Essential oils content, composition and antioxidant activity of lemon balm, mint and sweet basil from Serbia

Recent advances in the implementation of ultrasound technology for the extraction of essential oils from terrestrial plant materials: A comprehensive review

Ultrasound-assisted extraction (UAE) is an innovative process for recovering valuable substances and compounds from plants and various biomaterials. This technology holds promise for resource recovery while maintaining the quality of the extracted products. The review comprehensively discusses UAE's mechanism, applications, advantages, and limitations, focusing on extracting essential oils (EOs) from diverse terrestrial plant materials. These oils exhibit preservation, flavor enhancement, antimicrobial action, antioxidant effects, and anti-inflammatory benefits due to the diverse range of specific compounds in their composition. Conventional extraction techniques have been traditionally employed, and their limitations have prompted the introduction of novel extraction methods. Therefore, the review emphasizes that the use of UAE, alone or in combination with other cutting-edge technologies, can enhance the extraction of EOs. By promoting resource recovery, reduced energy consumption, and minimal solvent use, UAE paves the way for a more sustainable approach to harnessing the valuable properties of EOs. With its diverse applications in food, pharmaceuticals, and other industries, further research into UAE and its synergies with other cutting-edge technologies is required to unlock its full potential in sustainable resource recovery and product quality preservation.

Phytochemical compositions and antioxidant activity of green and purple basils altered by light intensity and harvesting time

Ocimum basilicum L. is one of the most important medicinal and vegetable crops due to its essential oil, pleasant aroma and taste. In this study, we evaluated the impact of different light intensities, including 100 %, 50 %, and 30 % of natural sunlight, on the growth, phytochemical compositions, and antioxidant activity of green and purple basil cultivars at two different harvest times: early morning and noon. The height of the plant, number of leaves per plant, length of the petiole, diameter of the stem, and fresh and dry weight of the shoot were all reduced by decreasing light intensity in both basil cultivars. When the plants of both cultivars were grown under full light intensity and were sampled at noon, they showed the highest phenolic and flavonoid contents. The highest antioxidant activity was detected in purple basil cultivars grown under 30 and 50 % of sunlight in both harvests. The green basil cultivar showed the highest antioxidant activity when exposed to 30 % sunlight and harvested in the early morning. The highest essential oil content and yield in both basil cultivars were obtained under full sunlight in the early morning harvests. In summary, light intensity and harvest time influence the phytochemical yield, composition, and growth of two studied basil cultivars. Optimal results, particularly for medicinal purposes, were achieved by morning harvesting to maximize the essential oil yield of basils.

Revelation of enzyme/transporter-mediated metabolic regulatory model for high-quality terpene accumulation in developing fruits of Lindera glauca

Lindera glauca with rich resource and fruit terpene has emerged as potential material for utilization in China, but different germplasms show a variation for essential oil content and volatile profiling. This work aimed to determine key regulators (enzymes or transporters) and unravel mechanism of governing high production of essential oil of L. glauca fruit (EO-LGF). Temporal analysis of fruit growth and EO-LGF accumulation (yield, volatile compounds and contents) during development revealed a notable change in the contents of EO-LGF and its 45 compounds in developing fruits, and the major groups were monoterpene and sesquiterpene, showing good antioxidant and antimicrobial activities. To highlight molecular mechanism that govern such difference in terpene content and compound in developing fruits, Genome-wide assay was used to annotate 104 genes for terpene-synthesis pathway based on recent transcriptome data, and the comparative associations of terpene accumulative amount with gene transcriptional level were conducted on developing fruits to identify some crucial determinants (enzymes and transporters) with metabolic regulation model for high-quality terpene accumulation, involving in carbon allocation (sucrose cleavage, glycolysis and OPP pathway), metabolite transport, isoprene precursor production, C5-unit formation (MEP and MVA pathways), and mono-/sesqui-terpene synthesis. Our findings may present strategy for engineering terpene accumulation for utilization.

