Modulating peppermint oil flavor release properties of emulsion-filled protein gels: Impact of cross-linking method and matrix composition

For some food applications, it is desirable to control the flavor release profiles of volatile flavor compounds. In this study, the effects of crosslinking method and protein composition on the flavor release properties of emulsion-filled protein hydrogels were explored, using peppermint essential oil as a model volatile compound. Emulsion-filled protein gels with different properties were prepared using different crosslinking methods and gelatin concentrations. Flavor release from the emulsion gels was then monitored using an electronic nose, gas chromatography-mass spectrometry (GC-MS), and sensory evaluation. Enzyme-crosslinked gels had greater hardness and storage modulus than heat-crosslinked ones. The hardness and storage modulus of the gels increased with increasing gelatin concentration. For similar gel compositions, flavor release and sensory perception were faster from the heat-crosslinked gels than the enzyme-crosslinked ones. For the same crosslinking method, flavor release and perception decreased with increasing gelatin concentration, which was attributed to retardation of flavor diffusion through the hydrogel matrix. Overall, this study shows that the release of hydrophobic aromatic substances can be modulated by controlling the composition and crosslinking of protein hydrogels, which may be useful for certain food applications.

Efficacy and safety of peppermint oil for the treatment in Japanese patients with irritable bowel syndrome: a prospective, open-label, and single-arm study

BACKGROUND

In Europe, an herbal medicine containing peppermint oil is widely used in patients with irritable bowel syndrome (IBS). In Japan, however, no clinical evidence for peppermint oil in IBS has been established, and it has not been approved as a drug for IBS. Accordingly, we conducted a clinical study to confirm the efficacy and safety of peppermint oil (ZO-Y60) in Japanese patients with IBS.

METHODS

The study was a multi-center, open-label, single-arm, phase 3 trial in Japanese outpatients with IBS aged 17-60 years and diagnosed according to the Rome III criteria. The subjects were treated with an oral capsule of ZO-Y60 three times a day before meals, for four weeks. The efficacy of ZO-Y60 was evaluated using the patient's global assessment (PtGA), IBS symptom severity score, stool frequency score, stool form score, and physician's global assessment (PGA). The safety of ZO-Y60 was also assessed.

RESULTS

Sixty-nine subjects were treated with ZO-Y60. During the four-week administration of ZO-Y60, the improvement rate of the PtGA was 71.6% (48/67) in week 2 and 85.1% (57/67) in week 4. It was also suggested that ZO-Y60 is effective against any type of IBS (IBS with constipation, IBS with diarrhea, and mixed/unsubtyped IBS). The improvement rate of the PGA was 73.1% (49/67) in week 2 and 85.1% (57/67) in week 4, also confirming the efficacy of ZO-Y60. Adverse events were observed in 14 subjects (20.3%), however, none of these adverse events were categorized as serious.

CONCLUSION

The efficacy of treatment was confirmed, subjective symptoms were improved, as was observed in previous clinical studies of ZO-Y60 conducted outside of Japan. All adverse reactions were previously known and were non-serious. These findings suggest that peppermint oil may be effective in the Japanese population and that it has an acceptable safety profile.

TRIAL REGISTRATION

JAPIC Clinical Trials Information number: JapicCTI-121727 https://jrct.niph.go.jp/en-latest-detail/jRCT1080221685 . Registration date: 2012-01-10.

Improved antioxidant activity and delivery of peppermint oil Pickering emulsion stabilized by resveratrol-grafted zein covalent conjugate/quaternary ammonium chitosan nanoparticles

Novel nanoparticles (Z-R/H) were successfully fabricated by a resveratrol-grafted zein covalent conjugate (Z-R) combined with quaternary ammonium chitosan (HTCC), which were used as stabilizers to prepare peppermint oil (PO) Pickering emulsions with antioxidant activity. HTCC effectively adjusted wettability of Z-R conjugate, and three-phase contact angle of Z-R/H3:1 was moderate (95.01°). The influencing factors of Pickering emulsion formation, including volume fraction of PO, concentration of Z-R/H, and mass ratio of Z-R to HTCC, were evaluated by droplet size, ζ-potential, microscopic observation, and stability index analysis. Pickering emulsions stabilized by Z-R/H3:1 showed excellent physical stability under heat treatment. Z-R/H nanoparticles adsorbed on the oil-water interface yielded a dense filling layer as a physical barrier to improve the emulsion stability, which was validated by confocal laser-scanning microscopy. After 4 weeks of storage, retention rate of PO in Pickering emulsion stabilized by Z-R/H3:1 remained high (72.1 %). Electronic nose analysis showed that Z-R/H3:1-stabilized emulsion effectively prevented volatilization of PO aroma components. Additionally, PO and Z-R/H nanoparticles provided an additive antioxidant effect of Pickering emulsions against DPPH and ABTS free radicals. In summary, these novel Z-R/H nanoparticle offer promising applications as a stabilizer with great potential in preparing functional Pickering emulsions to improve essential oil delivery.

Antibacterial and Antibiofilm Effects of Different Samples of Five Commercially Available Essential Oils

Essential oils (EOs) have gained economic importance due to their biological activities, and increasing amounts are demanded everywhere. However, substantial differences between the same essential oil samples from different suppliers are reported-concerning their chemical composition and bioactivities-due to numerous companies involved in EOs production and the continuous development of online sales. The present study investigates the antibacterial and antibiofilm activities of two to four samples of five commercially available essential oils (Oregano, Eucalyptus, Rosemary, Clove, and Peppermint oils) produced by autochthonous companies. The manufacturers provided all EOs' chemical compositions determined through GC-MS. The EOs' bioactivities were investigated in vitro against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The antibacterial and antibiofilm effects (ABE% and, respectively, ABfE%) were evaluated spectrophotometrically at 562 and 570 nm using microplate cultivation techniques. The essential oils' calculated parameters were compared with those of three standard broad-spectrum antibiotics: Amoxicillin/Clavulanic acid, Gentamycin, and Streptomycin. The results showed that at the first dilution (D1 = 25 mg/mL), all EOs exhibited antibacterial and antibiofilm activity against all Gram-positive and Gram-negative bacteria tested, and MIC value > 25 mg/mL. Generally, both effects progressively decreased from D1 to D3. Only EOs with a considerable content of highly active metabolites revealed insignificant differences. E. coli showed the lowest susceptibility to all commercially available essential oils-15 EO samples had undetected antibacterial and antibiofilm effects at D2 and D3. Peppermint and Clove oils recorded the most significant differences regarding chemical composition and antibacterial/antibiofilm activities. All registered differences could be due to different places for harvesting the raw plant material, various technological processes through which these essential oils were obtained, the preservation conditions, and complex interactions between constituents.

