Foliar applied potassium nanoparticles (K-NPs) and potassium sulfate on growth, physiological, and phytochemical parameters in Melissa officinalis L. under salt stress.

Salinity stress significantly constrains agricultural productivity and vegetation decline worldwide, particularly in Iran. Potassium, the second most prevalent nutrient in plants, is well known to be essential for cell metabolism. Here, the effects of potassium fertilizer in two biogenic nanoparticles (K-NPs) and conventional (potassium sulfate) forms (0.1 mg/ml) on Melissa officinalis L. under salinity (0, 50, 100, and 150 mM) were investigated. The results demonstrated that stress markers (electrolyte leakage, malondialdehyde, and hydrogen peroxide) increased as salinity levels increased. Plant growth parameters (shoot and root length, fresh and dry weight of shoot and root) and physiological and photosynthetic parameters (stomatal conductance, relative water content, chlorophyll fluorescence, and photosynthetic pigments) were reduced in salinized plants. The highest reduction in fresh weight root, dry weight root, fresh weight shoot, dry weight shoot, root length, and shoot length was recorded under 150 mM NaCl by 30.2%, 51.6%, 30.5%, 24.7%, 26.4%, and 21%, respectively. In contrast, bulk potassium sulfate and K-NPs increased these parameters. Furthermore, K-NPs improved M. officinalis tolerance to NaCl toxicity by enhancing the content of osmolytes such as proline, soluble sugars, and antioxidant enzymes, improving antioxidant contents such as phenols, tannins, anthocyanins, and flavonoids; increasing total protein; and lowering stress markers in plant tissues. Given the results of the physiological, biochemical, and phytochemical parameters obtained from this study, it can be stated that K-NPs, in comparison to the conventional form of potassium fertilizer, exhibit a greater potential to mitigate damages caused by salinity stress in M. officinalis plants.

Plantas com ação no sistema nervoso central que constam na relação nacional de plantas medicinais de interesse ao sus (RENISUS) / Plants acting on the central nervous system: review plantas com ação no sistema nervoso central que constam na relação nacional de plantas medicinais de interesse ao sus (RENISUS) / Plantas con acción sobre el sistema nervioso central incluidas en la lista nacional de plantas medicinales de interés para sus (RENISUS)

A depressão é uma doença grave que atinge a população em geral, estudos epidemiológicos estimam que a prevalência da depressão ao longo da vida no Brasil está em torno de 15,5%. Os fatores que desencadeiam o aparecimento da depressão incluem fatores sociais, psicológicos, biológicos e também fatores externos específicos como eventos estressantes, solidão, consumo de álcool e drogas, doenças crônicas e dar á luz (depressão pós-parto). O objetivo da presente pesquisa consistiu em realizar uma revisão bibliográfica sobre as principais plantas medicinais com ação antidepressiva. A ansiedade vem se tornando um dos principais problemas da atualidade, sendo intensificada pela pandemia causada pelo coronavírus, onde constatou-se que durante o pico da pandemia onde os casos confirmados de COVID-19 no Brasil ascenderam de 45.757 para 330.890, e as mortes, de 2.906 para 21.048, o sentimento de tristeza/depressão atingiu 40% dos adultos brasileiros. Os sintomas de depressão podem ser amenizados quando a disponibilidade sináptica de monoaminas são aumentadas, e esse aumento pode ocorrer através da diminuição da metabolização desses neurotransmissores. Neste sentido, busca-se através da farmacoterapia a utilização de antidepressivos que disponibilizem as monoaminas na fenda sináptica. A escolha do fármaco é feita com base nos sintomas da depressão e na boa resposta a uma determinada classe de antidepressivos. Em fevereiro de 2009 o Ministério da saúde lançou a Relação Nacional de Plantas Medicinais de Interesse ao SUS (RENISUS), contendo 71 espécies vegetais que são distribuídas de forma in natura nas unidades básicas de saúde (UBS). Destas, somente três espécies apresentam efeito antidepressivo e ansiolítico comprovados na literatura sendo Matricharia chamomilla, Erytrinum mulungu e a Passiflora incarnata que também fazem parte da RENISUS. Além destas, outras espécies como a Melissa officinalis, Lippia alba, Valeriana officinalis e Piper methysticum são utilizadas pela população para tratar ansiedade, insônia e depressão, sugerindo desta forma que estas espécies sejam incluídas na RENISUS.

