Improving nitrogen content in soil and lemon balm (Melissa officinalis L.) yield by purple nonsulfur bacteria Rhodopseudomonas palustris in two consecutive seasons.

The study was conducted to assess the effects of nitrogen (N)-fixing purple nonsulfur bacteria (PNSB) Rhodopseudomonas palustris TLS06, VNW02, VNW64, and VNS89 on soil fertility, N uptake, essential oil (EO) content, growth, and yield of lemon balm. The experiment followed a completely randomized block design with 9 treatments and 3 replications. The treatments consisted of (i) applying 100% N as the recommended fertilizer rate (RFR), (ii) applying 85% N as RFR, (iii) applying 70% N as RFR, (iv) applying 55% N as RFR, (v) the treatment ii combined with N-PNSB, (vi) the treatment iii combined with N-PNSB, (vii) the treatment iv combined with N-PNSB, (viii) 0% as RFR combined with N-PNSB, and (ix) 0% N as RFR. The results showed that applying N-PNSB increased the plant height, and the number of primary branches in both seasons. In addition, the treatment without N fertilizer combined with N-PNSB increased stem leaf biomass by 41.2 and 50.3% in both seasons as compared with the treatment without neither N fertilizer nor N-PNSB. For soil properties, among treatments without N fertilizer, the treatment with N-PNSB increased concentrations of NH4+, soluble P, and exchangeable K+ by 41.3, 41.4, and 26.8%, respectively, as compared with the treatment without N-PNSB at the end of the second season. Applying 85% N as RFR combined with N-PNSB had a greater yield by 5.78-11.8% as compared with the treatment with 100% N as RFR, and a greater EO content by 23% as compared with the treatment with 85% N as RFR.

Plasma Concentrations of Rosmarinic Acid in Patients on Antiretroviral Therapy: In Silico Exploration Based on Clinical Data.

Rosmarinic acid (RA) is a phenolic compound with antiviral properties, often encountered in dietary supplements and herbal drugs. Data on the pharmacokinetics of RA are lacking in cases of the chronic use of supplements containing this compound, and only limited data on the metabolism and distribution of RA are available. The aim of the study was to investigate the plasma levels of RA after 12 weeks of use and determine potential interactions of RA and selected antiretroviral drugs. Patients infected with human immunodeficiency virus took a supplement containing RA for 12 weeks, after which the RA concentrations in the plasma samples were analyzed. A detailed in silico analysis was conducted in order to elucidate the potential interactions between RA and the drugs efavirenz, darunavir and raltegravir. It was found that RA can be detected in patients' plasma samples, mainly in the form of sulphoglucuronide. The potential interactions are suggested on the level of liver metabolizing enzymes and efflux P-glycoprotein, with RA competing with antiretroviral drugs as a substrate in metabolism and distribution systems. The present study suggests that the simultaneous use of RA and antiretroviral therapy (containing efavirenz, darunavir or raltegravir) may affect the plasma levels of RA after prolonged supplementation.

The Valorisation of Melissa officinalis Distillation By-Products for the Production of Polyphenol-Rich Formulations.

Lemon balm (Melissa officinalis) is an aromatic and medicinal plant, rich in bioactive ingredients and with superior antioxidant activity. The essential oil of this plant is an expensive product, so the use of the by-products of the essential oil industry is particularly useful. The aim of this research was to process Melissa officinalis distillation by-products to develop a series of polyphenol-rich formulations. In the present research, lemon balm was distilled in a laboratory-scale distiller, and the recovered by-product was used for further successive extractions with acetone and water, using a fixed-bed semi-batch extractor. Acetone extract exhibited relatively poor results as far as yield, phenolic composition and antiradical activity are concerned. However, the aqueous extract presented high yield in both total phenolic content (i.e., 111 mg gallic acid equivalents (GAE)/g, on a dry herb basis (dw)), and anti-radical capacity (205 mg trolox equivalents (TE)/g dw). On a dried extract basis, the results were also impressive, with total phenols reaching 322 mg GAE/g dry extract and antiradical capacity at 593 mg TE/g dry extract. The phenolic components of the extract were identified and quantified by HPLC-DAD. Rosmarinic acid was the major component and amounted to 73.5 mg/g dry extract, while the total identified compounds were quantified at 165.9 mg/g dry extract. Finally, formulations with two different wall materials (gum arabic-maltodextrin and maltodextrin) and two different drying methods (spray-drying and freeze-drying) were applied and evaluated to assess their performance, yield, efficiency and shelf-life of total phenolic content and rosmarinic acid concentration. From the present investigation, it is concluded that after one year of storage, rosmarinic acid does not decrease significantly, while total phenolic content shows a similar decrease for all powders. According to the yield and efficiency of microencapsulation, maltodextrin alone was chosen as the wall material and freeze-drying as the preferred drying method.

