Biological effects of essential oils--a review.

Since the middle ages, essential oils have been widely used for bactericidal, virucidal, fungicidal, antiparasitical, insecticidal, medicinal and cosmetic applications, especially nowadays in pharmaceutical, sanitary, cosmetic, agricultural and food industries. Because of the mode of extraction, mostly by distillation from aromatic plants, they contain a variety of volatile molecules such as terpenes and terpenoids, phenol-derived aromatic components and aliphatic components. In vitro physicochemical assays characterise most of them as antioxidants. However, recent work shows that in eukaryotic cells, essential oils can act as prooxidants affecting inner cell membranes and organelles such as mitochondria. Depending on type and concentration, they exhibit cytotoxic effects on living cells but are usually non-genotoxic. In some cases, changes in intracellular redox potential and mitochondrial dysfunction induced by essential oils can be associated with their capacity to exert antigenotoxic effects. These findings suggest that, at least in part, the encountered beneficial effects of essential oils are due to prooxidant effects on the cellular level.

Investigation of the mutagenic and antimutagenic effects of Origanum compactum essential oil and some of its constituents.

In the present study, the chemical composition of Origanum compactum essential oil was determined by gas chromatography and mass spectrometry, and its mutagenic and antimutagenic activities were investigated by the somatic mutation and recombination test (SMART) in Drosophila melanogaster. No significant increase in the number of somatic mutations was observed with the essential oil tested using both the standard (ST) and high bio-activation (HB) cross. In order to investigate the antimutagenic effect of the essential oil, we have tested the effect on the indirect-acting mutagen urethane (URE), as well as the direct-acting mutagen methyl methanesulfonate (MMS). O. compactum essential oil showed a strong inhibitory effect against URE-induced mutagenicity, especially with the HB cross. However, only a weak inhibitory effect on the mutagenicity induced by MMS was observed. These results suggest that the detected antimutagenicity could be mediated by an inhibitory effect on metabolic activation. The essential oil was fractionated to identify the components responsible of the suppressing effect detected. Seven fractions were obtained: two of them showed the most potent inhibitory effect against URE-induced mutagenicity and were further fractionated. The sub-fractions obtained from the second chromatographic fractionation were tested for their antimutagenic activity, together with carvacrol and thymol. The highest antimutagenic effect obtained with the sub-fractions was similar to the effect of the crude essential oil, as well as to the effect of carvacrol alone. These results suggest the absence of a synergic antimutagenic effect between the components of O. compactum essential oil and indicate that carvacrol was the most active oil component.

Antigenotoxic effects of three essential oils in diploid yeast (Saccharomyces cerevisiae) after treatments with UVC radiation, 8-MOP plus UVA and MMS.

Essential oils (EOs) extracted from medicinal plants such as Origanum compactum, Artemisia herba alba and Cinnamomum camphora are known for their beneficial effects in humans. The present study was undertaken to investigate their possible antigenotoxic effects in an eukaryotic cell system, the yeast Saccharomyces cerevisiae. The EOs alone showed some cytotoxicity and cytoplasmic petite mutations, i.e. mitochondrial damage, but they were unable to induce nuclear genetic events. In combination with exposures to nuclear mutagens such as 254-nm UVC radiation, 8-methoxypsoralen (8-MOP) plus UVA radiation and methylmethane sulfonate (MMS), treatments with these EOs produced a striking increase in the amount of cytoplasmic petite mutations but caused a significant reduction in revertants and mitotic gene convertants induced among survivors of the diploid tester strain D7. In a corresponding rho0 strain, the level of nuclear genetic events induced by the nuclear mutagens UVC and 8-MOP plus UVA resulted in the same reduced level as the combined treatments with the EOs. This clearly suggests a close relationship between the enhancement of cytoplasmic petites (mitochondrial damage) in the presence of the EOs and the reduction of nuclear genetic events induced by UVC or 8-MOP plus UVA. After MMS plus EO treatment, induction of these latter events was comparable at least per surviving fraction in wildtype and rho0 cells, and apparently less dependent on cytoplasmic petite induction. Combined treatments with MMS and EOs clearly triggered switching towards late apoptosis/necrosis indicating an involvement of this phenomenon in EO-induced cell killing and concomitant decreases in nuclear genetic events. After UVC and 8-MOP plus UVA plus EO treatments, little apoptosis and necrosis were observed. The antigenotoxic effects of the EOs appeared to be predominantly linked to the induction of mitochondrial dysfunction.