Depression is a serious disease that affects the general population, epidemiological studies estimate that the prevalence of depression throughout life in Brazil is around 15.5%. The factors that trigger the onset of depression include social, psychological, biological and also specific external factors such as stressful events, loneliness, alcohol and drug consumption, chronic diseases and giving birth (postpartum depression). The objective of the present research was to carry out a literature review on the main medicinal plants with antidepressant action. Anxiety has become one of the main problems of today, being intensified by the pandemic caused by the coronavirus, where it was found that during the peak of the pandemic where confirmed cases of COVID-19 in Brazil rose from 45,757 to 330,890, and deaths, from 2,906 to 21,048, the feeling of sadness/depression reached 40% of Brazilian adults. Symptoms of depression can be alleviated when synaptic availability of monoamines is increased, and this increase can occur through decreased metabolization of these neurotransmitters. In this sense, the use of antidepressants that make monoamines available in the synaptic cleft is sought through pharmacotherapy. The choice of drug is based on symptoms of depression and good response to a particular class of antidepressants. In February 2009, the Ministry of Health launched the National List of Medicinal Plants of Interest to the SUS (RENISUS), containing 71 plant species that are distributed in natura form in basic health units (UBS). Of these, only three species have antidepressant and anxiolytic effects proven in the literature, being Matricharia chamomilla, Erytrinum mulungu and Passiflora incarnata, which are also part of RENISUS. In addition to these, other species such as Melissa officinalis, Lippia alba, Valeriana officinalis and Piper methysticum are used by the population to treat anxiety, insomnia and depression, thus suggesting that these species are included in RENISUS.

Los estudios epidemiológicos estiman que la prevalencia de la depresión a lo largo de la vida en Brasil es de alrededor del 15,5%. Los factores que desencadenan la aparición de la depresión son sociales, psicológicos, biológicos y también factores externos específicos, como los acontecimientos estresantes, la soledad, el consumo de alcohol y drogas, las enfermedades crónicas y el parto (depresión posparto). El objetivo de esta investigación fue realizar una revisión bibliográfica sobre las principales plantas medicinales con acción antidepresiva. La ansiedad se ha convertido en uno de los principales problemas de la actualidad, intensificándose por la pandemia causada por el coronavirus, donde se encontró que durante el pico de la pandemia donde los casos confirmados de COVID-19 en Brasil aumentaron de 45.757 a 330.890, y las muertes, de 2.906 a 21.048, el sentimiento de tristeza/depresión alcanzó el 40% de los adultos brasileños. Los síntomas de la depresión pueden aliviarse cuando se aumenta la disponibilidad sináptica de las monoaminas, y este aumento puede producirse mediante una disminución de la metabolización de estos neurotransmisores. En este sentido, se busca a través de la farmacoterapia el uso de antidepresivos que hagan disponibles las monoaminas en la hendidura sináptica. La elección del fármaco se hace en función de los síntomas de la depresión y de la buena respuesta a una clase concreta de antidepresivos. En febrero de 2009, el Ministerio de Salud lanzó la Lista Nacional de Plantas Medicinales de Interés para el SUS (RENISUS), que contiene 71 especies de plantas que se distribuyen in natura en unidades básicas de salud (UBS). De ellas, sólo tres especies tienen efectos antidepresivos y ansiolíticos probados en la literatura: Matricharia chamomilla, Erytrinum mulungu y Passiflora incarnata, que también forman parte del RENISUS. Además de éstas, otras especies como Melissa officinalis, Lippia alba, Valeriana officinalis y Piper methysticum son utilizadas por la población para tratar la ansiedad, el insomnio y la depresión, lo que sugiere que estas especies se incluyan en el RENISUS.