Comparison of in vitro and in vivo repellency bioassay methods for Ixodes scapularis nymphs

BACKGROUND

Numerous bioassay methods have been used to test the efficacy of repellents for ticks, but the comparability of results across different methods has only been evaluated in a single study. Of particular interest are comparisons between bioassays that use artificial containers (in vitro) with those conducted on a human subject (in vivo) for efficacy testing of new potential unregistered active ingredients, which most commonly use in vitro methods.

METHODS

We compared four different bioassay methods and evaluated three ingredients (DEET [N,N-Diethyl-meta-toluamide], peppermint oil and rosemary oil) and a negative control (ethanol) over a 6-h period. Two of the methods tested were in vivo bioassay methods in which the active ingredient was applied to human skin (finger and forearm bioassays), and the other two methods were in vitro methods using artificial containers (jar and petri dish bioassays). All four bioassays were conducted using Ixodes scapularis nymphs. We compared the results using nymphs from two different tick colonies that were derived from I. scapularis collected in the US states of Connecticut and Rhode Island (northern origin) and Oklahoma (southern origin), expecting that ticks of different origin would display differences in host-seeking behavior.

RESULTS

The results between bioassay methods did not differ significantly, even when comparing those that provide the stimulus of human skin with those that do not. We also found that tick colony source can impact the outcome of repellency bioassays due to differences in movement speed; behavioral differences were incorporated into the assay screening. DEET effectively repelled nymphs for the full 6-h duration of the study. Peppermint oil showed a similar repellent efficacy to DEET during the first hour, but it decreased sharply afterwards. Rosemary oil did not effectively repel nymphs across any of the time points.

CONCLUSIONS

The repellency results did not differ significantly between the four bioassay methods tested. The results also highlight the need to consider the geographic origin of ticks used in repellency bioassays in addition to species and life stage. Finally, our results indicate a limited repellent efficacy of the two essential oils tested, which highlights the need for further studies on the duration of repellency for similar botanically derived active ingredients and for evaluation of formulated products.

Cinnamon Oil Encapsulated with Silica Nanoparticles: Chemical Characterization and Evaluation of Insecticidal Activity Against the Rice Moth, Corcyra cephalonica

Cinnamon (Cinnamomum zeylanicum Blume) essential oil has vast potential as an antimicrobial but is limited by its volatility and rapid degradation. To decrease its volatility and prolong the efficacy of the biocide, cinnamon essential oil was encapsulated into mesoporous silica nanoparticles (MSNs). The characterization of MSNs and cinnamon oil encapsulated with silica nanoparticles (CESNs) was estimated. Additionally, their insecticidal activity against the rice moth Corcyra cephalonica (Stainton) larvae was evaluated. The MSN surface area decreased from 893.6 to 720 m² g^-1 and the pore volume also decreased from 0.824 to 0.7275 cc/g after loading with cinnamon oil. X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and N2 sorption by Brunauer-Emmett-Teller (BET) confirmed the successful formation and evolution of the synthesized MSNs and CESN structures. The surface characteristics of MSNs and CESNs were analyzed by scanning and transmission electron microscopy. Compared with the sub-lethal activity values, the order of toxicity after 6 days of exposure was MSNs ˃ CESN ˃ cinnamon oil ˃ silica gel ˃ peppermint oil. The efficacy of CESNs gradually increases its toxicity more than MSN after the 9th day of exposure.

Preparation and Optimization of Peppermint (Mentha Pipertia) Essential Oil Nanoemulsion with Effective Herbal Larvicidal, Pupicidal, and Ovicidal Activity against Anopheles Stephensi

OBJECTIVES

The Plasmodium parasite is transmitted directly to humans through the Anopheles mosquito bite and causes vector-borne Malaria disease, which leads to the transmission of the disease in Southeast Asia, including India. The problem of persistent toxicity, along with the growing incidence of insect resistance, has led to the use of green pesticides to control the spread of the disease in a cost-effective and environment-friendly manner. Based on this objective, this work investigated the larvicidal, pupicidal, and ovicidal activity of Mentha pipertia using a natural nanoemulsion technique.

METHODS

GC-MS characterized essential oils of Mentha pipertia leaves were formulated as a nanoemulsion for herbal larvicidal, pupicidal, and ovicidal activities. Size of the nanoemulsion was analyzed by photon correlation spectroscopy. The herbal activities against Anopheles Stephensi of nanoemulsion were evaluated in terms of the lethal concentration for 50% (LC50) and 90% (LC90) to prove low cost, pollution free active effective formulation.

RESULTS

Chiral, keto, and alcohol groups attached Mentha pipertia leaves essential oil nanoemulsions demonstrated good results in the larvicidal probit analysis, with values of LC50=09.67 ppm and LC90=20.60 ppm. Activity results of the most stable nano formulation with 9.89 nm size showed a significant increase when compared to the bulk.

CONCLUSION

The nanoemulsion of Mentha pipertia leaves can be a promising eco-friendly widely available, low-cost herbicide against the Anopheles mosquito.

