Peppermint

AIM: Biophenol-rich nutraceuticals may be an adjuvant treatment for Crohn's disease (CD), ulcerative colitis (UC), symptomatic uncomplicated diverticular disease (SUDD), and irritable bowel syndrome (IBS). This systematic review and meta-analysis aimed to determine the efficacy and safety of biophenol-rich nutraceutical supplementation on CD, UC, SUDD, and IBS on gastrointestinal symptoms (GIS), quality of life (QoL), inflammatory and oxidative stress biomarkers, and adverse events compared to usual care or placebo. METHODS: PubMed, Embase, CINAHL, and CENTRAL were searched for randomised controlled trials until 27 April 2020. Outcomes were GIS, inflammatory and oxidative stress markers, QoL, and adverse events. The Cochrane Risk of Bias tool and GRADE were used to appraise studies. Data were pooled using Revman. RESULTS: Twenty-three trials in CD, UC, and IBS patients were included. Compared with placebo, biophenol-rich nutraceuticals improved GIS (SMD: 0.43 [95%CI: 0.22, 0.63]; GRADE: very low) in UC, CD, and IBS participants. In UC and CD participants, biophenol-rich nutraceuticals improved CRP by 1.6 mg/L [95%CI:0.08, 3.11; GRADE: low], malondialdehyde by 1 mmol/L [95%CI:0.55, 1.38; GRADE: low]; but only resveratrol improved QoL (SMD: -0.84 [95%CI: -1.24, -0.44; GRADE: high). Resveratrol (for UC and CD participants) and peppermint oil (for IBS participants) had greater certainty in the evidence for improving GIS and QoL (GRADE: moderate to high). There was no effect on adverse events (P > .05). CONCLUSIONS: Biophenol-rich nutraceuticals may be an effective and safe adjuvant treatment for the management of CD, UC, and IBS; with higher certainty of evidence for resveratrol for UC and CD and peppermint oil for IBS. © 2021 The Authors. Nutrition & Dietetics published by John Wiley & Sons Australia, Ltd on behalf of Dietitians Australia.

BACKGROUND: Numerous meta-analyses have recently assessed the overall clinical benefit of single therapy options and groups of therapies in the irritable bowel syndrome (IBS). By large, this should enable physicians to select from a number of therapy options available. METHODS: We entered dichotomous outcome data from 121 IBS trials published over the last 35 years with different groups and subgroups of drugs (antispasmodics, motility-affecting agents, antidepressants, peppermint oil), dietary interventions (bran, probiotics), and psychotherapy (cognitive behavioral, psychodynamic, hypnotherapy, relaxation techniques) into meta-analytic tools and estimate the overall efficacy (odds ratio, number needed to treat). RESULTS: Highest efficacy is currently found for peppermint oil, followed by psychotherapeutic and psychopharmacological interventions and probiotics. Traditional antispasmodic therapy has a moderate efficacy, whereas the list of (partially failed or cancelled) motility affecting drugs yielded weak clinical results, and therapies by bran and fibers are of no value in IBS. CONCLUSION: Evidence-based therapy in IBS provides a number of effective treatment options beyond the fact that many novel compounds under development have failed to reach the market. An algorithm for clinical therapy decision is proposed.

Hypertension represents the predominant risk factor for cardiovascular disease morbidity and mortality; with significant healthcare utilization and expenditure. Pharmaceutical management is habitually adopted; although its long-term effectiveness remains ambiguous, and accompanying adverse effects are disquieting. Peppermint, which is rich in menthol and flavonoids, may exert potential benefits relevant to hypertension. This trial aimed to explore the effects of twice-daily peppermint oil supplementation in individuals with pre- and stage 1 hypertension. A 20 day, parallel randomized, placebo-controlled trial was adopted (NCT05561543). 40 individuals with pre- and stage 1 hypertension were randomly assigned to receive 100 μL per day of either peppermint oil or peppermint-flavoured placebo. The primary trial outcome was the between-group difference in systolic blood pressure from baseline to 20 days. Secondary outcome measurements were the between-group differences in anthropometric, haematological, diastolic blood pressure/resting heart rate, psychological wellbeing, and sleep efficacy indices. Statistical analysis was conducted on an intention-to-treat basis using baseline-adjusted linear regression models comparing post intervention values between trial arms with the corresponding baseline value entered as a covariate; adjusted mean differences (b), 95% confidence intervals, and effect sizes (d) were calculated. In relation to the primary outcome, adjusted systolic blood pressure at 20 days was significantly lower (b = -8.48 mmHg, 95% CI = -14.24 to -2.73, d = -0.94) in the peppermint trial arm (baseline = 130.05 mmHg, 20 days = 121.97 mmHg) than in placebo (baseline = 130.93 mmHg, 20 days = 131.05 mmHg). Loss to follow-up (N = 1) and adverse events (N = 1) were low, both occurring in the peppermint arm, and compliance was very high in the peppermint (93.3%) trial arm. Given the substantial health and economic burden associated with hypertension worldwide, these findings suggest that twice-daily peppermint supplementation may represent a simple, low-cost, and well-tolerated strategy to support blood pressure reduction in this population. Trial registration Cli

BACKGROUND: This study evaluated the effect of inhaled peppermint essential oil (PEO) aromatherapy on postoperative nausea and vomiting (PONV) in patients undergoing laparoscopic gynecologic surgery. METHODS: In this randomized controlled trial, 106 patients were assigned to either the PEO group or normal saline (NS) group. The PEO group received inhalational aromatherapy with 2% peppermint oil before induction, preoperatively, and immediately after extubation. The NS group received an identical intervention using 2 ml of 0.9% sodium chloride solution. RESULTS: Compared with the NS group, the PEO group had a significantly lower incidence of PONV within 24 h (52.8% vs. 73.6%; p = 0.043). The reduction was most notable during the first hour (45.3% vs. 73.6%; p = 0.047). The PEO group also demonstrated significantly improved anxiety scores at 0-24 h and 24-48 h, reduced pain catastrophizing, and decreased abdominal distension. CONCLUSION: Inhaled peppermint aromatherapy reduced the incidence of PONV, improved anxiety, decreased pain catastrophizing, and alleviated abdominal distension in patients undergoing laparoscopic gynecological surgery. CLINICAL TRIAL REGISTRATION: This study was registered in the Chinese Clinical Trial Registry. (Registration number: ChiCTR2400093289 Registration Date:2024-12-02).

