Bergamot Mint Research Articles

Effects of Mint Oils on the Human Oral Microbiome: A Pilot Study.

The oral microbiome is a diverse and complex ecosystem essential for maintaining oral and systemic health. Our study is the first to define the oral microbial community in Egyptian young adults and investigate the effects of natural antimicrobials on the oral microbiome. SuperMint (SM) is a proprietary blend of peppermint, Japanese mint, bergamot mint, and spearmint essential oils encapsulated in a tiny soft beadlet. This work aimed to evaluate the effects of SM beadlets on the oral microbiome. This study recruited twenty healthy participants. A baseline investigation of the oral microbiome of the selected participants was performed by collecting saliva and swab samples before treatment. Treatment included chewing four SM beadlets twice a day for 7 days, and then, post-administration saliva and swab samples were collected at the end of treatment. The oral microbiome samples were analyzed by the high-throughput amplicon sequencing of 16S rRNA gene fragments, and the community composition was determined. The results showed that the abundance of some microbial genera and families decreased after using SM, including Prevotella, Streptococcus, Neisseria, and Haemophilus. However, some genera showed inconsistent patterns. We also found that the subject's gender and SM usage were significantly associated with diverse microbial composition. The results suggest that SM treatment decreased the abundance of several bacteria associated with halitosis and periodontal diseases, such as Actinomyces and Streptococcus. Furthermore, Corynebacterium species increased and Streptococcus decreased after SM usage. More research is needed to fully understand the antimicrobial effects of mint oils and their potential applications in maintaining good oral health.

The Vapor Phase of Selected Essential Oils and Their Antifungal Activity In Vitro and In Situ against Penicillium commune, a Common Contaminant of Cheese.

This study aimed to determine the in vitro and in situ antifungal activity of (14) selected essential oils (EOS), namely clove, thyme, red thyme, litsea, eucalyptus, niaouli, fennel, anise, cumin, basil, rosemary, sage, bergamot mint, and marjoram, by vapor contact against the growth of two strains of Penicillium commune (KMi-183 and KMi-402). Furthermore, to exclude the negative effect of EOs on the lactic acid bacteria (LABs) (Streptococcus spp.) on cheeses, their influence was monitored. Next, the sensory evaluation of cheese treated by EOs was evaluated. The results show that litsea and clove EOs were the most effective in the vapor phase against both tested strains. These EOs were characterized by the highest amount of α- (40.00%) and β-Citral (34.35%) in litsea and eugenol (85.23%) in clove. The antitoxicogenic activity of less effective (in growth inhibition) EOs on cyclopiazonic acid (CPA) production by the tested strains was also observed. The growth of Streptococcus spp. (ranging from 8.11 to 9.69 log CFU/g) was not affected by the EOs in treated cheese. Even though the evaluators recognized some EOs in sensory evaluation by the triangle test, they did not have a negative effect on the taste and smell of the treated cheeses and were evaluated as edible. The antifungal activity of EOs against several types of microscopic fungi and their effect on the sensory properties of treated foods needs to be further tested to achieve the most effective protection of foods from their direct contaminants.

Chiral differentiation of terpenoids in bergamot mint (Mentha citrata) cultivar Kiran: A non-menthol mint essential oil

Mentha citrata, popularly known as bergamot mint,is one of the mint species which does not possess menthol, a terpenoid chemical constituent that gives the name Mentha to the genus. CSIR-CIMAP has developed a cultivar cv. Kiran by induced mutagenesis. Gas chromatographic (GC) analysis of the essential oil of this cultivar shows linalool (44.9 %) and linalyl acetate (28.7%) as the major constituents. Further, the enantioselective GC analysis of the essential oil to determine the enantiomeric ratio of linalool and linalyl acetate indicate that (R)-(-)-linalool is in 78.8% excess over its enantiomer, whereas (R)-(-)-linalyl acetate is present as a single enantiomer. Other chiral terpenoids resolved in the enantioselective GC analysis are (1S)-(-)-ß-pinene as the major exclusive enantiomer with 93.0% enantiomeric excess and (-)-sabinene with 60.2% enantiomeric excess than its enantiomers. The significance of enantiomer separation and enantiomeric excess of chiral terpenoids in the essential oil of M. citrata cv. Kiran is of great importance in ascertaining the authenticity of this essential oil.

