Biological Activities of Essential Oils: From Plant Chemoecology to Traditional Healing Systems
TL;DR: The paucity of in human studies limits the potential of essential oils as effective and safe phytotherapeutic agents, and more well-designed clinical trials are needed in order to ascertain the real efficacy and safety of these plant products.
Abstract: Essential oils are complex mixtures of hydrocarbons and their oxygenated derivatives arising from two different isoprenoid pathways. Essential oils are produced by glandular trichomes and other secretory structures, specialized secretory tissues mainly diffused onto the surface of plant organs, particularly flowers and leaves, thus exerting a pivotal ecological role in plant. In addition, essential oils have been used, since ancient times, in many different traditional healing systems all over the world, because of their biological activities. Many preclinical studies have documented antimicrobial, antioxidant, anti-inflammatory and anticancer activities of essential oils in a number of cell and animal models, also elucidating their mechanism of action and pharmacological targets, though the paucity of in human studies limits the potential of essential oils as effective and safe phytotherapeutic agents. More well-designed clinical trials are needed in order to ascertain the real efficacy and safety of these plant products.
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TL;DR: The present review illustrates the state‐of‐the‐art studies on the antimicrobial, antioxidant, and anticancer properties of CV.
Abstract: Carvacrol (CV) is a phenolic monoterpenoid found in essential oils of oregano (Origanum vulgare), thyme (Thymus vulgaris), pepperwort (Lepidium flavum), wild bergamot (Citrus aurantium bergamia), and other plants. Carvacrol possesses a wide range of bioactivities putatively useful for clinical applications such antimicrobial, antioxidant, and anticancer activities. Carvacrol antimicrobial activity is higher than that of other volatile compounds present in essential oils due to the presence of the free hydroxyl group, hydrophobicity, and the phenol moiety. The present review illustrates the state‐of‐the‐art studies on the antimicrobial, antioxidant, and anticancer properties of CV. It is particularly effective against food‐borne pathogens, including Escherichia coli, Salmonella, and Bacillus cereus. Carvacrol has high antioxidant activity and has been successfully used, mainly associated with thymol, as dietary phytoadditive to improve animal antioxidant status. The anticancer properties of CV have been reported in preclinical models of breast, liver, and lung carcinomas, acting on
proapoptotic processes. Besides the interesting properties of CV and the toxicological profile becoming definite, to date, human trials on CV are still lacking, and this largely impedes any conclusions of clinical relevance.
296 citations
TL;DR: Thymol exhibits antimicrobial, antioxidant, anticarcinogenesis, anti‐inflammatory, and antispasmodic activities, as well as a potential as a growth enhancer and immunomodulator; these bioactivities have been covered.
Abstract: Thymol is a naturally occurring phenol monoterpene derivative of cymene and isomer of carvacrol. Thymol (10-64%) is one of the major constituent of essential oils of thyme (Thymus vulgaris L., Lamiaceae), a medicinal plant with several therapeutic properties. This plant, native to Mediterranean regions, is commonly used as a culinary herb and also with a long history of use for different medicinal purposes. Nowadays, thymol and thyme present a wide range of functional possibilities in pharmacy, food, and cosmetic industry. The interest in the formulation of pharmaceuticals, nutraceuticals, and cosmeceuticals based on thymol is due to several studies that have evaluated the potential therapeutic uses of this compound for the treatment of disorders affecting the respiratory, nervous, and cardiovascular systems. Moreover, this compound also exhibits antimicrobial, antioxidant, anticarcinogenesis, anti-inflammatory, and antispasmodic activities, as well as a potential as a growth enhancer and immunomodulator. In the present review, these bioactivities have been covered because some of them can contribute to explain the ethnopharmacology of thymol and its main source, T. vulgaris. Other important aspects about thymol are discussed: its toxicity and bioavailability, metabolism, and distribution in animals and humans.
295 citations
TL;DR: This review summarizes the latest research studies about the most-active EOs that are known and used because of their antimicrobial properties and suggests that the antimicrobial activities of EOs are not preeminent for all strains.
Abstract: Herbs and the essential oils derived from them have been used from the beginning of human history for different purposes. Their beneficial properties have been applied to mask unpleasant odors, attract the attention of other people, add flavor and aroma properties to prepared dishes, perfumes, and cosmetics, etc. Herbs and essential oils (EOs) have also been used in medicine because of their biological properties, such as larvicidal action, analgesic and anti-inflammatory properties, antioxidant, fungicide, and antitumor activities, and many more. Many EOs exhibit antimicrobial properties, which is extremely important in fields of science and industry, such as medicine, agriculture, or cosmetology. Among the 250 EOs which are commercially available, about a dozen possess high antimicrobial potential. According to available papers and patents, EOs seem to be a potential alternative to synthetic compounds, especially because of the resistance that has been increasingly developed by pathogenic microorganisms. In this review we summarize the latest research studies about the most-active EOs that are known and used because of their antimicrobial properties. Finally, it is noteworthy that the antimicrobial activities of EOs are not preeminent for all strains. Further investigations should, thus, focus on targeting EOs and microorganisms.
254 citations
Cites background from "Biological Activities of Essential ..."
...5 mg/mL) were the most active against viral infections [96,97]....
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14 Nov 2019
TL;DR: The most prominent effects of α- and β-pinene are summarized, namely their cytogenetic, gastroprotective, anxiolytic, cytoprotective, anticonvulsant, and neuroprotective effects, as well as their effects against H2O2-stimulated oxidative stress, pancreatitis, stress- Stimulated hyperthermia, and pulpal pain.