Electro-hydrodynamic assisted synthesis of lecithin-stabilized peppermint oil-loaded alginate microbeads for intestinal drug delivery

Peppermint oil (PO) is the most prominent oil using in pharmaceutical formulations with its significant therapeutic value. In this sense, this oil is attracting considerable attention from the scientific community due to its traditional therapeutic claim, biological and pharmacological potential in recent research. An organic solvent-free and environment-friendly electrohydrodynamic assisted (EHDA) technique was employed to prepared PO-loaded alginate microbeads. The current study deals with the development, optimization, in vitro characterization, in vivo gastrointestinal tract drug distribution and ex-vivo mucoadhesive properties, antioxidant, and anti-inflammatory effects of PO-loaded alginate microbeads. The optimization results indicated the voltage and flow rate have a significant influence on microbeads size and sphericity factor and encapsulation efficiency. All these optimized microbeads showed a better drug release profile in simulated intestinal fluid (pH 6.8) at 2 h. However, a minor release was found in acidic media (pH 1.2) at 2 h. The optimized formulation showed excellent mucoadhesive properties in ex-vivo and good swelling characterization in intestine media. The microbeads were found to be well distributed in various parts of the intestine in in vivo study. PO-loaded alginate microbeads similarly showed potential antioxidant effects with drug release. The formulation exhibited possible improvement of irritable bowel syndrome (IBS) in MO-induced rats. It significantly suppressed proinflammatory cytokines, i.e., interleukin- IL-1β, and upregulated anti-inflammatory cytokine expression, i.e., IL-10. It would be a promising approach for targeted drug release after oral administration and could be considered an anti-inflammatory therapeutic strategy for treating IBS.

Fabrication and antibacterial evaluation of peppermint oil-loaded composite microcapsules by chitosan-decorated silica nanoparticles stabilized Pickering emulsion templating

Novel peppermint oil (PO)-loaded composite microcapsules (CM) with hydroxypropyl methyl cellulose (HPMC)/chitosan/silica shells were effectively fabricated by PO Pickering emulsion, which were stabilized with chitosan-decorated silica nanoparticles (CSN). The surface modification of chitosan could improve the hydrophobicity of silica nanoparticles and favor their adsorption at the oil-water interface of PO Pickering emulsions. The microcapsule composite shells were formed dependent on the electrostatic adsorption of HPMC and CSN, and further subjected to spray-drying. The peppermint oil-loaded composite microcapsules with 100% HPMC as wall material (PO-CM@100%HPMC) seemed to be optimum formulation based on the prolonged release, acceptable entrapment efficiency (89.1%) and drug loading (25.5%). The PO-CM@100%HPMC could remarkably prolong the stability of PO. Moreover, the PO-CM@100%HPMC had a long-term antimicrobial activity (85.4%) against S. aureus and E. coli even after storage for 60 days. Therefore, the Pickering emulsions based microcapsules seemed to be a promising strategy for antibacterial application for PO.

Oral IBGard™ Before Colonoscopy: A Single-Center Double-Blinded, Randomized, Placebo-Controlled Trial

BACKGROUND

Peppermint oil is well known to inhibit smooth muscle contractions, and its topical administration during colonoscopy is reported to reduce colonic spasms.

AIMS

We aimed to assess whether oral administration of IBGard™, a sustained-release peppermint oil formulation, before colonoscopy reduces spasms and improves adenoma detection rate (ADR).  METHODS: We performed a single-center randomized, double-blinded, placebo-controlled trial. Patients undergoing screening or surveillance colonoscopies were randomized to receive IBGard™ or placebo. The endoscopist graded spasms during insertion, inspection, and polypectomy. Bowel preparation, procedure time, and time of drug administration were documented. Statistical analysis was performed using the Student's t test and Wilcoxon rank-sum test.

RESULTS

There was no significant difference in baseline characteristics or dose-timing distribution between IBGard™ and placebo groups. Similarly, there was no difference in ADR (IBGard™ = 47.8%, placebo = 43.1%, p = 0.51), intubation spasm score (1.23 vs 1.2, p = 0.9), withdrawal spasm score (1.3 vs 1.23, p = 0.72), or polypectomy spasm score (0.52 vs 0.46, p = 0.69). Limiting the analysis to patients who received the drug more than 60 min prior to the start of the procedure did not produce any significant differences in these endpoints.

CONCLUSIONS

This randomized controlled trial failed to show benefit of orally administered IBGard™ prior to colonoscopy on the presence of colonic spasms or ADR. Because of its low barrier to widespread adoption, the use of appropriately formulated and timed oral peppermint oil warrants further study to determine its efficacy in reducing colonic spasms and improving colonoscopy quality.

Preparation of peppermint oil nanoemulsions: Investigation of stability, antibacterial mechanism and apoptosis effects

Peppermint oil (PO) is one of the most popular and widely used essential oils. However, due to volatile and poor water solubility of volatile oil, its application in the fields of medicine and food is limited. In order to solve this problem, the high speed shearing technology was used to prepare the nanoemulsion from PO. By using a series of characterization methods, such as turbiscan scanning spectrum, dynamic light scattering (DLS), confocal laser scanning microscope (CLSM), the best nanoemulsion formula was identified as PO 10 %, surfactant 8 % (Tween-60: EL-20 = 3:1) and deionized water 82 % (w/w). The inhibition strength of nanoemulsion on bacteria was evaluated by detecting the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) treated with peppermint oil nanoemulsion (PON) and observing the morphology of bacteria with biological scanning electron microscope (SEM). The results showed that PON had strong inhibitory effect on E. coli. At the concentration range of 0.02 μg/μL-0.2 μg/μL, the apoptosis rate of BEAS-2B cells was less than 10 % compared with control cells. All in all, the PON prepared under this formula is stable, which provides a reference for further exploration of essential oil as natural antibacterial materials in the future.

