Special Issue "Perspectives of Essential Oils"

A special issue of Biomolecules (ISSN 2218-273X). This special issue belongs to the section "Natural and Bio-inspired Molecules".

Deadline for manuscript submissions: closed (30 June 2020) | Viewed by 34527

Special Issue Editor

Prof. Dr. Il-Kwon Park
E-Mail Website
Guest Editor
Department of Forest Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
Interests: plant essential oils; phytochemicals; insecticidal activity; nematicidal activity; antifungal activity; antibacterial activity; mode of action; structure-activity relationship; insect pheromone; aggregation pheromone; sex pheromone; odorant binding protein of insect

Special Issue Information

Dear Colleagues,

Essential oil (EO) is a concentrated hydrophobic liquid extracted from plants by steam distillation, solvent extraction, maceration, or mechanical processing. EO has been widely used for perfumes, cosmetics, soaps, and other products for flavoring food and drink. Recently, many scientists have paid attention to the medical use of EOs. Many researches have reported the antibacterial, antifungal, antiparasitic, and antiviral activities of EOs and their components. Another promising use of EO is as a natural pesticide. Many plant essential oils and their components have been reported to exhibit antifungal, nematicidal, and insecticidal activities against plant pathogenic fungi, plant parasitic nematodes, and plant insect pests. The use of EOs as green pesticides rather than synthetic pesticides has ecological benefits such as decreased residual problem, safety to non-target organisms, and low environmental contamination.

This Special Issue aims to collect original papers and/or review papers dealing with complementary and alternative approaches to the study of the biological activity of EOs and their application in biological fields.

Prof. Il-Kwon Park
Guest Editor

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Keywords

  • essential oils
  • biological activity
  • medical use
  • natural pesticide
  • antioxidant
  • antiviral
  • antibacterial
  • antifungal
  • nematicidal
  • insecticidal
  • repellent
  • food preservation
  • chemical components
  • synergistic effect
  • mode of action
  • structure–activity relationship

Published Papers (17 papers)