BACKGROUND: Post-craniotomy headache (PCH) is a common clinical occurrence after craniotomy. Scalp nerve block (SNB) is often used for pain control during craniotomy. Peppermint essential oil (PEO) may alleviate pain under certain injury conditions by activating TRPM8, but its application after craniotomy remains unclear. This study aimed to investigate the individual and combined effects, and potential interaction, of scalp nerve block (SNB) and inhaled peppermint essential oil (PEO) aromatherapy on postoperative pain, quality of recovery, and perioperative indicators in patients undergoing supratentorial tumor resection. METHODS: One hundred patients scheduled for elective supratentorial tumor resection were randomly assigned to a control group (C group), scalp nerve block group (SNB group), peppermint essential oil group (PEO group), or combined SNB+PEO group (25 patients each). Numeric Rating Scale (NRS) pain scores, State Anxiety Inventory (SAI) scores, Quality of Recovery-15 (QoR-15) scores within 48 h postoperatively, extubation time, PACU stay duration, postoperative rescue analgesia rate, and postoperative hospital stay were recorded. RESULTS: No significant interaction was found between SNB and PEO on pain scores at any time point. The Ropivacaine Group (SNB & SNB+PEO) showed significantly lower NRS scores than the Saline Group (C & PEO) immediately after extubation (0.5 [0.0, 2.0] vs. 2.0 [0.0, 4.0], P = 0.013). The Aromatherapy Group (PEO & SNB+PEO) had significantly lower scores than the Placebo Group (C & SNB) at 24 h postoperatively (1.0 [0.8, 2.0] vs. 2.5 [1.0, 4.0], P < 0.001). SNB was a protective factor against intraoperative hypertension. PEO significantly improved QoR-15 scores at 48 h. CONCLUSION: The combination of SNB and PEO provides effective postoperative analgesia, improves recovery quality, reduces intraoperative hemodynamic fluctuations, and promotes early rehabilitation.

BACKGROUND: Postoperative delirium (POD), a serious complication in elderly patients following major surgery, is strongly associated with increased morbidity and mortality. While peppermint essential oil (PEO) demonstrates cognitive-enhancing and neuroprotective properties, its efficacy in reducing POD incidence remains unclear. This study aims to evaluate the impact of inhaled PEO aromatherapy on POD incidence within 3 days after major lower limb arthroplasty (THA/TKA) in patients aged ≥65 years. METHODS: A total of 178 elderly patients scheduled for THA/TKA were randomized to either the PEO group (n = 89) or normal saline (NS) group (n = 89). The primary endpoint was POD incidence within 3 days postoperatively. Secondary endpoints included: delirium severity, duration, and subtype; pain scores at rest and during activity within postoperative 3 days; anxiety scores within 2 days post-surgery; adverse event incidence; neutrophil-to-lymphocyte ratio (NLR); and hospital length of stay. RESULTS: All 178 patients completed the trial (median age 70 years; 98 women [55.1 %]). The PEO group showed significantly lower POD incidence within 3 days postoperatively (7.9 % vs 19.1 %; risk ratio 0.412, 95 % confidence interval [CI] [0.179, 0.944], risk difference -0.112, 95 % CI [-0.215, -0.014], P = 0.048), with reduced pain scores (rest/activity) within the first 3 postoperative days and lower anxiety scores within the first 2 postoperative days (all P < 0.05) compared to the NS group. CONCLUSION: Inhalation of PEO aromatherapy significantly reduces POD incidence within 3 days post-surgery and alleviates postoperative pain and anxiety in elderly patients undergoing major lower limb arthroplasty.

BACKGROUND: Postoperative nausea and vomiting (PONV) are common and distressing complications following laparoscopic cholecystectomy. This study evaluated the efficacy of sublingual peppermint (Mentha piperita L., M. piperita) and cardamom (Elettaria cardamomum, E. cardamomum) extract ice cubes in alleviating these symptoms and reducing the requirement for rescue antiemetics. METHODS: In this triple-blinded randomized controlled trial, 105 patients scheduled for elective laparoscopic cholecystectomy were enrolled. Participants were randomly allocated to one of three groups: M. piperita, E. cardamomum, or placebo. Following baseline assessment, the intervention consisted of four sublingual administrations (every 15 min) of a 1-cm ice cube. For the active groups, each ice cube was impregnated with six drops of 10 % essential oil extract. The primary outcome was nausea severity, measured by a Visual Analogue Scale (VAS) at baseline, 1 hour, and 3 h post-intervention. Secondary outcomes included the frequency of vomiting episodes and requests for antiemetic medication, recorded over a 4-hour postoperative period. RESULTS: While trends indicated a greater reduction in nausea severity, vomiting frequency, and antiemetic demand in the M. piperita group compared to the E. cardamomum group, the intergroup differences were not statistically significant (p > 0.05). Both intervention groups reported improved outcomes over the placebo group. CONCLUSIONS: The sublingual application of M. piperita or E. cardamomum extract ice cubes presents a simple, safe, and effective non-pharmacological adjunct for managing PONV in patients recovering from laparoscopic cholecystectomy.