Art of Prevention: Essential Oils - Natural Products Not Necessarily Safe

Aromatherapy is defined as the use of essential oils, through inhalation or direct application to the skin, to achieve physical, psychological, and spiritual well-being. It has become an increasingly popular trend in modern-day holistic approaches to health care. Essential oils are thought to be natural and pure products, some of the most common being lavender, tea tree, peppermint, and ylang-ylang. In recent years, however, the composition of these oils has been found to be more complex than previously thought. Increased use has led to increasing reports of allergic contact dermatitis (ACD), a delayed-type hypersensitivity reaction to allergens in sensitized individuals. Inquiring about essential oil use is important when conducting clinical evaluations of suspected ACD. Herein, the authors seek to highlight the possibility that natural products may not be necessarily as safe as once thought and in particular seek to highlight ACD caused by essential oils.

Menthacarin induces calcium ion influx in sensory neurons, macrophages and colonic organoids of mice

AIMS

Menthacarin is a herbal combination that is clinically used for the treatment of functional gastrointestinal disorders (FGIDs). In several clinical studies, Menthacarin reduced visceral hypersensitivity-related symptoms. Pathogenesis of visceral hypersensitivity is multifactorial. This involves several cell types and different transient receptor potential ion channels (TRPs); these ion channels are highly conductive for calcium ions. Since transient changes in cytosolic calcium levels are crucial for many functions of living cells, we investigated if Menthacarin can induce calcium influx in sensory, largely nociceptive, neurons from dorsal root ganglia (DRG), peritoneal macrophages (PMs) and colonic organoids.

MAIN METHODS

We employed the calcium imaging technique on sensory neurons from DRG, PMs and colonic organoids isolated from mice. All cells were superfused by Menthacarin at several concentrations (600, 1200, 1800 μg/ml) during the experiments, followed by calcium ionophor ionomycin (Iono., 1 μM) as a positive control.

KEY FINDINGS

Menthacarin induced concentration-dependent calcium ion influx in all investigated cell types. Furthermore, repeated applications of Menthacarin induced tachyphylaxis (desensitisation) of calcium responses in sensory neurons and colonic organoids.

SIGNIFICANCE

Menthacarin-induced calcium influx into sensory neurons, macrophages and colonic organoids is probably related to its clinical desensitising effects in patients with FGIDs.

Synthesis and characterization of novel organo-hydrogel based agar, glycerol and peppermint oil as a natural drug carrier/release material

The very recent Covid-19 pandemic has made the need to understand biocompatible polymers as support material in drug delivery systems and controlled release clearer, especially for organo-hydrogels. This study aims to synthesize various new polymeric materials called gels, hydrogels, and organo-hydrogels according to the monomer used and to investigate their use as drug release systems. The agar-glycerol (AG) pair was used to synthesize the polymers, N, N, methylene bisacrylamide (MBA, m) and glutaraldehyde (GA, g) were used as cross-linkers and peppermint oil (PmO) was included to obtain the organo-hydrogels. Therefore, one AG gel and two p (AG-m) and p (GA-g) hydrogels were synthesized within the scope of the study. Six different organo-hydrogels based on p(AG-m-PmO) or p (AG-g-PmO) were also synthesized by varying the amount of peppermint oil. Paracetamol and carboplatin were selected as the sample drugs. Synthesized gels, hydrogels and organo-hydrogels were characterized by FTIR and SEM analysis. Additionally, swelling behaviors of the synthesized gels were investigated in different media (ID water, tap water, ethanol, acetone, ethanol/ID water (1:1), acetone/ID water (1:1) and gasoline) and at different pHs. Moreover, it was determined that organo-hydrogels were blood compatible and had antioxidant properties based on hemolysis, blood clotting and antioxidant analysis. Therefore, the release of paracetamol (a known antipyretic-painkiller, recommended and used in the treatment of Covid-19) and carboplatin (widely used in cancer treatment) were studied. Evidently, as the amount of PMO oil increases, the -OH groups in organo-hydrogels will increase and the chemical and physical bonding rates will increase; therefore it was observed that increasing peppermint oil in the organo-hydrogels structure to 0.3 mL stimulated the release of the drugs. For instance, maximum paracetamol release amount from p(AG-g-PmO) and p(AG-m-PmO) organo-hydrogels was calculated to be 72.3% at pH 7.4 and 69.8% at pH 2.0, respectively. The maximum carboplatin release amount from p(AG-g-PmO) and p(AG-m-PmO) organo-hydrogels was calculated to be 99.7% at pH 7.4 and 100% at pH 7.4, respectively. It was concluded that the synthesized organo-hydrogels might easily be used as drug carrier and controlled drug release materials.

•

Novel organo-hydrogels were synthesized using agar, glycerol and peppermint oil for drug carrier and controlled release.

•

Biocompatibility and antioxidant properties of organo-hydrogels were investigated.

•

Covid-19 and cancer sensitive drugs (Paracetamol and Carboplatin) were accomplished.

•

The superior properties of the synthesized organo-hydrogels make them useful in biomedical, pharmaceutical and drug delivery systems applications.

Western herbal medicines in the treatment of irritable bowel syndrome: A systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy of Western herbal medicines in the treatment of irritable bowel syndrome (IBS).

DESIGN

A computer-based search of MEDLINE, EMBASE, CINAHL, AMED, GreenFILE, Health Source: Nursing/Academic Edition, and the Cochrane Library was conducted. A hand-search of the bibliographies of relevant papers and previous meta-analyses and reviews was also undertaken. Trials were included in the review if they were double-blind and placebo-controlled investigating the effects of Western herbal medicines on IBS-related symptoms or quality of life. There were no language restrictions. Eligibility assessment and data extraction were performed by two independent researchers. For herbal medicines where there was more than 1 trial of similar design, data were synthesised using relative risk of symptoms improving using the random effects model.

