Chemical composition, cytotoxicity, antimicrobial, antibiofilm, and anti-quorum sensing potential of Mentha Piperita essential oil against the oral pathogen Streptococcus mutans.

Dental caries is a highly prevalent oral disease affecting billions of individuals globally. The disease occurs chemically as a result of breakdown of the tooth surface attributed to metabolic activity in colonizing biofilm. Biofilms, composed of exopolysaccharides and proteins, protect bacteria like Streptococcus mutans, which is notable for its role in tooth decay due to its acid-producing abilities. While various antimicrobial agents may prevent biofilm formation, these drugs often produce side effects including enamel erosion and taste disturbances. This study aimed to examine utilization of the Mentha piperita essential oil as a potential antibiofilm activity agent against S. mutans. M. piperita oil significantly (1) reduced bacterial biofilm, (2) exhibited a synergistic effect when combined with chlorhexidine, and (3) did not induce cell toxicity. Chemical analysis identified the essential oil with 99.99% certainty, revealing menthol and menthone as the primary components, constituting approximately 42% and 26%, respectively. Further, M. piperita oil eradicated preformed biofilms and inhibited biofilm formation at sub-inhibitory concentrations. M. piperita oil also interfered with bacterial quorum sensing communication and did not produce any apparent cell toxicity in immortalized human keratinocytes (HaCaT). M. piperita represented an alternative substance for combating S. mutans and biofilm formation and a potential combination option with chlorhexidine to minimize side effects. An in-situ performance assessment requires further studies.

Phytochemical analysis of carotenoid profile in Mentha piperita and Artemisia vulgaris: cytotoxicity in tumoral cells and evaluation of plasmid DNA cleavage.

Several medicinal plants have been administered to cancer patients attributed to their anticarcinogenic and chemoprotective properties, in addition to lower toxicity compared to traditional therapies. The aim was to investigate the antioxidant properties and carotenoid composition of aqueous extracts of Mentha piperita or Artemisia vulgaris which were previously found to exert beneficial effects on human health through diet. aqueous extracts exhibited potent antioxidant activity. A diversity of carotenoids was identified in these extracts using HPLC-PDA-MS/MS. Both extracts contained predominantly all-trans-lutein as the main component within this class. In order to investigate antioxidant properties, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) techniques were used. The (3-4,5 dimethylthiazol-2, 5 diphenyl tetrazolium bromide) (MTT) and Crystal Violet assays assessed cellular cytotoxicity. Assessments of presence of reactive species were carried out following exposure of oral squamous cell carcinoma cell line (SCC-4) to various aqueous extracts of M piperita or A vulgaris utilizing dichlorofluorescein diacetate (DCFH-DA) and nitric oxide (NO) assays. Exposure to these extracts induced severe cytotoxic effects, which led to investigation of the biochemical and molecular mechanisms underlying this observed effect. Data demonstrated that both solutions induced oxidative stress and DNA damage, especially at higher concentrations using agarose gel subjected to electrophoresis. It is known that exposure to excess amounts of antioxidants results in a prooxidant effect which is beneficial in cancer therapy. Further, the extracts were found to reduce viability of SCC-4 in culture, indicating that this antitumoral activity may be of therapeutic importance and requires further study.

Exploring the Differential Impact of Salt Stress on Root Colonization Adaptation Mechanisms in Plant Growth-Promoting Rhizobacteria.

Salinity inhibits plant growth by affecting physiological processes, but soil microorganisms like plant growth-promoting rhizobacteria (PGPR) can alleviate abiotic stress and enhance crop productivity. However, it should be noted that rhizobacteria employ different approaches to deal with salt stress conditions and successfully colonize roots. The objective of this study was to investigate the effect of salt stress on bacterial survival mechanisms such as mobility, biofilm formation, and the autoaggregation capacity of three plant growth-promoting strains: Pseudomonas putida SJ04, Pseudomonas simiae WCS417r, and Bacillus amyloliquefaciens GB03. These strains were grown in diluted LB medium supplemented with 0, 100, 200, or 300 mM NaCl. Swimming and swarming mobility were evaluated in media supplemented with 0.3 and 0.5% agar, respectively. Biofilm formation capacity was quantified using the crystal violet method, and the autoaggregation capacity was measured spectrophotometrically. In addition, we evaluated in vitro the capacity of the strains to ameliorate the effects of saline stress in Mentha piperita. The study found that the GB03 strain exhibited enhanced swarming mobility when the salt concentration in the medium increased, resulting in a two-fold increase in the halo diameter at 300 mM. However, high concentrations of NaCl did not affect the swimming mobility. In contrast, swimming motility was reduced in WCS417r and SJ04 under salt stress. On the other hand, exposure to 300 mM NaCl resulted in a 180% increase in biofilm formation and a 30% rise in the percentage of autoaggregation in WCS417r. Conversely, the autoaggregation percentage of the strains SJ04 and GB03 remained unaffected by saline stress. However, for GB03, biofilm formation decreased by 80% at 300 mM. Simultaneously, inoculation with the three evaluated strains alleviated the detrimental effects of salinity on plant growth. Under 150 mM salt stress, all strains showed increased fresh weight, with GB03 and WCS417r improving by 40% and SJ04 exhibiting the most remarkable effect with a 70% rise compared to non-inoculated plants. Despite their different strategies for mitigating salt stress, the application of these strains presents a promising strategy for effectively mitigating the negative consequences of salt stress on plant cultivation.

