Plants of Genus Mentha: From Farm to Food Factory

Mechanism of Peppermint Extract-Induced Delay of 'Packham's Triumph' Pear (Pyrus communis L.) Postharvest Ripening

Postharvest ripening is correlated to the quality and shelf life of European pear fruit. In this study, the effects of peppermint extract on fruit phenotype, related physiological activities, and aroma components during postharvest ripening of the European pear variety 'Packham's Triumph' were examined. Fruit treated with 2.0 g L-1 peppermint extract for 12 h showed delayed softening by 4 d compared with that of the untreated control group. The peak values of ethylene and respiratory rate in fruit were reduced to a certain extent after peppermint extract treatment; however, the peppermint extract did not delay the occurrence of the respiratory climacteric peak. Peppermint extract treatment also did not significantly increase the content of the characteristic peppermint aroma in pear fruit. Further, widely targeted metabolome analysis revealed 298 significantly different metabolites, with flavonoids (40%) and lipid compounds (15%) accounting for the highest proportion on the first day after treatment. The Kyoto Encyclopedia of Genes and Genomes pathway result showed significant enrichment in the metabolic pathways of biosynthesis of flavonoid, isoflavonoid, flavone and flavonol, linoleic acid, and alpha-linolenic acid metabolism following peppermint extract treatment. The combined analysis of transcriptome and metabolome data showed significant enrichment in linoleic acid metabolism and alpha-linolenic acid metabolism on the first, third, and fifth days after peppermint extract treatment. This study indicates that peppermint extract mainly affects the pear fruit softening process in the early stage after treatment.

Morphological and genetic evidence suggest gene flow among native and naturalized mint species

PREMISE

Cultivation and naturalization of plants beyond their natural range can bring previously geographically isolated taxa together, increasing the opportunity for hybridization, the outcomes of which are not predictable. Here, we explored the phenotypic and genomic effects of interspecific gene flow following the widespread cultivation of Mentha spicata (spearmint), M. longifolia, and M. suaveolens.

METHODS

We morphologically evaluated 155 herbarium specimens of three Mentha species and sequenced the genomes of a subset of 93 specimens. We analyzed the whole genomes in a population and the phylogenetic framework and associated genomic classifications in conjunction with the morphological assessments.

RESULTS

The allopolyploid M. spicata, which likely evolved in cultivation, had altered trichome characters, that is possibly a product of human selection for a more palatable plant or a byproduct of selection for essential oils. There were signs of genetic admixture between mints, including allopolyploids, indicating that the reproductive barriers between Mentha species with differences in ploidy are likely incomplete. Still, despite gene flow between species, we found that genetic variants associated with the cultivated trichome morphology continue to segregate.

CONCLUSIONS

Although hybridization, allopolyploidization, and human selection during cultivation can increase species richness (e.g., by forming hybrid taxa), we showed that unless reproductive barriers are strong, these processes can also result in mixing of genes between species and the potential loss of natural biodiversity.

Alternative Crops for the European Tobacco Industry: A Systematic Review

Tobacco (Nicotiana tabacum L.) is a major industrial crop that has being cultivated for centuries for the manufacturing of cigarettes, cigars, and other smoking products. Due to its negative effects on both human health and the environment, the European Union has adopted strict policies that aspire to reduce the consumption of tobacco. Herbal cigarettes are alternative smoking products that are often advertised as healthier than conventional tobacco cigarettes and are especially popular in Asian markets. Even though the available literature suggests that they are equally detrimental to human health, the introduction of tobacco-alternative crops (TACs) to the European tobacco industry could smoothen the abandonment of tobacco, and eventually smoking products altogether, in the EU. The aim of the present systematic review was to compile a list of possible TACs that could be incorporated in the European smoking industry, and highlight their strengths and weaknesses. The most dominant crops in the literature (and in the existing market products) were calendula (Calendula officinalis L.), mullein (Verbascum thapsus L.), ginseng (Panax ginseng C.A.Mey.), tea (Camellia sinensis (L.) Kuntze), chamomile (Matricaria chamomilla L.), and mentha (Mentha spp.). Even though these crops are promising, further research is required for their incorporation in the European tobacco industry.

Functional Properties and Acceptability of Potentially Medicinal Tea Infusions Based on Equisetum arvense, Desmodium molliculum, and Mentha piperita

Natural herbal teas are one of the three most consumed beverages in the world, and despite their frequent use in the cosmetic, food, and pharmaceutical industries, there is still much to about them. This study aimed to determine the functional properties of tea infusions made from dried Equisetum arvense (EA), Desmodium molliculum (DM), and Mentha piperita (M) grown in the Peruvian Andes. Next, using a simplex design with unrestricted centroid amplified centroid, 12 combinations were obtained for the combination of dried leaves with EA: 0∼100%, DM: 0∼100%, and M: 0∼100% optimal combination of EA: 6.59%, DM: 84.62%, and M: 8.79% maximizes functional components for total polyphenols (2,831.18 mg EAG/100 g), flavonoids (37.73 mg CAT/g), and antioxidant capacity (145.99 μmol Trolox/g). It can be confirmed that dried mixtures of these plants made into tea are a significant source of bioactive molecules, have a tolerable flavor, and can be used for therapeutic purposes when consumed.

Antioxidant, Antimicrobial, and Insecticidal Properties of Chemically Characterized Essential Oils Extracted from Mentha longifolia: In Vitro and In Silico Analysis

The present study aimed to explore the phytochemical profile, and evaluate the antioxidant, antimicrobial, and insecticidal properties, of Moroccan Mentha longifolia L. essential oil (ML-EO) using in vitro and in silico assays. Noteworthily, as chromatography (GC-MS/MS) revealed that ML-EO is majorly composed of piperitenone oxide (53.43%), caryophyllene (20.02%), and (-) germacrene D (16.53%). It possesses excellent antioxidant activity with an IC50 of 1.49 ± 0.00 for DPPH and 0.051 ± 0.06 μg/mL for ABTS. Moreover, the RP and TAC activities were 0.80 ± 0.01 μg/mL and 315.532 ± 0.00 mg EAA/g, respectively. ML-EO exhibited a potent antimicrobial effect, specifically against Pseudomonas aeruginosa. It also exhibited strong antifungal ability, especially against Candida albicans. Regarding insecticidal activity, for ML-EO, a dose of 20 µL/mL produced a complete reduction in fecundity, fertility, and emergence of adult C. maculatus with mortality rates reaching 100%. In silico results showed that the antioxidant activity is mostly attributed to α-Cadinol, the antibacterial efficiency is attributed to piperitenone oxide, and antifungal capacity is related to cis-Muurola-4(15),5-diene and piperitenone oxide. Accordingly, ML-EO has high potential to be used as an alternative for preserving food and stored grain and protecting them against microbes and insect pests in the food and pharmaceutical sectors.

Mentha piperita: Essential Oil and Extracts, Their Biological Activities, and Perspectives on the Development of New Medicinal and Cosmetic Products

This review aims to analyze Mentha piperita L. as a potential raw material for the development of new health-promoting products (nutraceuticals, cosmetics, and pharmaceutical products). A lot of scientific publications were retrieved from the Scopus, PubMed, and Google Scholar databases which enable the study and generalization of the extraction procedures, key biologically active compounds of essential oil and extracts, biological properties, and therapeutic potential of M. piperita, along with perspectives on the development of its dosage forms, including combinations of synthetic active substances and herbal preparations of M. piperita. The results of this review indicate that M. piperita is a source rich in phytoconstituents of different chemical nature and can be regarded as a source of active substances to enhance health and to develop medicinal products for complementary therapy of various conditions, especially those related with oxidant stress, inflammation, and moderate infections. Essential oil has a broad spectrum of activities. Depending on the test and concentration, this essential oil has both anti- and prooxidant properties. Gram-positive bacteria are more sensitive to the essential oil of M. piperita than Gram-negative ones. This review also considered some facets of the standardization of essential oil and extracts of M. piperita. Among the identified phenolics of extracts were caffeic acid, rosmarinic acid, eriocitrin, luteolin derivates (luteolin-7-O-rutinoside, luteolin-7-O-glucoronide), and hesperidin. The concentration of these phenolics depends on the solvent used. This review also considered the relationships between the chemical component and biological activity. The results showed that the essential oil and extracts reduced inflammation in vitro by inhibiting the production of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), and in vivo by reducing the paw edema induced using carrageenan injection in rats. Therefore, herbal preparations of M. piperita are promising medicinal and cosmetic preparations for their usage in skincare and oral cavity care products with antimicrobial, anti-inflammatory, and wound-healing properties. This plant can also be regarded as a platform for the development of antibacterial preparations and combined anti-inflammatory and cardioprotective medicinal products (synthetic active substances plus herbal preparations). This review could be considered for the justification of the composition of some medicinal products during their pharmaceutical development for writing a registration dossier in the format of Common Technical Document.