RESULTS

Thirty-three trials were identified that met all eligibility criteria. Seventeen of these evaluated peppermint essential oil, fifteen other Western herbal medicines, and one trial evaluated peppermint oil in one arm and aniseed essential oil in the other arm. Eighteen different herbal preparations were evaluated in these trials. Data suggests that a number of Western herbal medicines may provide relief of IBS symptoms. Meta-analyses suggest that peppermint essential oil is both efficacious and well-tolerated in the short-term management of IBS. Aloe vera and asafoetida also demonstrated efficacy in reducing global IBS symptoms in meta-analyses. The herbal formulas STW 5, STW 5-II and Carmint, along with Ferula assa-foetida, Pimpenella anisum oil, the combination of Curcumin and Foeniculum vulgare oil, and the blend of Schinopsis lorentzii, Aesculus hippocastanum, and peppermint essential oil also demonstrated efficacy in rigorously-designed clinical trials.

CONCLUSION

A number of Western herbal medicines show promise in the treatment of IBS. With the exception of peppermint essential oil, Aloe vera, and asafoetida, however, none of the positive trials have been replicated. This lack of replication limits the capacity to make definitive statements of efficacy for these herbal medicines.

Peppermint Oil to Improve Visualization in Screening Colonoscopy: A Randomized Controlled Clinical Trial

Background

Screening colonoscopy has been associated with reduced mortality from colorectal cancer by means of early detection and timely treatment. However, visualization during colonoscopy is often impaired since the colon is naturally prone to peristalsis and spasm. There is evidence to suggest benefit of topical peppermint oil in causing smooth muscle relaxation, thereby decreasing peristalsis. The aim of our study was to determine if peppermint oil helps reduce colonic spasticity so as to allow for better visualization during screening colonoscopy.

Methods

We performed a randomized controlled, double-blinded, clinical trial where patients undergoing screening colonoscopy were assigned to receive either peppermint oil or placebo. Once cecum was reached, 50 mL of either solution was directly injected via the working channel of the colonoscope. Colonic peristalsis, spasticity and bowel visibility were documented. Bowel preparation quality, withdrawal time and adenoma detection rate (ADR) were also assessed. Continuous variables were analyzed using t-test or Wilcoxon rank-sum test while categorical variables were compared using the two-way Chi-square test.

Results

Forty-eight patients were included, of whom 24 patients received peppermint oil and 24 received placebo. Mean Boston bowel preparation score (BBPS) was excellent for both groups (8 points vs. 7.9 points; P = 0.98). Both mean total colonoscopy time (17.8 min vs. 21.9 min; P = 0.07) and mean cecal intubation time (7.2 min vs. 10.3 min; P = 0.04) were shorter with peppermint oil as compared to placebo. Complete absence of bowel spasticity was observed among 58.3% patients in the peppermint oil group as compared to 45.8% patients in the placebo group (P = 0.05). More than 75% of bowel was visualized in 83% of patients in both groups (P = 0.56). Mean ADR was higher in the peppermint group as compared to the placebo group (45.8% vs. 37.5%; P = 0.56).

Conclusion

Our study suggests that topical peppermint oil reduces bowel wall spasticity, which could lead to better visualization of the bowel during screening colonoscopy. Although use of peppermint oil was associated with better ADRs, these results did not achieve statistical significance. Larger sample size and use of alternative methods of peppermint oil administration allowing for more absorption time may establish stronger results.

The impact of peppermint oil on the irritable bowel syndrome: a meta-analysis of the pooled clinical data

Background

Peppermint oil (PO) has intrinsic properties that may benefit patients with irritable bowel syndrome (IBS) symptoms. The study objective was to determine the effect of peppermint oil in the treatment of the IBS.

Methods

We systematically searched MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (Cochrane CENTRAL), ClinicalTrials.gov, EMBASE (Ovid), and Web of Science for randomized controlled trials (RCTs) of PO for IBS. We appraised the eligible studies by the Cochrane risk of bias tool. We performed random-effects meta-analysis on primary outcomes including global improvement in IBS symptoms and abdominal pain. A PRISMA-compliant study protocol is registered in PROSPERO Register [2016, CRD42016050917].

Results

Twelve randomized trials with 835 patients were included. For global symptom improvement, the risk ratio (RR) from seven RCTs for the effect of PO (n = 253) versus placebo (n = 254) on global symptoms was 2.39 [95% confidence interval (CI): 1.93, 2.97], I² = 0%, z = 7.93 (p < 0.00001). Regarding abdominal pain, the RR from six RCTs for the effect of PO (n = 278) versus placebo (n = 278) was 1.78 [95% CI: 1.43, 2.20], I² = 0%, z = 5.23 (p < 0.00001). Overall, there were no differences in the reported adverse effects: PO (32 events, 344 total, 9.3%) versus placebo (20 events, 327 total, 6.1%) for eight RCTs; RR 1.40 [95% CI: 0.87, 2.26] I² = 0%, z = 1.39 (p = 0.16). The number needed to treat with PO to prevent one patient from having persistent symptoms was three for global symptoms and four for abdominal pain.

Conclusions

In the most comprehensive meta-analysis to date, PO was shown to be a safe and effective therapy for pain and global symptoms in adults with IBS.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2409-0) contains supplementary material, which is available to authorized users.

Comparative study of encapsulated peppermint and green tea essential oils in chitosan nanoparticles: Encapsulation, thermal stability, in-vitro release, antioxidant and antibacterial activities

Essential oils (EOs) such as Peppermint oil (PO) and Green Tea oil (GTO) have extensively been reported for their nutritional and biomedical properties. To overcome the sensitivity of EOs to the environmental conditions, nano-encapsulation has emerged as a method to address this limitation. In this work, PO and GTO were encapsulated in chitosan nanoparticles (CS NPs) following emulsification/ionic gelation method. The nano-encapsulated PO (CS/PO NPs) and GTO (CS/GTO NPs) were fully characterized by various methods. Spherical NPs with an average size range of 20-60 nm were revealed by TEM for both systems. The loading capacity reached 22.2% and 23.1%, for PO and GTO, respectively, and the in-vitro release followed a Fickian behavior in different buffer systems. The TGA thermograms of both nano-encapsulated EOs showed an increase in the temperature of maximum degradation rate up to 350 °C. The nano-encapsulation maintained the stability of the total phenolic contents in both EOs, improved the antioxidant activity by ~2 and 2.4-fold for PO and GTO respectively. Surprisingly, the antibacterial activity of CS/GTO NPs was more potent than CS/PO NPs and especially against Staphylococcus aureus with ~9.4 folds improvement compared to pure GTO, and ~4.7 fold against Escherichia coli.