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Research

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Article
Biological Activity of Humulus lupulus (L.) Essential Oil and Its Main Components against Sitophilus granarius (L.)
Biomolecules 2020, 10(8), 1108; https://doi.org/10.3390/biom10081108 - 25 Jul 2020
Cited by 9 | Viewed by 1319
Abstract
Besides its use in the brewing industry, hop cones appear as a powerful source of biologically active compounds, already checked for their putative anticancer, antimicrobial, and other bioactivities. Conversely, hop use in pest control remains to date under-investigated. Therefore, the biological activity of [...] Read more.
Besides its use in the brewing industry, hop cones appear as a powerful source of biologically active compounds, already checked for their putative anticancer, antimicrobial, and other bioactivities. Conversely, hop use in pest control remains to date under-investigated. Therefore, the biological activity of hop essential oil (EO) and its main constituents was investigated here against Sitophilus granarius. Adult contact toxicity was found 24 h after treatment with hop EO (LD50/LD90 13.30/40.23 µg/adult), and its three most abundant components, α-humulene, β-myrcene, and β-caryophyllene (LD50/LD90 41.87/73.51, 75.91/126.05, and 138.51/241.27 µg/adult, respectively); negligible variations at 48 h, except for α-humulene (LD50/LD90 26.83/49.49 µg/adult), were found. The fumigant toxicity of the EO and terpenes was also checked: in the absence of wheat grains, β-myrcene showed the highest inhalation toxicity (LC50/LC90 72.78/116.92 mg/L air), whereas α-humulene, β-caryophyllene, and the EO induced similar values (LC50/LC90 about 130/200 mg/L air); with the exception for EO, the wheat presence increased (30–50%) LC50/LC90 values. Moreover, EO and terpenes were perceived by insect antennae and elicited repellent activity. Only β-caryophyllene showed an anticholinesterase effect, this suggesting that different mechanisms of action should be responsible for hop EO toxicity. Therefore, hop EO appears suitable for developing control means against this pest. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
Antiarrhythmic Properties of Elsholtzia ciliata Essential Oil on Electrical Activity of the Isolated Rabbit Heart and Preferential Inhibition of Sodium Conductance
Biomolecules 2020, 10(6), 948; https://doi.org/10.3390/biom10060948 - 23 Jun 2020
Viewed by 1184
Abstract
Elsholtzia ciliata essential oil (E. ciliata) has been developed in Lithuania and internationally patented as exerting antiarrhythmic properties. Here we demonstrate the pharmacological effects of this herbal preparation on cardiac electrical activity. We used cardiac surface ECG and a combination of [...] Read more.
Elsholtzia ciliata essential oil (E. ciliata) has been developed in Lithuania and internationally patented as exerting antiarrhythmic properties. Here we demonstrate the pharmacological effects of this herbal preparation on cardiac electrical activity. We used cardiac surface ECG and a combination of microelectrode and optical mapping techniques to track the action potentials (APs) in the Langendorff-perfused rabbit heart model during atrial/endo-/epi-cardial pacing. Activation time, conduction velocity and AP duration (APD) maps were constructed. E. ciliata increased the QRS duration and shortened QT interval of ECG at concentrations of 0.01–0.1 μL/mL, whereas 0.3 μL/mL (0.03%) concentration resulted in marked strengthening of changes. In addition, the E. ciliata in a concentration dependent manner reduced the AP upstroke dV/dtmax and AP amplitude as well as APD. A marked attenuation of the AP dV/dtmax and a slowing spread of electrical signals suggest the impaired functioning of Na+-channels, and the effect was use-dependent. Importantly, all these changes were at least partially reversible. Our results indicate that E. ciliata modulates cardiac electrical activity preferentially inhibiting Na+ conductance, which may contribute to its effects as a natural antiarrhythmic medicine. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
Premna odorata: Seasonal Metabolic Variation in the Essential Oil Composition of Its Leaf and Verification of Its Anti-Ageing Potential via In Vitro Assays and Molecular Modelling
Biomolecules 2020, 10(6), 879; https://doi.org/10.3390/biom10060879 - 08 Jun 2020
Cited by 9 | Viewed by 1255
Abstract
