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PubMedDate not supplied

Lateralization of brain activation to imagination and smell of odors using functional magnetic resonance imaging (fMRI): left hemispheric localization of pleasant and right hemispheric localization of unpleasant odors.

PURPOSE: Our goal was to use functional MRI (fMRI) of brain to reveal activation in each cerebral hemisphere in response to imagination and smell of odors. METHOD: FMRI brain scans were obtained in 24 normal subjects using multislice fast low angle shot (FLASH) MRI in response to imagination of banana and peppermint odors and in response to smell of corresponding odors of amyl acetate and menthone, respectively, and of pyridine. Three coronal sections selected from anterior to posterior brain regions were used. Similar studies were obtained in two patients with hyposmia using FLASH MRI and in one patient with hyposmia using echo planar imaging (EPI) both before and after theophylline treatment that returned smell function to or toward normal in each patient and in two patients with birhinal phantosmia (persistent foul odor) and global phantogeusia (persistent foul taste) with FLASH and EPI fMRI before and after treatment with neuroleptic drugs that inhibited their phantosmia and phantogeusia. Activation images were derived using correlation analysis. Ratios of hemispheric areas of brain activation to total hemispheric brain areas were calculated for FLASH fMRI, and numerical counts of pixel clusters in each hemisphere were made for EPI studies. Total pixel cluster counts in localized regions of each hemispheric section were also obtained. RESULTS: In normal subjects, activation generally occurred in left (L) > right (R) brain hemisphere in response to banana and peppermint odor imagination and to smell of corresponding odors of amyl acetate and menthone. Whereas there were no overall hemispheric differences for pyridine odor, activation in men was R > L hemisphere. Although absolute activation in both L and R hemispheres in response to banana odor imagination and amyl acetate smell was men > women, the ratio of L to R activation was women > men. In hyposmic patients studied by FLASH fMRI, activation to banana odor imagination and amyl acetate smell was L > R hemisphere both before and after theophylline treatment. In the hyposmic patient studied with EPI before theophylline treatment, activation to banana and peppermint odor imagination and to amyl acetate, menthone, and pyridine smell was R > L hemisphere; after theophylline treatment restored normal smell function, activation shifted completely with banana and peppermint odor imagination and amyl acetate and menthone smell to L > R hemisphere, consistent with responses in normal subjects. However, this shift also occurred for pyridine smell, which is opposite to responses in normal control subjects. In patients with phantosmia and phantogeusia, activation to phantosmia and phantogeusia before treatment was R > L hemisphere; after treatment inhibited phantosmia and phantogeusia, activation shifted with a slight L > R hemispheric lateralization. Localization of all lateralized responses indicated that anterior frontal and temporal cortices were brain regions most involved with imagination and smell of odors and with phantosmia and phantogeusia presence. CONCLUSION: Imagination and smell of odors perceived as pleasant generally activated the dominant or L > R brain hemisphere. Smell of odors perceived as unpleasant and unpleasant phantosmia and phantogeusia generally activated the contralateral or R > L brain hemisphere. With remission of phantosmia and phantogeusia, hemispheric activation was not only inhibited, but also there was a slight shift to L > R hemispheric predominance. Predominant L > R hemispheric differences in brain activation in normal subjects occurred in the order amyl acetate > menthone > pyridine, consistent with the hypothesis that pleasant odors are more appreciated in L hemisphere and unpleasant odors more in R hemisphere. Anterior frontal and temporal cortex regions previously found activated by imagination and smell of odors and phantosmia and phantogeusia perception accounted for most hemispheric differences.

Adult↗

PubMed2000

Olfactory learning in the cricket Gryllus bimaculatus.