BACKGROUND: Knee osteoarthritis (KOA) is a prevalent degenerative joint disorder that significantly impairs physical function and daily activities. While conventional treatments focus on symptom management, complementary therapies such as aromatherapy massage have gained attention for their potential benefits. OBJECTIVE: This study evaluates the effects of peppermint oil aromatherapy massage on functional impairments in KOA patients. METHODS: A randomized controlled trial was conducted on 120 KOA patients at Shahid Beheshti Hospital, Kashan, Iran at October 2024 to December 2024. Participants were randomly assigned to three groups: intervention (peppermint oil massage), placebo (paraffin oil massage), and control (no intervention). The intervention and placebo groups received biweekly 15-min knee massages for four weeks. Functional outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) at baseline, post-intervention, and one-month follow-up. Statistical analyses included chi-square, ANOVA, and repeated measures ANOVA. RESULTS: Baseline characteristics and KOOS subscale scores were comparable across groups (p > 0.05). The intervention group demonstrated significant improvements in pain reduction, symptom relief, and daily function over time (p < 0.001), while no significant changes were observed in the sports and recreation subscale (p > 0.05). ANOVA confirmed significant intergroup differences in KOOS subscales of pain, symptoms, and daily function at all time points (p < 0.05), except for sports/recreation and quality of life (p > 0.05). CONCLUSION: Peppermint oil aromatherapy massage significantly alleviates KOA-related pain and functional impairment, enhancing daily activities and overall well-being. Given its non-invasive nature and ease of application, this intervention could be recommended as an adjunctive therapy for KOA management.

PURPOSE: Postoperative nausea and vomiting (PONV) is a group of symptoms that develop in patients within 24 hours after surgical intervention and are undesirable outcomes complicating patients' postoperative recovery. The purpose of this study was to establish the impact of ginger and peppermint essential oil inhalation for PONV in patients who underwent total thyroidectomy. DESIGN: Our study was designed as a randomized controlled experimental study. METHODS: Participants consisted of patients who underwent thyroidectomy surgery at Bezmialem Vakif University General Surgery Clinic between February 2021 and August 2022. The subjects were first divided randomly into three groups: a ginger group, a peppermint group, and a routine care group. Patients' pain, nausea, and vomiting severity were measured at 2, 6, and 24 hours. Patients' outcome was assessed using the visual analog scale and the Rhodes Nausea and Vomiting Index. FINDINGS: Significantly lower pain and nausea severity was found in the ginger group compared with the control group. Similarly, the peppermint group also showed significantly lower pain and nausea severity compared with the control group. Rhodes 1 item score was 0.48 ± 0.51 in the ginger group, 1.11 ± 0.64 in the peppermint group, and 1.37 ± 0.49 in the control group (P < .001). These findings suggest that both ginger and peppermint essential oils are effective in alleviating PONV symptoms, with each group showing significant improvement compared with the control group. CONCLUSIONS: Results support that ginger and mint might have a positive effect if used to improve postoperative recovery quality. This nursing intervention is recommended to prevent and minimize the PONV occurrence and is made of ginger and mint.

AIMS: There is a paucity of information on the pharmacokinetics (PK) and pharmacodynamics (PD) of menthol, the active ingredient in peppermint oil (PMO). We studied the PK of menthol (540 and 900 mg) in children and measured their effects on gut transit/contractility. METHODS: Children 7-12 years of age with functional abdominal pain underwent wireless motility capsule (WMC) testing. One week later, they were randomized to 540 mg or 900 mg of oral enteric-coated PMO. Blood was sampled over 24 h to determine menthol PK. The WMC test was repeated while they took their respective dose (180 mg thrice or 180 mg five times daily) for a week. RESULTS: Twenty-five children received 540 mg, and 15 received 900 mg (mean age 10.4 ± 1.1 years, 60% female). Peak plasma concentrations (Cmax) were observed at approximately 2.5 h post-dose. There was no evident dose effect for the apparent elimination rate constant, time of peak plasma concentration (Tmax), Cmax, total plasma clearance, nor the apparent volume of distribution. Mean area under the plasma concentration vs. time curve (AUC) for the 900 mg PMO dose cohort was approximately 1.5-fold higher compared with the 540 mg dose; the difference disappeared correcting for dose. Colonic and whole bowel transit time were significantly positively correlated with menthol AUC. The 900 mg (vs. 540 mg) dose decreased colonic (P = 0.002) and whole gut (P = 0.02) contraction frequency. CONCLUSIONS: The PK of menthol derived from PMO demonstrates apparent dose-proportionality, and gut transit and contractility are associated with the systemic concentration of menthol. © 2025 British Pharmacological Society.