Chemical Composition and Bioactivity of Dill Seed (Anethum graveolens L.) Essential Oil from Plants Grown under Shading

This study determined the content and composition of dill seed (Anethum graveolens L.) essential oil under varying light conditions: non-shaded plants in open fields and plants covered with pearl shade nets (40% shade index). Essential oil was extracted using Clevenger hydrodistillation. The essential oil content was 4.63% for non-shaded plants and 4.81% for shaded plants. GC/MS analysis revealed twenty-one and twenty-two components in dill seed from non-shaded and shaded plants, respectively. The terpenic fraction of essential oil from non-shaded plants consisted mainly of oxygen-containing monoterpene derivatives (53.6%), with carvone (46.1%) as the primary component, followed by monoterpene hydrocarbons (46.4%), predominantly limonene (43.8%). Essential oil from shaded plants contained a higher content of carvone (49.8%) and a lower content of limonene (37.8%) compared to essential oil from non-shaded plants. Non-shaded plant essential oil exhibited stronger antioxidant activity (EC50 value: 26.04 mg mL-1) than shaded plant essential oil (54.23 mg mL-1). Dill seed essential oil showed the most potent antimicrobial activity (disc diffusion method) against Escherichia coli (inhibition zone: 15-18 mm). Shaded plants demonstrated a positive influence of essential oil against Klebsiella pneumoniae. Carvone and its derivatives, as the main components, hold significant potential in the food industry and alternative medicines. A practical implication of this study could be higher plant densities or intercropping of dill, as it thrives with minimal light.

Nanosizing of Lavender, Basil, and Clove Essential Oils into Microemulsions for Enhanced Antioxidant Potential and Antibacterial and Antibiofilm Activities

Plant essential oils (EOs) possess significant bioactivities (antibacterial and antioxidant) and can be substituted for potentially harmful synthetic preservatives in the food industry. However, limited water solubility, bioavailability, volatility, and stability limit their use. Therefore, the goal of this research was nanosizing lavender essential oil (LEO), basil essential oil (BEO), and clove essential oil (CEO) in a microemulsion (ME) to improve their physicochemical attributes and bioefficacy. Tween 80 and Transcutol P were utilized for construction of pseudoternary phase diagrams. It was observed that the concentration of EOs had a great impact on the physicochemical and biological properties of MEs. A spherical droplet of MEs with a diameter of less than 20 nm with a narrower size distribution (polydispersity index (PDI) = 0.10-0.27) and a ζ potential of -0.27 to -9.03 was observed. ME formulations were also evaluated for viscosity, conductivity, and the refractive index. Moreover, the impact of delivery systems on the antibacterial property of EOs was assessed by determining the zone of inhibition and minimum inhibitory concentration against two distinct pathogen classes (S. aureus and E. coli). Crystal violet assay was used to measure the growth and development of biofilms. According to bioefficacy assays, ME demonstrated more efficient antibacterial activity against microorganisms at concentrations lower than pure EOs. CEO ME had superior activity againstS. aureus and E. coli. Similarly, dose-dependent antioxidant capacity was noted for MEs. Consequently, nanosized EO formulations with improved physicochemical properties and enhanced bioactivities can be employed in the food processing sector as a preservation agent.

Phytochemical Composition and Pharmacological Activities of Three Essential Oils Collected from Eastern Morocco (Origanum compactum, Salvia officinalis, and Syzygium aromaticum): A Comparative Study

Throughout history, essential oils have been employed for their pleasing scents and potential therapeutic benefits. These oils have shown promise in various areas, including aromatherapy, personal care products, natural remedies, and even as alternatives to traditional cleaning agents or pest control solutions. The study aimed to explore the chemical makeup, antioxidant, and antibacterial properties of Origanum compactum Benth., Salvia officinalis L., and Syzygium aromaticum (L.) Merr. et Perry. Initially, the composition of the three essential oils, O. compactum (HO), S. officinalis (HS), and S. aromaticum (HC) was analyzed using GC-MS technology, revealing significant differences in the identified compounds. α-thujone emerged as the predominant volatile component in the oils, making up 78.04% of the composition, followed by eugenol, which constituted 72.66% and 11.22% of the HC and HO oils, respectively. To gauge antioxidant capabilities, tests involving DPPH scavenging capacity and total antioxidant capacity were conducted. Antioxidant activity was determined through the phosphomolybdate test and the DPPH• radical scavenging activity, with the HO essential oil displaying significant scavenging capacity (IC50 of 0.12 ± 0.02 mg/mL), similar to ascorbic acid (IC50 of 0.26 ± 0.24 mg/mL). Similarly, the TAC assay for HO oil revealed an IC50 of 1086.81 ± 0.32 µM AAE/mg. Additionally, the oils' effectiveness against four bacterial strains, namely Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Listeria monocytogenes, and five fungi, Geotrichum candidum, Aspergillus niger, Saccharomyces cerevisiae, Candida glabrata, and Candida albicans, was tested in vitro. The examined essential oils generally exhibited limited antimicrobial effects, with the exception of HC oil, which demonstrated an exceptionally impressive level of antifungal activity. In order to clarify the antioxidant, antibacterial, and antifungal effects of the identified plant compounds, we employed computational methods, specifically molecular docking. This technique involved studying the interactions between these compounds and established protein targets associated with antioxidant, antibacterial, and antifungal activities.