The olfactory learning capability of the cricket Gryllus bimaculatus was studied. Crickets were deprived of drinking water for 4 days and were individually trained to associate peppermint with water and vanilla with NaCl solution. Their odour preference was tested before and after training by allowing them to choose between peppermint or vanilla sources. The time spent visiting each source served as a measure of odour preference. Crickets exhibited an initial preference for vanilla over peppermint, but preference for the latter increased after only one training session. The olfactory memory formed by a single training session decayed with time but remained for at least 24 h. Memory formed by three training sessions was extremely robust, and did not decay significantly between 1 and 7 days after training. The preference formed was easily altered by reversal training in which vanilla was associated with water and peppermint with saline solution. This study shows that crickets have a highly developed olfactory learning capability characterized by fast acquisition, long retention and easy rewriting of memory.

Animals↗

PubMed1996

Antibacterial and antifungal activity of ten essential oils in vitro.

The essential oils of aegle, ageratum, citronella, eucalyptus, geranium, lemongrass, orange, palmarosa, patchouli and peppermint, were tested for antibacterial activity against 22 bacteria, including Gram-positive cocci and rods and Gram-negative rods, and twelve fungi (3 yeast-like and 9 filamentous) by the disc diffusion method. Lemongrass, eucalyptus, peppermint and orange oils were effective against all the 22 bacterial strains. Aegle and palmarosa oils inhibited 21 bacteria; patchouli and ageratum oils inhibited 20 bacteria and citronella and geranium oils were inhibitory to 15 and 12 bacterial strains, respectively. All twelve fungi were inhibited by seven oils (aegle, citronella, geranium, lemongrass, orange, palmarosa and patchouli). Eucalyptus and peppermint oils were effective against eleven fungi. Ageratum oil was inhibitory to only four fungi tested. The MIC of eucalyptus, lemongrass, palmarosa and peppermint oils ranged from 0.16 to > 20 microliters ml-1 for eighteen bacteria and from 0.25 to 10 microliters ml-1 for twelve fungi.

Anti-Bacterial Agents↗

PubMed1996

Spatial distribution of [14C]2-deoxyglucose uptake in the glomerular layer of the rat olfactory bulb following early odor preference learning.

Previous work has shown that odors induce focal uptake of [14C]2-deoxyglucose (2-DG) within the glomerular layer of the main olfactory bulb and that the amount of 2-DG accumulated in these foci increases after early odor learning. To determine if learning-associated changes in 2-DG uptake occur across the entire glomerular layer, we have mapped uptake throughout the layer at fixed angles in coronal sections through the bulb. Resulting arrays for individual bulbs were corrected for differing bulb size and averaged across experimental groups to address the spatial distribution of uptake. The average arrays revealed at least three discrete fields of uptake in naive, peppermint-exposed rats at postnatal day 19 that were not seen in air-exposed littermates. In agreement with previous studies, early preference training with peppermint odor given on postnatal days 1-18 increased 2-DG uptake at postnatal day 19 within odor-dependent patches of uptake in the posterior half of the midlateral bulb, whereas odor-dependent, ventrolateral patches of uptake did not increase to the same extent. In addition, early preference learning was associated with significantly increased 2-DG uptake average over the entire analyzed glomerular layer. These increases were smaller than those within odor-dependent foci and were distributed widely across the glomerular layer, showing low overlap between trained and control rats in anterior regions where peppermint odor did not stimulate 2-DG uptake. The widely distributed increases in 2-DG uptake after learning may reflect changed activity of centrifugal projections that diffusely innervate the glomerular layer.

Animals↗

PubMed1998

Odor preferences in neonatal and weanling rats.

In order to establish odors which can be used in appetitive and aversive conditioning paradigms, naive rat pups, postnatal day 7 (i.e., PND 7) and weanlings (PND 25), were placed in a rectangular open field with an odorant at one or both ends. Time spent over each odor was measured for 3 min. At both ages subjects avoided peppermint, orange, and lemon odors in favor of fresh home-cage bedding. Comparing any of these three odorants with each other resulted in no significant differences in preferences. In experiments using banana odorant, equal time was spent between banana and no odorant. However, in a two-odorant choice between banana and peppermint, weanlings preferred banana whereas pups showed no preference. The results of this study indicate that in an appetitive learning paradigm, peppermint, orange, or lemon odors may be used, while in aversive learning paradigms banana odor may be more appropriate for weanlings.

