting effect of coffee was

explained mainly by its content of galloyl groups, but also by some

other factor, probably chlorogenic acid. It is concluded that the

content of iron-binding galloyl groups might be a major determinant of

the inhibitory effect of phenolic compounds on iron absorption from the

diet, whereas the phenolic catechol groups seem to be of minor

importance. The results further suggest that the group of condensed

tannins do not interfere with iron absorption.

 

Inhibitory effects of selected Turkish spices and oregano components on

some foodborne 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 foodborne 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.

 

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 sublethally 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 sublethally 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.

 

Molluscicidal activity of some Moroccan medicinal plants.

 

Hmamouchi M, Lahlou M, Agoumi A

 

Unite de recherche: Substances Naturelles, Faculte de Medecine et de

Pharmacie, Rabat, B.P. 6203, Rabat-Institut, Maroc

 

Among 14 plants of Moroccan folk medicine tested for molluscicidal

activity, ethyl acetate extract from Origanum compactum and hexane

extracts from both Chenopodium ambrosioides and Ruta chalepensis were

the most active (LC(90)=2.00, 2.23 and 2.23 mg l(-1), respectively)

against the schistosomiasis-transmitting snail Bulinus truncatus.

 

Evaluation of the long-term effects of oleum origani on the toxicity

induced by administration of streptozotocin in rats.

 

Lermioglu F, Bagci S, Onderoglu S, Ortac R, Tugrul L

 

Ege University, Faculty of Pharmacy, Department of Toxicology, Turkey.

lermiogluf

 

Oleum origani, the essential oil of Origanum onites L., is a traditional

plant material used in Turkey for the treatment of several diseases,

including diabetes mellitus. This study has evaluated the effect of

oleum origani on streptozotocin-induced tissue injury and haematological

changes. The effect of oleum origani on glycaemia was also studied.

Long-term administration of oleum origani resulted in significant

improvement of tissue injury induced by streptozotocin treatment. No

effect on blood glucose levels was detected. In addition, any visible

toxicity or disturbance of haematological parameters and tissue

structure attributable to the long-term use of oleum origani were not

established in normal rats. The data indicate that long-term use of

oleum origani might be effective in preventing or at least in retarding

the development of some complications of diabetes mellitus. Further

investigation is required to determine the underlying mechanism(s) of

the protective effect against tissue injury induced by

streptozotocin-treatment of rats.

 

Plants used for the treatment of diabetes in Israel.

 

Yaniv Z, Dafni A, Friedman J, Palevitch D

 

In an extensive ethnobotanical survey (130 informants) of the medicinal

plants of Israel, 16 species were found to be used for hypoglycaemic

treatments. The list includes Achillea fragrantissima (Forssk.)

Sch.-Bip, Ammi visnaga (L.) Lam, Atriplex halimus L., Capparis spinosa

L., Ceratonia siliqua L., Cleome droserifolia (Forssk.) Del., Eryngium

creticum Lam., Inula viscosa (L.) Ait., Matricaria aurea (Loefl.)

Sch.-Bip, Origanum syriaca L., Paronychia argentea Lam, Prosopis farcta

(Banks et Sol.) Macbride, Salvia fruticosa Mill., Sarcopoterium spinosum

(L.) Sp., and Teucrium polium L.; eight of them (marked with an

asterisk) are first recorded here as used for this purpose.

 

Effect of volatile substances from Origanum majorana and Ocimum

basilicum on spore respiration and germination of some soil fungi.

 

Afifi AF, Dowidar AE

 

Oxygen uptake by the spores of Fusarium moniliforme, F. oxysporum, F.

semitectum, F. solani, Mucor racemosus and Trichoderma viride was

increased in the presence of volatile substances extracted from Origanum

majorana and Ocimum basilicum. This increase was greater in the presence

of volatile substances from O. basilicum than O. majorana, except in the

case of F. semitectum where the reverse was true. A drop in the RQ of

all the germinating spores was observed in the presence of these

substances. Volatile substances from O. majorana reduced the spore

germination of M. racemosus whereas the spores of T. viride were

stimulated to germinate. Volatile substances from O. basilicum

stimulated the spore germination of M. racemosus whereas T. viride

spores were not affected.

 

Effects of some growth hormones on plant vigour and volatile oil of

Origanum majorana L.