Chemical Composition and Biological Screening of Essential Oils of Zanthoxylum armatum DC Leaves

Essential oil (ZVO) from Zanthoxylum armatum was extracted through hydro-distillation and tested for various biological activities. A total of 34 chemical constitutes were identified through GC-MS, the major constituents of ZVO were beta- Linalool (53.05%), Bergamot mint oil (12.73%), alpha-Limonene diepoxide (11.39%), alpha- pinene (4.08%), beta- Myrcene (3.69%) and D-Limonene (3.10%). ZVO showed significant antispasmodic effect and relaxed the isolated rabbit jejunum in spontaneous as well as in potassium chloride induced contraction. The maximum effect was observed against M. leutus followed by B. subtilis with percent zone of inhibition 28.45 and 20.45, respectively. A concentration dependent effect was also observed against available species of fungi. The maximum effect was observed against M. canis, C. albicans and C. glabrata with percent activity 84.87, 83 and 79, respectively. The oils were also found to have Cytotoxic and Phytotoxic potential.

Efficacy of Mentha × piperita and Mentha citrata essential oils against housefly, Musca domestica L.

The essential oils of two Mentha species: peppermint, Mentha piperita, and bergamot mint, Mentha citrata (both, Lamiales: Lamiaceae) were evaluated for its chemical composition and insecticidal activity against the housefly, Musca domestica L. (Diptera: Muscidae). The gas chromatographic–mass spectrometry (GC–MS) analysis of M.×piperita revealed menthol (26.53%), menthone (25.83%), menthyl acetate (7.35%) while M. citrata oil showed linalool acetate (26.69%) and d-linalool (24%) as major constituents. Analysis of M.×piperita oil vapour depicted increased menthone content while M. citrata oil vapour showed increase in linalool acetate and d-linalool content as compared to respective oils. Insecticidal activity of oils was assessed against larvae and pupae of housefly, through two different bioassays: contact toxicity and fumigation. For the larvicidal assay, lethal concentration, LC50 of M.×piperita oil, was 0.54μl/cm2 (contact toxicity) and 48.4μl/L (fumigation) while for M. citrata oil, it was 1.39μl/cm2 (contact toxicity) and 61.9μl/L (fumigation). Oil treated larvae showed swollen spinose areas and proliferation of spinous cells in the intersegmental region, and bleb formation at the anterior region. M.×piperita oil treated larvae showed significantly higher and acute proliferation of spinose cells and bleb formation than M. citrata oil. Pupicidal effectivity was measured in terms of percentage inhibition rate (PIR). For, M.×piperita oil, PIR was 100% for both contact toxicity and fumigation toxicity assay while M. citrata oil showed PIR of 68% and 57% for contact toxicity and fumigation assay, respectively. The present study established higher pupicidal and larvicidal efficacy of M.×piperita than M. citrata essential oil in contact toxicity as well as fumigation assay. The study demonstrates potentiality of both the Mentha oils as a control agent against housefly with M. piperita being better candidate among the two.

Repellent, larvicidal and pupicidal properties of essential oils and their formulations against the housefly, Musca domestica

The essential oils of six plant species [peppermint, Mentha piperita, and bergamot mint, Mentha citrata (both, Lamiales: Lamiaceae); blue gum, Eucalyptus globulus (Myrtales: Myrtaceae); lemongrass, Cymbopogon citratus, and khus grass, Vetiver zizanoides (both, Poales: Poaceae), and turmeric, Curcuma longa (Ziniberales: Zingiberaceae)] were screened for repellent, larvicidal and pupicidal activities against the housefly, Musca domestica L. (Diptera: Muscidae). Subsequently, emulsifiable concentrate (EC) formulations of the two most effective oils were prepared and tested in the laboratory as well as in the field. In repellency bioassays, M. piperita (RC(84) , 61.0 µg/cm(2) ) was found to be most effective, followed by E. globulus (RC(84) , 214.5 µg/cm(2) ) and C. citratus (RC(84) , 289.2 µg/cm(2) ). Formulated M. piperita and E. globulus showed RC(84) values of 1.6 µg/cm(2) and 4.1 µg/cm(2) , respectively. Formulated M. piperita and E. globulus achieved larval mortality (LC(50) ) in 72 h at 5.12 µg/cm(2) and 6.09 µg/cm(2) , respectively. In pupicidal bioassays, crude oils of M. piperita and E. globulus suppressed the emergence of adult flies by 100%. Field experiments with the M. piperita formulation showed reductions in fly density (number of flies/h) of 96% on treated cattle and 98% on treated plots. This study demonstrates the effectiveness of EC formulations of selected essential oils in reducing housefly populations in field conditions.