Salt-Induced Stress Impacts the Phytochemical Composition and Aromatic Profile of Three Types of Basil in a Genotype-Dependent Mode

Basil (Ocimum basilicum L.) is among the most widely used aromatic plants of Lamiaceae, often grown in areas where salinity is an adverse factor. Most studies on the effect of salinity on basil focused on the influence of salt stress on productive traits, while few reported on how it affects the phytochemical composition and the aroma profile. Three basil cultivars (Dark Opal, Italiano Classico, and Purple Ruffles) were grown hydroponically for 34 days with two nutrient solutions that differed in NaCl concentration [no NaCl (Control) and 60 mM NaCl]. Yield, secondary metabolite concentration (β-carotene and lutein), antioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reduction antioxidant power (FRAP)], and aroma profile based on composition of volatile organic compounds (VOCs) were appraised in response to salinity applications. Salt stress significantly reduced fresh yield in Italiano Classico and Dark Opal by 43.34 and 31.69%, respectively, while no effect was observed in Purple Ruffles. Furthermore, the salt-stress treatment increased β-carotene and lutein concentrations, DPPH, and FRAP activities, and the total nitrogen content of the latter cultivar. CG-MS analysis revealed significant differences in VOCs composition of the basil cultivars, with Italiano Classico and Dark Opal characterized by the predominance of linalool (average 37.52%), which, however, was negatively affected by salinity. In Purple Ruffles, the predominant VOC compound, estragole (79.50%), was not affected by the deleterious effects of NaCl-induced stress.

Exploring the multipotentiality of plant extracts for the green synthesis of iron nanoparticles: A study of adsorption capacity and dye degradation efficiency

The goal of the project was to create environmentally friendly and economically viable materials for thoroughly purifying contaminated water. An affordable, phytogenic, and multifunctional plant-based nanomaterial was prepared in this context. The work demonstrates an effective green synthesis method for producing iron nanoparticles (FeNPs) using six different plant extracts as a reducing agent. The characterization of green synthesized catalysts was concluded via Spectroscopy (tauc plot), XRD, FE-SEM, and FT-IR. The produced nanomaterial, which had an X-ray diffractogram (XRD) peak at 43.33⁰ and a size range of 1.82-63.63 nm, functioned as a highly effective nano-photocatalyst for the degradation of cationic dye. Due to the presence of a lower overall secondary metabolites quota, Ocimum sanctum plant extract reduced iron precursor produced the highest yield of dried NPs, followed by Azadirachta indica, Prosopis cineraria, Syzygium cumini, Citrus limon, and Salvadora oleoides. Further, the synthesized catalyst was tested for its effectiveness against gentian violet dye degradation. Ocimum sanctum plant extract reduced iron precursor produced the highest yield of dried NPs, followed by Azadirachta indica, Prosopis cineraria, Syzygium cumini, Citrus limon, and Salvadora oleoides, in that order. The dye removal efficiency of nanoparticles was 51% (Azadirachta indica), 83% (Ocimum sanctum), 59% (Syzygium cumini), 40% (Salvadora oleoides), 59% (Prosopis cineraria), and 63% (Citrus limon) after 12 h of visible light irradiation. The key factor in the process of deterioration is •O^2-. As a result, the nanoparticles can be used in antibacterial and photocatalytic processes. The reduced band gap was responsible for the increased photocatalytic quantity. The maximum adsorption capacity at the time of equilibrium was obtained in order as Ocimum sanctum > Citrus limon > Prosopis cineraria > Syzygium cumini > Azadirachta indica > Salvadora oleoides. The simplicity of production, low cost, magnetic property, and high adsorption capacity will increase the efficacy of the water treatment method. This article reports on the creation of unique iron nanoparticles and their use in the purification of water.