 

El-Antably HM, Ahmed SS, Eid MN

 

Origanum majorana L. treated with either 50 or 100 mg/l of maleic

hydrazide (MH), 2.4-dichlorophenoxy acetic acid (2.4-D),

N-dimethylaminosuccinamic acid (B995), [2-chloroethyl]-trimethyl

ammonium chloride (CCC), indol-3-yl-acetic acid (IAA) or gibberellic

acid (GA3) in the presence or absence of 25 mg/l kinetin, showed that

only 100 mg/l GA3 with or without kinetin was able to increase plant

height than all other treatments and the controls. On the other hand,

both IAA and GA3 concentrations and 2000 mg/l CCC markedly increased the

dry weight of the plants in the absence of kinetin, whereas when kinetin

was combined, only IAA in both concentrations increased the dry weight

of the whole plants. Concerning essential oil %, the highest yields were

obtained using 100 mg/l MH, 50 mg/l 2.4-D and 2000 mg/l CCC for leaves

and 100 mg/l MH, 1000 mg/l B995 and 50 mg/l 2.4-D for flowers in the

absence of kinetin, whereas in the presence of kinetin, the higher

yields of essential oil were obtained by using 1000 mg/l B995 and 25

mg/l 2.4-D for flowers and only 50 mg/l 2.4-D for leaves.

 

Inhibition of oxidation of human low-density lipoproteins by phenolic

substances in different essential oils varieties

 

Teissedre PL, Waterhouse AL

 

Universite de Montpellier I, Faculte de Pharmacie, Centre de Formation

et de Recherche en Oenologie, Av. Charles Flahault, 34060 Montpellier

Cedex 2, France, and Department of Viticulture and Enology, University

of California, Davis, Cali.

 

Phenolics antioxidant phytochemicals have been recently implicated for

the lower rates of cardiac disease mortality among people consuming a

Mediterranean diet. Essential oils are natural products extracted from

vegetable materials, which can be used as antibacterial, antifungal,

antioxidants, and anti-carcinogenic agents or to preserve and give

specific flavors to foods. The activities of 23 selected essential oils

in inhibiting the copper-catalyzed oxidation of human-low-density

lipoproteins (LDL) were determined in vitro. LDL oxidation was inhibited

between 6, 2, and 83% by 2 & mgr;M (GAE) total phenolics. The relative

inhibition of LDL oxidation was used to categorize the essential oils

into four groups below 2% when they contained methylchavicol, anethol,

p-cymen, apiole, cinnamic ether; 6-10% if they possessed a majority of

carvacrol, thymol, p-cymene, or vanillin; 10-50% for moderate amounts of

thymol, carvacrol, cuminol, or eugenol; and 50-100% when eugenol is the

major component. Total phenol content of essential oils gave a

correlation with LDL antioxidant activity of r = 0.75. The Activity of

each phenolics compound could play a role in protecting LDL against

oxidation if the substance is absorbed by the body.

 

Antimicrobial activity of carvacrol toward Bacillus cereus on rice.

 

Ultee A, Slump RA, Steging G, Smid EJ

 

Agrotechnological Research Institute (ATO-DLO), Wageningen, The

Netherlands. A.Ultee

 

The antimicrobial activity of carvacrol, a compound present in the

essential oil fraction of oreganum and thyme, toward the foodborne

pathogen Bacillus cereus on rice was studied. Carvacrol showed a

dose-related inhibition of growth of the pathogen. Concentrations of

0.15 mg/g and higher inhibited the growth and the extent of inhibition

depended on the initial inoculum size. To decrease the input of

carvacrol on the taste and flavor of the product, a combined treatment

with the structure analog cymene was tested. Due to the smell and taste

of carvacrol at high concentrations, carvacrol was combined with cymene,

a natural antimicrobial compound with a similar structure. A synergistic

effect was observed when 0.30 mg/g carvacrol was combined with 0.27 mg/g

cymene. Finally it was demonstrated that a common taste enhancer like

soya sauce also increased the antimicrobial action of carvacrol toward

B. cereus. The antimicrobial activity of carvacrol with cymene or soya

sauce was influenced by the addition of NaCl.

 

Botanical biocides. 4. Mosquitocidal activity of certain Thymus

capitatus constituents.

 

Mansour SA, Messeha SS, el-Gengaihi SE

 

Pesticide Chemistry Department, National Research Centre, Dokki, Cairo,

Egypt.