OBJECTIVES: Olfactory training is a recommended treatment in patients with olfactory dysfunction after COVID-19. However, the effectiveness of olfactory training in COVID-19-induced olfactory dysfunction has been studied; only a few studies have included a placebo group to compare the effect of traditional olfactory training with odor-free olfactory training. In this randomized placebo-controlled trial, we evaluate the effect of olfactory training with essential oils versus olfactory training with placebo oils in patients with post-COVID-19 olfactory dysfunction. METHODS: Sixty-five patients with COVID-19 induced olfactory dysfunction were randomized to the intervention or control group. Patients in the intervention group performed classic olfactory training with four essential oils (orange, lavender, clove, and peppermint) twice daily for 12 weeks, while the control group performed the same olfactory training but with odor-free placebo oils. Olfactory function was assessed using the Sniffin Sticks extended TDI test at baseline and at follow-up after the 12-week intervention. RESULTS: The intervention group did not significantly improve their olfactory function compared to the control group after olfactory training. Additionally, no associations were found between changes in olfactory function after olfactory training and age, gender, rhinitis, time since infection, or pre-infection vaccine. A regression analysis showed that the presence of parosmia was associated with reduced effectiveness of olfactory training. CONCLUSIONS: This study found that 12 weeks of classical olfactory training is not effective in the treatment of COVID-19 induced olfactory dysfunction. Moreover, the study indicates that parosmia reduces the effect of olfactory training significantly. TRIAL REGISTRATION: Clinicaltrials.gov registration number: NCT05539560. © 2025 The Author(s). The Laryngoscope published by Wiley Periodicals LLC on behalf of The American Laryngological, Rhinological and Otological Society, Inc.

The cognitive-enhancing effects of peppermint have been widely reported. Vasodilation, causing an increase in cerebral blood flow (CBF) in the prefrontal cortex, has been implicated as a possible mediator. We tested this here. A total of N = 25 individuals, all aged over 18 years, were recruited via convenience sampling. A randomized, single blind placebo-controlled, independent groups design was used to assess whether groups (peppermint vs. placebo control) could be differentiated with respect to change in cognition, assessed via a computerized battery, and change in cerebral blood flow, assessed with Near-Infrared-Spectroscopy (NIRS), from pre-post intervention. Groups disparities in both cognitive and cerebrovascular change scores (from pre-post intervention) emerged. Improvements in cognitive performance were better in the peppermint group. Increases in hemodynamic activity, indexed by Oxygenated (Oxy-Hb) and Total hemoglobin (Total-Hb), were also greater in the peppermint group. Cerebrovascular changes from pre-to post-intervention were unrelated to cognitive changes over the same period, ruling out mediation effects. In conclusion, 200 mL of peppermint, consumed as tea, effectively boosted cognition and cerebral blood flow in otherwise healthy adults. Increased cerebral blood flow, however, did not mediate the cognitive-enhancing effects of peppermint. Future research incorporating larger samples and exploring other neurophysiological mediators is encouraged. © 2025 The Author(s). Human Psychopharmacology: Clinical and Experimental published by John Wiley & Sons Ltd.

This study systematically evaluated the synergistic effects of terpinen-4-ol (T4O) with p-menthane-3,8-diol (PMD) for enhanced mosquito repellency. Through screening 20 essential oils, we identified six candidates (cinnamon, eucalyptus, tea tree, litsea cubeba, moxa, peppermint) demonstrating >85% repellency. GC-MS analysis revealed 17 candidate compounds, with T4O exhibiting strong electrophysiological responses (0.031 ± 0.002 mV). Molecular docking confirmed its high binding affinity to mosquito odorant-binding proteins, suggesting its potential as an olfactory disruptor. In PMD-based binary formulations: TP2 (20% T4O) achieved 86.9 ± 1.8% spatial repellency, 30.6% higher than PMD alone; TP1 (10% T4O) provided 6.58 ± 0.38 h of skin protection, extending PMD's efficacy by 21.6%; TP5 (50% T4O) enhanced fumigation efficacy, reducing KT50 to 3.00 ± 0.32 min (78.7% decrease); TP3 (30% T4O) reduced LC50 by 17.2-25.0% against larval instars I-IV. This work demonstrates T4O's multidimensional enhancement of PMD's efficacy, offering an effective natural alternative to synthetic repellents.

This study explores the antioxidant activity of green tea (Camellia sinensis, GT) and peppermint (Mentha × piperita, PM) infusions, individually and in combination, focusing on how preparation methods affect their efficacy. Antiradical and intracellular antioxidant activity was assessed using DPPH, ABTS, and DCF assays, alongside interaction analysis via combination index (CI) and dose reduction index (DRI). HPLC analysis determined the polyphenolic profiles of GT and PM. GT showed the strongest antioxidant activity, with the lowest IC50 values (4.81 µg/mL in DPPH, 2.70 µg/mL in ABTS, 3.71 µg/mL in DCF), indicating potent radical-scavenging potential. PM exhibited moderate antiradical capacity but similar intracellular activity (IC50 = 3.80 µg/mL). Co-maceration followed by lyophilization of GT:PM extracts led to nearly additive interactions (CI~1.0) and allowed significant dose reduction (DRI up to 4.44). In contrast, post-mixed extracts showed assay-dependent effects, including antagonism in intracellular ROS inhibition (CI = 1.83). Equimolar mixtures of model polyphenols: EGCG, quercetin, and rosmarinic acid demonstrated enhanced effects, with the strongest synergy in ternary mixtures (CI = 0.67-0.86), potentially achievable in GT:PM combinations. These findings highlight that extract preparation critically influences antioxidant efficacy, supporting co-maceration as a promising strategy for developing effective functional formulations based on plant extract combinations.