Effect of a Change in the CaCl2/Pectin Mass Ratio on the Particle Size, Rheology and Physical Stability of Lemon Essential Oil/W Emulgels

A three-step (rotor-stator-microfluidization-rotor stator) protocol was used to prepare 15% lemon essential oil in water emulgels using a mixture of Tween 80 and Span 20 surfactants as low molecular mass emulsifiers and 0.4% low-methoxyl citrus peel pectin as a gelling agent. Ca2+ was used as a gel-promoting agent. Different CaCl2/pectin mass ratio values from 0.3 to 0.7 were used. Emulgels showed a microstructure consisting of oil droplets embedded in a sheared gel matrix, as demonstrated by bright field optical microscopy. Laser diffraction tests showed multimodal particle size distributions due to the coexistence of oil droplets and gel-like particles. Multiple light scattering tests revealed that the physical stability of emulgels was longer as the CaCl2/pectin mass ratio decreased and that different destabilization mechanisms took place. Thus, incipient syneresis became more important with increasing CaCl2 concentration, but a parallel creaming mechanism was detected for CaCl2/pectin mass ratio values above 0.5. Dynamic viscoelastic and steady shear flow properties of the emulgels with the lowest and highest CaCl2/pectin mass ratio values were compared as a function of aging time. The lowest ratio yielded an emulgel with enhanced connectivity among fluid units as indicated by its wider linear viscoelastic region, higher storage modulus, loss modulus and viscosity values, and more shear thinning properties than those of the emulgel formulated with the highest CaCl2/pectin mass ratio. The evolution of the dynamic viscoelastic properties with aging time was consistent with the information provided by monitoring scans of backscattering as a function of sample height.

Antimicrobial Activity of Gelatin Nanofibers Enriched by Essential Oils against Cutibacterium acnes and Staphylococcus epidermidis

Acne vulgaris is a prevalent skin condition that is caused by an imbalance in skin microbiomes mainly by the overgrowth of strains such as Cutibacterium acnes and Staphylococcus epidermidis which affect both teenagers and adults. Drug resistance, dosing, mood alteration, and other issues hinder traditional therapy. This study aimed to create a novel dissolvable nanofiber patch containing essential oils (EOs) from Lavandula angustifolia and Mentha piperita for acne vulgaris treatment. The EOs were characterized based on antioxidant activity and chemical composition using HPLC and GC/MS analysis. The antimicrobial activity against C. acnes and S. epidermidis was observed by the determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The MICs were in the range of 5.7-9.4 μL/mL, and MBCs 9.4-25.0 μL/mL. The EOs were integrated into gelatin nanofibers by electrospinning and SEM images of the fibers were taken. Only the addition of 20% of pure essential oil led to minor diameter and morphology alteration. The agar diffusion tests were performed. Pure and diluted Eos in almond oil exhibited a strong antibacterial effect on C. acnes and S. epidermidis. After incorporation into nanofibers, we were able to focus the antimicrobial effect only on the spot of application with no effect on the surrounding microorganisms. Lastly, for cytotoxicity evaluation, and MTT assay was performed with promising results that samples in the tested range had a low impact on HaCaT cell line viability. In conclusion, our gelatin nanofibers containing EOs are suitable for further investigation as prospective antimicrobial patches for acne vulgaris local treatment.

Pheophorbide-a as a Light-Triggered Liposomal Switch: For the Controlled Release of Alpinia galanga (A. galanga) Essential Oil and Its Stability, Antioxidant, and Antibacterial Activity Assessment

In this study, Alpinia galanga essential oil liposomes (EO-Lip) were prepared with soybean lecithin and cholesterol as wall materials. A light-responsive liposome (EO-PLip) was designed for the controlled release of A. galanga oil based on the light-responsive properties of Pheophorbide-a. The dependence of Pheophorbide-a on illumination time was proved by UV spectroscopy. Characterization techniques such as UV spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy demonstrated that the essential oils were successfully encapsulated in liposomes. Moreover, the particle size of EO-PLip was 166.30 nm, the polydispersity index was 0.22, the zeta potential was -49.50 mV, and the encapsulation efficiency was 30.83%. Both EO-Lip and EO-Plip have high sustained-release effects on essential oil and showed light-responsive release characteristics under infrared stimulation. The prepared liposomes had good storage stability at 4 °C for 28 d. EO-PLip showed excellent transient antioxidant and bacteriostatic properties based on the ability to respond to light and slow release. This EO-PLip provided a platform for essential oils and might be used as a potent and controllable solution.