Effects of Harvest Time and Hydrodistillation Time on Yield, Composition, and Antioxidant Activity of Mint Essential Oil.

In this study, we assessed the effects of different harvest times (9 a.m., 1 p.m., and 5 p.m.) and hydrodistillation times (60, 90, and 120 min) on the yield, chemical composition, and antioxidant activity of the spearmint (Mentha spicata L.) essential oil (EO) sourced from the Amazon region. EO yield was ≥1.55% and was not significantly influenced (p ≥ 0.05) by the different harvest times and hydrodistillation times. Thirty-one different organic compounds were identified, of which menthol (91.56-95.68%), menthone (0.6-2.72%), and isomenthone (0.55-1.46%) were the major constituents. The highest menthol content in the EO was obtained from samples collected at 9 a.m., with a hydrodistillation time of 60-90 min, compared to other harvest and hydrodistillation times. This suggests that exposure to sun and light, which is greater at harvest times of 1 p.m. and 5 p.m., decreased the menthol content and altered the chemical composition of Mentha EO. Furthermore, the sample harvested at 9 a.m. and hydrodistilled for 60 min showed the highest antioxidant activity (61.67 equivalent mg of Trolox per g of EO), indicating that antioxidant activity is strongly affected by light exposure and the contact duration of the sample with boiling water during hydrodistillation.

Antifungal Activity and Alleviation of Salt Stress by Volatile Organic Compounds of Native Pseudomonas Obtained from Mentha piperita.

As salt stress has a negative impact on plant growth and crop yield, it is very important to identify and develop any available biotechnology which can improve the salt tolerance of plants. Inoculation with plant-growth-promoting rhizobacteria (PGPR) is a proven environmentally friendly biotechnological resource for increasing the salt stress tolerance of plants and has a potential in-field application. In addition, bacterial volatile organic compounds (mVOCs) are signal molecules that may have beneficial roles in the soil-plant-microbiome ecosystem. We investigated the effects of mVOCs emitted by Pseudomona putida SJ46 and SJ04 on Mentha piperita grown under different levels of NaCl stress by evaluating their growth-promoting potential and capacity to increase salt tolerance effects. Furthermore, we evaluated under control and salt stress conditions the biocontrol ability of VOCs emitted by both these strains to inhibit the growth of Alternaria alternata and Sclerotium rolfsii. The VOCs emitted by both strains under control conditions did not lead to an significant improvement in peppermint growth. However, under salt stress conditions (75 or 100 mM NaCl), an amelioration of its physiological status was observed, with this effect being greater at 100 mM NaCl. This led to an enhancement of the number of leaves and nodes and, increased the shoot fresh and root dry weight by approximately twice in relation to control stressed plants. Moreover, the VOCs released by the two bacteria grown in control or saline media showed a significant reduction in the mycelial growth of A. alternata. In contrast, S. rolfsii growth was reduced 40% by the mVOCs released only under control conditions, with no effects being observed under salt stress. We also explored the composition of the bacterial volatile profiles by means of a solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) analysis. From the headspace of SJ46, three VOCs were identified: n-octanol, decane and tetradecane. The emission of SJ04 had the same chromatographic profile, with the addition of two more compounds: 1-(N-phenyl carbamyl)-2-morpholino cyclohexene and tridecane. Only compounds that were not present in the headspace of the control groups were recorded. The salt stress conditions where the bacteria were grown did not qualitatively modify the mVOC emissions. Taken together, our results suggest that plant-associated rhizobacterial VOCs play a potentially important role in modulating plant salt tolerance and reducing fungal growth. Thus, biological resources represent novel tools for counteracting the deleterious effects of salt stress and have the potential to be exploited in sustainable agriculture. Nevertheless, future studies are necessary to investigate technological improvements for bacterial VOC application under greenhouse and open field conditions.

Hamburger made with mechanically separated poultry meat and essential oil of oregano or peppermint added as an antioxidant / Hamburguer elaborado com carne mecanicamente separada de aves e adicionado de óleo essencial de orégano ou hortelã-pimenta como antioxidante

The increased production of mechanically separated poultry meat has led to its use in the production of foods of higher commercial value, such as hamburgers. However, hamburgers are more susceptible to oxidation, therefore, the goal of this study was to evaluate the antioxidant and antibacterial properties of hamburgers made with mechanically separated meat (MSM) from broilers and broiler breeder hens supplemented with oregano (Origanum vulgare) or peppermint (Mentha piperita). Hamburgers with a synthetic antioxidant and three levels of oregano and peppermint essential oils were evaluated using a sensory acceptance test. An inclusion level of 0.04% for both essentials oils was chosen for this test to evaluate the physical-chemical compositions as well as the microbiological and antioxidant activities because an inclusion level of 0.08% received a lower score from the evaluators. Higher pH values were found in hamburgers made with broiler MSM (control (6.94) and peppermint essential oil (6.93) and in broiler breeder hens MSM supplemented with peppermint essential oil (6.89). When comparing the origin of MSM, lower pH values were found in the broiler hamburgers supplemented with oregano essential oils (6.83). The total coliform counts at day zero were significantly higher for the hamburgers made with broiler breeder hens MSM with oregano essential oil, however, broilers MSM supplemented with a synthetic antioxidant showed the lowest count when compared to that of the others. For Staphylococcus coagulase-negative bacteria, growth was observed only on day zero, with a low count in hamburgers made with broiler breeder hens MSM and broiler MSM supplemented with synthetic antioxidant or peppermint essential oil. Hamburgers made with MSM from broilers and broiler breeder hens supplemented with synthetic antioxidants showed higher antioxidant capacity with an average of 2378.75 and 2265.43 µmols equivalent Trolox/mg, respectively. Our results suggest that the essential oils of oregano or peppermint can be used in the formulation of hamburgers since they presented high sensory acceptability and reduced contamination.(AU)