Age Factors↗

PubMed1999

Regiospecific cytochrome P450 limonene hydroxylases from mint (Mentha) species: cDNA isolation, characterization, and functional expression of (-)-4S-limonene-3-hydroxylase and (-)-4S-limonene-6-hydroxylase.

The oxygenation pattern of the cyclic monoterpenoids of commercial mint (Mentha) species is determined by regiospecific cytochrome P450-catalyzed hydroxylation of the common olefinic precursor (-)-4S-limonene. In peppermint (Mentha x piperita), C3-allylic hydroxylation leads to (-)-trans-isopiperitenol, whereas in spearmint, C6-allylic hydroxylation leads to (-)-trans-carveol. The microsomal limonene-6-hydroxylase was purified from the oil glands of spearmint, and amino acid sequences from the homogeneous enzyme were used to design PCR primers with which a 500-bp amplicon was prepared. This nondegenerate probe was employed to screen a spearmint oil gland cDNA library from which the corresponding full-length cDNA was isolated and subsequently confirmed as the C6-hydroxylase by functional expression using the baculovirus-Spodoptera system. The probe was also utilized to isolate two closely related full-length cDNA species from a peppermint oil gland cDNA library which were confirmed as the limonene-3-hydroxylase by functional expression as before. Deduced sequence analysis of these regiospecific cytochrome P450 monooxygenases indicates that both enzymes bear a typical amino-terminal membrane anchor, consistent with the microsomal location of the native forms, exhibit calculated molecular weights of 56,149 (spearmint) and about 56,560 (peppermint), and are very similar in primary sequence (70% identity and 85% similarity). The availability of these regiochemically distinct, yet very closely related, recombinant hydroxylases and their corresponding genes provides a unique model system for understanding structure-function relationships in cytochrome P450 substrate binding and catalysis, and a means for transgenic manipulation of monoterpene biosynthetic pathways in plants.

Amino Acid Sequence↗

PubMed2001

Demonstration that menthofuran synthase of mint (Mentha) is a cytochrome P450 monooxygenase: cloning, functional expression, and characterization of the responsible gene.

(+)-Menthofuran is an undesirable monoterpenoid component of peppermint (Mentha x piperita) essential oil that is derived from the alpha,beta-unsaturated ketone (+)-pulegone. Microsomal preparations, from the oil gland secretory cells of a high (+)-menthofuran-producing chemotype of Mentha pulegium, transform (+)-pulegone to (+)-menthofuran in the presence of NADPH and molecular oxygen, implying that menthofuran is synthesized by a mechanism analogous to that of mammalian liver cytochrome P450s involving the hydroxylation of the syn-methyl group of (+)-pulegone, spontaneous intramolecular cyclization to the hemiketal, and dehydration to the furan. An abundant cytochrome P450 clone from a peppermint oil gland cell cDNA library was functionally expressed in Saccharomyces cerevisiae and Escherichia coli and shown to encode the (+)-menthofuran synthase (i.e., (+)-pulegone-9-hydroxylase). The full-length cDNA contains 1479 nucleotides, and encodes a protein of 493 amino acid residues of molecular weight 55,360, which bears all of the anticipated primary structural elements of a cytochrome P450 and most closely resembles (35% identity) a cytochrome P450 monoterpene hydroxylase, (+)-limonene-3-hydroxylase, from the same source. The availability of this gene permits transgenic manipulation of peppermint to improve the quality of the derived essential oil.

Amino Acid Sequence↗

PubMed2005

(-)-Menthol biosynthesis and molecular genetics.