 

Successive extraction of Thyme plant, Thymus capitatus (L.) Hoffm. and

Link (Lamiaceae), by different solvents of increasing polarity, showed

that potency was highly attributed to the non-polar fraction (e.g.,

petroleum ether) when tests were carried out against the larvae and

adults of Culex pipiens (L). Of special concern to the mosquitocidal

activity, the following fractions and isolates were recognized: the

volatile oil, unsaponifiable portion, and certain compounds isolated

from the unsaponifiable portion (e.g., Thymol, alpha-Amyrin, Carvacrol +

beta-Caryophyllene). The volatile oil, Thymol, and the unsaponifiable

portion proved high larvicidal potency against the tested insect (LC50 =

49.0, 58.0, and 100.0 ppm, respectively). Non-lethal concentrations of

these substances synergized the toxicity of Malathion, while induced

additive or antagonistic effects when mixed with Permethrin or

Pirimiphos-methyl. The unsaponifiable portion and volatile oil showed

the highest adulticidal potency (LC50 = 0.0070 and 0.0076 mg/cm2,

respectively). The efficacy of the tested candidates as repellent agents

was found in the following order: unsaponifiable portion > alpha-Amyrin

> Thymol > volatile oil > Carvacrol + beta-Caryophyllene. Thymol as well as

volatile oil

affected egg hatchability, causing Sterility Indices accounting for 0.70

and 0.74,

respectively, while the unsaponifiable portion showed lower degree of

sterility (0.81). The

results obtained in this study may shed light on the importance of T.

capitatus as a probable

source of some biologically active agents for mosquito control in the

future.

 

Effect of menthol and related terpenes on the percutaneous absorption of

propranolol across excised hairless mouse skin.

 

Kunta JR, Goskonda VR, Brotherton HO, Khan MA, Reddy IK

 

Division of Basic Pharmaceutical Sciences, Northeast Louisiana

University, Monroe 71209, USA.

 

The potential use of terpenes/terpenoids as penetration enhancers in the

transdermal delivery of propranolol hydrochloride (PL) was investigated.

PL was chosen for the reasons of its extensive first-pass metabolism and

short elimination half-life. The terpenes studied included L-menthol,

(+)-limonene, (+/-)-linalool, and carvacrol at 1%, 5%, and 10% w/v

concentrations. The diffusion of PL across excised hairless mouse skin

was determined using side-by-side diffusion cells. Flux, permeability

coefficient (Pm), and lag time (tL) were calculated. PL showed

comparable lag times with menthol at all three concentration levels. At

a 1% level of carvacrol, PL exhibited a 2.4- and 2.2-fold increase in

lag time compared with 5 and 10% levels of enhancer, respectively. In

the presence of limonene, PL had shown maximum lag time (between 3.0 and

3.3 h) at all three levels. In the case of linalool, the lag times for

PL with 5 and 10% levels of enhancer were 7.0- and 5.2-fold less

compared with 1% level. A significant (p < 0.05) concentration effect

was observed only with linalool. Hydrogel-based patches were formulated

with or without menthol as enhancer. Release profiles from the hydrogel

formulations obeyed zero-order kinetics. The permeability of propranolol

was significantly higher (p < 0.05) from the test patch than the control

(no enhancer) patch across the mouse skin. The mechanism of permeation

enhancement of menthol could involve its distribution preferentially

into the intercellular spaces of stratum corneum and the possible

reversible disruption of the intercellular lipid domain. The results

suggest the potential use of menthol as effective penetration enhancer

in the delivery of significant amounts of PL through skin.

 

Induction of geranyl pyrophosphate pyrophosphatase activity by

cholesterol-suppressive isoprenoids.

 

Case GL, He L, Mo H, Elson CE

 

Department of Nutritional Sciences, University of Wisconsin, Madison

53706, USA.

 

Diets supplemented (1 mmol/kg) with thymol, carvacrol, and beta-ionone

significantly decreased the serum cholesterol levels of cockerels. These

mevalonate-derived end products of plant secondary metabolism

(isoprenoids) had no impact on two cytosolic prenyl alcohol (and

ethanol) dehydrogenase activities; each treatment increased microsomal

geranyl pyrophosphate pyrophosphatase activity by greater than twofold.

The structural diversity of the isoprenoids which suppress cholesterol

synthesis may be reconciled by their ability to increase pyrophosphatase

activity, thus leading to the production of the endogenous,

post-transcriptional regulator of 3-hydroxy-3-methylglutaryl coenzyme A

reductase activity.

 

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 fungitoxic. Terpenoids, citral, geraniol, and

citronellol show best activities.

 

Insecticidal properties of several monoterpenoids to the house fly

(Diptera: Muscidae), red flour beetle (Coleoptera: Tenebrionidae), and

southern corn rootworm (Coleoptera: Chrysomelidae).