Determination of Polycyclic Aromatic Hydrocarbon Content in Garden Herbal Plants Using Liquid Chromatographic Analysis (HPLC-FL)

Polycyclic aromatic hydrocarbons (PAHs) are a group of chemical compounds generated as a result of the incomplete combustion of fossil fuels or wood. PAHs are known for their negative effect on living organisms, including teratogenic, carcinogenic and mutagenic activity. The objective of this study is to determine the contamination of three popular herbal species showing pro-health properties, i.e., lavender, parsley and mint, with polycyclic aromatic hydrocarbons, collected from three different backyard gardens in Poland. The concentration of PAHs in plant material was determined by high-performance liquid chromatography with a fluorescence detector (HPLC-FL). The concentration of eleven PAHs in plant material was determined with high-pressure liquid chromatography after extraction using the QuEChERS purification technique. Mint collected within an area of a mining and energy production complex (the city of Konin) was characterized by the highest Σ of 11 PAHs, equaled to 902.35 µg/g FW, with anthracene being the most abundant compound. However, it contained the lowest sum of PAHs, among all tested plants, with high carcinogenicity. Parsley from the city of Poznań showed the highest content of benzo[a]pyrene (BaP), showing the strongest carcinogenicity, while the highest value of BaP equivalent was calculated for mint collected in Konin. The obtained results suggest that the level and profile of plant contamination with PAHs depend on the species and the location of herb cultivation. In particular, mining and energy industry facilities are sources of PAHs, which contaminate plant material for further direct use or as bioactive herbal extracts.

A physiological and metabolomic analysis reveals the effect of shading intensity on blueberry fruit quality

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The FT1 shading treatment yielded the largest values for blueberry single fruit weight.

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The highest total phenol, anthocyanin and vitamin C contents under the FT1 shading treatment.

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470 known metabolites were obtained from blueberry fruits.

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This study provides scientific basis for improving the quality of blueberry fruit.

With the advancement of blueberry industrialization, cultivation measures for obtaining high-quality fruits and technologies for obtaining high levels of the main secondary metabolites have become inevitable requirements for further development of the blueberry industry. This study applied different shading treatments and found that the FT1 shading treatment yielded the largest values for the single fruit weight, solid longitudinal diameter and transverse diameter of blueberry fruit as well as the highest solidity-acid ratio and total phenol and vitamin C contents. Moreover, 470 known metabolites were obtained from blueberry fruits. Interestingly, the differentially abundant metabolites related to ABC transporters, pyrimidine metabolism, and purine metabolism pathways were commonly identified from the three comparisons, which indicated that these three metabolic pathways in blueberry fruits are vulnerable to shading treatment. This study provides a theoretical basis for the application of summer shading to improve the quality and antioxidant substances of small berries.

Effect of Melissa officinalis L. Essential Oil Nanoemulsions on Structure and Properties of Carboxymethyl Chitosan/Locust Bean Gum Composite Films

This study aimed to develop active films based on carboxymethyl chitosan (CMCS)/locust bean gum (LBG) films containing Melissa officinalis L. essential oil (MOEO) nanoemulsions. The results showed that the active films incorporated with MOEO nanoemulsion resulted in an increase in the elongation of break, water resistance and improved the film hydrophilicity. Elongation of break increased from 18.49% to 27.97% with the addition of 4% MOEO nanoemulsion. Water resistance was decreased from 56.32% to 25.43%, and water contact angle was increased from 75.13 to 83.86 with the addition of 4% MOEO nanoemulsion. However, the water vapor barrier properties and tensile strength decreased with the addition of MOEO nanoemulsions. The scanning electron microscopic images and Fourier transform infrared spectroscopy results showed that the MOEO was very compatible with the film materials and dispersed evenly in the films. At the same time, the addition of MOEO nanoemulsion significantly enhanced antioxidant and antibacterial activities of C/L-MOEO films. The antioxidant and antimicrobial activities of C/L-MOEO films were increased from 7.16% to 33.81% and 3.52% to 54.50%, respectively. In general, C/L-MOEO film has great application prospects.

Preparation, Characterization, and Antioxidant Activity of Nanoemulsions Incorporating Lemon Essential Oil

Lemon essential oil (LEO) is a kind of citrus essential oil with antioxidant, anti-inflammatory, and antimicrobial activities, but low water solubility and biological instability hinder its industrial application. In this study, LEO was nanoemulsified to solve these problems. The preparation procedure of lemon essential oil nanoemulsions (LEO-NEs) was optimized, and the physicochemical characterization and antioxidant activities were explored. Single-factor experiments (SFEs) and response surface methodology (RSM) were conducted for the effects on the mean droplet size of LEO-NEs. Five factors of SFE which may influence the droplet size were identified: HLB value, concentration of essential oil, concentration of surfactant, ultrasonic power, and ultrasonic time. On the basis of the SFE, the RSM approach was used to optimize the preparation procedure to obtain LEO-NEs with the smallest droplet size. LEO-NEs exhibited good antioxidant activity when the HLB value was 13, content of surfactant was 0.157 g/mL, ultrasonic time was 23.50 min, and ultrasonic power was 761.65 W. In conclusion, these results can provide a good theoretical basis for the industrial application of lemon essential oil.