NaCl-Induced Elicitation Alters Physiology and Increases Accumulation of Phenolic Compounds in Melissa officinalis L.

In nature, plants usually produce secondary metabolites as a defense mechanism against environmental stresses. Different stresses determine the chemical diversity of plant-specialized metabolism products. In this study, we applied an abiotic elicitor, i.e., NaCl, to enhance the biosynthesis and accumulation of phenolic secondary metabolites in Melissa officinalis L. Plants were subjected to salt stress treatment by application of NaCl solutions (0, 50, or 100 mM) to the pots. Generally, the NaCl treatments were found to inhibit the growth of plants, simultaneously enhancing the accumulation of phenolic compounds (total phenolics, soluble flavonols, anthocyanins, phenolic acids), especially at 100 mM NaCl. However, the salt stress did not disturb the accumulation of photosynthetic pigments and proper functioning of the PS II photosystem. Therefore, the proposed method of elicitation represents a convenient alternative to cell suspension or hydroponic techniques as it is easier and cheaper with simple application in lemon balm pot cultivation. The improvement of lemon balm quality by NaCl elicitation can potentially increase the level of health-promoting phytochemicals and the bioactivity of low-processed herbal products.

Effect of graphene / metal nanocomposites on the key genes involved in rosmarinic acid biosynthesis pathway and its accumulation in Melissa officinalis.

BACKGROUND: Recently, numerous investigations have been done to study graphene and silver nanoparticle in the fields of agriculture and medicine. In the present study, the green synthesis of nanoparticles with two concentrations (0, 40, 60 mM) and their effect on the molecular and biochemical biosynthesis pathway of rosmarinic acid in a new method, low cost, and safe for the environment has been investigated. The transcript levels of key genes in the rosmarinic acid biosynthesis pathway (Tyrosine aminotransferase, rosmarinic acid synthase, and phenylalanine-ammonia lyase) were studied using real-time quantitative polymerase chain reaction. Then, the rosmarinic acid content was evaluated using HPLC. RESULTS: The results showed that a concentration-dependent manner was observed in treated plants. At the biochemical level, the use of nanocomposites at concentration of 40 mM showed higher soluble carbohydrate (37%), flavonoids (21%), total phenol (35%) as well as total protein (47%) compared to the control plants. HPLC results showed that rosmarinic acid content in the treated plants with a low concentration of nanocomposite (40 mM) was more affected than plants treated with a high concentration of nanocomposite (60 mM) (26%) and also compared to other treatments. At the molecular level, the result showed that Tyrosine aminotransferase and rosmarinic acid synthase gene expression was positively correlated with both silver nanoparticle concentrations and nanocomposite treatments, but phenylalanine-ammonia lyase gene expression was positively correlated only with nanocomposite at 40 mM concentration. CONCLUDE: It can conclude that the nanocomposite at low concentration is more likely to induce molecular and biochemical parameters. And also, in the rosmarinic acid biosynthesis pathway, the Tyrosine aminotransferase -derived pathway is more efficient than the phenylalanine-ammonia lyase -derived pathway by causing a nano-elicitor. Therefore, it was concluded that studied elicitor at low concentration, can create plants with higher production capacity.

Eliciting effect of foliar application of chitosan lactate on the phytochemical properties of Ocimum basilicum L. and Melissa officinalis L.

