To: oils_herbs_etc@yahoogroups.com
From: Butch Owen <butchbsi@...>
Date: Sun, 06 Jun 2004 19:58:16 -0700
Subject: [oils_herbs_etc] Origanum and E. coli


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.