The metabolic variation in the essential oil composition of Premna odorata leaves obtained from different seasons was quantitatively and qualitatively determined employing GC/MS (Gas Chromatography coupled with Mass Spectrometry) and GC/FID (Gas chromatography equipped with flame ionization detector) techniques. It displayed the existence [...] Read more.
The metabolic variation in the essential oil composition of Premna odorata leaves obtained from different seasons was quantitatively and qualitatively determined employing GC/MS (Gas Chromatography coupled with Mass Spectrometry) and GC/FID (Gas chromatography equipped with flame ionization detector) techniques. It displayed the existence of 97 constituents accounting for 94.19%, 92.27%, 91.95% and 92.63% for POS (spring), POM (summer), POA (autumn) and POW (winter) whole essential oils. β-Caryophyllene constituting the main metabolite in the oil in the different seasons. To better visualize the differences between them, GC data were exposed to chemometric analysis. A PCA (principal component analysis) score plot revealed the closeness of POS and POW. Molecular modelling on collagenase, elastase and hyaluronidase enzymes active centres shows that different compounds existing in the essential oil of Premna odorata leaves shows binding to the active sites with variable degrees that suggested its anti-ageing potential. Palmitic acid displayed the highest fitting for both the collagenase and elastase active centres in both pH-based and rule-based ionization methods with ∆G equals −78.27 and −44.77 kcal/mol, respectively; meanwhile, heptacosane showed the highest fitting score in the hyaluronidase centre with ∆G = −43.78 kcal/mol. In vitro assays consolidates the obtained modelling studies in which essential oil shows considerable anti-elastase and anti-hyaluronidase potential as evidenced by their IC50 values being 49.3 and 37.7 μg/mL, respectively; meanwhile, the essential oil of Premna odorata leaves displayed mild anti-collagenase potential. Thus, it can be concluded that Premna odorata could serve as a promising anti-ageing naturally occurring drug that could be effectively incorporated by pharmaceutical industries in cosmetics combating ageing and skin wrinkling. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
TLC-Based Bioassay to Isolate Kairomones from Tea Tree Essential Oil That Attract Male Mediterranean Fruit Flies, Ceratitis capitata (Wiedemann)
Biomolecules 2020, 10(5), 683; https://doi.org/10.3390/biom10050683 - 28 Apr 2020
Cited by 7 | Viewed by 1750
Abstract
The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) poses a major threat to fruit and vegetable production in the United States and throughout the world. New attractants and detection methods could improve control strategies for this invasive pest. In this study, we [...] Read more.
The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) poses a major threat to fruit and vegetable production in the United States and throughout the world. New attractants and detection methods could improve control strategies for this invasive pest. In this study, we developed a method that combined thin-layer chromatography (TLC) of tea tree essential oil (TTO) (Melaleuca alternifolia) with short-range bioassays to isolate attractive kairomones for male C. capitata. After development, the TLC chromatogram indicated that TTO separated into five major spots, designated as zones 1 to 5. When the TLC plate was exposed to flies, zones 1 and 3 were strongly attractive to male C. capitata. To confirm activity, the developed TLC plate was cut into five zones which were then tested in short-range bioassays. Again, flies were observed to aggregate around zones 1 and 3, which corresponded with Rf values of 0.93 and 0.59. In addition, zones 1 to 5 were separated using preparative-TLC, and olfactory responses to volatile emissions from the five fractions were quantified by electroantennography (EAG). Highest amplitude EAG responses were recorded with fractions 1 and 3, further supporting the bioactivity of these samples. In conclusion, a TLC-based bioassay system can provide an effective, rapid screening protocol for initial isolation of insect kairomones from complex mixtures such as essential oils or plant extracts. Further analysis of TTO fractions 1 and 3 is needed to identify the specific constituents attractive to male C. capitata. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