BACKGROUND: The concurrent usage of herbal medicines with conventional therapies is an important concern in cancer treatment which can lead to unexpected consequences like herb-drug interactions. This study aimed to determine the prevalence of potential herb-drug interactions and to predict factors associated with herb-drug interactions for cancer patients. METHODS: This cross-sectional study was conducted among a convenience sample of 315 cancer patients referring to the oncology clinics of Kerman city in 2018. Data were collected via comprehensive face-to-face interviews and medical chart reviews. A drug interaction checker was used to determine herb-drug interactions. The information of patients was compared based on herb-drug interactions using bivariable logistic regression models, and predictors were determined by the multivariable logistic regression model. All analyses were performed by Stata software version 16. RESULTS: Of 262 patients (83.2% of the patients) who used herbal medicines, 209 patients [79.8% (95% Confidence Intervals (CI): 75.2 - 85.1)] had potential herb-drug interactions. Chamomile was the most popular herbal medicine (n = 163, 78.0%), and minor and moderate herb-drug interactions were caused by green tea (n = 34, 16.3%) and peppermint (n = 78, 37.5%). The number of chemotherapeutic agents (OR: 1.92, 95% CI: 1.43-2.58; P-value < 0.0001) and the experienced of pain during chemotherapy courses (OR = 2.22, 95%CI:1.00-4.94; P-value = 0.04) were some of the predictors of herb-drug interactions among cancer patients. CONCLUSION: Herbal medicine use during chemotherapy was found prevalent among cancer patients; of them, the experience of potential herb-drug interactions was highly frequent. Oncologists and clinical pharmacologists are recommended to take into account challenges associated with herb-drug interactions in their routine practices, particularly during chemotherapy among these patients. © 2023. The Author(s).

BACKGROUND: White tea, considered to be the oldest form of tea, is becoming a popular beverage for its organoleptic characteristics. Peppermint tea, used as a herbal remedy for centuries, is now also very popular throughout the world as herbal tea. What interested us was that in ancient China, peppermint was used in combination with tea as a detoxification or anti-inflammatory agent. However, there are few reports on the combined use of white tea and peppermint. Therefore, this study aims to investigate the antibacterial and anti-inflammatory activities of white tea in combination with peppermint. RESULTS: A synergistic inhibitory effect against four bacterial strains, especially against Staphylococcus argenteus, was observed in the combination of white tea and peppermint in vitro. In addition, the combined formula demonstrated a stronger anti-inflammatory effect in vivo than either of the two used alone, which was associated with the decrease of the pro-inflammatory cytokines of interleukin-6 (IL-6), interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). In a further mechanism study, it was found that white tea and peppermint inhibited the phosphorylation of p-IκB-α and mitogen-activated protein kinase (MAPK) at different degrees. While the enhanced anti-inflammatory effect of the combined formula was associated with the combination of NF-κB down-regulation and p-MAPK inhibition. CONCLUSION: In our study, it was for the first time shown that when white tea was combined with peppermint, the antibacterial and anti-inflammatory effects were enhanced. The results suggested an effective application of white tea in combination with peppermint as a potential antibacterial and anti-inflammatory functional food. © 2020 Society of Chemical Industry. © 2020 Society of Chemical Industry.

The checkerboard method was used to study the potential interactions between eight essential oils (Basil, Cinnamon, Eucalyptus, Mandarin, Oregano, Peppermint, Tea tree, and Thyme) when used as antibacterial agents against Bacillus cereus LSPQ 2872 and Paenibacillus amylolyticus ATCC 9995. The minimum inhibitory concentration (MIC) of each essential oil (EO) and the fractional inhibitory concentration (FIC) index for the binary combinations of essential oils (EOs) were determined. According to FIC index values, some of the compound binary combinations showed an additive effect; however, Thyme/Tea tree and Cinnamon/Thyme EOs exhibited a synergistic effect against P. amylolyticus and B. cereus, respectively. Cinnamon/Thyme EOs mixture exhibited no interactive effect against P. amylolyticus, but a synergistic effect against B. cereus. The combination of Oregano/Thyme EOs displayed the best antibacterial activity and showed a synergistic effect against B. cereus and P. amylolyticus bacteria. The Oregano/Thyme EOs mixture has potential application in food preservation to reduce the contamination of B. cereus and P. amylolyticus.

The effects of plant inoculation with plant growth-promoting rhizobacteria (PGPR) and those resulting from the exogenous application of salicylic acid (SA) or methyl jasmonte (MeJA) on total phenolic content (TPC) and monoterpenes in Mentha x piperita plants were investigated. Although the PGPR inoculation response has been studied for many plant species, the combination of PGPR and exogenous phytohormones has not been investigated in aromatic plant species. The exogenous application of SA produced an increase in TPC that, in general, was of a similar level when applied alone as when combined with PGPR. This increase in TPC was correlated with an increase in the activity of the enzyme phenylalanine ammonia lyase (PAL). Also, the application of MeJA at different concentrations in combination with inoculation with PGPR produced an increase in TPC, which was more relevant at 4 mM, with a synergism effect being observed. With respect to the main monoterpene concentrations present in peppermint essential oil (EO), it was observed that SA or MeJA application produced a significant increase similar to that of the combination with rhizobacteria. However, when plants were exposed to 2 mM MeJA and inoculated, an important increase was produced in the concentration on menthol, pulegone, linalool, limonene, and menthone concentrations. Rhizobacteria inoculation, the treatment with SA and MeJA, and the combination of both were found to affect the amount of the main monoterpenes present in the EO of M. piperita. For this reason, the expressions of genes related to the biosynthesis of monoterpene were evaluated, with this expression being positively affected by MeJA application and PGPR inoculation, but was not modified by SA application. Our results demonstrate that MeJA or SA application combined with inoculation with PGPR constitutes an advantageous management practice for improving the production of secondary metabolites from M. piperita.