Essential Oils of Mentha arvensis and Cinnamomum cassia Exhibit Distinct Antibacterial Activity at Different Temperatures In Vitro and on Chicken Skin

The bacterial contamination of meat is a global concern, especially for the risk of Salmonella infection that can lead to health issues. Artificial antibacterial compounds used to preserve fresh meat can have negative health effects. We investigated the potential of natural essential oils (EOs), namely Mentha arvensis (mint) and Cinnamomum cassia (cinnamon) EOs, to prevent contamination of the food pathogen, Salmonella enterica subsp. enterica serotype Typhimurium, in vitro and on chicken skin. The gas chromatography-mass spectrometry (GC-MS) technique was used to determine the compositions of mint EO (MEO) and cinnamon EO (CEO); the most abundant compound in MEO was menthol (68.61%), and the most abundant compound was cinnamaldehyde (83.32%) in CEO. The antibacterial activity of MEO and CEO were examined in vapor and direct contact with S. typhimurium at temperatures of 4 °C, 25 °C, and 37 °C. The minimal inhibitory concentration at 37 °C for MEO and CEO reached 20.83 µL/mL, and the minimal bactericidal concentration of CEO was the same, while for MEO, it was two-fold higher. We report that in most tested conditions in experiments performed in vitro and on chicken skin, CEO exhibits a stronger antibacterial effect than MEO. In the vapor phase, MEO was more effective against S. typhimurium than CEO at 4 °C. In direct contact, the growth of S. typhimurium was inhibited more efficiently by MEO than CEO at small concentrations and a longer exposure time at 37 °C. The exploration of CEO and MEO employment for the inhibition of Salmonella bacteria at different temperatures and conditions expands the possibilities of developing more environment- and consumer-friendly antibacterial protection for raw meat.

A Comprehensive Review of the Key Characteristics of the Genus Mentha, Natural Compounds and Biotechnological Approaches for the Production of Secondary Metabolites

Context

The genus Mentha is one of the most aromatic and well-known members of the Lamiaceae family. A wide range of bioactive compounds has been reported in mints. Regarding the high economic importance of Mentha plants due to the presence of valuable metabolites, the demand for their products is growing exponentially. Therefore, to supply such demand, new strategies should be adopted to improve the yield and medicinal quality of the products.

Evidence Acquisition

The current review is written based on scientific literature obtained from online databases, including Google Scholar, PubMed, Scopus, and Web of Science regarding the characteristic features of some species of the genus Mentha, their distribution and cultivation, main uses and benefits, phytochemical composition, biotechnological approaches for the production of secondary metabolites, and strategies for enhanced production of mints secondary metabolites.

Results

In this article, we offer an overview of the key characteristics, natural compounds, biological properties, and medicinal uses of the genus Mentha. Current research describes biotechnological techniques such as in vitro culture methods for the production of high-value secondary metabolites. This review also highlights the strategies such as elicitation, genetic, and metabolic engineering to improve the secondary compounds production level in mint plants. Overall, it can be concluded that identifying the biosynthetic pathways, leading to the accumulation of pharmaceutically important bioactive compounds, has paved the way for developing highly productive mint plants with improved phytochemical profiles.

A review of the bioactive properties of Mongolian plants, with a focus on their potential as natural food preservatives

Consumers have recently preferred food that is easy to make and of excellent quality, as well as food that is safe, natural, and minimally processed, but has a longer shelf life. Food deteriorates over time as a result of microbiological, chemical, or physical changes. Phytochemicals derived from medicinal and food plants have long been recognized for their biological activity to protect plants. These bioactivities are designed to increase the shelf life of food while inhibiting the growth of microorganisms. The use of natural plant food preservatives containing bioactive compounds as health-promoting agents is particularly intriguing. Furthermore, due to their effectiveness against food spoilage and foodborne pathogens, natural plant-origin antimicrobial compounds have been investigated as alternatives to synthetic antimicrobial compounds for preserving food quality. This review focused on the plant composition and properties that can be utilized as a natural food preservative, as well as the possibilities of using Mongolian medicinal plants.

Monitoring Genetic Erosion of Aromatic and Medicinal Plant Species in Alentejo (South Portugal)

The main goal of this work was to study the genetic erosion risk of plants with aromatic, medicinal and gastronomic applications in Portugal, particularly in the Alentejo region. The target species were coriander (Coriandrum sativum L.), hart's pennyroyal (Mentha cervina L.) and pennyroyal (Mentha pulegium L.). The methodology involved direct observations and surveys (2002/2003 and 2011). The GE formula applied in Hammer's studies was used to estimate genetic erosion. The main factors causing genetic erosion were the primary drivers of biodiversity loss: habitat loss, invasive species, and overexploitation influenced by human intervention such as the clearing of watercourses, vegetation control, grazing and desertification. The results indicate a reduction in individuals per species in Alentejo, with a net erosion loss of 11% for M. pulegium, 32% for M. cervina and 33% for C. sativum. The overall loss of accessions (genetic erosion risk) was higher in cultivated accessions (33%) than in wild accessions (11%), with an annual genetic erosion rate of 3.7% and 1.2%, respectively. The annual risk of genetic erosion for M. pulegium accessions collected in a natural habitat was 0.6%, which is much lower than the 3.7% for M. cervina. These results consolidate the importance of collecting and conserving genetic resources.

Research progress of Traditional Chinese Medicine (TCM) in targeting inflammation and lipid metabolism disorder for arteriosclerosis intervention: A review

Atherosclerosis (AS) is a chronic disease caused by inflammation and lipid deposition. Immune cells are extensively activated in the lesions, producing excessive pro-inflammatory cytokines, which accompany the entire pathological process of AS. In addition, the accumulation of lipid-mediated lipoproteins under the arterial intima is a crucial event in the development of AS, leading to vascular inflammation. Improving lipid metabolism disorders and inhibiting inflammatory reactions are the primary treatment methods currently used in medical practice to delay AS progression. With the development of traditional Chinese medicine (TCM), more mechanisms of action of the monomer of TCM, Chinese patent medicine, and compound prescription have been studied and explored. Research has shown that some Chinese medicines can participate in treating AS by targeting and improving lipid metabolism disorders and inhibiting inflammatory reactions. This review explores the research on Chinese herbal monomers, compound Chinese medicines, and formulae that improve lipid metabolism disorders and inhibit inflammatory reactions to provide new supplements for treating AS.

Quantitation and Stability of Nicotine in Canadian Vaping Liquids

Electronic cigarettes (e-cigarettes, vaping products) have become increasingly popular, with recent increases in use associated with closed systems delivering higher concentrations of nicotine. Most vaping products designed as an alternative to combustible cigarettes contain nicotine. A number of published studies have examined the reported concentrations of nicotine in vaping liquids (e-liquids) and found discrepancies between labelled and measured levels. Some discrepancy can also be explained by the lack of stability of nicotine in these types of products. Recently, a chemical analysis method for the quantitative determination of low and high levels of nicotine in vaping liquids was developed. This method uses dilution with acetonitrile prior to analysis with gas chromatograph mass spectrometry (GC-MS) in single ion monitoring mode (SIM). The developed method was validated using a laboratory-prepared vaping liquid as well as commercially available, nicotine-free products fortified with nicotine in the laboratory. The method detection limit (MDL) and the limit of quantitation (LOQ) for nicotine were calculated to be 0.002 mg/mL and 0.006 mg/mL, respectively. The newly developed method was applied to quantify nicotine in commercially available vaping liquids of various flavour profiles and across a wide range of nicotine concentrations, including those with nicotine salts. Furthermore, a subset of vaping liquids were analyzed to elucidate nicotine stability in various product subtypes. After a period of six months of accelerated storage to mimic one year, the overall mean percent of the original nicotine concentration remaining in the salt-based vaping products was 85% (minimum 64%, maximum 99%) while in the free-base nicotine products it was 74% (minimum 31%, maximum 106%). Nicotine stability in vaping liquids was found to be influenced by the nicotine form (pH) of formulation and its chemical composition. Non-targeted, qualitative analysis of chemical composition of vaping products showed that most constituents were identified and found to be remaining in the products following stability trials; however, three new compounds were tentatively identified in some vaping liquids at the end of the stability trials. Stability studies and the accurate quantitation of nicotine in vaping products can help inform product standards related to the safety, quality and utility of vaping products as a smoking cessation tool.