(-)-Menthol is the most familiar of the monoterpenes as both a pure natural product and as the principal and characteristic constituent of the essential oil of peppermint (Mentha x piperita). In this paper, we review the biosynthesis and molecular genetics of (-)-menthol production in peppermint. In Mentha species, essential oil biosynthesis and storage is restricted to the peltate glandular trichomes (oil glands) on the aerial surfaces of the plant. A mechanical method for the isolation of metabolically functional oil glands, has provided a system for precursor feeding studies to elucidate pathway steps, as well as a highly enriched source of the relevant biosynthetic enzymes and of their corresponding transcripts with which cDNA libraries have been constructed to permit cloning and characterization of key structural genes. The biosynthesis of (-)-menthol from primary metabolism requires eight enzymatic steps, and involves the formation and subsequent cyclization of the universal monoterpene precursor geranyl diphosphate to the parent olefin (-)-(4S)-limonene as the first committed reaction of the sequence. Following hydroxylation at C3, a series of four redox transformations and an isomerization occur in a general "allylic oxidation-conjugate reduction" scheme that installs three chiral centers on the substituted cyclohexanoid ring to yield (-)-(1R, 3R, 4S)-menthol. The properties of each enzyme and gene of menthol biosynthesis are described, as are their probable evolutionary origins in primary metabolism. The organization of menthol biosynthesis is complex in involving four subcellular compartments, and regulation of the pathway appears to reside largely at the level of gene expression. Genetic engineering to up-regulate a flux-limiting step and down-regulate a side route reaction has led to improvement in the composition and yield of peppermint oil.

Genetic Engineering↗

PubMed2005

Effects of unconditioned and conditioned social defeat on alcohol self-administration and reinstatement of alcohol seeking in rats.

RATIONALE AND OBJECTIVES: We and others have shown that a stressor commonly used in laboratory studies, intermittent footshock, reinstates alcohol seeking in a rat relapse model. The effects of more ethologically relevant stressors on reinstatement have not been examined. Here, we characterized the effects of social defeat (a naturalistic stressor) or a cue associated with the defeat experience on reinstatement of alcohol seeking. We also examined the effect of unconditioned and conditioned social defeat on alcohol self-administration. METHODS: Rats were trained to self-administer alcohol (12% w/v, 1 h day(-1)), and after stable responding, one group of animals received five exposures to social defeat paired with peppermint odor prior to daily self-administration sessions. After three more self-administration sessions, these rats were tested for the effects of the peppermint odor cue on self-administration. In another group of rats, the effects of three daily exposures to social defeat paired with peppermint odor on extinction of responding were examined. After further extinction sessions, the effect of the odor cue on reinstatement was tested in these animals. The acute effect of social defeat on reinstatement was examined in another group of animals. RESULTS: Acute exposure to social defeat decreased alcohol self-administration, reduced rates of responding during extinction, and did not reinstate alcohol seeking. Exposure to a discrete odor cue previously paired with social defeat decreased alcohol self-administration but induced modest reinstatement of alcohol seeking. CONCLUSIONS: Results provide the first demonstration of reinstatement of alcohol seeking by a cue paired with social defeat and are also in agreement with previous findings on the suppressive effect of social defeat stress on alcohol self-administration.

Animals↗

PubMed2001

In vitro study on the transfer of volatile oil components.

The following volatile oils were tested in vitro: chamomile (Matricaria recutica L.), peppermint (Mentha piperita L.) and sage (Salvia officinalis L.) to obtain information on which components of volatile oils or minerals are able to pass through the membranes under different conditions. The transfer of chamomile and peppermint oil from aqueous volatile oil to the stomach (pH=1.1) and then to the plasma (pH=7.5) was studied, and the transfer of sage oil through the skin (from pH=5.5 to pH=7.5) was examined. The transfer of some components was more favorable than that of others. The transfer of chamomile oil was faster to buffer pH=1.1 than from buffer pH=1.1 to buffer pH=7.5 and most of the components, except for chamazulene, passed through the membranes. In the case of peppermint the components went through the membranes in the first 15 min although the main components mostly remained in the initial solution. The sage oil transferred showed the same characteristics as the starting oil. A small amount of metal present in the volatile oils also passed through the membranes. The transfer of metals varied, depending on the time, type of the oil, metal quality and the conditions applied.

Hydrogen-Ion Concentration↗

PubMed1999

Isopentenyl diphosphate biosynthesis via a mevalonate-independent pathway: isopentenyl monophosphate kinase catalyzes the terminal enzymatic step.