Mentha piperita L. essential oil (EO) is employed for external use as antipruritic, astringent, rubefacient and antiseptic. Several studies demonstrated its significant antiviral, antifungal and antibacterial properties. The aim of this work is the study of the synergistic effects of M. piperita EO with antibacterials and antifungals that are widely available and currently prescribed in therapies against infections. The observed strong synergy may constitute a potential new approach to counter the increasing phenomenon of multidrug resistant bacteria and fungi. In vitro efficacy of the association M. piperita EO/drugs was evaluated against a large panel of Gram-positive and Gram-negative bacteria and yeast strains. The antimicrobial effects were studied by checkerboard microdilution method. The synergistic effect of M. piperita EO with gentamicin resulted in a strong growth inhibition for all the bacterial species under study. The synergistic effect observed for M. piperita EO and antifungals was less pronounced.

AIM: This study aimed to test biofilm inhibition activities of each of essential oils (EOs), main compounds of EOs and enzymes against pathogenic Klebsiella pneumoniae. METHODS AND RESULTS: The effect of seven EOs and three enzymes was tested on formation and eradication of K. pneumoniae biofilm. Peppermint oil showed a robust biofilm inhibitory effect, causing inhibition that ranged from 69·2 to 98·2% at 5 μl ml-1 . Thyme oil was found to have the best biofilm eradication ability, causing eradication that ranged from 80·1 to 98·0% at 10 μl ml-1 . The most effective EOs were analysed by GC/MS, to determine the major chemical constitutes of each oil. Pure menthol was found to cause 75·3-97·5% biofilm inhibition at 2·5 μg ml-1 , whereas thymol caused 85·1-97·8% biofilm eradication at 5 μg ml-1 . However, moderate inhibition activity was detected for α-amylase and bromelain, while poor activity was detected for β-amylase. Ciprofloxacin combination with thyme oil and thymol was found to enhance antibiotic activity, and affect biofilm cell viability. The observed inhibitory/eradication activity on K. pneumoniae biofilms was confirmed by scanning electron microscopy. CONCLUSIONS: Thyme and peppermint EOs, and their active components are promising antibiofilm agents alone and/or in combination with ciprofloxacin to inhibit/eradicate biofilms of K. pneumoniae. SIGNIFICANCE AND IMPACT OF THE STUDY: The presented results suggest the potential application of EOs against infections, caused by biofilm-producing K. pneumoniae, to prevent biofilm formation or decrease their resistance threshold. Moreover, the combination of EOs with ciprofloxacin minimizes the antibiotic concentration used and accordingly the potential accompanying toxic side effects. © 2018 The Society for Applied Microbiology.

The antifungal activities of eight essential oils (EOs) namely basil, cinnamon, eucalyptus, mandarin, oregano, peppermint, tea tree and thyme were evaluated for their ability to inhibit growth of Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus and Penicillium chrysogenum. The antifungal activity of the EOs was assessed by the minimum inhibitory concentration (MIC) using 96-well microplate analysis. The interactions between different EO combinations were done by the checkerboard technique. The highest antifungal activity was exhibited by oregano and thyme which showed lower MIC values amongst all the tested fungi. The antifungal activity of the other EOs could be appropriately ranked in a descending sequence of cinnamon, peppermint, tea tree and basil. Eucalyptus and mandarin showed the least efficiency as they could not inhibit any of the fungal growth at 10,000 ppm. The interaction between these two EOs also showed no interaction on the tested species. A combined formulation of oregano and thyme resulted in a synergistic effect, showing enhanced efficiency against A. flavus and A. parasiticus and P. chrysogenum. Mixtures of peppermint and tea tree produced synergistic effect against A. niger. Application of a modified Gompertz model considering fungal growth parameters like maximum colony diameter, maximum growth rate and lag time periods, under the various EO treatment scenarios, showed that the model could adequately describe and predict the growth of the tested fungi under these conditions.

PURPOSE: In recent years, a number of natural medicines have been reported to have inductive or inhibitive effects on the activity of drug metabolizing enzymes, upon co-administration with prescribed medicines. However, information regarding natural medicine-drug interactions that influence drug metabolism is limited owing to the lack of efficient screening method for such interactions. Therefore, to understand whether P450 activity is affected by natural medicine in small intestines, we have established frozen recombinant P450-expressing cells infected with human CYP3A4 expressing adenovirus (Ad-CYP3A4) to evaluate the effect of natural medicines on CYP3A4 activity. METHODS: Ad-CYP3A4 cells were created by infecting HepG2 cells with Ad-CYP3A4 at 10 multiplicity of infection (MOI) and these cells were stored using cryopreservation medium (fAd-CYP3A4 cells) to obtain long-term consistent data and stable supplies of cells expressing a constant level of CYP3A4 activity. RESULTS: The CYP3A4 activity in fAd-CYP3A4 cells remained unaffected at the end of each frozen period (0, 1, 2, and 6 months). Inhibitory effect on CYP3A4 activity by typical inhibitors (ketoconazole, hyperforin) and natural medicines (Cat's Claw, Devil's Claw, Feverfew, Peppermint Oil, Red Clover, and Siberian Eleuthero) were evaluated. The inhibitors had nearly equal IC50 values in fAd-CYP3A4 cells, Ad-CYP3A4 cells and recombinant CYP3A4 microsomes. Cat's Claw, Peppermint Oil and Siberian Eleuthero inhibited CYP3A4 activity more potently than 0.1 μM ketoconazole in fAd-CYP3A4 cells. CONCLUSIONS: In the present study, we have successfully developed a highly reproducible system to evaluate CYP3A4 inhibition in small intestines by natural medicines.