A Novel Ileocolonic Release Peppermint Oil Capsule for Treatment of Irritable Bowel Syndrome: A Phase I Study in Healthy Volunteers

INTRODUCTION

Peppermint oil (PO) has been shown to reduce abdominal pain in patients with irritable bowel syndrome (IBS). PO is assumed to induce intestinal smooth muscle relaxation and desensitization of nociceptive nerve afferents. To increase colonic PO concentration, an ileocolonic release peppermint oil (IC-PO) capsule has been developed. The aim of this study was to compare pharmacokinetic parameters of the currently available small intestinal release PO (SI-PO) and the novel IC-PO.

METHODS

In this randomized, double-blind, crossover study, subjects received 182 mg of either SI-PO or IC-PO in a crossover design with a washout period of more than 14 days. Blood samples were collected to determine menthol glucuronide concentrations.

RESULTS

Eight healthy volunteers (50% female, median age 22) were included. The time to reach the maximum concentration (T_max) of IC-PO was significantly longer compared to SI-PO with a median (IQR) of 360 (360-405) versus 180 (120-180) min. The lag time (T_lag) was significantly longer with a median (IQR) of 225 (204-284) for IC-PO compared to 37 (6-65) min for SI-PO. The areas under the menthol glucuronide plasma concentration-time curves were significantly smaller with a median (IQR) of 2331 μg h/L (2006-2510) for IC-PO compared to 2623 μg h/L (2471-2920) for SI-PO. No significant differences were found in peak concentrations and elimination half-lives.

CONCLUSION

IC-PO has a significantly delayed peak menthol glucuronide concentration and T_lag, both pointing to the release of PO in the more distal part of the intestine. This may enhance therapeutic efficacy as it results in increased exposure of colonic mucosal afferents to the PO. A randomized controlled trial investigating the efficacy of SI and IC-PO in IBS is currently ongoing.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02291445, EudraCT database 2014-004195-32.

Effectiveness of Menthacarin on symptoms of irritable bowel syndrome

Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are common functional gastrointestinal disorders with overlapping symptoms. Effectiveness and safety of Menthacarin (Menthacarin® is the active ingredient of the product Carmenthin® [Dr. Willmar Schwabe GmbH & Co. KG, Karlsruhe, Germany]) in FD treatment were already demonstrated. We assessed the effectiveness of Menthacarin in reducing concomitant IBS-associated symptoms in FD patients. A systematic search to identify eligible double-blind, randomized controlled trials (RCTs) investigating Menthacarin in FD patients and focusing on IBS-associated symptoms was performed. Three out of five identified RCTs included a total of 111 eligible subjects, which allowed for summary statistics and inclusion into subgroup analysis for FD patients with IBS-associated symptoms. With pain intensity values decreasing by 50–75% on average during 28 days of treatment in patients with accompanying IBS, the subgroup analysis indicates beneficial treatment effects of Menthacarin that are similar to those found for FD patients in the primary analyses. The reduction of IBS-associated symptoms in FD patients suggests Menthacarin as a treatment option for IBS patients.

The effect of premedication with peppermint oil capsules (Colpermin) prior to colonoscopy: A double blind randomized placebo-controlled trial

BACKGROUND AND STUDY AIMS

Colonoscopy is the cornerstone of diagnosing colonic diseases. Investigators have evaluated the effectiveness of antispasmodic agents in colonoscopy with conflicting evidence. The aim of this study is to determine the efficacy of enteric coated peppermint oil capsules (Colpermin®), an antispasmodic agent, on outcomes during colonoscopy.

PATIENTS AND METHODS

A total of 80 patients undergoing elective colonoscopy were recruited and randomized in a double blinded fashion to receive either placebo or peppermint oil capsules administered 4 h prior to the procedure.

RESULTS

Peppermint oil capsules did not affect caecal intubation time when compared with placebo. Patients' tolerance, endoscopist's satisfaction and demand on sedation were also not affected.

CONCLUSION

This randomized controlled trial does not support the routine use of peppermint oil capsules prior to colonoscopy as a tool for procedure optimization, and patients' and endoscopist's satisfaction.

Evaluation of four commercial natural products for repellency and toxicity against the lone star tick, Amblyomma americanum (Acari: Ixodidae)

Lone star ticks are aggressive ectoparasites of domestic and wild animals, as well as humans. These ticks can transmit many pathogens that cause disease including Erhlichia and tularemia. Common compounds used for personal protection and area sprays are N-diethyl-3-methyl benzamide (DEET) and permethrin, but public concern over personal and environmental safety require the development of new, safer products. In the current study, four commercially available products (Wondercide, Essentria IC³, Vet's Best, and Mosquito Barrier) were tested for both repellent and toxic effects against lone star tick nymphs and adults. Overall, all four products were more effective against nymphs than against adults. Wondercide and Essentria IC³ were as toxic to nymphs as permethrin at concentrations of 3.13% and higher, and as repellent as DEET at all concentrations. Nymphs were also repelled by Mosquito Barrier and Vet's Best, but these products had about half or less of the repellent effects of Wondercide and Essentria IC³ at most of the concentrations. Adult ticks were repelled similarly by all products at all tested concentrations, but at lower levels than nymphs. Toxicity of the four tested products on adults was similar at concentrations of 12.5% and below, less than half of what was observed with permethrin with declining effectiveness as concentrations decreased. Overall, these four products may offer a natural way to repel lone star ticks, but further field testing is needed to determine rates of application and residual activity.