 

Rice PJ, Coats JR

 

Department of Entomology, Iowa State University, Ames 50011.

 

House flies, Musca domestica (L.), and their eggs were treated with 22

monoterpenoids to determine the topical, fumigant, and ovicidal activity

of each compound. Fumigant activity of 14 monoterpenoids were examined

further using red flour beetles, Tribolium castaneum (Herbst).

Third-instar southern corn rootworm, Diabrotica undecimpunctata howardi

Barber, were treated with carvacrol, citral, citronellal, menthol,

pulegone, verbenol, and verbenone to determine their activity on larvae.

Structure-activity relationships were evaluated with the toxicity data.

We made comparisons between monocyclic aromatic, acyclic aliphatic,

monocyclic aliphatic, and bicyclic aliphatic alcohols, ketones,

aldehydes, and acids to determine toxicity differences involving the

skeletal structure, amount of saturation, and associated functional

groups of monoterapenoids. Ketones were more effective than alcohols in

the topical, fumigant (T. castaneum), and ovicidal bioassays and less

toxic than an analogous aldehyde in the topical, fumigant (M.

domestica), and ovicidal bioassays. Aldehydes were more toxic than

alcohols in the topical and fumigant (M. domestica) bioassays. In the

topical and ovicidal bioassays, aromatic or acyclic alcohols, or both,

were more effective than monocyclic and bicyclic alcohols. Vapors of

bicyclic ketones were more toxic than monocyclic ketones to adult M.

domestica. Monoterpenoid alcohols containing three carbon-carbon double

bonds were more effective than saturated alcohols in the topical and

larval bioassays. A mono-unsaturated ketone was more toxic than a

structurally similar saturated ketone and two di-unsaturated ketones

when it was applied topically to adult M. domestica. A saturated

monocyclic ketone inhibited egg hatch more effectively than unsaturated

monocyclic ketones.

 

[Antibacterial activity of thymol, carvacrol and cinnamaldehyde alone or

in combination].

 

Didry N, Dubreuil L, Pinkas M

 

Laboratoires de Pharmacognosie, Faculte des Sciences pharmaceutiques et

biologiques, Lille, France.

 

The antimicrobial activity of thymol, carvacrol and cinnamaldehyde was

tested by several methods on bacteria involved in upper respiratory

tract infections. Their combinations were investigated too. The broad

spectrum of activity and the synergistic effect observed with some

combinations (specially thymol and carvacrol) could allowed the use of

the three compounds alone or, like thymol an carvacrol, combined during

the treatment of respiratory infections.

 

Activity of thymol, carvacrol, cinnamaldehyde and eugenol on oral

bacteria.

 

Didry N, Dubreuil L, Pinkas M

 

Laboratoire de Matiere medicale, Faculte des Sciences Pharmaceutiques et

Biologiques, Lille, France.

 

The antimicrobial activity of thymol, carvacrol, cinnamaldehyde and

eugenol alone or combined was tested by micromethods on eight oral

bacteria. The compounds showed an inhibitory activity on seven

microorganisms and a synergistic effect was observed with certain

combinations. The four compounds can be used alone or combined, as

eugenol and thymol, eugenol and carvacrol, thymol and carvacrol, during

the treatment of oral infectious diseases.

 

Antioxidant actions of thymol, carvacrol, 6-gingerol, zingerone and

hydroxytyrosol.

 

Aeschbach R, Loliger J, Scott BC, Murcia A, Butler J, Halliwell B,

Aruoma OI

 

Centre de Recherche, Nestec SA, Vers-Chez-les-Blanc, Lausanne,

Switzerland.

 

Antioxidants minimize oxidation of the lipid components in foods. There

is an increasing interest in the use of natural and/or synthetic

antioxidants in food preservation, but it is important to evaluate such

compounds fully for both antioxidant and pro-oxidant properties. The

properties of thymol, carvacrol, 6-ginerol, hydroxytyrosol and zingerone

were characterized in detail. Thymol, carvacrol, 6-gingerol and

hydroxytyrosol decreased peroxidation of phospholipid liposomes in the

presence of iron(III) and ascorbate, but zingerone had only a weak

inhibitory effect on the system. The compounds were good scavengers of

peroxyl radicals (CCl3O2; calculated rate constants > 10(6) M-1 sec-1)

generated by pulse radiolysis. Thymol, carvacrol, 6-gingerol and

zingerone were not able to accelerate DNA damage in the

bleomycin-Fe(III) system. Hydroxytyrosol promoted deoxyribose damage in

the deoxyribose assay and also promoted DNA damage in the

bleomycin-Fe(III) system. This promotion was inhibited strongly in the

deoxyribose assay by the addition of bovine serum albumin to the

reaction mixtures. Our data suggest that thymol, carvacrol and

6-gingerol possess useful antioxidant properties and may become

important in the search for 'natural' replacements for 'synthetic'

antioxidant food

 

Factors that interact with the antibacterial action of thyme essential

oil and its active constituents.