O aumento da produção de carne mecanicamente separada (CMS) de aves levou a indústria a buscar seu uso na produção de produtos de maior valor comercial, como os hambúrgueres. No entanto, os hambúrgueres são mais susceptíveis a oxidação, em vista disso, o objetivo desse trabalho foi avaliar hambúrgueres elaborados com CMS de frangos e galinhas pesadas e adicionados de óleos essenciais de orégano (Origanum vulgare) ou hortelã-pimenta (Mentha piperita) como antioxidantes e antibacterianos. Para o teste de aceitação sensorial, foi avaliado um antioxidante sintético e mais três níveis de óleos essenciais de orégano e hortelã-pimenta. A partir desse teste, foi escolhido o nível de inclusão de 0,04% de ambos os óleos essenciais para realizar as análises físico-químicas, microbiológica e capacidade antioxidante, uma vez que o nível de 0,08% recebeu a menor nota pelos avaliadores. Em relação ao pH, maior valor foi encontrado nos hambúrgueres elaborados com CMS de frango (controle 6,94) e óleo essencial de hortelã-pimenta (6,93) e CMS de galinhas pesadas e adicionados de óleo essencial de hortelã-pimenta (6,89). Ao comparar individualmente a origem da CMS, menor valor de pH foi encontrado para o hambúrguer de frango adicionado de óleo essencial de orégano (6,83). As contagens de coliformes totais, no dia zero, foi significativamente maior para os hambúrgueres elaborados com CMS de galinhas pesadas adicionados de óleo essencial de orégano, porém, a CMS de frangos acrescida de antioxidante sintético apresentou a menor contagem quando comparado aos demais. Já para Staphylococcus coagulase negativa, houve crescimento apenas no dia zero, com baixas contagens nos hambúrgueres elaborados com CMS de galinhas pesadas e de frangos adicionados de antioxidante sintético ou óleo essencial de hortelã-pimenta. Hambúrgueres elaborados com CMS de frangos e galinhas pesadas adicionados de antioxidante sintético apresentaram maior capacidade antioxidante, uma vez que apresentaram média de 2378,75 e 2265,43 µmols equivalente Trolox/mg respectivamente para frangos e galinhas pesadas. Conclui-se que os óleos essenciais de orégano ou hortelã-pimenta podem ser utilizados na formulação dos hambúrgueres, uma vez que apresentam boa aceitabilidade e reduzem as contaminações.(AU)

Effect of Adding Matricaria recutita L., Cymbopogon citratus, or Mentha piperita L. Extracts to Fermented Orange Beverage: Sensory Evaluation, Physicochemical Characterization, and Prediction of Toxic Risks and Biological Activity In Silico.

Fermentation is an important tool in producing functional beverages through agro-industrial wastes, and medicinal and aromatic plants due to the specific content of bioactive molecules. Therefore, this study evaluated the contribution of Matricaria recutita (chamomile), Cymbopogon citratus (lemongrass), or Mentha piperita (peppermint) extracts to the phytochemical profile and potential biological effects of a functional fermented orange beverage in vitro and in silico. The concentrations of aromatic herbal extracts that yielded the best sensory performance for fermented beverages were selected for analyses that involved characterizing the fermented beverages. The beverages that received the extracts (2%) had the highest phenolic and flavonoid content and antioxidant potential compared to the control. Hesperidin (124-130 mg L-1), narirutin (66-70 mg L-1), chlorogenic (11-16 mg L-1), caffeic (5.3-5.5 mg L-1), and ferulic (1-1.7 mg L-1) acids were found in the different formulations. The in silico analysis suggested that the evaluated compounds do not present a toxicity risk (mutagenicity, carcinogenicity, hepatotoxicity, and ability to penetrate the blood-brain barrier). Additionally, they can contribute to the biological effects of therapeutic importance, such as antioxidant, gastroprotective, and anti-ulcerative properties, and the Mentha piperita L. extract presented the greatest potential among the evaluated herbs for use in functional fermented beverages.

Histological and molecular evaluation of Mentha arvensis extract on a polycystic ovary syndrome rat model.