Optimum Inhibition of Amphotericin-B-Resistant Candida albicans Strain in Single- and Mixed-Species Biofilms by Candida and Non-Candida Terpenoids
Biomolecules 2020, 10(2), 342; https://doi.org/10.3390/biom10020342 - 21 Feb 2020
Cited by 9 | Viewed by 1439
Abstract
Candida albicans is one of the most common human fungal pathogens and represents the most important cause of opportunistic mycoses worldwide. Surgical devices including catheters are easily contaminated with C. albicans via its formation of drug-resistant biofilms. In this study, amphotericin-B-resistant C. albicans [...] Read more.
Candida albicans is one of the most common human fungal pathogens and represents the most important cause of opportunistic mycoses worldwide. Surgical devices including catheters are easily contaminated with C. albicans via its formation of drug-resistant biofilms. In this study, amphotericin-B-resistant C. albicans strains were isolated from surgical devices at an intensive care center. The objective of this study was to develop optimized effective inhibitory treatment of resistant C. albicans by terpenoids, known to be produced naturally as protective signals. Endogenously produced farnesol by C. albicans yeast and plant terpenoids, carvacrol, and cuminaldehyde were tested separately or in combination on amphotericin-B-resistant C. albicans in either single- or mixed-infections. The results showed that farnesol did not inhibit hyphae formation when associated with bacteria. Carvacrol and cuminaldehyde showed variable inhibitory effects on C. albicans yeast compared to hyphae formation. A combination of farnesol with carvacrol showed synergistic inhibitory activities not only on C. albicans yeast and hyphae, but also on biofilms formed from single- and mixed-species and at reduced doses. The combined terpenoids also showed biofilm-penetration capability. The aforementioned terpenoid combination will not only be useful in the treatment of different resistant Candida forms, but also in the safe prevention of biofilm formation. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
Seasonal and Antioxidant Evaluation of Essential Oil from Eugenia uniflora L., Curzerene-Rich, Thermally Produced in Situ
Biomolecules 2020, 10(2), 328; https://doi.org/10.3390/biom10020328 - 19 Feb 2020
Cited by 15 | Viewed by 1637
Abstract
The essential oil of Eugenia uniflora has been attributed anti-depressive, antinociceptive, antileishmanial, larvicidal, antioxidant, antibacterial, and antifungal activities. It is known that the cultivation of this plant can be affected by seasonality, promoting alteration in the oil composition and its biological activities. This [...] Read more.
The essential oil of Eugenia uniflora has been attributed anti-depressive, antinociceptive, antileishmanial, larvicidal, antioxidant, antibacterial, and antifungal activities. It is known that the cultivation of this plant can be affected by seasonality, promoting alteration in the oil composition and its biological activities. This study aims to perform the annual evaluation of the curzerene-type oil of E. uniflora and determine its antioxidant activity. The oil yield from the dry season (1.4 ± 0.6%) did not differ statistically from that of the rainy season (1.8 ± 0.8%). Curzerene, an oxygenated sesquiterpene, was the principal constituent, and its percentage showed no significant difference between the two periods: dry (42.7% ± 6.1) and rainy (40.8 ± 5.9%). Principal component and hierarchical cluster analyses presented a high level of similarity between the monthly samples of the oils. Also, in the annual study, the yield and composition of the oils did not present a significant correlation with the climatic variables. The antioxidant activity of the oils showed inhibition of DPPH radicals with an average value of 55.0 ± 6.6%. The high curzerene content in the monthly oils of E. uniflora suggests their potential for use as a future phytotherapeutic alternative. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
Chemical Composition of Essential Oils from Different Parts of Zingiber kerrii Craib and Their Antibacterial, Antioxidant, and Tyrosinase Inhibitory Activities
Biomolecules 2020, 10(2), 228; https://doi.org/10.3390/biom10020228 - 04 Feb 2020
Cited by 5 | Viewed by 1246
Abstract
The essential oils of the fresh rhizomes; flowers; and leaves of Zingiber kerrii Craib were investigated using different extraction techniques; including solid-phase microextraction (SPME), hydrodistillation (HD), and organic solvent (OS), and characterized by gas chromatography–mass spectrometry (GC–MS). A total of 37 SPME; 19 [...] Read more.