Phytochemical Composition and Antioxidant, Anti-Acetylcholinesterase, and Anti-α-Glucosidase Activity of Thymus carnosus Extracts: A Three-Year Study on the Impact of Annual Variation and Geographic Location

Thymus carnosus Boiss. is a near-threatened species, and, as for many species, its potential for medicinal purposes may be lost if measures towards plant protection are not taken. A way of preserving these species is to increase knowledge about their medicinal properties and economic potential. Thus, with the objective of studying the potentiality of introducing T. carnosus as a crop, the stability of the phytochemical profile of T. carnosus was studied during a period of three years by comparing the phytochemical profile of extracts obtained from plants harvested in two different edaphoclimatic locations, as well as by comparing the respective bioactivities, namely, antioxidant, antidiabetic, antiaging, and neuroprotective activities. It was reported, for the first time, the effect of annual variation and geographic location in the phytochemical composition of aqueous decoction and hydroethanolic extracts of T. carnosus. In addition, the presence of two salvianolic acid B/E isomers in T. carnosus extracts is here described for the first time. Despite the variations in phytochemical composition, according to harvesting location or year, T. carnosus extracts maintain high antioxidant activity, assessed by their capacity to scavenge ABTS^•+, ^•OH , NO^•, O₂^•- radicals, as well as to prevent β-carotene bleaching. All extracts presented significant potential to inhibit acetylcholinesterase (AChE), tyrosinase, and α-glucosidase, denoting neuroprotective, anti-aging, and anti-diabetic potential. In conclusion, the vegetative stage and location of harvest are key factors to obtain the maximum potential of this species, namely, a phytochemical profile with health benefit bioactivities.

Nutritionally rich biochemical profile in essential oil of various Mentha species and their antimicrobial activities

The Mentha species of family Lamiaceae are famous for their flavor and are commercially used in many food products worldwide. They are widely used to cure digestive problems as well as a natural source of antioxidants and antimicrobials. In this report, the essential oils (EOs) of five Mentha species, namely Mentha citrata, Mentha x piperita, Mentha pulegium, Mentha spicata, and Mentha suaveolens were extracted and their chemical diversity was investigated through gas chromatography-mass spectroscopy (GC-MS). The differential doses (5, 10, and 15 µl) of EOs were tested for antimicrobial potential against two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), five gram-negative bacteria (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Proteus mirabilis and Klebsiella pneumoniae) and a fungal strain (Candida albicans). The GC-MS results revealed the major components in the EOs were Carvone, Linalool, Hotrienol, Menthol, Isopulegone, Furanone, Piperitone, and Thymol. Moreover, the higher dose (15 µl) of EOs of M. citrata inhibited the growth of S. typhi and C. albicans (35.8 ± 2.4 and 35.2 ± 2.5 mm), M. x piperita inhibited E. coli, B. subtilis, and C. albicans (28.5 ± 3.5, 26.1 ± 2.1, and 25.4 ± 1.1 mm), M. pulegium inhibited K. pneumoniae, B. subtilis, and C. albicans (26.8 ± 1.8, 24.2 ± 2.2, and 25.3 ± 0.9 mm), M. spicata significantly inhibited S. typhi and B. subtilis (35.7 ± 2.7 and 36.3 ± 2.1 mm), and M. suaveolens inhibited K. pneumoniae, C. albicans, and S. typhi (30.8 ± 1.9, 26.9 ± 1.1, and 20.1 ± 0.8 mm) respectively. This study concluded that the EOs of M. citrata was effective against S. typhi and C. albicans. The M. x piperita exhibited strong activities against E. coli, B. subtilis, and C. albicans. Furthermore, the M. pulegium strongly inhibited the growth of K. pneumoniae and C. albicans. The EO of M. spicata was more potent against S. typhi and B. subtilis, while the M. suaveolens was comparatively more effective against S. typhi, K. pneumoniae, and C. albicans. These EOs offer a natural source of antimicrobial agents with high commercial values and social acceptance and could be scale up by food and pharmaceutical industries to control pathogenic diseases.

Transcriptome analysis of transcription factors and enzymes involved in monoterpenoid biosynthesis in different chemotypes of Mentha haplocalyx Briq

Background

The main active ingredients of Mentha haplocalyx Briq. essential oils are monoterpenes. According to the component of essential oils, M. haplocalyx can be divided into different chemotypes. Chemotype variation is widespread in Mentha plants but its formation mechanism is unclear.

Methods

We selected the stable chemotype l-menthol, pulegone, and carvone of M. haplocalyx for transcriptome sequencing. To further investigate the variation of chemotypes, we analyzed the correlation between differential transcription factors (TFs) and key enzymes.

Results

Fourteen unigenes related to monoterpenoid biosynthesis were identified, among which (+)-pulegone reductase (PR) and (-)-menthol dehydrogenase (MD) were significantly upregulated in l-menthol chemotype and (-)-limonene 6-hydroxylase was significantly upregulated in carvone chemotype. In addition, 2,599 TFs from 66 families were identified from transcriptome data and the differential TFs included 113 TFs from 34 families. The families of bHLH, bZIP, AP2/ERF, MYB, and WRKY were highly correlated with the key enzymes PR, MD, and (-)-limonene 3-hydroxylase (L3OH) in different M. haplocalyx chemotypes (r > 0.85). The results indicate that these TFs regulate the variation of different chemotypes by regulating the expression patterns of PR, MD, and L3OH. The results of this study provide a basis for revealing the molecular mechanism of the formation of different chemotypes and offer strategies for effective breeding and metabolic engineering of different chemotypes in M. haplocalyx.

Effect-Directed, Chemical and Taxonomic Profiling of Peppermint Proprietary Varieties and Corresponding Leaf Extracts

During the development of novel, standardized peppermint extracts targeting functional applications, it is critical to adequately characterize raw material plant sources to assure quality and consistency of the end-product. This study aimed to characterize existing and proprietary, newly bred varieties of peppermint and their corresponding aqueous extract products. Taxonomy was confirmed through genetic authenticity assessment. Non-target effect-directed profiling was developed using high-performance thin-layer chromatography-multi-imaging-effect-directed assays (HPTLC-UV/Vis/FLD-EDA). Results demonstrated substantial differences in compounds associated with functional attributes, notably antioxidant potential, between the peppermint samples. Further chemical analysis by high-performance liquid chromatography-photodiode array/mass spectrometry detection (HPLC-PDA/MS) and headspace solid-phase microextraction-gas chromatography-flame ionization/MS detection (headspace SPME-GC-FID/MS) confirmed compositional differences. A broad variability in the contents of flavonoids and volatiles was observed. The peppermint samples were further screened for their antioxidant potential using the Caenorhabditis elegans model, and the results indicated concordance with observed content differences of the identified functional compounds. These results documented variability among raw materials of peppermint leaves, which can yield highly variable extract products that may result in differing effects on functional targets in vivo. Hence, product standardization via effect-directed profiles is proposed as an appropriate tool.