Medicinal Foods for Functional GI Disorders

PURPOSE OF REVIEW

Over the past 10 years, there has been a dramatic increase in basic and clinical research involving functional gastrointestinal disorders (FGIDs). New diagnostic and biomarker procedures are helping to identify physiologic disruptions associated with FGIDs on cellular and molecular levels. Simultaneously, clinicians are using new approaches to help manage patients with FGIDs. Among these, an important component of care has been the use of medical foods. These include probiotics, prebiotics, synbiotics, peppermint oil, caraway oil, curcumin, bovine immunoglobulin and many others.

RECENT FINDINGS

The putative effects of different medical foods make these therapies attractive for the management of FGIDs. These include effects on several pathophysiological mechanisms such as anti-inflammatory, smooth muscle relaxation, analgesia, mitigation of gut barrier dysfunction, and stimulation or inhibition of gastrointestinal receptors. Recent research has also demonstrated the efficacy of medical food products such as peppermint oil and serum-derived bovine immunoglobulin for the management of irritable bowel syndrome. Older data supports the probiotic VSL#3 and Bifidobacterium species. For functional dyspepsia, positive effects have been observed with the combination of caraway seed oil and peppermint oil as well as with STW-5, a botanical combination preparation, although robust RCTs are lacking. With advancing knowledge regarding the pathogenesis of FGIDs, it is likely that the compounds available in the medical food category will increase dramatically, and they could play an important role in the management of several common and bothersome gastrointestinal conditions in the future.

Open-label versus double-blind placebo treatment in irritable bowel syndrome: study protocol for a randomized controlled trial

BACKGROUND

Placebo medications, by definition, are composed of inactive ingredients that have no physiological effect on symptoms. Nonetheless, administration of placebo in randomized controlled trials (RCTs) and in clinical settings has been demonstrated to have significant impact on many physical and psychological complaints. Until recently, conventional wisdom has suggested that patients must believe that placebo pills actually contain (or, at least, might possibly contain) active medication in order to elicit a response to placebo. However, several recent RCTs, including patients with irritable bowel syndrome (IBS), chronic low back pain, and episodic migraine, have demonstrated that individuals receiving open-label placebo (OLP) can still experience symptomatic improvement and benefit from honestly described placebo treatment.

METHODS AND DESIGN

This paper describes an innovative multidisciplinary trial design (n = 280) that attempts to replicate and expand upon an earlier IBS OLP study. The current study will compare OLP to double-blind placebo (DBP) administration which is made possible by including a nested, double-blind RCT comparing DBP and peppermint oil. The study also examines possible genetic and psychological predictors of OLP and seeks to better understand participants' experiences with OLP and DBP through a series of extensive interviews with a randomly selected subgroup.

DISCUSSION

OLP treatment is a novel strategy for ethically harnessing placebo effects. It has potential to re-frame theories of placebo and to influence how physicians can optimize watch-and-wait strategies for common, subjective symptoms. The current study aims to dramatically expand what we know about OLP by comparing, for the first time, OLP and DBP administration. Adopting a unique, multidisciplinary approach, the study also explores genetic, psychological and experiential dimensions of OLP. The paper ends with an extensive discussion of the "culture" of the trial as well as potential mechanisms of OLP and ethical implications.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier: NCT02802241 . Registered on 14 June 2016.

Determination of Menthol in Plasma and Urine by Gas Chromatography/Mass Spectrometry (GC/MS)

Menthol, a monoterpene, is a principal component of peppermint oil and is used extensively in consumer products as a flavoring aid. It is also commonly used medicinally as a topical skin coolant; to treat inflammation of the mucous membranes, digestive problems, and irritable bowel syndrome (IBS); and in preventing spasms during endoscopy and for its spasmolytic effect on the smooth muscle of the gastrointestinal tract. Menthol has a half life of 3-6 h and is rapidly metabolized to menthol glucuronide which is detectable in urine and serum following menthol use. We describe a method for the determination of total menthol in human plasma and urine using liquid/liquid extraction, gas chromatography/mass spectrometry (GC/MS) in selected ion monitoring mode and menthol-d4 as the internal standard. Controls are prepared with menthol glucuronide and all samples undergo enzymatic hydrolysis for the quantification of total menthol. The method has a linear range of 5-1000 ng/mL, and coefficient of variation <10%.

A Novel Delivery System of Peppermint Oil Is an Effective Therapy for Irritable Bowel Syndrome Symptoms

BACKGROUND

Peppermint oil (PO) has shown promise as an IBS therapy, but previous trials have demonstrated variable efficacy and tolerability results.

AIMS

To evaluate the efficacy and tolerability of a novel formulation of PO designed for sustained release in the small intestine in patients with IBS-M and IBS-D.

METHODS

This is a 4-week, randomized, double-blind, placebo-controlled clinical trial of PO or identical placebo 3 times daily in patients fulfilling Rome III criteria for IBS-M or IBS-D. The primary endpoint was the change from baseline in the Total IBS Symptom Score (TISS) after 4 weeks of treatment.

RESULTS

Seventy-two patients (mean age 40.7 years, 75 % female, 77.8 % white) were randomized to PO (n = 35) or placebo (n = 37). At 4 weeks, PO was associated with a 40 % reduction in the TISS from baseline (mean change -1.16, SD ± 0.807), superior to the 24.3 % decrease (mean change -0.70, SD ± 0.737) observed with placebo (P = 0.0246). The decrease in the TISS of 19.6 % (mean change -0.55, SD ± 0.613) in the PO group at 24 h was also significantly larger than placebo (-10.3 %, mean change -0.27, SD ± 0.342) (P = 0.0092). At trial completion, patients in the PO group experienced greater improvement in multiple individual gastrointestinal symptoms as well as in severe or unbearable symptoms, compared to placebo. PO was well tolerated with few adverse events.

CONCLUSIONS

A novel PO formulation designed for sustained release in the small intestine is a safe, effective treatment capable of providing rapid relief of IBS symptoms.