Enantiomeric Composition of (3R)-(-)- and (3S)-(+)-Linalool in Various Essential Oils of Indian Origin by Enantioselective Capillary Gas Chromatography-Flame Ionization and Mass Spectrometry Detection Methods

Enantiomeric ratios of linalool have been determined in various authentic essential oils of Indian origin using 10% heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin as a chiral stationary phase. A complete enantiomeric excess (ee) for (3S)-(+)-linalool was characteristic of Lippia alba and Cinnamomum tamala leaf oils while less than 90% excess was noticed in Zanthoxylum armatum leaf, Zingiber roseum root/rhizome and Citrus sinensis leaf oils. On the contrary, an enantiomeric excess of (3R)-(-)-linalool characterizes essential oils of basil (100% for Ocimum basilicum) and bergamot mint (72 to 75% for Mentha citrata). Notably, some essential oils containing both enantiomers in equal ratios or in racemic forms are rose, geranium, lemongrass and Origanum. The enantiomeric composition studies are discussed as indicators of origin authenticity and quality of essential oil of Indian origin.

The application of a SERS fiber probe for the investigation of sensitive biological samples

The applicability of an etched and silver or gold coated SERS fiber probe in combination with a commercially available laboratory micro-Raman setup or a home built mobile micro-Raman setup to perform on-site field measurements was evaluated and successfully tested on different biological samples. The SERS fiber probe allows one to perform measurements with high spatial resolution. Simultaneously, the laser power used for Raman spectroscopy on biological samples as compared with conventional Raman experiments can be reduced by more than two orders of magnitude. This experimental arrangement was tested to investigate sensitive biological samples like mint plants (Bergamot mint, spear mint) and citrus fruits (kumquat). Furthermore, traces of fungicides on wine leaves were detected by means of such a SERS fiber probe setup.

Molecular cloning and characterization of a new linalool synthase

Mentha citrata Ehrh. (bergamot mint; Lamiaceae) produces an essential oil containing only the acyclic monoterpenol (−)-3 R-linalool and its acetate ester. A cloning strategy based upon the assumption that the responsible monoterpene synthase would resemble, in sequence, monoterpene cyclases from this plant family yielded a cDNA encoding the (−)-3 R-linalool synthase. The nucleotide sequence of this monoterpene synthase is similar to those of several monoterpene cyclases from the mint (Lamiaceae) family (62–72% identity), but differs substantially from that of 3 S-linalool synthase from Clarkia (41% identity; this composite gene appears to be of recent origin) and from that of 3 R-linalool synthase from Artemisia (52% identity; the functional role of this gene is uncertain). Heterologous expression in Escherichia coli of a truncated version of the cDNA (in which the plastidial transit peptide was deleted) allowed purification and characterization of the enzyme, which was shown to possess most properties similar to other known monoterpene cyclases, but with a K m value for the natural substrate, geranyl diphosphate, of 56 μM with k cat of 0.83 s −1. These kinetic constants for this 3 R-linalool synthase are higher than those of any defined monoterpene cyclase, but the kinetic efficiency does not approach that reported for the 3 S-linalool synthase from Clarkia. Although linalyl diphosphate is an enzyme-bound intermediate of monoterpene cyclase reactions, this tertiary allylic isomer of the geranyl substrate is not an efficient precursor of linalool with the M. citrata synthase. Modeling of the active site of this linalool synthase from Mentha and comparison to the modeled active sites of phylogenetically related monoterpene cyclases revealed structural differences in the binding of the diphosphate moiety which initiates the ionization step of the electrophilic reaction sequence and in the access of water to the active site to permit stereoselective quenching of the initially formed carbocationic intermediate to produce 3 R-linalool.