Pedoclimatic Conditions Influence the Morphological, Phytochemical and Biological Features of Mentha pulegium L

In this study, Mentha pulegium leaves and flowers harvested in three different Sicilian areas were investigated from a micromorphological, phytochemical and biological point of view. Light and scanning electron microscopy showed the presence of spherocrystalline masses of diosmin both in the leaf epidermal cells and in thin flower petals. Two different chemotypes were identified (I, kaempferide/rosmarinic acid; II, jaceidin isomer A). Phytochemical screening identified plant from collection site II as the richest in total phenolics (16.74 g GAE/100 g DE) and that from collection site I as the richest in flavonoids (46.56 g RE/100 g DE). Seventy-seven metabolites were identified both in flower and leaf extracts. Plant from site II showed the best antioxidant (0.90-83.72 µg/mL) and anti-inflammatory (27.44-196.31 µg/mL) activity expressed as half-maximal inhibitory concentration (IC₅₀) evaluated by DPPH, TEAC, FRAP, ORAC, BSA denaturation and protease inhibition assays. These data were also corroborated by in vitro cell-based assays on lymphocytes and erythrocytes. Moreover, plant of site II showed the best antiangiogenic properties (IC₅₀ 33.43-33.60 µg/mL) in vivo on a chick chorioallantoic membrane. In conclusion, pedoclimatic conditions influence the chemotype and the biological activity of M. pulegium, with chemotype I showing the most promising biological properties.

Mentha: Nutritional and Health Attributes to Treat Various Ailments Including Cardiovascular Diseases

A poor diet, resulting in malnutrition, is a critical challenge that leads to a variety of metabolic disorders, including obesity, diabetes, and cardiovascular diseases. Mentha species are famous as therapeutic herbs and have long served as herbal medicine. Recently, the demand for its products, such as herbal drugs, medicines, and natural herbal formulations, has increased significantly. However, the available literature lacks a thorough overview of Mentha phytochemicals' effects for reducing malnutritional risks against cardiovascular diseases. In this context, we aimed to review the recent advances of Mentha phytochemicals and future challenges for reducing malnutritional risks in cardiovascular patients. Current studies indicated that Mentha species phytochemicals possess unique antimicrobial, antidiabetic, cytotoxic, and antioxidant potential, which can be used as herbal medicine directly or indirectly (such as food ingredients) and are effective in controlling and curing cardiovascular diseases. The presence of aromatic and flavor compounds of Mentha species greatly enhance the nutritional values of the food. Further interdisciplinary investigations are pivotal to explore main volatile compounds, synergistic actions of phytochemicals, organoleptic effects, and stability of Mentha sp. phytochemicals.

Headspace Solid-Phase Micro-Extraction Versus Hydrodistillation of Volatile Compounds from Leaves of Cultivated Mentha Taxa: Markers of Safe Chemotypes

Various mint taxa are widely cultivated and are used not only for medicinal purposes but also in cosmetic and industrial applications. The development of new varieties or cultivars of mint generates difficulties in their correct identification and safe use. Volatile organic compounds (VOCs) from the leaves of seven different taxa of the genus Mentha obtained by hydrodistillation (HD) and headspace solid-phase microextraction (HS-SPME) were analyzed using gas chromatography-mass spectrometry (GC-MS). Principal component analysis (PCA) was also performed. Comparative GC-MS analysis of the obtained extracts showed similarity in the major compounds. PCA data allowed the separation of two groups of chemotypes among the analyzed mints, characterized by the abundance of piperitenone oxide and carvone. Two out of seven analyzed taxa were not previously examined for VOC profile, one was examined only for patent application purposes, and six out of seven were investigated for the first time using the HS-SPME technique. The presented analysis provides new data on the abundance and qualitative characterization of VOCs in the studied mint plants and on the safety of their use, related to the possibility of the presence of potentially toxic components. HS-SPME is a valuable method to extend the characterization of the VOC profile obtained by hydrodistillation.

Seasonal Variation of Aromatic Plants under Cultivation Conditions

In this study, five plant species, members of the Lamiaceae family, namely Salvia officinalis L., Salvia rosmarinus Spenn, Mentha × piperita L., Mentha spicata L. and Origanum vulgare subsp. hirtum (Link) Ietswaart, were studied for the influence of harvesting time on the herb crop yield, the volatile compounds (EOs) content/yield and their chemical composition. EOs were isolated by means of hydro-distillation from different plant parts at different growth stages. Their components were analyzed by gas chromatography coupled with mass spectrometry (GC-MS). The highest yields of EOs were obtained at the full flowering stage and important changes were observed in their composition. The fluctuations in the percentage composition of the major compounds in the EOs, throughout harvesting time, were observed at camphor/α-thujone for S. officinalis, camphor/1,8-cineole for S. rosmarinus, linalool/linalyl acetate and carvone/limonene for M. × piperita and M. spicata, respectively. The chemotype of O. vulgare subsp. hirtum was identified as carvacrol. The optimization of harvesting time could lead to increased crop production and better EOs quality control, with numerous industrial benefits upon the commercial production of such products.

Impact of Growth Sites on the Phenolic Contents and Antioxidant Activities of Three Algerian Mentha Species (M. pulegium L., M. rotundifolia (L.) Huds., and M. spicata L.)

Research studies about the effect of environmental agents on the accumulation of phenolic compounds in medicinal plants are required to establish a set of optimal growth conditions. Hence, in this work, we considered the impact of habitat types, soil composition, climatic factors, and altitude on the content of phenolics in Mentha species [M. pulegium L. (MP), M. rotundifolia (L.) Huds. (MR), and M. spicata L. (MS)] grown in different regions of Algeria. The phenolic contents and antioxidant activities were analyzed using spectrophotometric and HPTLC methods. The harvesting localities differ by their altitudes and climates, but their soils are quite similar, characterized by slight alkalinity, moderate humidity, no-salinity, and high levels in organic matter. Both the contents in total phenolics (TPC), total flavonoids (TFC), and rosmarinic acid (RAC), and the antioxidant activities of Mentha samples collected from these Algerian localities are affected by the geographical regions of origin. The samples of MS and MP from the Khemis–Miliana region showed the highest concentration in TPC (MS, 7853 ± 265 mg GAE/100 g DW; MP, 5250 ± 191 mg GAE/100 g DW), while in Chemini, the MR samples were the richest in these compounds (MR, 3568 ± 195 mg GAE/100 g DW). Otherwise, the MP (from Tichy), MR (from Tajboudjth), and MS (from Khemis–Miliana) specimens exhibited the highest levels of TFC and RAC. The antioxidant levels in a total activity test (reduction of phosphomolybdate) appear correlated with the total phenolic contents, but this was not the case for most of the important ROS-scavenging and iron-chelating capacities for which the quality of polyphenols is probably more important than their amounts. A principal component analysis (PCA) score plot indicates that all of the Mentha samples can be divided into four groups. These discriminated groups appear comparatively similar in phenolic contents and antioxidant activities. As for the harvest localities, the Mentha samples were divided into four groups in which the phenolic contents and antioxidant activities were comparatively equivalent.

Antiviral Activity of Selected Lamiaceae Essential Oils and Their Monoterpenes Against SARS-Cov-2

This study presents the very first report on the in vitro antiviral activity of selected essential oils of Lamiaceae plant species and their monoterpenes against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Nineteen essential oils were obtained by hydrodistillation of dried plant material, and their monoterpene profiles were determined. In addition, the exact concentrations of each monoterpene that were found at a significant level were defined. Both essential oils and their monoterpene components were tested for cytotoxic and antiviral activity against SARS-CoV-2 in infected Vero 76 cells. The results showed that the essential oils of four Mentha species, i.e., M. aquatica L. cv. Veronica, M. pulegium L., M. microphylla K.Koch, and M. x villosa Huds., but also Micromeria thymifolia (Scop.) Fritsch and Ziziphora clinopodioides Lam., and five different monoterpenes, i.e., carvacrol, carvone, 1,8-cineol, menthofuran, and pulegone, inhibited the SARS-CoV-2 replication in the infected cells. However, the antiviral activity varied both among essential oils and monoterpenes. Carvone and carvacrol exhibited moderate antiviral activity with IC50 concentrations of 80.23 ± 6.07 μM and 86.55 ± 12.73 μM, respectively, while the other monoterpenes were less active (IC50 > 100.00 μM). Structure-activity relations of related monoterpenes showed that the presence of keto and hydroxyl groups is associated with the activity of carvone and carvacrol, respectively. Furthermore, the carvone-rich essential oil of M. x villosa had the greatest activity among all active essential oils (IC50 127.00 ± 4.63 ppm) while the other active oils exhibited mild (140 ppm < IC50 < 200 ppm) to weak antiviral activity (IC50 > 200 ppm). Both essential oils and monoterpenes showed limited or no cytotoxicity against Vero 76 cells. Hierarchical cluster analysis showed that the differences in the antiviral activity of essential oils were directly attributed to the antiviral efficacies of their particular single monoterpenes. The findings presented here on the novel antiviral property of plant essential oils and monoterpenes might be used in the development of different measures against SARS-CoV-2.