PURPOSE: This study was done to examine the effects of oral care with essential oil in improving the oral health status of hospice patients with terminal cancer. METHODS: The participants were 43 patients with terminal cancer admitted to K hospital in G city, Korea. Twenty-two patients were assigned to the experimental group and 21 to the control group. Participants in the experimental group received special mouth care with essential oil (application of essential oil mixture consisting of geranium, lavender, tea tree, and peppermint). The control group received special mouth care with 0.9% saline. The special mouth care was performed twice daily for one week in both groups. The scores for subjective oral comfortness, objective oral state, and numbers of colonizing Candida albicans were measured before and after the treatment. RESULTS: The score for subjective oral comfortness and objective oral state were significantly higher in the experimental group compared to the control group. The numbers of colonizing Candida albicans significantly decreased in the experimental group compared to the control group. CONCLUSION: Oral care with essential oil could be an effective oral health nursing intervention for hospice patients with terminal cancer.

Pain perception is a multidimensional process encompassing sensory, affective, and cognitive components. In recent years, accumulating evidence suggests that olfactory stimulation can modulate pain perception through neurophysiological and emotional mechanisms. However, systematic understanding of how olfactory processing contributes to analgesia across different experimental and clinical contexts remains limited. This review aims to provide an integrative overview of current evidence regarding the role of olfactory pathways in pain modulation, summarizing findings from human and animal studies that investigated the analgesic potential of volatile compounds. A systematic literature search was conducted across PubMed, Web of Science, OVID, Cochrane Reviews, Embase, CNKI, and WanFang databases. A total of 4360 records were retrieved, screened for relevance, and refined to 147 studies, including 138 human-based and 9 animal-based investigations. Lavender, peppermint, chamomile, bergamot, and citrus-derived oils were most frequently associated with analgesic outcomes. Olfactory stimulation was found to modulate pain via central integrative circuits involving affective, autonomic, and sensory processing, engaging conserved pathways that support descending pain inhibition. Olfactory stimulation by specific flavor and fragrance compounds holds translational potential for non-pharmacological pain management. Nevertheless, methodological standardization and mechanistic validation are necessary to advance this emerging field. © 2026 Federation of American Societies for Experimental Biology.

This study synthesizes the evidence on effective interventions for the prevention of breastfeeding-related nipple-areolar injuries. A systematic review was performed and guided by the evidence synthesis manual of the Joan Briggs Institute, carried out in six databases, with only intervention studies. Interventions with a positive outcome for the prevention of nipple-areolar lesions were considered effective. Methodological quality was assessed by the Grading of Recommendations Assessment, Development and Evaluation. The final sample of 14 articles found the following to be effective strategies: educational practices (simulations and demonstrations of the breastfeeding technique, with a qualified professional or by video) and the use of peppermint (aqueous solution or gel), extra virgin olive oil, honey, guaiazulene ointment, and venix caseosa. Each intervention was used in specific situations and ways, which should be considered for use in clinical practice. The interventions discussed can help prevent nipple-areolar lesions and breastfeeding difficulties, encouraging breastfeeding.

CONTEXT: Collective evidence has highlighted the strong interplay of the diet with mood and mental health. The diet is a topic of interest from a public health perspective as it may provide an adoptable lifestyle approach for improving mental health in the population. Among dietary constituents, flavonoids have been identified as particularly relevant for mental health. OBJECTIVE: The aim of this review was to evaluate the effects of dietary flavonoids on mental health in healthy populations across the lifespan. DATA SOURCES: Experimental human trials with study participants of any age, sex, or ethnicity were eligible for inclusion in this review if they included supplementation with at least 1 flavonoid-rich food (<15 mg/100 g/mL flavonoid constituents) either as lyophilized powder or whole food and measured at least 1 mood outcome. The PubMed, Web of Science, and Scopus databases were searched with no restriction on publication start date to October 2024. The Evidence Analysis Manual Quality Criteria Checklist (QCC) from the Academy of Nutrition and Dietetics Evidence Analysis Library® was used to assess methodology and risk of bias. DATA EXTRACTION: A total of 38 experimental studies met eligibility criteria, 13 exploring acute effects of flavonoids and 25 utilising a chronic design. DATA ANALYSIS: The included studies explored a range of flavonoid-containing foods, with a majority (n = 9) utilizing cocoa as an intervention vehicle. Five of the 13 acute studies reported benefits (3 wild blueberry, 1 purple grape juice, 1 orange juice); and 12 of 25 chronic studies showed findings in favor of flavonoid supplementation (2 cocoa, 2 blueberry, 2 cherry, 1 peppermint, 1 orange juice, 1 walnut, 1 green tea, and 2 mixed foods), suggesting chronic supplementation may benefit mood and mental health. CONCLUSIONS: Further studies are required to understand the effects of dietary flavonoids utilizing consistent methodology and dosing, as well as to explore mechanistic links with mental health across the lifespan. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration No. [CRD42021293040]. © The Author(s) 2025. Published by Oxford University Press on behalf of the Interna