OBJECTIVE: This study aimed to investigate the impact of Mentha arvensis on a rat model of polycystic ovary syndrome (PCOS). METHODS: The PCOS rat model was made by the daily subcutaneous injection of testosterone enanthate (250mg/kg) for 21 days. Thirty rats were divided into five groups, including a healthy control group and four PCOS groups treated with various concentrations of hydroalcoholic extract of Mentha arvensis (0, 50, 100 and 200mg/kg). LH and FSH were measured in the blood. The ovaries were used for histological investigation, Cyp17 and Ptgs2 genes expression and total antioxidant capacity. RESULTS: Our results indicated that the level of LH and FSH hormones in treated PCOS rats with various concentrations of M. arvensis were reduced in comparison with the untreated PCOS group (p>0.01). Mentha arvensis in the highest concentration (200mg/kg) decreased the number of cysts in this group in comparison with the untreated PCOS group (p<0.01). The expression of Cyp17 and Ptgs2 genes in the treated group with the highest concentration of hydroalcoholic extract were decreased in comparison with the untreated PCOS group (p<0.05). Moreover, the antioxidant capacity in the rats receiving Mentha arvensis hydroalcoholic extract was significantly increased in comparison with that from the untreated PCOS rats (p<0.05). CONCLUSIONS: For the first time, Mentha arvensis hydroalcoholic extract proved to reduce some polycystic ovary syndrome symptoms. In the present experiment, a dose of 200mg/kg of Mentha arvensis hydroalcoholic extract was regarded as the most efficient dose.

Therapeutic bath of mint hydrolate in the control of monogenea for four tilapia species / Banho terapêutico de hidrolato de hortelã no controle de parasitas para quatro espécies de tilápia

This work aimed to evaluate a therapeutic bath of mint (Mentha x villosa) hydrolate in the control of monogeneans for four tilapia species (Oreochromis niloticus, Oreochromis aureus, Oreochromis mossambicus, and Oreochromis hornorum) reared in the same environment (pond). After two months, 60 individuals of O. niloticus were divided into six groups of ten fish each. Three of them were submitted to a 1-hour therapeutic bath of mint hydrolate at the concentration of 20 mL·L-1, and the others were used as a control group. This process was repeated for O. aureus, O. mossambicus and O. hornorum. After that, mucus and gills were analyzed to determine parasitological indices (prevalence, mean abundance, and mean intensity) for monogeneans. The efficacy of mint hydrolate bath was set as 73.5, 79, 80.7, and 84.5% for O. hornorum, O. aureus, O. mossambicus and O. niloticus, respectively, against the monogeneans in the mucus. All species in this work demonstrated similar parasitic susceptibility when reared in the same environment. In addition, the use of mint therapeutic bath demonstrated efficacy in the control of monogeneans in mucus for all evaluated species.(AU)

Este trabalho teve como objetivo avaliar um banho terapêutico de hidrolato de hortelã (Mentha x villosa) no controle de monogenéticos para quatro espécies de tilápia (Oreochromis niloticus, Oreochromis aureus, Oreochromis mossambicus e Oreochromis hornorum) criadas no mesmo ambiente (viveiro). Após dois meses, 60 indivíduos de O. niloticus foram divididos em seis grupos de dez peixes cada um. Três deles foram submetidos a um banho terapêutico de uma hora de hidrolato de hortelã na concentração de 20 mL·L-1, e os demais foram utilizados como grupo controle. Esse processo foi repetido para O. aureus, O. mossambicus e O. hornorum. Em seguida, o muco e as brânquias foram analisados para determinar os índices parasitológicos (prevalência, abundância média e intensidade média). A eficácia do banho de hidrolato de hortelã no muco foi medida em 73,5, 79, 80,7 e 84,5% para O. hornorum, O. aureus, O. mossambicus e O. niloticus, respectivamente. Todas as espécies de tilápia avaliadas neste trabalho demonstraram suscetibilidade parasitária semelhante quando criadas no mesmo ambiente, no entanto o uso do banho terapêutico de hortelã demonstrou eficácia no controle de monogenéticos no muco para todas as espécies avaliadas.(AU)

Essential oil in the management of the seed bank of infestant plants / Óleo essencial no manejo de banco de sementes de plantas infestantes

The weed seed bank causes damage to agriculture, due to competition with cultivated plants and raising production costs, Cenchrus echinatushas a high seed multiplication and dissemination mechanism and Conyzabonariensisglyphosate resistance mechanism. The objective was to evaluate the potential of Menthaarvensisessential oil by means of fumigation in the weed seed bank. Soil samples (2 kg per treatment) were collected, homogenized and subjected to fumigation for 24 and 48 hours at concentrations of 2.5% and 5.0% of essential oil. The soil was solarized (control) and dried in the shade for three days as a witness. Then, 500 g of soil were distributed in four trays in a completely randomized design, where they received irrigation, identification and registration of emerging seedlings. Data were checked for normality and homogeneity of variance, transformed when necessary and submitted to analysis of variance at a 5% significance level. The averages were performed by Tukey and Dunnet tests at 5% probability. It was concluded that fumigation reduced grass and horseweed emergence regardless of dose and exposure time, with results similar to solarization.(AU)

O banco de sementes de plantas daninhas ocasionadanos a agricultura, devidoa competição com plantas cultivadas e elevando custos de produção, o Cenchrus echinatustemalto mecanismo de multiplicação e disseminação de sementes e a Conyzabonariensis mecanismo de resistência ao glifosato. Objetivou-seavaliar o potencial do óleo essencial de Mentha arvensispor meio da fumigação sobre o banco de sementes de plantas daninhas. As amostras de solo (2 kgpor tratamento) foram coletadas, homogeneizadas e submetidas à fumigação por 24 e 48 horas nas concentrações de 2,5% e 5,0% de óleo essencial, sendo solo solarizado (controle) e solo seco a sombra por três dias como testemunha. Em seguida, 500g de solo foi distribuída em quatro bandejas em delineamento inteiramente ao acaso, onde receberam irrigações,identificação e registros das plântulas emergentes. Os dados foram verificados anormalidade e homogeneidade de variância, transformados quando necessário e submetidos à análise de variância ao nível de significância de 5%. As médias foram realizadas pelos testes deTukey eDunnet a 5% de probabilidade. Conclui-se que a fumigação reduziua emergência docapim carrapichoe buva independente da dose e o tempo de exposição, com resultado similar a solarização.(AU)

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.