Cytotoxicity and gene induction by some essential oils in the yeast Saccharomyces cerevisiae.

In order to get an insight into the possible genotoxicity of essential oils (EOs) used in traditional pharmacological applications we tested five different oils extracted from the medicinal plants Origanum compactum, Coriandrum sativum, Artemisia herba alba, Cinnamomum camphora (Ravintsara aromatica) and Helichrysum italicum (Calendula officinalis) for genotoxic effects using the yeast Saccharomyces cerevisiae. Clear cytotoxic effects were observed in the diploid yeast strain D7, with the cells being more sensitive to EOs in exponential than in stationary growth phase. The cytotoxicity decreased in the following order: Origanum compactum>Coriandrum sativum>Artemisia herba alba>Cinnamomum camphora>Helichrysum italicum. In the same order, all EOs, except that derived from Helichrysum italicum, clearly induced cytoplasmic petite mutations indicating damage to mitochondrial DNA. However, no nuclear genetic events such as point mutations or mitotic intragenic or intergenic recombination were induced. The capacity of EOs to induce nuclear DNA damage-responsive genes was tested using suitable Lac-Z fusion strains for RNR3 and RAD51, which are genes involved in DNA metabolism and DNA repair, respectively. At equitoxic doses, all EOs demonstrated significant gene induction, approximately the same as that caused by hydrogen peroxide, but much lower than that caused by methyl methanesulfonate (MMS). EOs affect mitochondrial structure and function and can stimulate the transcriptional expression of DNA damage-responsive genes. The induction of mitochondrial damage by EOs appears to be closely linked to overall cellular cytotoxicity and appears to mask the occurrence of nuclear genetic events. EO-induced cytotoxicity involves oxidative stress, as is evident from the protection observed in the presence of ROS inhibitors such as glutathione, catalase or the iron-chelating agent deferoxamine.

Adenovirus detection in shellfish and urban sewage in Morocco (Casablanca region) by the polymerase chain reaction.

Human enteric viruses are largely excreted in faeces. These resistance of these viruses in the environment makes their faecal-oral transmission easier. Filter feeder organisms such as the mussels are bio-accumulators of viruses contaminating their aquatic environment. Thus, undercooked shellfish consumption involves sanitary risks. Thirty samples of mussels (Mytilus sp.), were tested, half were from an aquaculture origin, the others were from an area more exposed to faecal pollution. Fifteen sewage samples from this last area were also examined. Viruses were extracted from the digestive tissue by direct elution method in a glycine/NaCl pH 9.5 buffer followed by PEG 8000 precipitation. The PEG pellets were used for DNA extraction by proteinase K and phenol/chloroform. The molecular characterization, by PCR using specific adenovirus primers revealed that shellfish growing on Mohammedia (a town in the Casablanca outskirts) littoral are contaminated whereas those chosen from aquaculture and bought in the central market were not contaminated.

Antimutagenic properties of bell and black peppers.

The wing Somatic Mutation And Recombination Test (SMART) in Drosophila melanogaster was used to study the modulating action of bell pepper (Capsicum annuum) and black pepper (Piper nigrum) in combination with the alkylating agent methyl methanesulfonate (MMS) and the promutagen agent ethyl carbamate (EC). Larvae trans-heterozygous for the third chromosome recessive markers multiple wing hairs (mwh) and flare-3 [flr(3)] were fed genotoxins alone or in combination with each of the two spices. Genetic changes induced in somatic cells of the wing's imaginal discs lead to the formation of mutant clones on the wing blade. Our results showed that bell pepper was effective in reducing the mutational events induced by EC and MMS and black pepper was only effective against EC. Pretreatment of 2-day-old larvae with the spices for 24 h followed by a treatment with EC and MMS was only effective in reducing mutations induced by EC. Suppression of metabolic activation or interaction with the active groups of mutagens could be mechanisms by which the spices exert their antimutagenic action.