An increase in the content of secondary metabolites in herbal plants is desirable due to their therapeutic and nutraceutical properties. Therefore, the effects of foliar spray of 100 mg/L or 500 mg/L of chitosan lactate (ChL) on the accumulation of selected phenolics and physiological parameters of basil and lemon balm were investigated. In basil, the concentration of rosmarinic acid (RA) increased after application of 100 mg/L of ChL. In turn, in lemon balm both ChL concentrations increased the accumulation of RA and anthocyanins, while the level of total phenolic compounds (TPC) was elevated only at the dose of 100 mg/L of ChL. Elicitation of basil with 500 mg/L of ChL increased the shoot biomass. Therefore, such an elicitor as ChL can enhance the accumulation of valuable phytochemicals in Lamiaceae species. This simple and non-laborious method can be used for elicitation of herbal plants in production of functional food.

Physiological and molecular mechanisms underlying salicylic acid-mitigated mercury toxicity in lemon balm (Melissa officinalis L.).

Mercury (Hg) is one of the most toxic heavy metals with strong negative effects on the plant growth and functions. Salicylic acid (SA) is an important signaling molecule which confers tolerance to metal toxicities but little is known about the mechanisms of SA-mediated alleviation of Hg stress. Here, physiochemical and molecular responses of Hg-stressed lemon balm (Melissa officinalis L.) to exogenous SA were investigated to reveal SA-induced tolerance mechanisms. The CHLG gene of lemon balm which encodes chlorophyll synthase was also partly isolated and sequenced for the first time. Hg stress markedly decreased growth, relative water content (RWC) and photosynthetic pigments of the plant. However, exogenous SA significantly mitigated the toxic effects of mercury on the growth and RWC and enabled plant to maintain chlorophylls to the similar levels of unstressed plants. Hg-induced oxidative damage was also reduced following treatment with SA and treated plants showed the lower extent of lipid peroxidation which was accompanied with the higher free proline and phenolics contents and elevation of the antioxidant capacity as evidenced by DPPH radical scavenging and FRAP assays. Moreover, SA treatment resulted in up-regulation of CHLG and phenylalanine ammonia-lyase (PAL) genes as key components of chlorophyll and phenylpropanoid routes, respectively. Our results collectively indicate the ameliorative effects of exogenous SA in mercury toxicity through coordinated alternations in plant metabolic processes which provide insights to better understand mechanisms of Hg tolerance in lemon balm plant.

Associated Effects of Cadmium and Copper Alter the Heavy Metals Uptake by Melissa Officinalis.

Lemon balm (Melissa officinalis) is a popular herb widely used in medicine. It is often cultivated in soils with substantial heavy metal content. Here we investigate the associated effects of cadmium and copper on the plant growth parameters augmented by the manganese, zinc, and lead uptake indicators. The concentration of all elements in soil and plants was determined by the HR-CS FAAS with the ContrAA 300 Analytik Jena spectrometer. Bioavailable and total forms calculated for all examined metals were augmented by the soil analyses. The index of chlorophyll content in leaves, the activity of net photosynthesis, stomatal conductance, transpiration rate, and intercellular concentration of CO2 were also investigated. Either Cd or Cu acting alone at high concentrations in soil are toxic to plants as indicated by chlorophyll indices and gas exchange parameters. Surprisingly, this effect was not observed when both metals were administered together. The sole cadmium or copper supplementations hampered the plant's growth, lowered the leaf area, and altered the plant's stem elongation. Analysis of variance showed that cadmium and copper treatments of lemon balm significantly influenced manganese, lead, and zinc concentration in roots and above ground parts.

Can Ozone Alter the Terpenoid Composition and Membrane Integrity of in vitro Melissa officinalis Shoots?

Ozone affects volatile organic compounds that protect plants from biotic and abiotic stress. In vitro Melissa officinalis shoots were exposed to ozone (200 ppb, 3 h) in controlled environmental conditions: leaf pigments, membrane integrity and headspace composition were assayed during fumigation and after the recovery period (3 h from the beginning of the exposure, FBE). At the end of the exposure, no injury was observed in untreated and treated shoots, although an evident increase in lipid peroxidation was reported (+38.5 and +37.2% of TBARS levels in comparison with controls, respectively after 1 and 3 h FBE). The levels of total carotenoids significantly rose as a normal response mechanism to oxidative stress. SPME-GS-MS analysis showed that, as a consequence of the fumigation, the trends in non-terpenoid compounds increased after 1 and 3 h FBE. This suggests that the concentration and the duration of the treatment were enough to cause a breakdown of cells (as evidenced by increased TBARS levels) and involves an association between volatile products of the lipoxygenase pathway (LOX products) and membrane degradation.