In plants, the biosynthesis of isopentenyl diphosphate, the central precursor of all isoprenoids, proceeds via two separate pathways. The cytosolic compartment harbors the mevalonate pathway, whereas the newly discovered deoxyxylulose 5-phosphate pathway, which also operates in certain eubacteria, including Escherichia coli, is localized to plastids. Only the first two steps of the plastidial pathway, which involve the condensation of pyruvate and glyceraldehyde 3-phosphate to deoxyxylulose 5-phosphate followed by intramolecular rearrangement and reduction to 2-C-methylerythritol 4-phosphate, have been established. Here we report the cloning from peppermint (Mentha x piperita) and E. coli, and expression, of a kinase that catalyzes the phosphorylation of isopentenyl monophosphate as the last step of this biosynthetic sequence to isopentenyl diphosphate. The plant gene defines an ORF of 1,218 bp that, when the proposed plastidial targeting sequence is excluded, corresponds to approximately 308 aa with a mature size of approximately 33 kDa. The E. coli gene (ychB), which is located at 27.2 min of the chromosomal map, consists of 852 nt, encoding a deduced enzyme of 283 aa with a size of 31 kDa. These enzymes represent a conserved class of the GHMP family of kinases, which includes galactokinase, homoserine kinase, mevalonate kinase, and phosphomevalonate kinase, with homologues in plants and several eubacteria. Besides the preferred substrate isopentenyl monophosphate, the recombinant peppermint and E. coli kinases also phosphorylate isopentenol, and, much less efficiently, dimethylallyl alcohol, but dimethylallyl monophosphate does not serve as a substrate. Incubation of secretory cells isolated from peppermint glandular trichomes with isopentenyl monophosphate resulted in the rapid production of monoterpenes and sesquiterpenes, confirming that isopentenyl monophosphate is the physiologically relevant, terminal intermediate of the deoxyxylulose 5-phosphate pathway.

Amino Acid Sequence↗

PubMed2004

Toxicity of plant essential oils to Tetranychus urticae (Acari: Tetranychidae) and Phytoseiulus persimilis (Acari: Phytoseiidae).

Fifty-three plant essential oils were tested for their toxicity against eggs and adults of Tetranychus urticae Koch as well as adults of Phytoseiulus persimilis Athias-Henriot, by using a filter paper diffusion bioassay without allowing direct contact. Responses varied according to oil type and dose, and mite species. In a plastic container (4.5 by 9.5 cm) bioassay at 14 x 10(-3) microl/ml air, caraway seed, citronella java, lemon eucalyptus, pennyroyal, and peppermint oils gave > 90% mortality against adult T. urticae, whereas 82 and 81% mortality was observed with sage and spearmint oils, respectively. With the exception of sage oil, the other six essential oils were highly effective against T. urticae eggs at 9.3 x 10(-3) microl/ml air. Against adult P. persimilis, these six test oils caused > 90% mortality at 7.1 x 10(-3) microl/ml air. Particularly peppermint oil at 4.7 x 10(-3) microl/ml air was highly toxic. In an acrylic cage (30 by 30 by 40 cm ) test, lemon eucalyptus, pennyroyal, peppermint, and spearmint oils were highly effective against adult T. urticae at 1.4 x 10(-3) microl/ml air. These results indicate that the mode of delivery of these essential oils was largely a result of action in the vapor phase via the respiratory system. The essential oils described herein merit further study as potential fumigants for T. urticae control.

Animals↗

PubMed1999

Repellency of essential oils to mosquitoes (Diptera: Culicidae).