Spearmint (Mentha spicata L.) Phytochemical Profile: Impact of Pre/Post-Harvest Processing and Extractive Recovery.

The purpose of this study was to chemically compare samples of Mentha spicata (marketing byproducts, production byproducts, and export material), cultivated in the open field and under greenhouse, using an integrated approach by HPLC/DAD and GC/MS analysis. The presence of phenolic compounds was higher in the marketing byproducts cultivated in the open field. Marketing byproducts also had the highest amount of carvone. For this reason, this byproduct was selected as a candidate for the development of natural ingredients. With the best selected material, the optimization of simultaneous high-intensity ultrasound-assisted extraction processes was proposed for the recovery of the compounds of interest. This extraction was defined by Peleg's equation and polynomial regression analysis. Modeling showed that the factors amplitude, time, and solvent were found to be significant in the recovery process (p < 0.005). The maximum amount of compounds was obtained using 90% amplitude for 5 min and ethanol/water mixture (80:20) for extraction to simultaneously obtain phenolic and terpenoid compounds. This system obtained the highest amount of monoterpenoid and sesquiterpenoid compounds from the essential oil of M. spicata (64.93% vs. 84.55%). Thus, with an efficient and eco-friendly method, it was possible to optimize the extraction of compounds in M. spicata as a starting point for the use of its byproducts.

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.

Green synthesis of silver nanoparticles using leaf extracts of Mentha arvensis Linn. and demonstration of their in vitro antibacterial activities

Abstract A study was carried out to synthesize silver nanoparticles (Ag-NPs) using plant extracts and to explore their pharmaceutical application as antibacterial agents. Dried leaves of Mentha arvensis Linn. were powdered and extracts were prepared using three different organic solvents. Preliminary screening on antibacterial activity by agar well diffusion method indicated that the methanolic extract possessed higher potential than the other two. Phytochemical analysis of the leaf extract revealed that it possesses tannins, steroids, terpenoids and flavonoids. Ag-NPs prepared using this extract were of spherical to cuboidal shape ranging in size from 40 to 70 nm. It retained essential chemical groups and had the required surface plasmon resonance. Further to the antimicrobial assay, the Ag-NPs, in contrast to the whole methanolic leaf extract, showed better (100% vs. 80%) bactericidal activity against the indicator organisms. The zones of growth inhibition for gram positive bacteria ranged between 14±0.6 and 23±0.3, while it was between 12±0.6 and 22±0.2 for gram negative bacteria. The Ag-NPs presented the minimum inhibitory concentration values of 250 µg/mL for gram positive bacteria and 250 - 500 µg/mL for gram negative bacteria. These findings suggest that the natural compounds present in M. arvensis L. possess the potency to facilitate the synthesis and antibacterial action of Ag-NPs.

Bioacessibility of phenolic compounds and antioxidant capacity in organic peppermint leaves

ABSTRACT The objective of this study was to analyze the chemical composition and bioaccessibility of phenolic compounds as well as their antioxidant capabilities of organic peppermint leaves after each phase of simulated digestion. Moisture was determined until a constant weight was obtained in an oven at 105 °C; ash was determined after sample calcination in a muffle furnace at 550 °C. The protein concentration was determined by the Macro-Kjeldahl method and lipid content by hot-extraction in a Soxhlet apparatus. Carbohydrates were calculated from differences and energy values based on the Atwater conversion factors. Total phenolic, flavonoid content, and antioxidant activity were determined by spectrophotometry. A four-step procedure was used for in vitro digestion. Organic peppermint was found to contain the following: 78% moisture, 1.7% ash, 1.5% lipids, 0.3% proteins, 17.7% carbohydrates, and a total of 85.5 kcal/100 g. Values of 705 mg GAE/100 g of phenolic, 918 mg QE/100 g of flavonoids, and 58.8 mg/g of vitamin C were also measured. It was discovered that total phenolics had the highest bioaccessible fraction relative to flavonoids; the salivary phase was identified as that with the highest release of these compounds and thus the phase in which peppermint showed significant antioxidant activity (1509 μmol TEAC/100g). This study demonstrated that organic peppermint has a high content of phenolic compounds that can be extracted from the alimentary matrix in the salivary and intestinal phases of the digestive system. Because of the antioxidant activity of these compounds, the use of this aromatic plant as seasonings and spices is relevant.