Antioxidant Activity and Photosynthesis Efficiency in Melissa officinalis Subjected to Heavy Metals Stress.

The aim of this study was to assess influence of cadmium and zinc treatments on antioxidant activity combined with the photosynthesis efficiency in a popular herb lemon balm (Melissa officinalis L.). Plants were grown under greenhouse conditions by the pot method. The Mn, Cu, Cd, and Zn contents in soil and plants were measured by HR-CS FAAS. The activity of net photosynthesis, stomatal conductance, transpiration rate, intercellular CO2, and index of chlorophyll in leaves were determined for all investigated species. Reduction of the net photosynthesis was observed for cultivations subjected to either Zn or Cd treatments. Phenolic contents were determined by the chemical Folin-Ciocalteu method, while enhanced voltammetric analysis was applied to assess the antioxidant properties of plant extracts. Both of these approaches yielded similar results. Herbal extracts had exceptional antioxidant capacities and were good scavengers of free radicals and reactive oxygen species. Structural similarity of cadmium and zinc facilitated their mutual structural exchange and prompted substantial expansion of phenolics under the mixed Zn and Cd treatments.

Nip it in the Bud: Botanicals for Anxiety - a Practical Prescriber's Guide.

PURPOSE OF REVIEW: The goal of this paper is to summarize the evidence for the use of botanical medicines for the treatment of anxiety disorders. We sought to make this review practical for psychiatrists and psychiatric prescribers. RECENT FINDINGS: In 2018, the Natural Medicines database produced a Clinical Management of Anxiety guide that summarized the conventional and natural treatments of anxiety disorders. Based on this guide, four herbal supplements (also referred to as botanicals) were selected for deeper study including kava, lavender, lemon balm and passionflower. All four were considered possibly safe and possibly effective according to the Natural Medicines database. There is scientific evidence supporting the use of kava, lavender, lemon balm and passionflower in anxiety disorders. Lavender appears to have the best available evidence including comparable efficacy to conventional first line treatments and is available in a patented form that was used in the cited studies (Silexan).

Change in Secondary Metabolites and Expression Pattern of Key Rosmarinic Acid Related Genes in Iranian Lemon Balm (Melissa officinalis L.) Ecotypes Using Methyl Jasmonate Treatments.

The medicinal herb, lemon balm (Melissa officinalis L.), which is high in rosmarinic acid (RA), has well-known therapeutic value. The goals of this study were to investigate the effects of methyl jasmonate (MeJA) on RA content, total phenolic content (TPC), and total flavonoid content (TFC), as well as changes in expression of their biosynthesis-related key genes (MoPAL, Mo4CL, and MoRAS) in Iranian lemon balm ecotypes, as first reported. Our results revealed that MeJA doses significantly increase the RA content, TPC, and TFC in both ecotypes compared with the control samples. Additionally, the higher expression levels of MoPAL, Mo4CL, and MoRAS following treatment were linked to RA accumulation in all treatments for both Iranian lemon balm ecotypes. After 24 h of exposure to 150 µM MeJA concentration, HPLC analysis showed that MeJA significantly increased RA content in Esfahan and Ilam ecotypes, which was about 4.18- and 7.43-fold higher than untreated plants. Our findings suggested that MeJA has a considerable influence on RA, TPC, and TFC accumulation in MeJA-treated Iranian M. officinalis, which might be the result of gene activation from the phenylpropanoid pathway. As a result of our findings, we now have a better understanding of the molecular processes behind RA production in lemon balm plants.

Use of Plant-Derived Natural Products in Sleep Disturbances.