The repellency of different concentrations (5, 10, 25, 50, 75, and 100%) and combinations of 5 essential oils (Bourbon geranium, cedarwood, clove, peppermint, and thyme) to Aedes aegypti (L.) and Anopheles albimanus Wiedemann when applied to human skin was determined in laboratory tests. Cedarwood oil failed to repel mosquitoes and only high concentrations of peppermint oil repelled Ae. aegypti. None of the oils tested prevented mosquito bite when used at the 5 or 10% concentration. Thyme and clove oils were the most effective mosquito repellents and provided 1 1/2 to 3 1/2 h of protection, depending on oil concentration. Clove oil (50%) combined with geranium oil (50%) or with thyme oil (50%) prevented biting by An. albimanus for 1 1/4 to 2 1/2 h. The potential for using essential oils as topical mosquito repellents may be limited by user acceptability; clove, thyme, and peppermint oils can be irritating to the skin, whereas both human subjects in this study judged the odor of clove and thyme oils unacceptable at concentrations > or = 25%.

Aedes↗

PubMed1998

Sex difference and testosterone modulation of pheromone-induced NeuronalFos in the Ferret's main olfactory bulb and hypothalamus.

A carnivore, the ferret possesses a vomeronasal organ--accessory olfactory bulb (VNO-AOB) projection to the hypothalamus; however, little is known about its function. Pheromones in soiled bedding from estrous female ferrets or an artificial peppermint odor significantly augmented nuclear Fos protein immunoreactivity (Fos-IR), a marker of neural activation, in several main olfactory bulb (MOB) sites but not in the AOB of gonadectomized male and females. Testosterone propionate (TP) significantly augmented the MOB's neuronal Fos responses to estrous females' pheromones, but not to peppermint. Estrous odors, but not peppermint, also augmented neuronal Fos-IR in the medial preoptic area (mPOA) of female, but not male, subjects. Pheromones in soiled bedding from breeding male ferrets significantly augmented neuronal Fos-IR in the MOB and in the medial amygdala of gonadectomized, TP-treated male and female subjects. Again, male pheromones failed to influence neuronal Fos-IR in the AOB of either sex, and only females showed significant increases in neuronal Fos-IR in the lateral aspect of the ventromedial nucleus and mPOA. These results point to an essential role among higher mammals of the main olfactory epithelium-MOB projection to the hypothalamus in detecting and processing pheromones. Gonadectomized ferrets showed significant increases in sniffing behavior when placed on either female or male bedding. This occurred regardless of whether they had received TP or oil vehicle, suggesting that testosterone's facilitation of neuronal Fos responses to estrous females' odors in the MOB of both sexes cannot be attributed to increased scent gathering. Androgen receptor-IR was present in the MOB granule cell layer of male and female ferrets, raising the possibility that testosterone acts directly on these cells to augment their responsiveness to pheromones.

Animals↗

PubMed2004

Organization of monoterpene biosynthesis in Mentha. Immunocytochemical localizations of geranyl diphosphate synthase, limonene-6-hydroxylase, isopiperitenol dehydrogenase, and pulegone reductase.

We present immunocytochemical localizations of four enzymes involved in p-menthane monoterpene biosynthesis in mint: the large and small subunits of peppermint (Mentha x piperita) geranyl diphosphate synthase, spearmint (Mentha spicata) (-)-(4S)-limonene-6-hydroxylase, peppermint (-)-trans-isopiperitenol dehydrogenase, and peppermint (+)-pulegone reductase. All were localized to the secretory cells of peltate glandular trichomes with abundant labeling corresponding to the secretory phase of gland development. Immunogold labeling of geranyl diphosphate synthase occurred within secretory cell leucoplasts, (-)-4S-limonene-6-hydroxylase labeling was associated with gland cell endoplasmic reticulum, (-)-trans-isopiperitenol dehydrogenase labeling was restricted to secretory cell mitochondria, while (+)-pulegone reductase labeling occurred only in secretory cell cytoplasm. We discuss this pathway compartmentalization in relation to possible mechanisms for the intracellular movement of monoterpene metabolites, and for monoterpene secretion into the extracellular essential oil storage cavity.

Alcohol Oxidoreductases↗

PubMed2006

Natural oils affect the human skin integrity and the percutaneous penetration of benzoic acid dose-dependently.