The essential oils of the fresh rhizomes; flowers; and leaves of Zingiber kerrii Craib were investigated using different extraction techniques; including solid-phase microextraction (SPME), hydrodistillation (HD), and organic solvent (OS), and characterized by gas chromatography–mass spectrometry (GC–MS). A total of 37 SPME; 19 HD; and 36 OS compounds were identified from the rhizome extract of Z. kerrii; with the major components being α-pinene; β-pinene; and terpinen-4-ol; respectively. From the flower extract; 16 SPME; 2 HD; and 10 OS compounds were identified; (E)-caryophyllene was found as a major compound by these techniques. The leaf extract exhibited 20 SPME; 13 HD; and 14 OS compounds; with α-pinene; (E)-caryophyllene; and n-hexadecanoic acid being the major compounds; respectively. The rhizome extract showed tyrosinase inhibitory activity of 71.60% and a total phenolic content of 22.4 mg gallic acid/g. The IC50 values of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays were 25.2 µg/mL and 153.6 µg/mL; respectively; and the ferric ion reducing antioxidant power (FRAP) assay value was 318.5 µM ascorbic acid equivalent (AAE)/g extract. The rhizome extract showed weak antibacterial activity. This extract showed no adverse toxicity in human keratinocyte (HaCaT) cell lines at concentrations below 200 µg/mL. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
Biological Activity of Thyme White Essential Oil Stabilized by Cellulose Nanocrystals
Biomolecules 2019, 9(12), 799; https://doi.org/10.3390/biom9120799 - 28 Nov 2019
Cited by 17 | Viewed by 1824
Abstract
Cellulose nanocrystals (CNCs) are produced by sulfonic acid hydrolysis and used for the formation of Pickering emulsion (PE) with thyme white essential oil (EO). Highly volatile and hydrophobic thyme white is encapsulated in PE by the amphiphilicity of CNCs. Encapsulation of EO in [...] Read more.
Cellulose nanocrystals (CNCs) are produced by sulfonic acid hydrolysis and used for the formation of Pickering emulsion (PE) with thyme white essential oil (EO). Highly volatile and hydrophobic thyme white is encapsulated in PE by the amphiphilicity of CNCs. Encapsulation of EO in a CNC shell is determined by confocal microscopy with distinct fluorescent labelling. The amount of CNC affects the size distribution of PE, and the emulsion stability is confirmed by rheological property. The antimicrobial activity of the emulsion is evaluated against Escherichia coli and Staphylococcus aureus by minimal inhibitory concentration and minimum bactericidal concentration. The larvicidal activity is also investigated against Aedes albopictus by dispersing the emulsion in water. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
The Antifungal Effect of Garlic Essential Oil on Phytophthora nicotianae and the Inhibitory Component Involved
Biomolecules 2019, 9(10), 632; https://doi.org/10.3390/biom9100632 - 21 Oct 2019
Cited by 18 | Viewed by 1686
Abstract
This study explored the chemical compositions of garlic essential oil, the inhibitory activity of garlic essential oil and diallyl disulfide (DADS) against Phytophthora nicotianae, and the effects on mycelial plasma membrane permeability and P. nicotianae inhibition. In total, 29 compounds were detected [...] Read more.
This study explored the chemical compositions of garlic essential oil, the inhibitory activity of garlic essential oil and diallyl disulfide (DADS) against Phytophthora nicotianae, and the effects on mycelial plasma membrane permeability and P. nicotianae inhibition. In total, 29 compounds were detected in garlic essential oil, of which 26 were detected by gas chromatography‒mass spectrometry (GC-MS) and 21 by headspace solid-phase microextraction (HS-SPME) GC-MS. DADS (60.12% and 19.09%) and trisulfide di-2-propenyl (14.18% and 17.98%) were the major components identified by HS-SPME GC-MS and GC-MS analysis, respectively. Half-inhibitory concentration (Ec50, antagonism) and minimum inhibitory concentration (MIC, fumigation) of DADS against P. nicotianae were 150.83 μL/L and 20 μL/L, respectively, while Ec50 of garlic essential oil was 1108.25 μL/L. Mycelial membrane permeability gradually increased in a concentration-dependent manner, and cell death increased at 450 μL/L DADS. Furthermore, DADS treatment significantly reduced the incidence of tobacco black shank and the number of P. nicotianae pathogens in rhizosphere soil. DADS also promoted root development of tobacco seedlings at low concentrations, which was inhibited at high concentrations. Therefore, DADS may play an important role in the antifungal effect against P. nicotianae by destroying mycelial cell membrane integrity, causing an increase in cell membrane permeability, and leading to cell death. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