Sleep disorders have a high prevalence both in the general population and especially in specific populations such older adults and oncologic patients. Impacting on quality of life, they often translate in drug prescription, with consequent increased risk of drug-drug interactions and adverse drug reactions. In the last years several products derived from plants have been developed with the aim of treating insomnia with lower risk of side effects. Despite several studies have been performed with this aim, the available evidence is inconclusive, and reviews summarizing the most recent evidences on the effectiveness of plant-derived products in treating insomnia are lacking.This narrative review aims at summarizing the evidences of the mechanism of action, effectiveness and safety of the most commonly used plant-derived products for the treatment of sleep disorders (Valerian, Lemon balm, Passionflower, Chamomile, Hops, and Jujube).

The effects of lemon balm (Melissa officinalis L.) on depression and anxiety in clinical trials: A systematic review and meta-analysis.

A systematic review and a meta-analytic approach were considered to investigate the effects of lemon balm as a medicinal herb on anxiety and depression in clinical trials and its side effects. All randomized clinical trials published up to October 30, 2020 that examined lemon balm in patients with symptoms of depression or anxiety, with acute or chronic manifestations, were searched in 12 online databases. Statistical analysis was performed using RevMan software. Continuous data were analyzed using standardized mean differences. Statistical heterogeneity was assessed using Chi2 , I2 , and p value tests. Based on meta-analysis results, lemon balm significantly improved mean anxiety and depression scores compared with the placebo (SMD: -0.98; 95% CI: -1.63 to -0.33; p = 0.003), (SMD: -0.47; 95% CI: -0.73 to -0.21; p = 0.0005) respectively, without serious side effects. Current evidence suggests that lemon balm may be effective in improving anxiety and depressive symptoms, particularly in the acute setting. Due to the high level of heterogeneity between studies, results should be interpreted with caution. The small number of clinical trials and differences between their methods were the limitations of the present study. Further high-quality studies are needed to firmly establish the clinical efficacy of the lemon balm.

Effect of Melissa officinalis on systolic and diastolic blood pressures in essential hypertension: A double-blind crossover clinical trial.

For a long time, Melissa officinalis (M. officinalis) has been used to treat cardiovascular diseases. Therefore, this study aimed at evaluating the effects of M. officinalis on systolic and diastolic blood pressures in hypertensive patients. We conducted a double-blind, controlled, randomized crossover clinical trial on 49 patients who received either M. officinalis capsules (400 mg/d; n = 23) or the placebo (n = 26) three times per day for a 4-week period. After a 2-week washout period, the M. officinalis group received placebo and the other group received M. officinalis for another 4-week period. The systolic and diastolic blood pressures were measured once at baseline and then every 2 weeks for 10 weeks. The statistical analysis of the obtained data revealed that the chronology of the consumption of M. officinalis and placebo had no effect on the systolic and diastolic blood pressures in these two studied groups. Moreover, it was found that systolic and diastolic blood pressures significantly decreased after the consumption of M. officinalis, compared to placebo. Systolic and diastolic blood pressures in group A at the beginning of the study were 152.30 ± 5.312 mmHg and 95.52 ± 1.988 mmHg, respectively, and, after the first phase (drug use), reached 129.88 ± 9.009 mmHg and 80.13 ± 5.488 mmHg, respectively. Systolic and diastolic blood pressures in group B at the beginning of the study was 152.26 ± 5.640 mmHg and 94.44 ± 2.607 mmHg, respectively, and after the second phase (drug use), reached 131.77 ± 8.091 mmHg and 81.46 ± 7.426 mmHg, (p = .005), respectively. Also, no significant side effects were observed during the study. According to the results, M. officinalis can reduce systolic and diastolic blood pressures of the patients with essential hypertension.

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.

Six Common Herbs with Distinctive Bioactive, Antioxidant Components. A Review of Their Separation Techniques.

Rosemary, oregano, pink savory, lemon balm, St. John's wort, and saffron are common herbs wildly grown and easily cultivated in many countries. All of them are rich in antioxidant compounds that exhibit several biological and health activities. They are commercialized as spices, traditional medicines, or raw materials for the production of essential oils. The whole herbs or the residues of their current use are potential sources for the recovery of natural antioxidant extracts. Finding effective and feasible extraction and purification methods is a major challenge for the industrial production of natural antioxidant extracts. In this respect, the present paper is an extensive literature review of the solvents and extraction methods that have been tested on these herbs. Green solvents and novel extraction methods that can be easily scaled up for industrial application are critically discussed.

Essential Oils of New Lippia alba Genotypes Analyzed by Flow-Modulated Comprehensive Two-Dimensional Gas Chromatography (GC×GC) and Chemometric Analysis.