 

Juven BJ, Kanner J, Schved F, Weisslowicz H

 

Institute of Technology and Storage of Agricultural Products, Volcani

Centre, Bet Dagan, Israel.

 

The viable counts of Salmonella typhimurium on nutrient agar (NA)

decreased upon the addition of either the essential oil of thyme or its

constituent thymol, especially under anaerobic conditions. Antagonistic

effects of thymol against Staphylococcus aureus were also greater under

anaerobic conditions. In contrast to the phenolic constituents of the

oil, thymol and carvacrol, the chemically related terpenes p-cymene and

gamma-terpinene had no antagonistic effects against Salm. typhimurium.

The addition of Desferal to NA counteracted the antibacterial effects of

both thyme oil and thymol. No support was obtained, however, for a

possible role of iron in the oxygen-related antibacterial action of the

thyme oil and thymol or for the observed effect of Desferal. In the

presence of thymol, the viable counts of Salm. typhimurium obtained on a

minimal medium (MM) were lower than those obtained on NA. Addition of

bovine serum albumin (BSA) neutralized the antibacterial action of

thymol. It is suggested that the effects of BSA or Desferal are due to

their ability to bind phenolic compounds through their amino and

hydroxylamine groups, respectively, thus preventing complexation

reactions between the oil phenolic constituents and bacterial membrane

proteins. This hypothesis is supported by the marked decrease in the

viable counts of Salm. typhimurium caused by either thyme oil or thymol

when the pH of the medium was changed from 6.5 to 5.5 or the

concentration of Tween 80 in the medium was reduced.

 

 

Studies of the antibacterial activity of plant extracts and their

constituents against periodontopathic bacteria.

 

Osawa K, Matsumoto T, Maruyama T, Takiguchi T, Okuda K, Takazoe I

 

Department of Microbiology, Tokyo Dental College.

 

Plant extracts and their constituents were tested for antibacterial

activity against periodontopathic bacteria, including Actinobacillus,

Capnocytophaga, Fusobacterium, Eikenella and Bacteroides species. The

essential oils of two labiatae plants, Mosla chinensis Maxim. and

Pogostemon cablin Benth., and five terpenoids, hinokitiol, thymol,

carvacrol, patchoulialcohol and pogostone, showed antibacterial

activity. The terpenoids were especially effective against Bacteroides

species.

 

 

Metabolism in rats of p-cymene derivatives: carvacrol and thymol.

 

Austgulen LT, Solheim E, Scheline RR

 

Department of Pharmacology and Toxicology, School of Medicine,

University of Bergen, Norway.

 

The metabolism of carvacrol and thymol in rats was studied using gas

chromatographic-mass spectrometric methods. The urinary excretion of

metabolites was rapid. Only very small amounts were excreted after 24

hrs. Although large quantities of carvacrol and, especially, thymol were

excreted unchanged (or as their glucuronide and sulphate conjugates),

extensive oxidation of the methyl and isopropyl groups also occurred.

This resulted in the formation of derivatives of benzyl alcohol and

2-phenylpropanol and their corresponding carboxylic acids. In contrast,

ring hydroxylation of the two phenols was a minor reaction.

 

p-Cymene metabolism in rats and guinea-pigs.

 

Walde A, Ve B, Scheline RR, Monge P

 

The metabolism of p-cymene was studied in rats and guinea-pigs.

Following intragastric or inhalation dosage (100 mg/kg) urinary

metabolite excretion was nearly complete within 48 h, amounting to

60-80% dose. The inhalation experiments gave the lowest values. 18

urinary metabolites were detected and identified. Of these, rats did not

excrete two and guinea-pigs did not excrete a third. No

ring-hydroxylation of p-cymene was detected in rats, but guinea-pigs

formed small amounts of carvacrol and hydroxycarvacrol. Oxidation of

both the methyl and isopropyl groups of p-cymene occurred extensively in

both species. The following types of metabolites were formed: monohydric

alcohols, diols, mono- and di-carboxylic acids and hydroxyacids.

Conjugation with glycine of the cumic acid formed was extensive in

guinea-pigs.

 

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.