Fumigant Antifungal Activity via Reactive Oxygen Species of Thymus vulgaris and Satureja hortensis Essential Oils and Constituents against Raffaelea quercus-mongolicae and Rhizoctonia solani
Biomolecules 2019, 9(10), 561; https://doi.org/10.3390/biom9100561 - 03 Oct 2019
Cited by 9 | Viewed by 1445
Abstract
In this study, the fumigant antifungal activity of 10 Lamiaceae plant essential oils was evaluated against two phytopathogenic fungi, Raffaelea quercus-mongolicae, and Rhizoctonia solani. Among the tested essential oils, thyme white (Thymus vulgaris) and summer savory (Satureja hortensis) essential [...] Read more.
In this study, the fumigant antifungal activity of 10 Lamiaceae plant essential oils was evaluated against two phytopathogenic fungi, Raffaelea quercus-mongolicae, and Rhizoctonia solani. Among the tested essential oils, thyme white (Thymus vulgaris) and summer savory (Satureja hortensis) essential oils exhibited the strongest fumigant antifungal activity against the phytopathogenic fungi. We analyzed the chemical composition of two active essential oils and tested the fumigant antifungal activities of the identified compounds. Among the tested compounds, thymol and carvacrol had potent fumigant antifungal activity. We observed reactive oxygen species (ROS) generation in two fungi treated with thymol and carvacrol. Confocal laser scanning microscopy images of fungi stained with propidium iodide showed that thymol and carvacrol disrupted fungal cell membranes. Our results indicated that ROS generated by thymol and carvacrol damaged the cell membrane of R. querqus-mongolicae and R. solani, causing cell death. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Article
Chemical Composition and Biological Activities of Artemisia pedemontana subsp. assoana Essential Oils and Hydrolate
Biomolecules 2019, 9(10), 558; https://doi.org/10.3390/biom9100558 - 02 Oct 2019
Cited by 14 | Viewed by 1620
Abstract
Given the importance of the genus Artemisia as a source of valuable natural products, the rare plant Artemisia pedemontana subspecies assoana, endemic to the Iberian Peninsula, has been experimentally cultivated in the greenhouse and aeroponically, to produce biomass for essential oil (EO) extraction. [...] Read more.
Given the importance of the genus Artemisia as a source of valuable natural products, the rare plant Artemisia pedemontana subspecies assoana, endemic to the Iberian Peninsula, has been experimentally cultivated in the greenhouse and aeroponically, to produce biomass for essential oil (EO) extraction. The chemical composition of the EOs was analyzed, and their plant protection (insects: Spodoptera littoralis, Rhopalosiphum padi, and Myzus persicae; plants: Lactuca sativa and Lolium perenne; fungi: Aspergillus niger; and nematode: Meloidogyne javanica) and antiparasitic (Trypanosoma cruzi, Phytomonas davidi, and antiplasmodial by the ferriprotoporphyrin biocrystallization inhibition test) properties were studied, in addition to the hydrolate by-product. The EOs showed a 1,8-cineole and camphor profile, with quantitative and qualitative chemical differences between the cultivation methods. These oils had moderate insect antifeedant, antifungal, and phytotoxic effects; were trypanocidel; and exhibited moderate phytomonacidal effects, while the hydrolate showed a strong nematicidal activity. Both EOs were similarly antifeedant; the EO from the greenhouse plants (flowering stage) was more biocidal (antifungal, nematicidal, and phytotoxic) than the EO from the aeroponic plants (growing stage), which was more antiparasitic. The major components of the oils (1,8-cineole and camphor), or their 1:1 combination, did not explain any of these effects. We can conclude that these EOs have potential applications as insect antifeedants, and as antifungal or antiparasitic agents, depending on the cultivation method, and that the hydrolate byproduct is a potent nematicidal. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Review