Development of suitable sampling methods for the arthropods of four mint species

In order to develop suitable sampling methods for the arthropods of four mint species, namely Japanese mint (Mentha arvensis L.- var. Hybrid 77), peppermint (M. piperita L.-var. MP-1), bergamot mint (M. citrata Ehrhrt- var. Kiran) and spearmint (M. spicata L.- var. MSS-5), six general sampling methods viz. ground cloth, sticker, sweep net, water trap, whole plant observation (WPO) and whole plant harvest (WPH) were evaluated under field conditions at the Research Farm of Central Institute of Medicinal and Aromatic Plants, Lucknow, India. The mint pest complex on all the mint species included Aphis craccivora, Chrotogonus trachypterus, Leptocorisa varicornis, Coccinella septempunctata, Bemisia tabaci, an unidentified lygeid bug, Brumoides suturalis, Propylea dissecta, Crysolina exanthematica, Dysdercus cingulatus and Plusia orichalcea. Overall, the ground cloth, sweep net, water trap and sticker methods were found to be more efficient and successful for sampling the arthropods of mint crops than the WPO and WPH methods. The shortest sampling time was required when using the sticker (3–6 seconds per sweep) and the sweep net (7–8 seconds per sweep) methods. This information may be useful in developing an integrated pest management programme for mint.

Irrigation and nitrogen requirements of Bergamot mint on a sandy loam soil under sub-tropical conditions

A field experiment was conducted with Bergamot mint ( Mentha citrata Ehrh) var. Kiran at Lucknow, India in 1992 and 1993 under four soil moisture regimes (0.6, 0.9, 1.2 and 1.5 irrigation water: cumulative pan evaporation (IW:CPE) ratio) and four levels of nitrogen (0, 80, 160, 240 kg ha −1). Soil moisture regimes maintained at 1.2 IW:CPE ratio significantly increased the crop growth, and herb and essential oil yields as compared with those having 0.6 and 0.9 IW: CPE ratio. The former produced 86.4% and 10.0% higher fresh herbage than the latter two moisture regimes, with a 63% and 12.7% increase in essential oil yield, respectively. Application of 160 kg N ha −1 was found to be the best with respect to the yield of the crop, but increased levels beyond this did not cause deleterious effects on the synthesis of monoterpenes in the essential oil. High moisture regimes maintained during summer months proved significantly better for efficient utilization of water and nutrient by the crop. The quality of the essential oil in terms of its two major constituents, linalool and linalyl acetate increased favourably up to 1.2 IW:CPE ratio, while the former decreased and the latter improved slightly with the higher moisture conditions prevailed during both the harvest. Higher rate of N fertilization (240 kg ha −1) favoured the synthesis of linalool, a major constituent of essential oil only during the first harvest. It is concluded that the Bergamot mint should be irrigated at 1.2 IW:CPE ratio with an application of 160 kg N ha −1 in the sub-tropical climate of India

Response of mint species to nitrogen fertilization

SUMMARYHerbage and oil yields of Mentha arvensis (Japanese mint), M. piperita (peppermint) and M. spicata (spearmint) increased significantly with N fertilization up to 100 kg N/ha and those of M. citrata (bergamot mint) with up to 150 kg N/ha. Plant height, leaf: stem ratio and leaf area index increased with N application; and oil content decreased in all the species. Economic optimum doses of N for M. arvensis, M. piperita and M. spicata were 167, 153 and 145 kg N/ha, respectively and their oil yields expected from the response equation were 190, 103 and 50 kg/ha, respectively. The calculated optimum fertilizer rate for M. citrata was 225 kg N/ha, giving a yield of 193 kg oil/ha. Oil quality did not vary appreciably with N fertilization.

Essential Oils and their Constituents XXIII: Chemotaxonomy of the Genus Mentha

Essential oils derived from Mentha aquatica L.; M. citrata Ehrh. (bergamot mint); M. pulegium L. (European and North African pennyroyal); Hedeoma pulegioides (L.) Pers. (American pennyroyal); M. rotundifolia and M. sylvestris L. were examined by gas-liquid partition chromatography using a polar (SAIB) and nonpolar (Ucon) substrate, respectively. Quantitative data illustrating the extent of compositional differences between these products are presented and compared with similar criteria of authenticity for M. arvensis (mint); M. piperita (peppermint); M. cardiaca, M. spicata , and M. viridis (spearmints). The occurrence of isopiperitenone as a major constituent of M. rotundifolia derived from a French mutant strain and the detection of several terpenoids occurring as trace constituents in these species are reported for the first time. Correlation of the chemical data illustrates their value in plant classification.