Introducing Three New Fruit-Scented Mints to Farmlands: Insights on Drug Yield, Essential-Oil Quality, and Antioxidant Properties

Mint species are one of the most traded medicinal plants with a wide array of applications in the food, pharmaceutical, and perfumery industries. Here, a field experiment based on completely randomized block design (RCBD) aimed to compare drug yield, antioxidant properties, and essential-oil (EO) quality of three newly introduced mints (i.e., ginger mint, pineapple mint, and grapefruit mint) with a chiefly cultivated one (i.e., peppermint). The results manifested that dry-weight yield and EO yield of grapefruit mint (310 g/m² and 5.18 g/m², respectively) was approximately 2 times more than that of others. The highest EO content (i.e., 3.12%, v/w)) was obtained from the ginger mint; however, there were no significant differences among the other three mints. The highest total flavonoids content and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of both methanolic and ethanolic extracts were found in pineapple and grapefruit mint. Methanolic extract of ginger mint yielded the highest total polyphenol content, whereas the ethanolic extract of pineapple mint showed the highest total polyphenol content. According to mean comparisons, the EO of ginger mint exhibited the highest antioxidant activity (EC₅₀ value = 2.23 µL/mL), while EO of peppermint showed the lowest antioxidant activity (EC₅₀ value = 48.23 µL/mL). Gas chromatography analysis identified four EO types among these mints: (i) grapefruit mint EO rich in linalool (51.7%) and linalyl acetate (28.38%); (ii) ginger mint EO rich in linalool (59.16%); (iii) pineapple mint EO rich in piperitone oxide (77.65%); and (iv) peppermint EO rich in menthol (35.65%). The findings of the present study provide new insights into the cultivation of preferable mints possessing desired characteristics for food and drug industries.

Gastrointestinal effects of Mentha aquatica L. essential oil

Found in humid regions and waterways and popularly used to treat gastrointestinal problems among other applications, the present study evaluated the M. aquatica essential oil (OEMa) as a therapeutic alternative to treat gastrointestinal disorders. Produced by steam distillation, chemical composition of OEMa was determined by GC-MS analysis. The ethanol-induced ulcer and the dose-repeated acetylsalicylic acid (ASA)-induced gastrointestinal lesions models in rats evaluated, respectively, the prophylactic and curative effects of EOMa on peptic ulcers. The EOMa's effect on gastric secretion, gastric mucus and gastrointestinal motility were evaluated in in vivo models. The curative effect of EOMa on acute colitis was evaluated using the DSS-induced colitis model in mice. Obtained in 0.17% yield (w/w), with carvone (54.82 ± 1.39 g/100 g oil) as the main constituent, EOMa (at 75 mg/kg) showed potent gastroprotective effect (> 90%) mediated by non-protein sulfhydryl compounds (NPSH) and nitric oxide (NO) modulation alongside reduction in gastric secretion volume and total acidity. EOMa did not affect gastric mucus production and gastrointestinal motility. In dose-repeated ASA-induced gastrointestinal lesions model, EOMa (at 25 mg/kg) promoted the inflammatory process resolution both in gastric and duodenal walls by modulating NPSH, NO and myeloperoxidase levels. Despite delaying in 2 days the clinical symptoms worsening, EOMa (at 25 mg/kg) was not able to protect colon tissues from DSS-induced acute colitis as evidenced by macroscopic, biochemical, and histopathological parameters. This is the first report of Mentha aquatica essential oil as a promising herbal medicine for peptic ulcers treatment together with an adjuvant effect in IBD.

Phytotherapeutic Approaches to the Prevention of Age-Related Changes and the Extension of Active Longevity

Maintaining quality of life with an increase in life expectancy is considered one of the global problems of our time. This review explores the possibility of using natural plant compounds with antioxidant, anti-inflammatory, anti-glycation, and anti-neurodegenerative properties to slow down the onset of age-related changes. Age-related changes such as a decrease in mental abilities, the development of inflammatory processes, and increased risk of developing type 2 diabetes have a significant impact on maintaining quality of life. Herbal preparations can play an essential role in preventing and treating neurodegenerative diseases that accompany age-related changes, including Alzheimer’s and Parkinson’s diseases. Medicinal plants have known sedative, muscle relaxant, neuroprotective, nootropic, and antiparkinsonian properties. The secondary metabolites, mainly polyphenolic compounds, are valuable substances for the development of new anti-inflammatory and hypoglycemic agents. Understanding how mixtures of plants and their biologically active substances work together to achieve a specific biological effect can help develop targeted drugs to prevent diseases associated with aging and age-related changes. Understanding the mechanisms of the biological activity of plant complexes and mixtures determines the prospects for using metabolomic and biochemical methods to prolong active longevity.

Development of a fully water-dilutable mint concentrate based on a food-approved microemulsion

Mentha spicata L. disappears in winter. The lack of fresh mint during the cold season can be a limiting factor for the preparation of mint tea. A fresh taste source that can be kept during winter is mint essential oil. As the oil is not soluble in water, a food-approved, water-soluble essential oil microemulsion was studied, investigating different surfactants, in particular Tween® 60. The challenge was to dissolve an extremely hydrophobic essential oil in a homogeneous, stable, transparent, and spontaneously forming solution of exclusively edible additives without adulterating the original fresh taste of the mint. Making use of the microemulsions' water and oil pseudo-phases, hydrophilic sweeteners and hydrophobic dyes could be incorporated to imitate mint leaf infusions aromatically and visually. The resulting formulation was a concentrate, consisting of ∼ 90% green components, which could be diluted with water or tea to obtain a beverage with a pleasant minty taste.

Medicinal Plants for Anti-neurodegenerative diseases in West Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Neurodegenerative diseases are neuronal diseases that affect the brain components by degenerating the structure and function of the central or peripheral nervous system progressively. It is a leading cause of death and affects huge amount of people worldwide. Plant-based medicines have been utilised in the therapies for many illnesses that have defied western treatments, including neurodegenerative diseases.

AIM OF THIS REVIEW

This review presents an overview of the major neurodegenerative diseases and reported prominent medicinal plants used in managing those diseases in West Africa.

METHODS

Scientific articles regarding medicinal plants and their usefulness in managing neurodegenerative diseases in West Africa were pooled from different scientific databases. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses to filter articles based on their relevance. Pharmacological activity, plant parts used, experimental models, and some isolated chemical compounds of those plants were summarised.

RESULTS

In the West Africa region, Fabaceae (19%) and Solanaceae (13%) have the highest representation of plant families used to treat neurological diseases, while Apocynaceae, Asteraceae, Euphorbiaceae have also been utilised. Flavonoids, alkaloids, phenolic compounds, terpenoids, coumarins present in those plants and their derivatives are reported to possess neuro-protective effects. Biochemical enzymes correlating to antioxidants, anti-inflammatory effects are the potential targets against neurodegenerative diseases.

CONCLUSION

Medicinal plants for anti-neurodegenerative diseases in West Africa have been documented with their neuropharmacological activities. Plant families such as Fabaceae, Solanaceae, Apocynaceae, Asteraceae, and Euphorbiaceae could be a major natural source for discovery of anti-neurodegenerative drugs, thus the metabolites from them should be given priority for neurological research. This review will provide clues for further investigations on the screening and development of anti-neurodegenerative natural products from West African medicinal plants.

Efficacy of Gold Nanoparticles against Drug-Resistant Nosocomial Fungal Pathogens and Their Extracellular Enzymes: Resistance Profiling towards Established Antifungal Agents

Drug resistance of filamentous fungi to the commonly used antifungal agents is a major concern in medicine. Therefore, an effective approach to treat several opportunistic fungal infections is the need of the hour. Mentha piperita is used in home remedies to treat different disorders. Isolates of fungi were taken from hospitals in Riyadh, Saudi Arabia, and identified using molecular tools. Amphotericin B, Voriconazole, and Micafungin were applied to screen the resistance of these isolates using both disc and broth microdilution techniques. An aqueous extract of Mentha piperita was utilized to synthesize AuNPs and the nanoparticles were characterized using UV-Vis, FTIR, TEM, EDAX, and XRD. The AuNPs were tested for antifungal activity against the nosocomial fungal pathogens and the activity of extracellular enzymes of such pathogens were analyzed after treatment with AuNPs. We conclude that AuNPs synthesized using Mentha piperita do not possess especially effective antifungal properties against multi-drug resistant Aspergillus species. Five out of eighteen isolates were inhibited by AuNPs. When inhibition was observed, significant alterations in the activity profile of extracellular enzymes of the nosocomial fungi were observed.