The Antimicrobial Effect of Melissa officinalis L. Essential Oil on Vibrio parahaemolyticus: Insights Based on the Cell Membrane and External Structure

The study was to evaluate the antimicrobial impacts on Melissa officinalis L. essential oil (MOEO) against Vibrio parahaemolyticus. The minimum inhibitory concentration (MIC) of MOEO on Vibrio parahaemolyticus was 1 μL⋅mL^–1. The kill-time curve exhibited that MOEO had good antimicrobial activity. The analysis of cellular ingredients leakage and cell viability illustrated that MOEO has destruction to the morphology of the cell membrane. The damage to the membrane integrity by MOEO has been confirmed by transmission and scanning electron microscopy, obvious morphological and ultrastructural changes were observed in the treated bacterial cells. The MOEO at 0.5 μL⋅mL^–1 can inhibit the biofilm formation, biofilm motility, and extracellular polysaccharide production. Meanwhile, the qPCR results exhibited MOEO inhibited the expression of virulence genes. The findings showed that MOEO exerted its antimicrobial effect mainly by destroying the membrane, which indicated its potential as a natural food preservative.

Biochemical Characterization of Some Varieties of Apricot Present in the Vesuvius Area, Southern Italy

The witnesses of the millenary history of Campania felix in southern Italy highlighted that several fruit and vegetables cultivated in such territory could potentially be a treasure trove of important health elements. Our work evaluated the content of β-carotene, ascorbic acid, and total phenolics and the antioxidant activity of ten typical varieties of apricots cultivated in the Vesuvius area in the Campania region. The total polyphenols varied between 10.24 and 34.04 mg/100 g of a fresh sample. The amount of ascorbic acid also varied greatly, ranging from 2.65 to 10.65 mg/100 g of a fresh product. B-Carotene reached values up to 0.522 mg/100 g of the fresh sample. The correlation analysis performed, accounting for these parameters, showed that the antioxidant activity, calculated by 2,2-diphenyl-1-picrylhydrazyl (DPPH assay) and azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) tests, was influenced mainly by the content of total polyphenols, with ρ = −0.762 and ρ = 0.875 when we considered DPPH and ABTS tests, respectively, slightly less by the content of ascorbic acid, and not by β-carotene. The dendrogram clustered eight varieties into two main groups; on the other hand, two varieties (“Vitillo” and “Preveta bella”) seemed hierarchically distant. The gas chromatography–mass spectrometry (GC–MS) analysis of volatile organic compounds (VOCs), herein performed for the first time, demonstrated the influence of the varieties on the VOC profiles, both from a qualitative and semiquantitative perspective, discriminating the varieties in different clusters, each of which was characterized by specific notes. α-Terpinolene was the only terpene identified by GC–MS that appeared to affect the antioxidant activity.

Shading of Medical Plants Affects the Phytochemical Quality of Herbal Extracts

The manipulation of light intensity by shade nets can lead to exchanges in the phytochemical quality and antioxidants ofsome herbs. This study aimed to determine whether shading by pearl nets (50% shade index) could improve the bioactive compounds in several medicinal herbs such as thyme (Thymus vulgaris L.), marjoram (Origanum majorana L.), oregano (Origanum vulgare L.), lemon balm (Melissa officinalis L.), and peppermint (Mentha piperita L.), and their correspondingherbal extracts during a four-week maceration process in ethanol. Oregano and thyme provided the highest yield of total extractive substances (TES) from both shaded and non-shaded plants. Among all studied herbs, the highest level of antioxidants, expressed as total phenolic content (TPC) was found in extracts from shaded plants of lemon balm. Herbal extracts produced from non-shaded thyme and marjoram had higher flavonoid contents compared to herbal extracts from shaded plants. Accumulation of the investigated secondary metabolites depends more on the specificity of a plant species rather than light intensity. This study was an initial step in the production of medicinal plants with an increased quantity of antioxidant and other bioactive compounds during the maceration process in extracts, aimed to be used as natural alcoholic productwith added value.