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Review
Essentials Oils from Brazilian Eugenia and Syzygium Species and Their Biological Activities
Biomolecules 2020, 10(8), 1155; https://doi.org/10.3390/biom10081155 - 06 Aug 2020
Cited by 11 | Viewed by 1483
Abstract
The Eugenia and Syzygium genera include approximately 1000 and 1800 species, respectively, and both belong to the Myrtaceae. Their species present economic and medicinal importance and pharmacological properties. Due to their chemical diversity and biological activity, we are reporting the essential oils of [...] Read more.
The Eugenia and Syzygium genera include approximately 1000 and 1800 species, respectively, and both belong to the Myrtaceae. Their species present economic and medicinal importance and pharmacological properties. Due to their chemical diversity and biological activity, we are reporting the essential oils of 48 species of these two genera, which grow in South America and found mainly in Brazil. Chemically, a total of 127 oil samples have been described and displayed a higher intraspecific and interspecific diversity for both Eugenia spp. and Syzygium spp., according to the site of collection or seasonality. The main volatile compounds were sesquiterpene hydrocarbons and oxygenated sesquiterpenes, mainly with caryophyllane and germacrane skeletons and monoterpenes of mostly the pinane type. The oils presented many biological activities, especially antimicrobial (antifungal and antibacterial), anticholinesterase, anticancer (breast, gastric, melanoma, prostate), antiprotozoal (Leishmania spp.), antioxidant, acaricidal, antinociceptive and anti-inflammatory. These studies can contribute to the rational and economic exploration of Eugenia and Syzygium species once they have been identified as potent natural and alternative sources to the production of new herbal medicines. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Review
Immunomodulatory Activities of Selected Essential Oils
by , and
Biomolecules 2020, 10(8), 1139; https://doi.org/10.3390/biom10081139 - 03 Aug 2020
Cited by 23 | Viewed by 2624
Abstract
Recently, the application of herbal medicine for the prevention and treatment of diseases has gained increasing attention. Essential oils (EOs) are generally known to exert various pharmacological effects, such as antiallergic, anticancer, anti-inflammatory, and immunomodulatory effects. Current literature involving in vitro and in [...] Read more.
Recently, the application of herbal medicine for the prevention and treatment of diseases has gained increasing attention. Essential oils (EOs) are generally known to exert various pharmacological effects, such as antiallergic, anticancer, anti-inflammatory, and immunomodulatory effects. Current literature involving in vitro and in vivo studies indicates the potential of various herbal essential oils as suitable immunomodulators for the alternative treatment of infectious or immune diseases. This review highlights the cellular effects induced by EOs, as well as the molecular impacts of EOs on cytokines, immunoglobulins, or regulatory pathways. The results reviewed in this article revealed a significant reduction in relevant proinflammatory cytokines, as well as induction of anti-inflammatory markers. Remarkably, very little clinical study data involving the immunomodulatory effects of EOs are available. Furthermore, several studies led to contradictory results, emphasizing the need for a multiapproach system to better characterize EOs. While immunomodulatory effects were reported, the toxic potential of EOs must be clearly considered in order to secure future applications. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Review
Bioactive Natural Compounds and Antioxidant Activity of Essential Oils from Spice Plants: New Findings and Potential Applications
Biomolecules 2020, 10(7), 988; https://doi.org/10.3390/biom10070988 - 01 Jul 2020
Cited by 62 | Viewed by 5499
Abstract
Spice plants have a great influence on world history. For centuries, different civilizations have used them to condiment the foods of kings and nobles and applied them as embalming preservatives, perfumes, cosmetics, and medicines in different regions of the world. In general, these [...] Read more.
Spice plants have a great influence on world history. For centuries, different civilizations have used them to condiment the foods of kings and nobles and applied them as embalming preservatives, perfumes, cosmetics, and medicines in different regions of the world. In general, these plants have formed the basis of traditional medicine and some of their derived substances have been utilized to treat different human diseases. Essential oils (EOs) obtained from these plants have been also used as therapeutic agents and have shown supportive uses in remedial practices. The discovery and development of bioactive compounds from these natural products, based on their traditional uses, play an important role in developing the scientific evidence of their potential pharmaceutical, cosmetic, and food applications. In the present review, using recent studies, we exhibit a general overview of the main aspects related to the importance of spice plants widely used in traditional medicine: Cinnamomum zeylanicum (true cinnamon), Mentha piperita (peppermint), Ocimum basilicum (basil), Origanum vulgare (oregano), Piper nigrum (black pepper), Rosmarinus officinalis (rosemary), and Thymus vulgaris (thyme); and we discuss new findings of the bioactive compounds obtained from their EOs, their potential applications, as well as their molecular mechanisms of action, focusing on their antioxidant activity. We also exhibit the main in vitro methods applied to determine the antioxidant activities of these natural products. Full article
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Review
Chemical Diversity and Biological Activities of Essential Oils from Licaria, Nectrandra and Ocotea Species (Lauraceae) with Occurrence in Brazilian Biomes