RESUMEN El objetivo de este estudio fue analizar la composición química de hojas de menta orgánica y la bioaccesibilidad de los compuestos fenólicos así como su capacidad antioxidante. Se determinó la humedad hasta obtener un peso constante en el horno a 105 °C, la ceniza se determinó en un horno de mufla a 550 °C. La concentración de proteína se determinó mediante el método Macro-Kjeldahl y los lípidos mediante extracción en un aparato Soxhlet. Los carbohidratos se calcularon por diferencia y energía basadas en los factores de conversión de Atwater. El contenido fenólico y la actividad antioxidante se determinaron por espectrofotometría. Se usó un procedimiento de cuatro pasos para la digestión in vitro. La menta orgánica contiene 78% de humedad, 1,7% de cenizas, 1,5% de lípidos, 0,3% de proteínas, 17,7% de carbohidratos y 85,5 kcal/100 g. También se midieron valores de 705 mg GAE/100g de fenólico, 918 mg QE/100 g de flavonoides y 58,8 mg/g de vitamina C. Se descubrió que los fenólicos tenían la fracción bioaccesible más alta en relación con los flavonoides; la fase salival se identificó como aquella con la mayor liberación de estos compuestos y, por lo tanto, la menta mostró una actividad antioxidante significativa (1509 μmol de TEAC/100 g). La menta orgánica tiene un alto contenido de fenólicos que se pueden extraer en las fases salival e intestinal. Debido a la actividad antioxidante de estos compuestos, el uso de esta planta como condimentos y especias es relevante.

Chemical compositions, radical scavenging capacities and antimicrobial activities in seeds of Satureja hortensis L. and Mentha spicata L. subsp. spicata from Turkey / Composições químicas, capacidades radicais eliminadoras e atividades antimicrobianas em sementes de Satureja hortensis L. e Mentha spicata L. subsp. spicata da Turquia

Abstract The present study determined some biological compounds, radical scavenging activity and antimicrobial capacity in seeds of Satureja hortensis L. and Mentha spicata L. subsp. spicata. Alpha-linolenic acid (C18:3 n3) has been found to be the major polyunsaturated fatty acid of Satureja hortensis L. (66.24 ± 1.24%) and Mentha spicata L. subsp. spicata (48.17 ± 1.01%). Linoleic acid (C18:2 n6) is identified as the second major polyunsaturated fatty acid in the present study and oleic acid (C18:1 n9) is determined as the major monounsaturated fatty acid. Current study showed that Satureja hortensis L. and Mentha spicata L. subsp. spicata have low levels of saturated fatty acids. It has been demonstrated that ergosterol (263.1 ± 2.14 µg/g), stigmasterol (39.07 ± 0.91 µg/g) and beta-sitosterol (14.64 ± 0.49 µg/g) have been found in Mentha spicata L. subsp. spicata, while ergosterol (69.41 ± 1.75 µg/g) and beta-sitosterol (19.81 ± 1.14 µg/g) have been determined in Satureja hortensis L. Also, this study determined that Satureja hortensis L. and Mentha spicata L. subsp. spicata have low lipide-soluble vitamin content. Furthermore, it has been found that Satureja hortensis L. contains naringenin (612.57 ± 2.57 µg/g), morin (86.97 ± 1.12 µg/g), quercetin (22.87 ± 0.75 µg/g), and kaempferol (20.11 ± 0.94 µg/g) while naringenin (135.91 ± 1.91 µg/g), naringin (61.23 ± 2.15 µg/g) and quercetin (47.51 ± 1.17 µg/g) have been detected as major flavonoids in the seeds of Mentha spicata L. subsp. spicata. The results of the present study suggest that methanol extracts of Satureja hortensis L. and Mentha spicata L. subsp. spicata have significant free radical scavenging activity. The present results revealed that Satureja hortensis L. and Mentha spicata L. subsp. spicata showed major activity against gram-positive and gram-negative microorganisms, fungi and yeast.

Resumo O presente estudo determinou alguns compostos biológicos, atividade de eliminação de radicais e capacidade antimicrobiana em sementes de Satureja hortensis L. e Mentha spicata L. subsp. spicata. O ácido alfa-linolênico (C18: 3 n3) foi o principal ácido graxo poliinsaturado de Satureja hortensis L. (66,24 ± 1,24%) e Mentha spicata L. subsp. spicata (48,17 ± 1,01%). O ácido linoléico (C18: 2 n6) é identificado como o segundo principal ácido graxo poliinsaturado no presente estudo e o ácido oleico (C18: 1 n9) é determinado como o principal ácido graxo monoinsaturado. O estudo atual mostrou que Satureja hortensis L. e Mentha spicata L. subsp. spicata tem baixos níveis de ácidos graxos saturados. Foi demonstrado que ergosterol (263,1 ± 2,14 µg/g), estigmasterol (39,07 ± 0,91 µg/g) e beta-sitosterol (14,64 ± 0,49 µg/g) foram encontrados em Mentha spicata L. subsp. spicata, enquanto o ergosterol (69,41 ± 1,75 µg/g) e beta-sitosterol (19,81 ± 1,14 µg/g) também foram determinados em Satureja hortensis L., este estudo determinou que Satureja hortensis L. e Mentha spicata L. subsp. spicata tem baixo teor de vitaminas lipossolúveis. Além disso, verificou-se que S. hortensis L. contém naringenina (612,57 ± 2,57 µg/g), morina (86,97 ± 1,12 µg/g), quercetina (22,87 ± 0,75 µg/g) e kaempferol (20,11 ± 0,94 µg/g) enquanto a naringenina (135,91 ± 1,91 µg/g), a naringina (61,23 ± 2,15 µg/g) e a quercetina (47,51 ± 1,17 µg/g) foram detectadas como flavonóides importantes nas sementes de Mentha spicata L. subsp. spicata. Os resultados do presente estudo sugerem que os extratos metanólicos de S. hortensis L. e Mentha spicata L. subsp. spicata tem significativa atividade de eliminação de radicais livres. Os presentes resultados revelaram que Satureja hortensis L. e Mentha spicata L. subsp. spicata mostrou atividade importante contra microrganismos gram-positivos e gram-negativos, fungos e leveduras.