Challenges in Medicinal and Aromatic Plants DNA Barcoding-Lessons from the Lamiaceae

The potential value of DNA barcoding for the identification of medicinal plants and authentication of traded plant materials has been widely recognized; however, a number of challenges remain before DNA methods are fully accepted as an essential quality control method by industry and regulatory authorities. The successes and limitations of conventional DNA barcoding are considered in relation to important members of the Lamiaceae. The mint family (Lamiaceae) contains over one thousand species recorded as having a medicinal use, with many more exploited in food and cosmetics for their aromatic properties. The family is characterized by a diversity of secondary products, most notably the essential oils (EOs) produced in external glandular structures on the aerial parts of the plant that typify well-known plants of the basil (Ocimum), lavender (Lavandula), mint (Mentha), thyme (Thymus), sage (Salvia) and related genera. This complex, species-rich family includes widely cultivated commercial hybrids and endangered wild-harvested traditional medicines, and examples of potential toxic adulterants within the family are explored in detail. The opportunities provided by next generation sequencing technologies to whole plastome barcoding and nuclear genome sequencing are also discussed with relevant examples.

Biosynthesis and characterization of iron oxide nanoparticles from Mentha spicata and screening its combating potential against Phytophthora infestans

Plant pathogens cause serious diseases to agricultural crops which lead to food insecurity in the world. To combat plant pathogens, various strategies have been developed including the use of agrochemicals. The overuse of these chemicals is now leading to the pesticide-resistant capability of pathogens. To overcome this problem, modern nanobiotechnology offers the production of alternative nano drugs. In this study, we used Mentha spicata for the synthesis of iron oxide nanoparticles using the green synthesis method. The synthesis of Fe₂O₃ NPs was confirmed through various characterizations. UV-Vis analysis detected a characteristic absorbance at the spectral range of 272 nm. The SEM micrographic analysis at various magnifications displayed circular or rod-shaped nanoparticles with a size ranging from 21 to 82 nm. The elemental EDX characterization showed intense peaks with a weight percent of 57, 34.93, and 8.07 for Fe, O, and, Cl respectively. TGA analysis showed that weight loss at 44-182, 500, and 660°C with no further modification indicates the thermal stability of iron oxide nanoparticles. FTIR spectrum of uncalined detects various bands at 3331, 1625, and 1,437 cm^-1 for the hydroxyl group. After calcination two bands at 527 and 434 cm^-1 were observed for Fe-O. The antimicrobial in vitro study showed maximum growth inhibition of Phytophthora infestans by the concentration of 100 μg ml^-1 of Fe₂O₃-PE and Fe₂O₃ NPs. Therefore, this study resulted that bio-stable iron oxide nanoparticles can be used as alternative antimicrobial agents.

Flavoring and extending the shelf life of cucumber juice with aroma compounds-rich herbal extracts at 4 °C through controlling chemical and microbial fluctuations

This work aims to enhance the flavor of functional cucumber juice using herbal extracts of peppermint, basil, lavender, and lemongrass ethanolic extracts and extend its lifetime by controlling the chemical and microbial fluctuations. Cucumber juices were processed as; non-supplemented (J-Con), J-PME, J-BE, J-LE, and J-LEE supplemented with peppermint, basil, lavender, and lemongrass ethanolic extracts, respectively. Peppermint extract was significantly scavenged 88% of DPPH radicals and inhibited the growth of tested gram-positive, gram-negative bacteria and fungi followed by the lemongrass extract. The antioxidant activity of cucumber juices increased due to polyphenols and aroma compounds in the added extracts. However, the antioxidant content was decreased after two months of storage at 4 °C, due to the decrease in polyphenols. The flavor compounds were determined using GC mass, wherein hydrocarbons, acids, alcohols, and carbonyl compounds were the main aroma contents in cucumber juices, and their contents decreased with storage time. Peppermint and lemongrass extracts were significantly (p ≤ 0.05) increased the whiteness of J-PME, and J-LEE, respectively. The highest score of flavor and taste was observed in J-PME that scored 8.3 based on panelists' reports followed by J-LEE. The PME was significantly maintained 91% of the odor and color of J-PME as compared to other juices.

Lamiaceae Essential Oils, Phytochemical Profile, Antioxidant, and Biological Activities

Medicinal and aromatic plants present important active compounds that have potential for use in food, pharmaceutical, and agriculture industries. In this sense, the present work aimed to conduct a literature review on the potential applications of essential oils from Lamiaceae species. Antioxidant, anti-inflammatory, and antimicrobial activities were evaluated. The importance of this study is demonstrated as a way to theoretically provide information on the use of different plants belonging to the Lamiaceae family, especially with regard to the physical, chemical, and biological properties of its essential oils.

GC-MS Metabolomics profiling and HR-APCI-MS characterization of potential anticancer compounds and antimicrobial activities of extracts from Picrorhiza kurroa roots

The present study explores pharmacological potential and phytochemicals profiling of Picrorhiza kurroa extracts against mammalian cancer cell lines and pathogenic microbes. Bioactive extracts from roots of Picrorhiza kurroa were recovered in the methanol, 50% aqueous dichloromethane (50 : 50 v/v) and n-hexane. Antimicrobial activity of the bioactive extracts was assessed against selected strains of bacteria and pathogenic fungi. Aqueous dichloromethane extract showed highest zone of growth inhibition (39.06 ± 1.0 mm) towards Staphylococcus aureus bacteria while methanolic extract showed the lowest inhibition (6.3 ± 4.1 mm) to Escherichia coli bacteria. The tested extracts such as methanol and aqueous dichloromethane exhibited higher inhibition antifungal activity against Aspergillus flavus compared to Fusarium oxysporum. As far as cytotoxicity (MTT assay) of the tested extracts is concerned, n-hexane and aqueous dichloromethane extracts were found to be very active against all cancer cell lines (breast cancer MCF7, MDA-MB-231, SKBR3 and ovarian cancer SKOV3). A preliminary phytochemicals profiling was performed in extracts using GC-MS. Several fractions of active extract were separated with HPLC and analyzed using High Resolution Atmospheric Pressure Chemical Ionization Mass Spectrometry (HR-APCI-MS). Two purified compounds (Dihydromikanolide and 1,3-Dicyclohexyl-4-(cyclohexylimino)-2-(cyclohexylethylamino)-3,4-dihydro-1,3-diazetium) were further evaluated for their anticancer activity against ovarian cancer cell line. Our findings depict that all the tested extracts showed considerable anticancer potential through cell viability assays. The purified compound 1 - Dihydromikanolide from methanolic extract was found to be active against ovarian cancer cells and can be explored as a promising nutra-pharmaceutical candidate against ovarian cancer. However, further studies exploring the molecular pathways and in vivo testing are required.

Chemotypes and Their Stability in Mentha longifolia (L.) L.-A Comprehensive Study of Five Accessions

Mentha longifolia (L.) L. is the most widespread wild-growing mint species found, and its chemical composition is extremely diverse. We studied the essential oil (EO) yield, composition, and chemotaxonomy of five, northern Hungarian accessions of the species in a cultivation experiment covering two vegetation years at two parallel sites. The long-term goal is to establish the cultivation of this stress-tolerant species in Hungary as a source of flavoring and preservative agents for commercial use. Essential oil yield (1-2 mL/100 g) was observed to be dependent on both the accession and the year. Accession HV1 is assumed to be a new, presumably rare chemotype containing carvacrol (19.28-20.56%), 1,8-cineole (14.87-17.45%), thymol (13.36-13.90%), carvacryl acetate (8.81-10.40%), and para-cymene (7.24-8.01%). Only minor fluctuations occurred in concentrations of these constituents due to habitats and years. A radical change in essential oil composition was observed in accession HV2, as one batch was based on thymol (19.79%) and 1,8-cineole (14.93%), while the others were rich in dihydrocarvone isomers (up to 69%). Although this needs further investigation, it does explain the coexistence of limonene-oxo and γ-terpinene pathways in horsemint. According to the literature, the pathway leading to thymol isomers and/or esters may be rare in the entire Mentha genus. We also demonstrated that known chemotypes of horsemint may differ in variability of their EO composition. Our results also led to the conclusion that any declaration on chemotype needs detailed examination and is not realistic on the basis of a single sample. Assumptions were made about the potential areas of utilization: beside fragrance and flavoring uses of essential oils free from pulegone and menthofurane, thymol-based ones may be used as antioxidative and anti-spoilage agents.