AIM: To evaluate the effectiveness of aromatherapy in reducing physiological and psychological symptoms during pregnancy. METHODS: This review followed the JBI methodological guidelines for Systematic Reviews of Effectiveness and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Guided by the PICO framework: population (P) comprised pregnant women; intervention (I) was aromatherapy; comparison (C) included conventional treatment, other complementary therapies, or placebo; outcomes (O) involved physiological and psychological symptoms. Experimental and quasi-experimental studies involving pregnant women who received aromatherapy to manage these symptoms were included. Nine databases were searched in January 2022 and August 2024, including Medline, CINAHL, SCOPUS, and Web of Science, yielding 1063 registers. RESULTS: Twenty-one studies were included (16 randomised controlled trials and five quasi-experimental), conducted in Iran, Indonesia, Japan, and Taiwan. Meta-analysis revealed that aromatherapy significantly reduced nausea and vomiting (standardised mean difference [SMD] = -0.92; 95 % confidence interval [CI]: -1.09, -0.74) and maternal anxiety (SMD = -0.67; 95 % CI: -0.95, -0.40). Improvements in sleep quality were also noted (mean difference = -1.55; 95 % CI: -2.09, -1.01). CONCLUSION: Aromatherapy appears to be an effective and safe option for alleviating certain gestational symptoms. Citrus essential oils such as peppermint, bitter orange, lemon, and mint have been shown to reduce nausea and vomiting. Citrus aurantium, Rosa damascene, mint, and orange blossom have demonstrated efficacy in reducing maternal anxiety. Citrus aurantium, orange blossom, and lavender may also improve sleep quality. However, further high-quality studies with larger sample sizes are warranted. REGISTRATION: This systematic review was registered in PROSPERO.

BACKGROUND: Pressure injuries (PIs) are a major global health challenge. As PI-related healthcare costs continue to rise and patient safety is increasingly impacted, nurses are actively working to design and implement effective prevention strategies, particularly focusing on skin care, to prevent PIs in high-risk patients. Recent advances in incorporating plant-based topical agents into comprehensive care bundles for PI prevention have shown promising potential, though the results remain somewhat variable. OBJECTIVE: To evaluate effectiveness of plant-based topical agents in preventing PIs and their impact on PI incidence, time to PI formation and adverse events. METHODS: A systematic review was performed and reported according to the PRISMA guidelines. PubMed, Cochrane Library, EMBASE, PROQUEST Health Research Premium Collection, Clinical Key, MEDLINE, CINAHL, Google Scholar, and Airiti Library from database inception to May 2024.Two researchers independently screened randomised controlled trials published in Chinese and English. Screening, data extraction, and quality evaluation were independently performed by two reviewers using the Cochrane RoB 2.0 tool and GRADE to assess the strength of evidence. Disagreements were resolved by a third reviewer. Due to the heterogeneity of the intervention, a meta-analysis was not feasible; consequently, the findings were synthesised narratively. RESULTS: Ten randomised controlled trials were included, consisting of 2364 patients without PI and no sensitivity to plant-based topical agents. The plant-based topical agents used in the interventions included olive oil (n = 6), sweet almond oil (n = 1), aloe vera gel (n = 2), aloe vera gel-olive oil compound (n = 1), peppermint oil gel (n = 1), and henna paste (n = 1). PI incidence was lower in the intervention groups compared to control groups, but the time to PI formation was inconsistent. No or mild adverse events were reported. The overall risk of bias was categorised as 'some concerns' (n = 5) and 'high risk' (n = 5). CONCLUSIONS: This review found that different plant-based topical agents can be effective in preventing PI and can be an option for PI prevention. Higher-qual

BACKGROUND: Infants who are not exclusively breastfed are more vulnerable to gastroenteritis, respiratory illness, and type 1 diabetes mellitus. Mothers who do not breastfeed their infants are at a higher risk of cancer. This systematic review and meta-analysis aimed to synthesize evidence regarding the effectiveness of applying lanolin, aloe vera, and peppermint for alleviating nipple pain and nipple trauma among lactating mothers. METHODS: Electronic databases, including PubMed (MEDLINE), Cochrane, Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, Web of Science, Scopus, and Clinical Key, were searched for studies published in English from January 2000 to December 2022. Nipple pain and nipple trauma were the primary outcomes analysed, and a meta-analysis was conducted via RevMan v5.4. RESULTS: The reviewed trials involved 1,495 participants from 11 studies, with an average participant age of 29 ± 5 years. The application of lanolin significantly reduced nipple pain and nipple trauma in lactating mothers. The application of peppermint significantly reduced nipple trauma in lactating mothers. CONCLUSION: The application of lanolin or peppermint is a beneficial preventive intervention for reducing nipple trauma and pain. © 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

CONTEXT: There is still debate regarding the effect of nutritional interventions in improving irritable bowel syndrome (IBS) symptoms. OBJECTIVES: The aim was to examine the evidence certainty and validity of all existing meta-analyses of intervention trials on nutritional interventions in patients with IBS. DATA SOURCES: Scopus, PubMed, and Web of Science were reviewed until June 2023. DATA EXTRACTION: Meta-analyses assessing the impacts of nutritional interventions in adults with IBS were entered. Effect sizes of nutritional interventions were recalculated by applying a random-effects model. GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) was implemented to determine evidence certainty. RESULTS: A total of 175 trials in 58 meta-analyses were entered describing the effects of 11 nutritional interventions on IBS-related outcomes. Nutritional interventions had beneficial effects on some IBS-related outcomes. For instance, soluble fiber, peppermint oil, and aloe vera improved IBS symptoms, and vitamin D3 and curcumin improved IBS symptom severity. Tongxieyaofang improved abdominal pain severity and stool frequency. Nevertheless, these outcomes have mainly shown small effects and low to very low evidence certainty. With regard to abdominal pain after probiotic supplementation (relative risk [RR]: 4.04; 95% confidence interval [CI]: 2.36, 6.92; GRADE = moderate) and IBS symptoms after a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet (RR: 1.48; 95% CI: 1.14, 1.93; GRADE = moderate), there was evidence that probiotics and a low-FODMAP diet can confer clinical and favorable effects. CONCLUSION: The current review does not support nutritional interventions for improving IBS symptoms. With regard to probiotics and a low-FODMAP diet, considering limitations like short-term study duration, there was an influential clinical impact. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42023429991. © The Author(s) 2024. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: [email protected].