Chemical compositions, radical scavenging capacities and antimicrobial activities in seeds of Satureja hortensis L. and Mentha spicata L. subsp. spicata from Turkey / Composições químicas, capacidades radicais eliminadoras e atividades antimicrobianas em sementes de Satureja hortensis L. e Mentha spicata L. subsp. spicata da Turquia

The present study determined some biological compounds, radical scavenging activity and antimicrobial capacity in seeds of Satureja hortensis L. and Mentha spicata L. subsp. spicata. Alpha-linolenic acid (C18:3 n3) has been found to be the major polyunsaturated fatty acid of Satureja hortensis L. (66.24 ± 1.24%) and Mentha spicata L. subsp. spicata (48.17 ± 1.01%). Linoleic acid (C18:2 n6) is identified as the second major polyunsaturated fatty acid in the present study and oleic acid (C18:1 n9) is determined as the major monounsaturated fatty acid. Current study showed that Satureja hortensis L. and Mentha spicata L. subsp. spicata have low levels of saturated fatty acids. It has been demonstrated that ergosterol (263.1 ± 2.14 µg/g), stigmasterol (39.07 ± 0.91 µg/g) and beta-sitosterol (14.64 ± 0.49 µg/g) have been found in Mentha spicata L. subsp. spicata, while ergosterol (69.41 ± 1.75 µg/g) and beta-sitosterol (19.81 ± 1.14 µg/g) have been determined in Satureja hortensis L. Also, this study determined that Satureja hortensis L. and Mentha spicata L. subsp. spicata have low lipide-soluble vitamin content. Furthermore, it has been found that Satureja hortensis L. contains naringenin (612.57 ± 2.57 µg/g), morin (86.97 ± 1.12 µg/g), quercetin (22.87 ± 0.75 µg/g), and kaempferol (20.11 ± 0.94 µg/g) while naringenin (135.91 ± 1.91 µg/g), naringin (61.23 ± 2.15 µg/g) and quercetin (47.51 ± 1.17 µg/g) have been detected as major flavonoids in the seeds of Mentha spicata L. subsp. spicata. The results of the present study suggest that methanol extracts of Satureja hortensis L. and Mentha spicata L. subsp. spicata have significant free radical scavenging activity. The present results revealed that Satureja hortensis L. and Mentha spicata L. subsp. spicata showed major activity against gram-positive and gram-negative microorganisms, fungi and yeast.(AU)

O presente estudo determinou alguns compostos biológicos, atividade de eliminação de radicais e capacidade antimicrobiana em sementes de Satureja hortensis L. e Mentha spicata L. subsp. spicata. O ácido alfa-linolênico (C18: 3 n3) foi o principal ácido graxo poliinsaturado de Satureja hortensis L. (66,24 ± 1,24%) e Mentha spicata L. subsp. spicata (48,17 ± 1,01%). O ácido linoléico (C18: 2 n6) é identificado como o segundo principal ácido graxo poliinsaturado no presente estudo e o ácido oleico (C18: 1 n9) é determinado como o principal ácido graxo monoinsaturado. O estudo atual mostrou que Satureja hortensis L. e Mentha spicata L. subsp. spicata tem baixos níveis de ácidos graxos saturados. Foi demonstrado que ergosterol (263,1 ± 2,14 µg/g), estigmasterol (39,07 ± 0,91 µg/g) e beta-sitosterol (14,64 ± 0,49 µg/g) foram encontrados em Mentha spicata L. subsp. spicata, enquanto o ergosterol (69,41 ± 1,75 µg/g) e beta-sitosterol (19,81 ± 1,14 µg/g) também foram determinados em Satureja hortensis L., este estudo determinou que Satureja hortensis L. e Mentha spicata L. subsp. spicata tem baixo teor de vitaminas lipossolúveis. Além disso, verificou-se que S. hortensis L. contém naringenina (612,57 ± 2,57 µg/g), morina (86,97 ± 1,12 µg/g), quercetina (22,87 ± 0,75 µg/g) e kaempferol (20,11 ± 0,94 µg/g) enquanto a naringenina (135,91 ± 1,91 µg/g), a naringina (61,23 ± 2,15 µg/g) e a quercetina (47,51 ± 1,17 µg/g) foram detectadas como flavonóides importantes nas sementes de Mentha spicata L. subsp. spicata. Os resultados do presente estudo sugerem que os extratos metanólicos de S. hortensis L. e Mentha spicata L. subsp. spicata tem significativa atividade de eliminação de radicais livres. Os presentes resultados revelaram que Satureja hortensis L. e Mentha spicata L. subsp. spicata mostrou atividade importante contra microrganismos gram-positivos e gram-negativos, fungos e leveduras.(AU)

A simple method to determine antioxidant status in aromatic plants subjected to drought stress.