Salt Stress Affects Plastid Ultrastructure and Photosynthetic Activity but Not the Essential Oil Composition in Spearmint (Mentha spicata L. var. crispa "Moroccan")

High levels of soil salinity affect plant growth, reproduction, water and ion uptake, and plant metabolism in a complex manner. In this work, the effect of salt stress on vegetative growth, photosynthetic activity, and chloroplast ultrastructure of spearmint (Mentha spicata L. var. crispa "Moroccan") was investigated. After 2 weeks of low concentration treatments (5, 25, and 50 mM NaCl) of freshly cut shoots, we observed that the stem-derived adventitious root formation, which is a major mean for vegetative reproduction among mints, was completely inhibited at 50 mM NaCl concentration. One-week-long, high concentration (150 mM NaCl) salt stress, and isosmotic polyethylene glycol (PEG) 6000 treatments were compared in intact (rooted) plants and freshly cut, i.e., rootless shoots. Our data showed that roots have an important role in mitigating the deleterious effects of both the osmotic (PEG treatment) and specific ionic components of high salinity stress. At 50 mM NaCl or above, the ionic component of salt stress caused strong and irreversible physiological alterations. The effects include a decrease in relative water content, the maximal and actual quantum efficiency of photosystem II, relative chlorophyll content, as well as disorganization of the native chlorophyll-protein complexes as revealed by 77 K fluorescence spectroscopy. In addition, important ultrastructural damage was observed by transmission electron microscopy such as the swelling of the thylakoid lumen at 50 mM NaCl treatment. Interestingly, in almost fully dry leaf regions and leaves, granum structure was relatively well retained, however, their disorganization occurred in leaf chloroplasts of rooted spearmint treated with 150 mM NaCl. This loss of granum regularity was also confirmed in the leaves of these plants using small-angle neutron scattering measurements of intact leaves of 150 mM NaCl-stressed rooted plants. At the same time, solid-phase microextraction of spearmint leaves followed by gas chromatography and mass spectrometry (GC/MS) analyses revealed that the essential oil composition of spearmint was unaffected by the treatments applied in this work. Taken together, the used spearmint cultivar tolerates low salinity levels. However, at 50 mM NaCl concentration and above, the ionic components of the stress strongly inhibit adventitious root formation and thus their clonal propagation, and severely damage the photosynthetic apparatus.

The traditional uses, phytochemistry and pharmacology of spearmint (Mentha spicata L.): A review

ETHNOPHARMACOLOGY RELEVANCE

Mentha spicata L. (Lamiaceae), commonly called Spearmint, is wildly cultivated worldwide for its remarkable aroma and commercial value. In addition to traditional foods flavouring agent, M. spicata is well known for its traditional medicinal uses, particularly for the treatment of cold, cough, asthma, fever, obesity, jaundice and digestive problems.

AIM OF THE REVIEW

This review aims to critically appraise scientific literature regarding the traditional uses, bioactive chemical constituents and pharmacological activities of M. spicata.

MATERIALS AND METHODS

A review of the literature information on M. spicata was searched from scientific electronic search databases (Google Scholar, PubMed, Web of Science, ACS, Science Direct, Taylor and Francis, Wiley, Springer and SCOPUS. Structures for secondary metabolites were confirmed using PubChem and ChemSpider.

RESULTS

The studies conducted on either crude extracts, essential oil or isolated pure compounds from M. spicata had reported a varied range of biological effects including antibacterial, antifungal, antioxidant, hepatoprotective, antidiabetic, cytotoxic, anti-inflammatory, larvicidal activity, antigenotoxic potential and antiandrogenic activities. Phytochemical analysis of various parts of M. spicata revealed 35 chemical constituents, belonging to phenolic acids, flavonoids and lignans.

CONCLUSION

The review finding indicates that the pharmacological properties of M. spicata supported its traditional uses. The essential oils and extracts showed remarkable antimicrobial, antioxidant, anticancer, anti-inflammatory and hepatoprotective activities. However, more studies, especially in vivo experiments and clinical trials of the human to evaluate cellular and molecular mechanisms based pharmacological, bioactive effectiveness and safety investigation, should be undertaken in the future to provide stronger scientific proof for their traditional medicinal properties.

Mint Oils: In Vitro Ability to Perform Anti-Inflammatory, Antioxidant, and Antimicrobial Activities and to Enhance Intestinal Barrier Integrity

The objectives of the study were to test the biological activities of peppermint and spearmint oils via (i) measuring in vitro anti-inflammatory effects with porcine alveolar macrophages (PAMs), (ii) determining the barrier integrity of IPEC-J2 by analyzing transepithelial electrical resistance (TEER), (iii) testing their antioxidant activities, and (iv) investigating the antimicrobial activity against enterotoxigenic Escherichia coli (ETEC) F18+. Briefly, (i) macrophages were seeded at 10⁶ cells/mL and treated (24 h) with mint oils and lipopolysaccharide (LPS). The treatments were 2 (0 or 1 μg/mL of LPS) × 5 (0, 25, 50, 100, 200 µg/mL of mint oils). The supernatants were collected for TNF-α and IL-1β measurement by ELISA; (ii) IPEC-J2 cells were seeded at 5 × 10⁵ cells/mL and treated with mint oils (0, 25, 50, 100, and 200 μg/mL). TEER (Ωcm²) was measured at 0, 24, 48, and 72 h; (iii) the antioxidant activity was assessed (0, 1, 50, 100, 200, 500, and 600 mg/mL) using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and reducing power assays; (iv) overnight-grown ETEC F18+ were quantified (CFU/mL) after supplementing with peppermint and spearmint oils (0, 1.44, 2.87, 5.75, 11.50, and 23.00 mg/mL). All data were analyzed using the MIXED procedure. Both mint oils significantly inhibited (p < 0.05) IL-1β and TNF-α secretion from LPS-stimulated PAMs. Mint oil treatments did not affect TEER in IPEC-J2. Spearmint and peppermint oils exhibited (p < 0.05) strong antioxidant activities in DPPH and reducing power assays. Both mint oils also dose-dependently inhibited (p < 0.05) the growth of ETEC F18+ in vitro. The results of the study indicated that both mint oils are great candidate feed additives due to their in vitro anti-inflammatory, antioxidant, and antimicrobial effects. Further research is needed to evaluate their efficacy in vivo.

Mentha aquatica L. aerial parts: in vitro anti-proliferative evaluation on human tumour and non-tumour cell lines

Bearing in mind the several medicinal properties of Mentha genus, this work aimed to evaluate the anti-proliferative potential of the ethanolic extract (EE) and fractions from M. aquatica L aerial parts. Using the anti-proliferative protocol developed by the NCI/USA, four fractions (F2 - F4 and F6) obtained from EE showed promising anti-proliferative profile against a panel of human tumor and non-tumor cell lines. After 24-h exposure, F2 (0.25 µg/mL) showed potent and irreversible anti-proliferative effect without inducing cell cycle arrest in both NCI-H460 and MCF-7 cells, without (anti) estrogenic activity. These effects were lost after storage of F2 diluted in dimethyl sulfoxide at -80 °C during 2 weeks. Analysis by gas chromatography coupled to mass detection evidenced some chemical changes induced by F2 storage in solution. The present study demonstrated the anti-proliferative effect of M. aquatica. Further studies are necessary to determine better storage conditions to enhance F2 stability.