Tragacanth gum as a natural polymeric wall for producing antimicrobial nanocapsules loaded with plant extract

Tragacanth gum as a biocompatible and biodegradable polymer with good properties including emulsifying, viscosity and cross-linking ability can be used as the wall material in encapsulation of different compounds, specifically plant extracts. In this paper, for the first time, Tragacanth gum was used to produce nanocapsules containing plant extract through microemulsion method. The effect of different parameters on the average size of prepared nanocapsules in presence of aluminum and calcium chloride through ultrasonic and magnetic stirrer was investigated. The high efficient nanocapsules were prepared with spherical shape and smooth surface. The average size of nanocapsules prepared through ultrasonic using aluminum chloride (22nm) was smaller than other products. The structure of prepared nanocapsules was studied by FT-IR spectroscopy. Antimicrobial activity of different nanocapsules against Escherichia coli, Staphylococcus aureus and Candida albicans was investigated by shake flask method during their release showed 100% microbial reduction after 12h stirring.

Peppermint Oil Promotes Hair Growth without Toxic Signs

Peppermint (Mentha piperita) is a plant native to Europe and has been widely used as a carminative and gastric stimulant worldwide. This plant also has been used in cosmetic formulations as a fragrance component and skin conditioning agent. This study investigated the effect of peppermint oil on hair growth in C57BL/6 mice. The animals were randomized into 4 groups based on different topical applications: saline (SA), jojoba oil (JO), 3% minoxidil (MXD), and 3% peppermint oil (PEO). The hair growth effects of the 4-week topical applications were evaluated in terms of hair growth, histological analysis, enzymatic activity of alkaline phosphatase (ALP), and gene expression of insulin-like growth factor-1 (IGF-1), known bio-markers for the enhanced hair growth. Of the 4 experimental groups, PEO group showed the most prominent hair growth effects; a significant increase in dermal thickness, follicle number, and follicle depth. ALP activity and IGF-1 expression also significantly increased in PEO group. Body weight gain and food efficiency were not significantly different between groups. These results suggest that PEO induces a rapid anagen stage and could be used for a practical agent for hair growth without change of body weight gain and food efficiency.

Research on choleretic effect of menthol, menthone, pluegone, isomenthone, and limonene in DanShu capsule

Danshu capsule (DSC) is a medicinal compound in traditional Chinese medicine (TCM). It is commonly used for the treatment of acute & chronic cholecystitis as well as choleithiasis. To study its choleretic effect, healthy rats were randomly divided into DSC high (DSCH, 900mg/kg), medium (DSCM, 450mg/kg), and low (DSCL, 225mg/kg) group, Xiaoyan Lidan tablet (XYLDT, 750mg/kg), and saline group. The bile was collected for 1h after 20-minute stabilization as the base level, and at 1h, 2h, 3h, and 4h after drug administration, respectively. Bile volume, total cholesterol, and total bile acid were measured at each time point. The results revealed that DSC significantly stimulated bile secretion, decreased total cholesterol level and increased total bile acid level. Therefore, it had choleretic effects. To identify the active components contributing to its choleretic effects, five major constituents which are menthol (39.33mg/kg), menthone (18.02mg/kg), isomenthone (8.18mg/kg), pluegone (3.31mg/kg), and limonene (4.39mg/kg) were tested on our rat model. The results showed that menthol and limonene could promote bile secretion when compared to DSC treatment (p > 0.05); Menthol, menthol and limonene could significantly decrease total cholesterol level (p<0.05 or p<0.01) as well as increase total bile acid level (p<0.05 or p<0.01); Isomenthone, as a isomer of menthone, existed slightly choleretic effects; Pluegone had no obvious role in bile acid efflux. These findings indicated that the choleretic effects of DSC may be attributed mainly to its three major constituents: menthol, menthone and limonene.

Thermal and UV stability of β-carotene dissolved in peppermint oil microemulsified by sunflower lecithin and Tween 20 blend

Microemulsions are suitable for simultaneous delivery of flavour oils and lipophilic bioactive compounds in transparent beverages. In the present study, the feasibility of delivering β-carotene in microemulsions formulated with peppermint oil and a blend of Tween® 20 and various amounts of sunflower lecithin was investigated. The poorly water- and oil-soluble β-carotene was dissolved in the transparent microemulsions that had particles smaller than 10nm and were stable during ambient storage for 65 d. The inclusion of β-carotene did not change the flow-behaviour and Newtonian viscosity. The degradation of β-carotene in microemulsions during ambient storage, ultraviolet radiation, and thermal treatments at 60 and 80 °C followed first order kinetics and was greatly suppressed when compared to the solution control. The antioxidant potential of peppermint oil and a greater content of lecithin in microemulsions enabled the better protection of β-carotene. The studied microemulsions may find various applications in manufacturing transparent beverages.

Irritable bowel syndrome: a concise review of current treatment concepts

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders causing patients to seek medical treatment. It is relatively resource intensive and the source of significant morbidity. Recent insights into the pathophysiology and treatment of IBS has given clinicians more options than ever to contend with this disorder. The purpose of our paper is to review older, "classic" treatments for IBS as well as newer agents and "alternative" therapies. We discuss the evidence base of these drugs and provide context to help develop appropriate treatment plans for IBS patients.

Effect of peppermint oil on serum lipid peroxidation and hepatic enzymes after immobility stress in mice

This study was undertaken to determine the influences of various doses of peppermint oil on the hepatic en-zymes, alanine transaminase, apartate tranaminase, alkaline phosphotase and gamma glutamyl transferase and the level of malondialdehyde in the serum of mice with and without immobility stress. The mice exposed to drink water, 0.9, 27 and 60 mg/kg peppermint oil from the days 1 to 5 for a period of 4 h before and after immobility stress. Serum MDA in-creased in treatment group II, III and IV after immobility stress. There was a significant decrease in ALT in treatment group III and IV after immobility stress. There were also significant decreases in ALP and GGT in treatment group IV af-ter immobility stress. This result may suggest that, MDA level is higher in immobilization stress group than in the un-immobilized animals in serum and this results show that enzyme activities decreased after immobilization stress.