Drought is a major environmental stress factor that affects the growth and development of plants. All plants have to maintain the reactive oxygen species within certain levels for normal cellular homeostasis by means of their antioxidant systems, which can be classified as enzymatic and non-enzymatic. Plants under drought stress generate an excess production of reactive oxygen species. At high concentrations, this can be detrimental by producing damage to the protein structures and inhibiting enzymes, as well as oxidizing macromolecules, which may eventually lead to cell death. There has been increasing attention paid to the antioxidant capacity of aromatic/medicinal plants, with a high antioxidant content having been reported in some plant extracts, such as in Mentha piperita (peppermint). Peppermint plants cultivated under drought stress also present high levels of phenolic compounds, peroxidase enzyme activity and lipid peroxidation of membranes. A simple and inexpensive laboratory class is proposed for teaching some mechanisms that plants have evolved to avoid reactive oxygen species damage. The series of lab experiments described is aimed at demonstrating the antioxidant status in aromatic plants subjected to drought stress, by measuring total phenolic compound content (non-enzymatic antioxidant compound), peroxidase activity (enzymatic antioxidant) and malondialdehyde, as convenient biomarkers for lipid peroxidation. The proposed class will be carried out by undergraduate students of the advanced biochemistry course, as part of our biology and agronomy studies. The experiment presented is intended to be used as a vehicle to emphasize the concepts that students have learned in their lectures. This lab exercise to be carried out by the students has dual goals: to apply a methodology only learned superficially on previous courses, and also to increase their understanding of how plants developed resistance mechanisms in order to tolerate drought stress.

Modulation of membrane physical properties by natural insecticidal ketones.

The insecticidal activity of Mentha oil and its main components has been tested and established for various insects/pests. Several mint ketones have demonstrated to act on GABAA receptors (GABAA-R), a transmembrane channel target of several important insecticides whose activity can be modulated by surface-active compounds and by changes in the physical properties of the lipid membrane. In the present work, we analyze the capacity of monoterpenic ketones most commonly found in Mentha species, pulegone and menthone, to interact with DPPC membranes by molecular dynamics (MD) simulations and Langmuir monolayers. The experimental results indicate that the presence of menthone and pulegone in the subphase modify the interfacial characteristics of DPPC isotherms. The changes were reflected as expansion of the isotherms and disappearance or bringing forward of DPPC phase transition. MD simulation corroborate these results and indicate that both ketones are located at the region of the carbonyl group, at the interface with the acyl chains. Ketone intercalation between lipid molecules would induce an increasing intermolecular interaction, diminishing the film elasticity and causing an ordering effect. Our results suggest that the insecticidal activity of both ketones could involve their interaction with lipid molecules causing disturbance of the cell membrane as postulated for several larvicide compounds, or at least modulating the receptor surrounding.

Seasonal variation in essential oil content and chemical profile of mint in southeast of Brazil / Variação sazonal no teor e perfil químico do óleo essencial de menta no sudeste do Brasil

ABSTRACT: This study evaluated the influence of seasonality in essential oil (EO) chemical composition of Mentha x piperita L. and Mentha viridis L. grown in southeast of Brazil. Leaves were collected from November 2011 until August 2013, in the middle of the following seasons: Spring (November), Summer (February), Autumn (May) and Winter (August). EO extraction was carried out by hydrodistillation in Clevenger apparatus for 1 hour. Chemical composition of EO was analyzed by GC-FID and GC-MS. The EO content and its chemical composition were influenced by seasonality in both species. The highest EO content was obtained for M. x piperita during spring (4.26%) and for M. viridis during spring (3.30%) and summer (3.70%). Mentha x piperita increased menthol (16.31 to 41.26%), neomenthol (3.02 to 6.39%) and menthone (5.56 to 41.58%) contents during spring and summer, respectively. Whereas, M. viridis EO content did not show a quality response pattern in relation to seasonality. Therefore, harvest time for M. x piperita is recommended during spring, and for M. viridis is recommended during spring and summer.

RESUMO: O estudo teve como objetivo avaliar a influência da sazonalidade na composição química do óleo essencial (OE) de Mentha x piperita L. e Mentha viridis L. cultivadas no sudeste do Brasil. As folhas foram coletadas de novembro de 2011 até agosto de 2013, em meados das seguintes estações: primavera (novembro), verão (fevereiro), outono (maio) e inverno (agosto). A extração do OE foi realizada por hidrodestilação em aparelho de Clevenger por uma hora. A composição química do EO foi analisada por GC-FID and GC-MS. O teor de OE e sua composição química foram influenciados pela sazonalidade em ambas as espécies. O maior teor de OE foi obtido para M. x piperita na primavera (4,26%) e para M. viridis na primavera (3,30%) e verão (3,70%). Mentha x piperita aumentou o conteúdo de mentol (16,31 a 41,26%), neomentol (3,02 a 6,39%) e mentona (5,56 a 41,58%) durante a primavera e o verão, respectivamente. Já o conteúdo de OE de M. viridis não apresentou padrão de resposta de qualidade em relação à sazonalidade. Portanto, a colheita para M. x piperita é recomendada durante a primavera, e para M. viridis é recomendada durante a primavera e verão.