The evaluation of phenolic content, in vitro antioxidant and antibacterial activity of Mentha piperita extracts obtained by natural deep eutectic solvents

The focus of this study was to evaluate whether six choline chloride-based natural deep eutectic solvents (NADES) could serve as solvents for the extraction of bioactives from the leaves of Mentha piperita. NADES extracted significantly higher amounts of phenols from peppermint than 70% ethanol and may be useful in the extraction of targeted major compounds from peppermint, like rosmarinic acid, at a similar level as 70% ethanol. The microdilution method for in vitro antibacterial activity showed that all NADES exhibit bacterial growth inhibition at a lower concentration than 70% ethanol, especially NADESs containing organic acids. The majority of NADES extracts neutralize DPPH radical at a lower concentration than conventional solvent and showed similar ability to reduce Fe³⁺ to Fe²⁺ ions in FRAP assay. NADES can be useful in the isolation of phenolic compounds from plant sources and should be considered as novel, sustainable, and low-cost solvents with a variety of applications.

In Silico and In Vitro Evaluation of the Antimicrobial and Antioxidant Potential of Mentha × smithiana R. GRAHAM Essential Oil from Western Romania

This study was conducted to identify the volatile compounds of Mentha × smithiana essential oil (MSEO) and evaluate its antioxidant and antibacterial potential. The essential oil (EO) content was assessed by gas chromatography-mass spectrometry (GC-MS). Carvone (55.71%), limonene (18.83%), trans-carveol (3.54%), cis-carveol (2.72%), beta-bourbonene (1.94%), and caryophyllene oxide (1.59%) were the main identified compounds. The MSEO displayed broad-spectrum antibacterial effects and was also found to be the most effective antifungal agent against Candida albicans and Candida parapsilosis. The antioxidant activity of MSEO was tested against cold-pressed sunflower oil by peroxide, thiobarbituric acid, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), and β-carotene/linoleic acid bleaching methods. The EO showed strong antioxidant effects as reflected by IC50 values of 0.83 ± 0.01 mg/mL and relative antioxidative activity of 87.32 ± 0.03% in DPPH and β-carotene/linoleic acid bleaching assays, respectively. Moreover, in the first 8 days of the incubation period, the inhibition of primary and secondary oxidation compounds induced by the MSEO (0.3 mg/mL) was significantly stronger (p < 0.05) than that of butylated hydroxyanisole. In silico molecular docking studies were conducted to highlight the underlying antimicrobial mechanism as well as the in vitro antioxidant potential. Recorded data showed that the antimicrobial activity of MSEO compounds could be exerted through the D-Alanine-d-alanine ligase (DDl) inhibition and may be attributed to a cumulative effect. The most active compounds are minor components of the MSEO. Docking results also revealed that several mint EO components could exert their in vitro antioxidant activity by employing xanthine oxidase inhibition. Consequently, MSEO could be a new natural source of antioxidants and antiseptics, with potential applications in the food and pharmaceutical industries as an alternative to the utilization of synthetic additives.

Phenolic Compounds and Biological Activity of Selected Mentha Species

Mentha species are widely used as food, medicine, spices, and flavoring agents. Thus, chemical composition is an important parameter for assessing the quality of mints. In general, the contents of menthol, menthone, eucalyptol, and limonene comprise one of the major parameters for assessing the quality of commercially important mints. Building further on the phytochemical characterization of the quality of Mentha species, this work was focused on the composition of phenolic compounds in methanolic extracts. Thirteen Mentha species were grown under the same environmental conditions, and their methanolic extracts were subjected to the LC-MS/MS (liquid chromatography-tandem mass spectrometry) profiling of phenolics and the testing their biological activities, i.e., antioxidant and tyrosinase inhibition activities, which are important features for the cosmetic industry. The total phenolic content (TPC) ranged from 14.81 ± 1.09 mg GAE (gallic acid equivalents)/g for Mentha cervina to 58.93. ± 8.39 mg GAE/g for Mentha suaveolens. The antioxidant activity of examined Mentha related with the content of the phenolic compounds and ranged from 22.79 ± 1.85 to 106.04 ± 3.26 mg TE (Trolox equivalents)/g for M. cervina and Mentha x villosa, respectively. Additionally, Mentha pulegium (123.89 ± 5.64 mg KAE (kojic acid equivalents)/g) and Mentha x piperita (102.82 ± 15.16 mg KAE/g) showed a strong inhibition of the enzyme tyrosinase, which is related to skin hyperpigmentation. The most abundant compound in all samples was rosmarinic acid, ranging from 1363.38 ± 8323 to 2557.08 ± 64.21 μg/g. In general, the levels of phenolic acids in all examined mint extracts did not significantly differ. On the contrary, the levels of flavonoids varied within the species, especially in the case of hesperidin (from 0.73 ± 0.02 to 109. 39 ± 2.01 μg/g), luteolin (from 1.84 ± 0.11 to 31.03 ± 0.16 μg/g), and kaempferol (from 1.30 ± 0.17 to 33.68 ± 0.81 μg/g). Overall results indicated that all examined mints possess significant amounts of phenolic compounds that are responsible for antioxidant activity and, to some extent, for tyrosinase inhibition activity. Phenolics also proved to be adequate compounds, together with terpenoids, for the characterization of Mentha sp. Additionally, citrus-scented Mentha x villosa could be selected as a good candidate for the food and pharmaceutical industry, especially due its chemical composition and easy cultivation, even in winter continental conditions.

The Wonderful Activities of the Genus Mentha: Not Only Antioxidant Properties

Medicinal plants and their derived compounds have drawn the attention of researchers due to their considerable impact on human health. Among medicinal plants, mint (Mentha species) exhibits multiple health beneficial properties, such as prevention from cancer development and anti-obesity, antimicrobial, anti-inflammatory, anti-diabetic, and cardioprotective effects, as a result of its antioxidant potential, combined with low toxicity and high efficacy. Mentha species are widely used in savory dishes, food, beverages, and confectionary products. Phytochemicals derived from mint also showed anticancer activity against different types of human cancers such as cervix, lung, breast and many others. Mint essential oils show a great cytotoxicity potential, by modulating MAPK and PI3k/Akt pathways; they also induce apoptosis, suppress invasion and migration potential of cancer cells lines along with cell cycle arrest, upregulation of Bax and p53 genes, modulation of TNF, IL-6, IFN-γ, IL-8, and induction of senescence phenotype. Essential oils from mint have also been found to exert antibacterial activities against Bacillus subtilis, Streptococcus aureus, Pseudomonas aeruginosa, and many others. The current review highlights the antimicrobial role of mint-derived compounds and essential oils with a special emphasis on anticancer activities, clinical data and adverse effects displayed by such versatile plants.

The metabolomic analysis of five Mentha species: cytotoxicity, anti-Helicobacter assessment, and the development of polymeric micelles for enhancing the anti-Helicobacter activity

Mentha species are medicinally used worldwide and remain attractive for research due to the diversity of their phytoconstituents and large therapeutic indices for various ailments. This study used the metabolomics examination of five Mentha species (M. suaveolens, M. sylvestris, M. piperita, M. longifolia, and M. viridis) to justify their cytotoxicity and their anti-Helicobacter effects. The activities of species were correlated with their phytochemical profiles by orthogonal partial least square discriminant analysis (OPLS-DA). Tentatively characterized phytoconstituents using liquid chromatography high-resolution electrospray ionization mass spectrometry (LC-HR-ESI-MS) included 49 compounds: 14 flavonoids, 10 caffeic acid esters, 7 phenolic acids, and other constituents. M. piperita showed the highest cytotoxicity to HepG2 (human hepatoma), MCF-7 (human breast adenocarcinoma), and CACO2 (human colon adenocarcinoma) cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. OPLS-DA and dereplication studies predicted that the cytotoxic activity was related to benzyl glucopyranoside-sulfate, a lignin glycoside. Furthermore, M. viridis was effective in suppressing the growth of Helicobacter pylori at a concentration of 50 mg mL-1. OPLS-DA predicted that this activity was related to a dihydroxytrimethoxyflavone. M. viridis extract was formulated with Pluronic® F127 to develop polymeric micelles as a nanocarrier that enhanced the anti-Helicobacter activity of the extract and provided minimum inhibitory concentrations and minimum bactericidal concentrations of 6.5 and 50 mg mL-1, respectively. This activity was also correlated to tentatively identified constituents, including rosmarinic acid, catechins, carvone, and piperitone oxide.