Metabolic Profiling of Nine Mentha Species and Prediction of Their Antioxidant Properties Using Chemometrics

Mentha piperita silver nanoparticle-loaded hydrocolloid film for enhanced diabetic wound healing in rats

OBJECTIVE

To investigate the role of Mentha piperita silver nanoparticle-loaded carbopol gel for enhanced wound healing in a diabetic rat model. This research further aims to explore bioactive compounds derived from Mentha piperita obtained from high altitude.

METHOD

Methanolic extracts of Mentha piperita (MP), Mentha spicata (MS) and Mentha longifolia (ML) were used to synthesise silver nanoparticles (AgNP). AgNP synthesis was confirmed by ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The antioxidant activity was assessed by 2, 2-diphenyl-1-picrylhydrazyl (DDPH) assay. Antiglycation potential was determined by measuring the fluorescent advanced glycation end products. The bioactive compound identified in the Mentha piperita methanolic (MPM) fraction through electrospray ionisation tandem mass spectrometric analysis (ESI-MS) was responsible for the highest antiglycation. The effects of MPM and MPM.AgNP-loaded Carbopol (Sanare Lab, India) on wound healing were compared in male, alloxan-induced, diabetic albino rats (200-250g), divided into control and treated groups. Effects on wound healing were assessed via histopathology.

RESULTS

UV-Vis and FTIR confirmed NP synthesis with peaks for flavonoids and polyphenols. SEM and XRD explored the cubical, 30-63nm crystalline NP. The maximum antioxidant and antiglycation potential was observed in order of; MP.AgNP>MS.AgNP>ML.AgNP. The highest antioxidant activity was observed by methanolic and aqueous MP.AgNPs (88.55% and 83.63%, respectively) at 2mg.ml-1, and (75.16% and 69.73%, respectively) at 1mg.ml-1, compared to ascorbic acid (acting as a positive control, 90.01%). MPM.AgNPs demonstrated the best antiglycation potential of 75.2% and 83.3% at 1mg.ml-1 and 2mg.ml-1, respectively, comparable to positive control (rutin: 88.1%) at 14 days post-incubation. A similar trend was observed for antimicrobial activity against Bacillus subtilis, Micrococcus luteus and Escherichia coli with an inhibition zone of 21mm, 21.6mm and 24.6mm. Rosmarinic acid was the active compound present in Mentha piperita, as identified by ESI-MS. MPM.AgNP-loaded Carbopol resulted in 100% wound closure compared with control at 20 days post-wounding. In the treatment group, re-epithelialisation was achieved by day 18, compared with 25 days for the positive control group.

CONCLUSION

MPM.AgNP-loaded Carbopol demonstrated safer and more effective biological properties, hence accelerating the diabetic excision wound healing process in alloxan-induced diabetic rats.

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.

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.

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.

Towards Bioprospection of Commercial Materials of Mentha spicata L. Using a Combined Strategy of Metabolomics and Biological Activity Analyses

Spearmint (Mentha spicata L.) has been widely studied for its diversity of compounds for product generation. However, studies describing the chemical and biological characteristics of commercial spearmint materials from different origins are scarce. For this reason, this research aimed to bioprospecting spearmint from three origins: Colombia (Col), Mexico (Mex), and Egypt (Eg). We performed a biological activity analysis, such as FRAP, DPPH, and ABTS, inhibition potential of S. pyogenes, K. pneumoniae, E. coli, P. aeuroginosa, S. aureus, S aureus Methicillin-Resistant, and E. faecalis. Furthermore, we performed chemical assays, such as total polyphenol and rosmarinic acid, and untargeted metabolomics via HPLC-MS/MS. Finally, we developed a causality analysis to integrate biological activities with chemical analyses. We found significant differences between the samples for the total polyphenol and rosmarinic acid contents, FRAP, and inhibition analyses for Methicillin-Resistant S. aureus and E. faecalis. Also, clear metabolic differentiation was observed among the three commercial materials evaluated. These results allow us to propose data-driven uses for the three spearmint materials available in current markets.