Lippia alba (Mill.) N. E. Br. (Verbenaceae) is an aromatic shrub whose essential oils have stood out as a promising source for application in several industrial fields. In this study, the essential oils chemical characterization of eight new L. alba genotypes was performed. The selected materials were collected from the Active Germplasm Bank of the Agronomic Institute and the essential oils were extracted by hydrodistillation. Flow-modulated comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) was employed for chemical characterization and evaluation of possible co-eluted compounds. In addition, the chemical analyses were submitted to multivariate statistical analyses. From this investigation, 73 metabolites were identified in the essential oils of the genotypes, from which α-pinene, ß-myrcene, 1,8-cineole, linalool, neral, geranial, and caryophyllene oxide were the most abundant compounds among the accessions. This is the first report disclosing α-pinene in higher amounts in L. alba (19.69%). In addition, sabinene, trans-verbenol, myrtenol, (E)-caryophyllene, α-guaiene, germacrene D, and α-bulnesene were also found in relevant quantities in some of the genotypes, and myrtenal and myrtenol could be well separated through the second dimension. Such results contributed to the understanding of the chemical composition of those new genotypes, being important to drive a future industrial applicability and studies in genetic breeding.

Addition of Valerian and Lemon Balm Extract to Quetiapine Reduces Agitation in Critically Ill Patients with Delirium: A Pilot Randomized Clinical Trial.

BACKGROUND: This study was pointed to evaluate the efficacy and safety of valerian and lemon balm additional to the quetiapine in critically ill patients with delirium and agitation. METHODS: We conducted a randomized, double-blind, placebo-controlled study. Fifty-three adult intensive care unit (ICU) patients (according to ICU Confusion Assessment Method scores) who were treated for delirium received quetiapine and Neurogol syrup (a combination of valerian and lemon balm) or placebo 5 mL every 12 hours for five consecutive days. Improvement in agitation according to the Richmond Sedation and Restlessness Scale was considered the main outcome. RESULTS: The trial was completed for 53 patients (27 in the treatment group and 26 in the placebo group). The baseline characteristics between the groups were similar. In the treatment group, the number of agitated patients was significantly reduced and the difference was statistically significant (p = 0.000). Compared with the placebo group, the length of ICU stay in the treatment group was significantly reduced (p = 0.001). The Glasgow Coma Scale improved significantly at the end of day 5 (p = 0.04). There was no statistical difference in the improvement of delirium between the study groups (p = 0.14). Neurogol syrup was well tolerated. CONCLUSION: The addition of Neurogol to quetiapine (a combination of valerian and lemon balm) can reduce agitation and shorten the length of stay in the ICU without adverse effects. Clearly, more research is still needed to investigate the role of herbal medicines in ICUs and their efficacy and safety. HOW TO CITE THIS ARTICLE: Alikiaie B, Shahmoradi E, Yekdaneh A, Mousavi S. Addition of Valerian and Lemon Balm Extract to Quetiapine Reduces Agitation in Critically Ill Patients with Delirium: A Pilot Randomized Clinical Trial. Indian J Crit Care Med 2021;25(7):785-790.

Lemon Balm Extract ALS-L1023 Regulates Obesity and Improves Insulin Sensitivity via Activation of Hepatic PPARα in High-Fat Diet-Fed Obese C57BL/6J Mice.

Our previous studies demonstrated that peroxisome proliferator-activated receptor α (PPARα) activation reduces weight gain and improves insulin sensitivity in obese mice. Since excess lipid accumulation in non-adipose tissues is suggested to be responsible for the development of insulin resistance, this study was undertaken to examine whether the lemon balm extract ALS-L1023 regulates hepatic lipid accumulation, obesity, and insulin resistance and to determine whether its mechanism of action involves PPARα. Administration of ALS-L1023 to high-fat-diet-induced obese mice caused reductions in body weight gain, visceral fat mass, and visceral adipocyte size without changes of food consumption profiles. ALS-L1023 improved hyperglycemia, hyperinsulinemia, glucose and insulin tolerance, and normalized insulin-positive ß-cell area in obese mice. ALS-L1023 decreased hepatic lipid accumulation and concomitantly increased the expression of PPARα target genes responsible for fatty acid ß-oxidation in livers. In accordance with the in vivo data, ALS-L1023 reduced lipid accumulation and stimulated PPARα reporter gene expression in HepG2 cells. These effects of ALS-L1023 were comparable to those of the PPARα ligand fenofibrate, while the PPARα antagonist GW6471 inhibited the actions of ALS-L1023 on lipid accumulation and PPARα luciferase activity in HepG2 cells. Higher phosphorylated protein kinase B (pAkt)/Akt ratios and lower expression of gluconeogenesis genes were observed in the livers of ALS-L1023-treated mice. These results indicate that ALS-L1023 may inhibit obesity and improve insulin sensitivity in part through inhibition of hepatic lipid accumulation via hepatic PPARα activation.