How sensitive is Melissa officinalis to realistic ozone concentrations?

Lemon balm (Melissa officinalis, L.; Lamiaceae) was exposed to realistic ozone (O3) dosages (80 ppb for 5 h), because high background levels of O3 are considered to be as harmful as episodic O3 regimes. Temporal alterations of different ecophysiological, biochemical and structural parameters were investigated in order to test if this species can be considered as an O3-bioindicator regarding changes in background concentrations. At the end of ozone exposure, the plants did not exhibit any visible foliar symptoms, as only at microscopic level a small number of dead cells were found. Photosynthetic processes, however, were significantly affected. During and after the treatment, ozone induced a reduction in CO2 fixation capacity (up to 52% after 12 h from the beginning of the treatment) due to mesophyllic limitations. Intercellular CO2 concentration significantly increased in comparison to controls (+90% at the end of the post-fumigation period). Furthermore impairment of carboxylation efficiency (-71% at the end of the post-fumigation period compared to controls in filtered air) and membrane damage in terms of integrity (as demonstrated by a significant rise in solute leakage) were observed. A regulatory adjustment of photosynthetic processes was highlighted during the post-fumigation period by the higher values of qNP and (1-q(P)) and therefore suggests a tendency to reduce the light energy used in photochemistry at the expense of the capacity to dissipate the excess as excitation energy. In addition, the chlorophyll a/b ratio and the de-epoxidation index increased, showing a rearrangement of the pigment composition of the photosynthetic apparatus and a marked activation of photoprotective mechanisms.

Signaling molecules and cell death in Melissa officinalis plants exposed to ozone.

KEY MESSAGE: The study focuses on the interaction between reactive oxygen species and hormones that regulate the programmed cell death in plants of Melissa officinalis exposed to ozone. Interaction between hormone and redox signaling pathways has been investigated in ozone-stressed (200 ppb, 5 h) lemon balm to verify if the response resembles the biotic defense reactions. In comparison to controls, plants exhibited foliar injury and the cell death was induced by (1) biphasic production of hydrogen peroxide and superoxide radical; (2) hormonal regulation of ozone-induced lesion formation with a significant production of ethylene, salicylic, jasmonic and abscisic acid; (3) ozone degradation to reactive oxygen species and their detoxification by some enzymatic (such as superoxide dismutase) and non-enzymatic antioxidant systems (such as ascorbic acid, glutathione and carotenoids), that worked in cooperation without providing a defense against free radicals (such as confirmed by the modification of the antioxidant properties of leaf tissue). This integrated view showed that reactive oxygen species interact with hormonal signaling pathway regulating cell death and the sensitivity of lemon balm to ozone.

Effects of IAA, IBA, NAA, and GA3 on rooting and morphological features of Melissa officinalis L. stem cuttings.

This study analyzed the potential of producing Melissa officinalis L. using stem cuttings. Four different hormones (IAA, IBA, NAA, and GA3) were applied to the cuttings, with and without buds, in two doses (1000 mg/L and 5000 mg/L), and after 60 days, 10 morphological characteristics of newly generated plants were detected, and a statistical analysis was carried out. The results of the study show that the cuttings with at least one bud must be used in order to produce M. officinalis using stem cuttings. Even though the auxin group hormones (IAA, IBA, and NAA) do not have an apparent effect on rooting percentage, these hormones were detected to affect the morphological characteristics of the newly generated plants, especially root generation. GA3 application has a considerable effect on stem height.