Essential Oils and Their Constituents XX: Detection and Estimation of Menthofuran in Mentha arvensis and Other Mint Species by Coupled Gas-Liquid—Thin-Layer Chromatography

The occurrence of menthofuran in Mentha arvensis is reported for the first time. From 0.01 to 0.04 per cent of the heterocycle was determined by means of coupled gas-liquid—thin-layer chromatography in genuine essential oils obtained from plants grown in Argentina, Brazil, Formosa, India, Japan, and South Africa. Its presence at such low concentrations could not be detected by conventional chemical tests, e.g., Flückiger's reaction, or by modern instrumental techniques, including ultraviolet and infrared spectrophotometry applied to analytical specimens directly. The classical distinction between Mentha piperita (peppermint) and M. arvensis (mint), ostensibly based on the presence or absence of menthofuran, is therefore no longer justifiable. Other mint species, including spearmints (Mentha cardiaca Gerard ex Baker cultivar Scotch or Highland spearmint, Mentha spicata L. cultivar common or native American spearmint, and Mentha viridis), pennyroyal (Mentha pulegium L. and Hedeoma pulegioides (L.) Pers.), bergamot mint (Mentha citrata Ehrh.), Mentha sylvestris L., and Mentha rotundifolia, contained trace amounts of menthofuran also. The experimental data suggest a reappraisal of presently acknowledged concepts regarding both biogenesis and chemotaxonomy of the genus Mentha. The occurrence of menthofuran in Mentha arvensis is reported for the first time. From 0.01 to 0.04 per cent of the heterocycle was determined by means of coupled gas-liquid—thin-layer chromatography in genuine essential oils obtained from plants grown in Argentina, Brazil, Formosa, India, Japan, and South Africa. Its presence at such low concentrations could not be detected by conventional chemical tests, e.g., Flückiger's reaction, or by modern instrumental techniques, including ultraviolet and infrared spectrophotometry applied to analytical specimens directly. The classical distinction between Mentha piperita (peppermint) and M. arvensis (mint), ostensibly based on the presence or absence of menthofuran, is therefore no longer justifiable. Other mint species, including spearmints (Mentha cardiaca Gerard ex Baker cultivar Scotch or Highland spearmint, Mentha spicata L. cultivar common or native American spearmint, and Mentha viridis), pennyroyal (Mentha pulegium L. and Hedeoma pulegioides (L.) Pers.), bergamot mint (Mentha citrata Ehrh.), Mentha sylvestris L., and Mentha rotundifolia, contained trace amounts of menthofuran also. The experimental data suggest a reappraisal of presently acknowledged concepts regarding both biogenesis and chemotaxonomy of the genus Mentha.

Stainless chromium steels

Mentha is a genus of perennial aromatic herbs belonging to family Lamiaceae, distributed mostly in temperate and sub-temperate regions. The herb (foliage) on distillation yields essential oil containing a large variety of aroma chemicals in varying composition. These oils and their aroma chemicals command a huge and world-wide demand in international trade. The genus contains about 25 species, of which Japanese mint (M. arvensis), Pepper mint (M. piperita) Spear mint (M. spicata) and Bergamot mint (M. citrata) are the better known species of commerce for their oil and aroma isolates like menthol, carvone, linalyl acetate, and linalool, etc., for use in pharmaceutical, food, flavor, cosmetics, beverages and allied industries. Peppermint, also known as black mint, candy mint or Mitcham commercially, is a source of fragrant volatile essential oil, known for its sweet flavor. Peppermint oil is one of the most popular and widely used essential oils in flavoring of pharmaceuticals and preparations for oral care, cough syrups, chewing gums, confectionery and beverages. The leaves and also its oil have medicinal properties as a carminative and gastric stimulant. The oil has been reported to have antibacterial, antiviral, anti-parasitic and antifungal activities.