Natural oils are extensively used in cosmetics and as treatment for a growing number of more or less specific ailments. Skin irritation and cases of allergy have repeatedly been described in the literature following exposure to these oils. The present study evaluated the extent to which three natural oils (eucalyptus oil, tea tree oil, peppermint oil) would affect the skin integrity and the percutaneous penetration of benzoic acid when applied topically in relevant concentrations. An experimental in vitro model using static diffusion cells mounted with human breast or abdominal skin was applied. The three natural oils decreased the skin integrity dose-dependently. Concomitant dermal exposure to low concentrations of peppermint oil reduced the percutaneous penetration of benzoic acid. The present study lends support to the notion that low concentrations of peppermint oil may act protective against percutaneous penetration of some chemicals, whereas higher concentrations may decrease the integrity of the dermal barrier.

Adult↗

PubMed2001

Effect of herbal teas on hepatic drug metabolizing enzymes in rats.

We have investigated the effect of herbal teas (peppermint, chamomile and dandelion) on the activity of hepatic phase I and phase II metabolizing enzymes using rat liver microsomes. Female Wistar rats were divided into six groups (n = 5 each). Three groups had free access to a tea solution (2%) while the control group had water. Two groups received either green tea extract (0.1%) or aqueous caffeine solution (0.0625%). After four weeks of pretreatment, different cytochrome P450 (CYP) isoforms and phase II enzyme activities were determined by incubation of liver microsomes or cytosol with appropriate substrates. Activity of CYP1A2 in the liver microsomes of rats receiving dandelion, peppermint or chamomile tea was significantly decreased (P < 0.05) to 15%, 24% and 39% of the control value, respectively. CYP1A2 activity was significantly increased by pretreatment with caffeine solution. No alterations were observed in the activities of CYP2D and CYP3A in any group of the pretreated rats. Activity of CYP2E in rats receiving dandelion or peppermint tea was significantly lower than in the control group, 48% and 60% of the control, respectively. There was a dramatic increase (244% of control) in the activity of phase II detoxifying enzyme UDP-glucuronosyl transferase in the dandelion tea-pretreated group. There was no change in the activity of glutathione-S-transferase. The results suggested that, like green and black teas, certain herbal teas can cause modulation of phase I and phase II drug metabolizing enzymes.

Animals↗

PubMed2003

Systematic review of treatments for recurrent abdominal pain.

OBJECTIVE: To conduct a systematic review of evaluated treatments for recurrent abdominal pain (RAP) in children. METHODS: Online bibliographic databases were searched for the terms "recurrent abdominal pain," "functional abdominal pain," "children," or "alternative therapies" in articles classified as randomized controlled trials. The abstracts or full text of 57 relevant articles were examined; 10 of these met inclusion criteria. Inclusion criteria required that the study involve children aged 5 to 18 years, subjects have a diagnosis of RAP, and that subjects were allocated randomly to treatment or control groups. The methodology and findings of these articles were evaluated critically, and data were extracted from each article regarding study methods, specific interventions, outcomes measured, and results. RESULTS: Studies that evaluated famotidine, pizotifen, cognitive-behavioral therapy, biofeedback, and peppermint oil enteric-coated capsules showed a decrease in measured pain outcomes for those who received the interventions when compared with others in control groups. The studies that evaluated dietary interventions had conflicting results, in the case of fiber, or showed no efficacy, in the case of lactose avoidance. CONCLUSIONS: Evidence for efficacy of treatment of RAP in children was found for therapies that used famotidine, pizotifen, cognitive-behavioral therapy, biofeedback, and peppermint oil enteric-coated capsules. The effects of dietary fiber were less conclusive, and the use of a lactose-free diet showed no improvement. There seemed to be greater improvement when therapy (famotidine, pizotifen, peppermint oil) was targeted to the specific functional gastrointestinal disorder (dyspepsia, abdominal migraine, irritable bowel syndrome). The behavioral interventions seemed to have a general positive effect on children with nonspecific RAP. Many of these therapies have not been used widely as standard treatment for children with RAP. Although the mechanism of action for each effective therapy is not fully understood, each is believed to be safe for use in RAP.

Abdominal Pain↗