Preparation of a new three-component deep eutectic solvent and its use as an extraction solvent in dispersive liquid-liquid microextraction of pesticides in green tea and herbal distillates.

BACKGROUND: A new solvent, deep eutectic solvent, in which there is growing interest, has been prepared and used as an extraction solvent in the dispersive liquid-liquid method of microextraction. To prepare the solvent, dichloroacetic acid, l-menthol, and n-butanol are mixed at a molar ratio of 4:1:1 and the deep eutectic solvent is formed after heating. Then a dispersive liquid-liquid microextraction method using the prepared solvent is used for the extraction and preconcentration of some pesticides from an aqueous sample. To carry out the procedure, the deep eutectic solvent is mixed with methanol and rapidly injected by a syringe into the aqueous sample containing the analytes. After centrifuging, an aliquot of the sedimented phase is injected into the gas chromatograph. The influence of several variables on the extraction efficiency was investigated and optimized. RESULTS: Extraction recoveries and enrichment factors were obtained in the ranges of 53-86% and 1760-2853, respectively. The intra- (n = 6) and inter-day (n = 5) precision of the method was satisfactory, with relative standard deviations ≤ 7% obtained at two concentrations of 10 and 50 µg L-1 of each analyte. Moreover, detection and quantification limits for the target analytes were obtained in the ranges of 0.11-0.23 and 0.38-0.74 µg L-1 , respectively. CONCLUSION: Different samples, including green tea, rose water, lemon balm, mint, and pussy willow distillates were analyzed successfully using the method that was developed, and chlorpyrifos was found in rose water at a concentration of 17 ± 1 µg L-1 (n = 3). © 2019 Society of Chemical Industry.

Effect of lemon balm (Melissa officinalis) extract on growth performance, digestive and antioxidant enzyme activities, and immune responses in rainbow trout (Oncorhynchus mykiss).

This study was conducted to determine the effects of dietary supplementation of lemon balm (Melissa officinalis) aqueous methanolic extract on growth performance, blood parameters, digestive and antioxidant enzyme activities, and non-specific immune responses in rainbow trout (Oncorhynchus mykiss). Fish with an average weight of 23.03 ± 0.07 g were fed a diet supplemented with an aqueous methanolic extract of lemon balm at a dose of 0 (control), 0.1 (LB0.1), 0.5 (LB0.5), and 1 g kg-1 (LB1) for 75 days. The final weight, weight gain, and specific growth rate were observed to be significantly increased in LB0.5 and LB1 groups compared with that of the control. No differences were observed in feed conversion ratio values. WBC increased at the 45th day of the study in LB0.1 group. No differences were determined in RBC (P > 0.05). At the end of the study, lipase increased significantly in all experimental groups compared with the control. Pepsin was also elevated in LB0.5 and LB1 groups compared with the control. Increased trypsin was determined in LB1 group (P < 0.05). SOD activity increased at the end of the study in LB1 group (P < 0.05). CAT values had no differences compared with control. GR activity increased in all experimental groups compared with control. GPx improved in LB0.5 and LB1 groups significantly (P < 0.05). Lipid peroxidation was decreased in LB1 group compared with that of control, but this decrease was not significant (P < 0.05). Oxidative radical production and lysozyme activity significantly increased in LB1 group (P < 0.05). The highest MPO was determined in control group (P < 0.05). Current results suggest that lemon balm extract stimulates growth promoting antioxidant and immune responses in rainbow trout.

Efficacy of Melissa officinalis L. (lemon balm) extract on glycemic control and cardiovascular risk factors in individuals with type 2 diabetes: A randomized, double-blind, clinical trial.