Genotoxicity and antigenotoxicity of some essential oils evaluated by wing spot test of Drosophila melanogaster.

Essential oils extracted from the three medicinal plants; Helichrysum italicum, Ledum groenlandicum and Ravensara aromatica, together with their mixture were tested for their genotoxic and antigenotoxic activities against urethane, a well-known promutagen. We have adopted the somatic mutations and recombination test (SMART) in the wings of Drosophila melanogaster. Three days old larvae, trans-heterozygous for two genetic markers mwh and flr, were treated by essential oil and/or urethane. A negative control corresponding to solvent was also used. Our results do not show any significant effect of the oils tested but they reduce the mutation ratio resulting from urethane. The mixture of the three oils at equal volume seems to be the most effective. The antimutagenic effect of these oils could be explained by the interaction of their constituents with cytochrome P-450 activation system leading to a reduction of the formation of the active metabolite. The effect could also be attributed to certain molecules that are involved in these oils.

[Antimutagens and anticarcinogenic agents, identification and mechanisms of action of food xenobiotics]. / Antimutagènes et anticarcinogènes, identification et mécanismes d'action des xénobiotiques alimentaires.

Antimutagens and anticarcinogens are natural or synthetic substances able to inhibit or to reduce spontaneous or induced DNA alteration. These inhibitors act at different levels from the penetration of the xenobiotic to the expression of the mutation and cancer. They act in extracellular and intracellular levels; they react directly with mutagens or on the processes of their activation. Antimutagens and anticarcinogens also act on DNA-repair process.

A dose dependent anti-genotoxic effect of turmeric.

The anti-genotoxic action of turmeric was evaluated by Somatic Mutation and Recombination Test (SMART). As described in other mutagenecity tests, turmeric showed non mutagenic effects in the SMART. The well known powerful mutagen urethane was used as a model to evaluate the anti-genotoxicity of turmeric. Combined treatment of urethane and turmeric displayed, throughout all concentrations assayed, an inhibition of the genotoxic effect of urethane by turmeric. This anti-genotoxic effect was proportional to the concentrations applied. The results obtained, both in single and combined treatments indicate the suitability of the wing spot test for miming the normal intake of substances.

Endocrine and neuroendocrine effects of Azadirachtin in adult females of the earwig Labidura riparia.

In previous studies we have shown that injection of the insect growth regulator Azadirachtin (AZA) into young vitellogenic females induces inhibition of vitellogenesis in a dose-dependent manner. Juvenile hormone treatment rescues vitellogenin synthesis and ovarian growth. The cytopathological effects on ovaries and fat body are not linked to an inhibition of feeding. In this work we investigated the effects of AZA on the endocrine and neuroendocrine system. Enzyme immunoassay reveals that ovarian ecdysteroid levels are drastically reduced, in a dose-dependent fashion, by AZA. Ultrastructural study indicates that corpus allatum cells exhibit signs of inactivity and degenerative changes after AZA exposure. Using an antibody against allastostatin-3 of Blatella germanica (BLAST-3), we show the appearance of strong immunoreactivity of numerous cells and axons in the brain of AZA-injected females. We conclude that vitellogenesis inhibition by AZA consists of a direct cytotoxic effect as well as a generalized disruption of endocrine and neuroendocrine functions.

Effect of Azadirachtin on vitellogenesis of Labidura riparia (Insect Dermaptera).

This study investigates the effects of the insect growth regulator Azadirachtin (AZA) on the ultrastructure of ovaries and fat body of the earwig Labidura riparia. Ovarian development is severely reduced in AZA-injected females in a dose-dependent manner. Follicles exhibit degenerative changes, separation of follicle cells from the oocyte, and lack of pinocytotic vesicles as of yolk spheres in cortical ooplasm. Adipocytes show fragmented rough endoplasmic reticulum (RER), numerous autophagic vacuoles, multivesicular bodies, osmiophilic lipid droplets, and many large glycogen areas. Gel electrophoresis reveals that vitellogenin is absent from both fat body and hemolymph, and that vitellin is not deposited in the ovary. These pathological effects are not linked to an absence of feeding. The effect of AZA on vitellogenesis is rescuable by Juvenile hormone (JH) treatment. The inhibition of vitellogenesis by AZA is discussed on the basis of its direct cytotoxic effect as well as its interference with the neuroendocrine system.