The role of plant-derived natural antioxidants in reduction of oxidative stress

Free radicals are a group of damaging molecules produced during the normal metabolism of cells in the human body. Exposure to ultraviolet radiation, cigarette smoking, and other environmental pollutants enhances free radicals in the human body. The destructive effects of free radicals may also cause harm to membranes, enzymes, and DNA, leading to several human diseases such as cancer, atherosclerosis, malaria, coronavirus disease (COVID-19), rheumatoid arthritis, and neurodegenerative illnesses. This process occurs when there is an imbalance between free radicals and antioxidant defenses. Since antioxidants scavenge free radicals and repair damaged cells, increasing the consumption of fruits and vegetables containing high antioxidant values is recommended to slow down oxidative stress in the body. Additionally, natural products demonstrated a wide range of biological impacts such as anti-inflammatory, anti-aging, anti-atherosclerosis, and anti-cancer properties. Hence, in this review article, our goal is to explore the role of natural therapeutic antioxidant effects to reduce oxidative stress in the diseases.

Metabolomics of Chlorophylls and Carotenoids: Analytical Methods and Metabolome-Based Studies

Chlorophylls and carotenoids are two families of antioxidants present in daily ingested foods, whose recognition as added-value ingredients runs in parallel with the increasing number of demonstrated functional properties. Both groups include a complex and vast number of compounds, and extraction and analysis methods evolved recently to a modern protocol. New methodologies are more potent, precise, and accurate, but their application requires a better understanding of the technical and biological context. Therefore, the present review compiles the basic knowledge and recent advances of the metabolomics of chlorophylls and carotenoids, including the interrelation with the primary metabolism. The study includes material preparation and extraction protocols, the instrumental techniques for the acquisition of spectroscopic and spectrometric properties, the workflows and software tools for data pre-processing and analysis, and the application of mass spectrometry to pigment metabolomics. In addition, the review encompasses a critical description of studies where metabolomics analyses of chlorophylls and carotenoids were developed as an approach to analyzing the effects of biotic and abiotic stressors on living organisms.

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.

Evaluation of multielement/proximate composition and bioactive phenolics contents of unconventional edible plants from Brazil using multivariate analysis techniques

Unconventional edible plants (UEP) are potential supplementary sources of minerals and bioactive compounds. However, there is still a gap in the literature on UEP composition. In this study, the multielement/proximate composition of ten UEP from Brazil was evaluated by ICP OES. Furthermore, phenolic bioactives were quantified by HPLC-UV-DAD. The UEP showed high moisture content (84.85-95.27%) and elements (in mg Kg^-1): Al (122-657), Ca (145-14,229), Cu (8.3-18.81), Fe (177-586), K (12.46-34.50%), Mg (157-1,552), Mn (16.85-84.96), Na (1,107-23,775), P (2,535-6,127), Si (189-1,695), Sr (25.56-104.63) and Zn (0.3-72.31). Nine phenolic bioactive compounds (1-2,147) and three flavonoids (1-2,042 mg Kg^-1) were determined. PCA and HCA grouped samples (Java ginseng, Coriander, Spearmint and Indian borage) rich in minerals. Spearmint showed high levels of transcinamic acid, kaempferol and quercetin. This study contributes to the scientific development and use of UEP.

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.

Data handling and data analysis in metabolomic studies of essential oils using GC-MS

Gas chromatography electron impact ionization mass spectrometry (GC-EI-MS) has been, and remains, the most widely applied analytical technique for metabolomic studies of essential oils. GC-EI-MS analysis of complex samples, such as essential oils, creates a large volume of data. Creating predictive models for such samples and observing patterns within complex data sets presents a significant challenge and requires application of robust data handling and data analysis methods. Accordingly, a wide variety of software and algorithms has been investigated and developed for this purpose over the years. This review provides an overview and summary of that research effort, and attempts to classify and compare different data handling and data analysis procedures that have been reported to-date in the metabolomic study of essential oils using GC-EI-MS.

Roles and action mechanisms of herbs added to the emulsion on its lipid oxidation

Quality of food emulsions is mainly determined by their physicochemical stability such as lipid oxidation, and herbs as antioxidative food materials are added to improve their quality and shelf-life. Despite the extensive researches, the chemistry and implications of herb addition in the lipid oxidation of emulsions are still confusing. This review intended to provide the information on the roles and action mechanisms of herbs in the lipid oxidation of food emulsions, with focuses on polyphenols. Polyphenols act as antioxidants mainly via reactive oxygen species scavenging and metal chelating; however, their oxidation products and reducing capacity to more reactive metal ions increase the lipid oxidation. Factors such as structure, concentration, and distribution determine their anti- or prooxidant role. Interactions, synergism and antagonism, among polyphenol compounds and the effects of tocopherols derived from oil on the antioxidant activity of herbs were also described with the involving action mechanisms.