Melissa officinalis is a plenteous source of antioxidant flavonols and flavonoids that contain health-promoting and antidiabetic properties, so this study was undertaken to provide the first assessment of the antidiabetic properties of hydroalcoholic extract of M. officinalis in type 2 diabetic patients. We did a randomized, placebo-controlled trial which included 62 patients, receiving either M. officinalis capsules (700 mg/d; n = 31) or the placebo (n = 31) twice daily for 12 weeks. There were significant differences in serum FBS (P = 0.007), HbA1c (P = 0.002), ß-cell activity (P = 0.05), TG (P = 0.04), HDL-c (P = 0.05), hs-CRP (P = 0.001), and systolic blood pressure (P = 0.04) between the two groups at the end of the study; but total cholesterol, LDL-c, insulin, and HOMA-IR showed no significant changes between the groups. In M. officinalis group, there was a significant change in HDL-c (P = 0.009) and QUICKI (P = 0.005) compared with baseline values. No adverse effects were observed. It seems that M. officinalis is safe and effective in improvement of lipid profile, glycemic control, and reduction of inflammation.

Stabilizing corn oil using the lemon balm (Melissa officinalis) antioxidants extracted by subcritical water.

This research was set up to identify the impact of the antioxidant compounds present in lemon balm extract (LBE) as obtained by the subcritical water (SBCW) method on the oxidative stability of corn oil. An extraction yield of 28.52% was obtained for the SBCW and rosmarinic acid was identified to be the predominant phenolic compound present in the LBE. The total phenolic content of the LBE was found to be 212.74 mg gallic acid/g extract. Subsequently, 200, 400, 800, 1600 and 3200 ppm of the LBE were added to corn oil and its peroxide value (PV), acid value (AV), conjugated diene (CD), carbonyl value (CV), oxidative stability index (OSI), total polar compound and total phenolic compounds were compared to control and the sample containing 200 ppm of the BHA throughout the 16-day Schaal oven test at 70 °C. Our findings indicated that the corn oil containing greater LBE concentration had lower PV, AV, CD, and CV but greater OSI than the control sample. Evaluation of total polar compounds confirmed lower extent of the compounds with high polarity in the greater levels of the LBE. Finally, the LBE was able to slow down the rancidity of corn oil and the samples with higher LBE exhibited gentle oxidation rate.

Biodiversity within Melissa officinalis: Variability of Bioactive Compounds in a Cultivated Collection.

Phytochemical characters were evaluated in a five-year-old lemon balm collection consisting of 15 and 13 subspecies officinalis and altissima accessions, respectively. Stems were lower in essential oil than leaves. First cut leaves (June) gave more oil than those of the second cut (August). Subspecies officinalis plants had leaf oils rich in geranial, neral and citronellal in various proportions in the first cut. However, in the second cut the oils from all accessions appeared very similar with 80-90% geranial plus neral. Leaf oils of subsp. altissima contained sesquiterpenes (ß-caryophyllene, caryophyllene oxide, germacrene D) and also further monoterpenes in the second cut. Leaves had higher rosmarinic acid (RA) contents than stems. More RA was in subsp. officinalis than subsp. altissima leaves. First cut leaves were richer in RA than those from second cut. Total phenolics and antioxidant parameters showed that lemon balm is a valuable source of plant antioxidants.

A Comparative Study on Essential Oil Intraspecific and Seasonal Variations: Melissa romana Mill. and Melissa officinalis L. from Sardinia.

Two species of Melissa are currently present in Sardinia: Melissa officinalis L. and Melissa romana Mill. Our research can only count on a few supported evidences (as reported in Flora Italiana and Moris) and some notes on new stations in Sardinia that give us some information about morphology, distribution, bioecological, and ethnobotanical characteristics of both species. In this paper, we present the results of the research about morphological aspects of M. romana vs. M. officinalis, and their essential oils in different stations at different phenological periods. Moreover, we compared the essential oil of M. romana with the one obtained from M. officinalis growing in the few naturalized stations still present in Sardinia. The most evident morphological differences between the two entities are the long-stalked capitate glandular trichomes, shorts and inclined capitate trichomes, and peltate hairs. The chemical composition of essential oil presents several significant differences between the species. In fact, oils show that in none of the phenological stages, M. romana recalls in its composition M. officinalis. Major distinctions are also evident between dry and fresh plants, and among essential oils distilled in different seasons.