[Effect of the nature of the heteroatom of a monosaccharide derivative on its inhibitory action in relation to P-type calcium channels expressed in the Xenopus oocyte]. / Influence de la nature de l'hétéroatome d'un dérivé monosaccharidique sur son action inhibitrice vis à vis de canaux calciques apparentés au type P exprimés dans l'ovocyte de Xenopus.

Our results demonstrate that saccharidic derivatives obtained by adding a C8 alkyl group through various heteroatomes (O, N or S) to a monoacetonide residue possess an inhibitory effect towards putative P-type calcium channels expressed in Xenopus oocytes. These derivatives partially and reversibly inhibit the activity these channels without changing their electrophysiological properties. Nevertheless, the derivative containing the heteroatome N also affects the fast and tetrodotoxin-sensitive sodium channel activity. Thus, only ether and thioether compounds (heteroatome O or S) can be selected for their inhibitory effect on P-type apparented calcium channels.

Stimulation of motility and energy metabolism of spermatozoa from asthenozoospermic patients by 17 beta-estradiol.

Spermatozoa from nine asthenozoospermic patients were incubated for 3 h in Krebs Phosphate Ringer (KRP), supplemented or not with 17 beta-estradiol. 17 beta-estradiol increased the mean velocity and maintained the percentage of motility during the first 2 h of incubation. Oxydative metabolism and intracellular ATP concentrations were enhanced, too, whereas glycolysis remained unchanged.

[Comparative study of epididymal disorders in two populations of male patients consulting for infertility: one from the Maghreb region of North Africa and the other of European origin]. / Etude comparative des pathologies epididymaires dans deux populations d'hommes consultant pour infecondite: l'une maghrebine, l'autre europeene.

PIP: The authors carried out a retrospective study of 162 cases of male infertility explored in a hospital unit in Lyon, France. Assays of 1 -alpha-1,4-glucosidase (epididymal function marker) backed up by clinical findings were used to select 3 types of epididymal malfunction. 1) There was complete obliteration of the epididymal duct, resulting in azoospermia. This diagnosis was based on both testicular biopsy findings, demonstrating unimpaired spermatogenesis and on the dramatically reduced level of assayed activity ( 40 mIU/ejaculation), as well as on clinical findings. 2) There was anamalous epididymal function combined with moderate oligoasthenozoospermia or normospermia. In these cases, low levels of assayed activity do not parallel fairly high sperm counts (between 20-30 million spermatozoal/ml). 3) There were those cases which were difficult to interpret and which involved severe oligoasthenozoospermia ( 5 million/ml) and reduced level of epididymal marker, suggesting partial blockage of the epididymis due to a focus of infection. Varicoceles were found more frequently among the European population, whereas a history of genital infection was more frequent among the North African population. However, when the various types of abnormality in the spermatogram were related to patient history and epididymal abnormality, no differences were found between the 2 populations. (author's modified)^ieng

Effects of estradiol and its antagonist tamoxifen on motility and metabolism of human spermatozoa.

An investigation was conducted to evaluate the motility and metabolism of human spermatozoa incubated at 37 degrees Celsius for 3 hours in a krebs phosphate Ringer solution containing different concentrations of 17beta-estradiol and tamoxifen. 17beta-estradiol (17beta E2) stimulated significantly the motility of human spermatozoa. The oxidative metabolism and the intracellular ATP concentrations are enhanced with 10-20 mcg/ml of 17beta E2; the lactate production remains unchanged however. Tamoxifen, an antiestrogen, inhibited the motility of spermatozoa, and was toxic at high concentrations. Its effects on the energetic metabolism is dose-dependent; it increases the oxidative metabolism and decreases the lactate production and intracellular ATP at 3 mcg/ml.