Biomolecules 2020, 10(6), 869; https://doi.org/10.3390/biom10060869 - 05 Jun 2020
Cited by 3 | Viewed by 1189
Abstract
Lauraceae species are known as excellent essential oil (EO) producers, and their taxa are distributed throughout the territory of Brazil. This study presents a systematic review of chemical composition, seasonal studies, occurrence of chemical profiles, and biological activities to EOs of species of [...] Read more.
Lauraceae species are known as excellent essential oil (EO) producers, and their taxa are distributed throughout the territory of Brazil. This study presents a systematic review of chemical composition, seasonal studies, occurrence of chemical profiles, and biological activities to EOs of species of Licaria, Nectandra, and Ocotea genera collected in different Brazilian biomes. Based on our survey, 39 species were studied, with a total of 86 oils extracted from seeds, leaves, stem barks, and twigs. The most representative geographic area in specimens was the Atlantic Forest (14 spp., 30 samples) followed by the Amazon (13 spp., 30 samples), Cerrado (6 spp., 14 samples), Pampa (4 spp., 10 samples), and Caatinga (2 spp., 2 samples) forests. The majority of compound classes identified in the oils were sesquiterpene hydrocarbons and oxygenated sesquiterpenoids. Among them, β-caryophyllene, germacrene D, bicyclogermacrene, caryophyllene oxide, α-bisabolol, and bicyclogermacrenal were the main constituents. Additionally, large amounts of phenylpropanoids and monoterpenes such as safrole, 6-methoxyelemicin, apiole, limonene, α-pinene, β-pinene, 1,8-cineole, and camphor were reported. Nectandra megatopomica showed considerable variation with the occurrence of fourteen chemical profiles according to seasonality and collection site. Several biological activities have been attributed to these oils, especially cytotoxic, antibacterial, antioxidant and antifungal potential, among other pharmacological applications. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Review
Essential Oils of Lamiaceae Family Plants as Antifungals
Biomolecules 2020, 10(1), 103; https://doi.org/10.3390/biom10010103 - 07 Jan 2020
Cited by 52 | Viewed by 3201
Abstract
The incidence of fungal infections has been steadily increasing in recent years. Systemic mycoses are characterized by the highest mortality. At the same time, the frequency of infections caused by drug-resistant strains and new pathogens e.g., Candida auris increases. An alternative to medicines [...] Read more.
The incidence of fungal infections has been steadily increasing in recent years. Systemic mycoses are characterized by the highest mortality. At the same time, the frequency of infections caused by drug-resistant strains and new pathogens e.g., Candida auris increases. An alternative to medicines may be essential oils, which can have a broad antimicrobial spectrum. Rich in the essential oils are plants from the Lamiaceae family. In this review are presented antifungal activities of essential oils from 72 Lamiaceae plants. More than half of these have good activity (minimum inhibitory concentrations (MICs) < 1000 µg/mL) against fungi. The best activity (MICs < 100) have essential oils from some species of the genera Clinopodium, Lavandula, Mentha, Thymbra, and Thymus. In some cases were observed significant discrepancies between different studies. In the review are also shown the most important compounds of described essential oils. To the chemical components most commonly found as the main ingredients include β-caryophyllene (41 plants), linalool (27 plants), limonene (26), β-pinene (25), 1,8-cineole (22), carvacrol (21), α-pinene (21), p-cymene (20), γ-terpinene (20), and thymol (20). Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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Review
Anticonvulsant Essential Oils and Their Relationship with Oxidative Stress in Epilepsy
Biomolecules 2019, 9(12), 835; https://doi.org/10.3390/biom9120835 - 06 Dec 2019
Cited by 19 | Viewed by 3094
Abstract
Epilepsy is a most disabling neurological disorder affecting all age groups. Among the various mechanisms that may result in epilepsy, neuronal hyperexcitability and oxidative injury produced by an excessive formation of free radicals may play a role in the development of this pathology. [...] Read more.
Epilepsy is a most disabling neurological disorder affecting all age groups. Among the various mechanisms that may result in epilepsy, neuronal hyperexcitability and oxidative injury produced by an excessive formation of free radicals may play a role in the development of this pathology. Therefore, new treatment approaches are needed to address resistant conditions that do not respond fully to current antiepileptic drugs. This paper reviews studies on the anticonvulsant activities of essential oils and their chemical constituents. Data from studies published from January 2011 to December 2018 was selected from the PubMed database for examination. The bioactivity of 19 essential oils and 16 constituents is described. Apiaceae and Lamiaceae were the most promising botanical families due to the largest number of reports about plant species from these families that produce anticonvulsant essential oils. Among the evaluated compounds, β-caryophyllene, borneol, eugenol and nerolidol were the constituents that presented antioxidant properties related to anticonvulsant action. These data show the potential of these natural products as health promoting agents and use against various types of seizure disorders. Their properties on oxidative stress may contribute to the control of this neurological condition. However, further studies on the toxicological profile and mechanism of action of essential oils are needed. Full article
(This article belongs to the Special Issue Perspectives of Essential Oils)
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