Comparative metabolic profiling of cultivated and wild black soybeans reveals distinct metabolic alterations associated with their domestication

Generally, cultivated black soybean (CBS) has been used as a major source of various nutrients for humans and animals. To assess the metabolic alterations induced by domestication in soybean, we performed a comprehensive metabolite profiling of 56 soybean varieties, including 28 CBS and 28 wild black soybean (WBS) varieties. A total of 48 metabolites were characterized, including 45 primary and 3 secondary metabolites, from CBS and WBS. The results of principal component analysis and hierarchical cluster analysis (HCA) revealed significant metabolic differences between CBS and WBS that were closely related to metabolic pathways. The results indicate that flavonoids correlated positively with phenylalanine, a precursor for phenylpropanoid biosynthesis; the contents of flavonoids and phenylpropanoids were higher in WBS. Pathway analysis revealed that CBS contained large amounts of TCA cycle intermediates, amino acids, and fatty acids as a result of increased energy metabolism, amino acid metabolism, and seed filling. The projection to latent structure method, using the partial least squares method, was applied to predict the flavonoid content in soybean seed, which indicated that sucrose, threonic acid, citric acid, and fatty acids are important in predicting the antioxidant content of samples. This work will provide important information for designing new soybean cultivars with enhanced nutritional and agricultural traits.

Changes in the Content of Phenolic Compounds and Biological Activity in Traditional Mexican Herbal Infusions with Different Drying Methods

Mexican spices are used in the supplementation of the human diet and as medicinal herbs for the particularly high amounts of compounds capable of deactivating free radicals. In addition, these spices can have beneficial effects on chronic, no-transmissible diseases such as type II diabetes and hypertension arterial. The objective of this study is to determine the content of phenolic compounds on the antioxidant activity and inhibitory enzymes of α-amylase, α-glucosidase and angiotensin-converting enzyme in melissa, peppermint, thyme and mint, which are subjected to microwave drying, conventional and freeze-drying to be used as alternative treatments. Spices were evaluated to determine total phenols, flavonoids, tannins, 2,2-Diphenyl-1-picrylhydrazyl (DPPH), (2,2'-azino-bis- (3-ethyl benzothiazolin-6-ammonium sulphonate) (ABTS) and Ferric Reducing/Antioxidant Power (FRAP), enzymatic activity. The investigation showed that conventional drying caused a decrease in antioxidant properties and inhibitory activity, in some species, while remained preserved in microwave drying and freeze-drying. The activity of polyphenol oxides and peroxidase decreases with high temperatures and these increase with the use of cold temperatures. This study aims to determine the extent of optimal drying required to preserve phenolic compounds, and the positive effect on antioxidant activity and enzymatic activity in in vitro models, which will produce benefits for the infusion processing industry and the pharmaceutical industry.

Dynamics of Short-Term Metabolic Profiling in Radish Sprouts (Raphanus sativus L.) in Response to Nitrogen Deficiency

Nitrogen (N) is a macronutrient important for the survival of plants. To investigate the effects of N deficiency, a time-course metabolic profiling of radish sprouts was performed. A total of 81 metabolites—including organic acids, inorganic acid, amino acids, sugars, sugar alcohols, amines, amide, sugar phosphates, policosanols, tocopherols, phytosterols, carotenoids, chlorophylls, and glucosinolates—were characterized. Principal component analysis and heat map showed distinction between samples grown under different N conditions, as well as with time. Using PathVisio, metabolic shift in biosynthetic pathways was visualized using the metabolite data obtained for 7 days. The amino acids associated with glucosinolates accumulated as an immediate response against –N condition. The synthesis of pigments and glucosinolates was decreased, but monosaccharides and γ-tocopherol were increased as antioxidants in radish sprouts grown in –N condition. These results indicate that in radish sprouts, response to N deficiency occurred quickly and dynamically. Thus, this metabolic phenotype reveals that radish responds quickly to N deficiency by increasing the content of soluble sugars and γ-tocopherol, which acts as a defense mechanism after the germination of radish seeds.