Abstract: α- and β-pinene are well-known representatives of the monoterpenes group, and are found in many plants’ essential oils. A wide range of pharmacological activities have been reported, including antibiotic resistance modulation, anticoagulant, antitumor, antimicrobial, antimalarial, antioxidant, anti-inflammatory, anti-Leishmania, and analgesic effects. This article aims to summarize the most prominent effects of α- and β-pinene, namely their cytogenetic, gastroprotective, anxiolytic, cytoprotective, anticonvulsant, and neuroprotective effects, as well as their effects against H2O2-stimulated oxidative stress, pancreatitis, stress-stimulated hyperthermia, and pulpal pain. Finally, we will also discuss the bioavailability, administration, as well as their biological activity and clinical applications.
248 citations
TL;DR: The aim of this manuscript is to review the latest evidence regarding essential oils of oregano and their beneficial effects on health.
Abstract: Essential oils of oregano are widely recognized for their antimicrobial activity, as well as their antiviral and antifungal properties. Nevertheless, recent investigations have demonstrated that these compounds are also potent antioxidant, anti-inflammatory, antidiabetic and cancer suppressor agents. These properties of oregano essential oils are of potential interest to the food, cosmetic and pharmaceutical industries. The aim of this manuscript is to review the latest evidence regarding essential oils of oregano and their beneficial effects on health.
196 citations
Cites background from "Biological Activities of Essential ..."
...Different mechanisms such antioxidant, antimutagenic, antiproliferative, among others are responsible for their chemopreventive properties [155] The antiproliferative effects of EOs have been demonstrated in diverse cancer cell models through several pathways [156]....
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TL;DR: In vitro studies have demonstrated antibacterial activity of essential oils (EOs) against Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Shigella dysenteria, Bacillus cereus and Staphylococcus aureus at levels between 0.2 and 10 microl ml(-1).
9,091 citations
"Biological Activities of Essential ..." refers background in this paper
...This is due to their well-studied biological effects which include antimicrobial [201,202], phsycoactive [202,203], and antidiabetic [204] activities, among others....
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TL;DR: Findings suggest that, at least in part, the encountered beneficial effects of essential oils are due to prooxidant effects on the cellular level.
6,174 citations
"Biological Activities of Essential ..." refers background in this paper
...The cytotoxic properties of essential oils result from the complex interaction between the different classes of compounds such as phenols, aldehydes, ketones, alcohols, esters, ethers or hydrocarbons [29,32,33]....
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...Many of these molecules are found in low concentrations, while few of them are the main components that can represent up to 70% of total oil and will be the main responsible for the biological effects of the oil [29,30]....
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TL;DR: The volatile oils of black pepper, clove, and thyme exhibited considerable inhibitory effects against all the organisms under test while their major components demonstrated various degrees of growth inhibition.
Abstract: The volatile oils of black pepper [Piper nigrum L. (Piperaceae)], clove [Syzygium aromaticum (L.) Merr. & Perry (Myrtaceae)], geranium [Pelargonium graveolens L'Herit (Geraniaceae)], nutmeg [Myristica fragrans Houtt. (Myristicaceae), oregano [Origanum vulgare ssp. hirtum (Link) Letsw. (Lamiaceae)] and thyme [Thymus vulgaris L. (Lamiaceae)] were assessed for antibacterial activity against 25 different genera of bacteria. These included animal and plant pathogens, food poisoning and spoilage bacteria. The volatile oils exhibited considerable inhibitory effects against all the organisms under test while their major components demonstrated various degrees of growth inhibition.
4,014 citations
"Biological Activities of Essential ..." refers background in this paper
...The importance of the hydroxyl group in the phenolic structure was confirmed by the higher antimicrobial activity when carvacrol or eugenol was compared to their respective methyl ether [36,38]....
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...The presence of components with phenolic structures or aldehydes, such as thymol, carvacrol, eugenol, cinnamaldehyde and citral, were greatly active against microorganisms [36,37]....
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TL;DR: The relationship between butterflies and their food plants is investigated, the examination of patterns of interaction between two major groups of organisms with a close and evident ecological relationship, such as plants and herbivores.
Abstract: One of the least understood aspects of population biology is community evolution-the evolutionary interactions found among different kinds or organisms where exchange of genetic information among the kinds is assumed to be minimal or absent. Studies of community evolution have, in general, tended to be narrow in scope and to ignore the reciprocal aspects of these interactions. Indeed, one group of organisms is all too often viewed'as a kind of physical constant. In an extreme example a parasitologist might not consider the evolutionary history and responses of hosts, while a specialist in vertebrates might assume species of vertebrate parasites to be invariate entities. This viewpoint is one factor in the general lack of progress toward the understanding of organic diversification. One approach to what we would like to call coevolution is the examination of patterns of interaction between two major groups of organisms with a close and evident ecological relationship, such as plants and herbivores. The considerable amount of information available about butterflies and their food plants make them particularly suitable for these investigations. Further, recent detailed investigations have provided a relatively firm basis for statements about the phenetic relationships of the various higher groups of Papilionoidea (Ehrlich, 1958, and unpubl.). It should, however, be remembered that we are considering the butterflies as a model. They are only one of the many groups of herbivorous organisms coevolving with plants. In this paper, we shall investigate the relationship between butterflies and their food
3,932 citations
"Biological Activities of Essential ..." refers background in this paper
...The co-evolutionary hypothesis, as presented by Fraenkel, Erlich and others since the 1960s [3,4] proposes that plant-animal relationship is a fundamental factor for increasing biodiversity in both insects and plants [5] and that SMs are part of a chemical defense system that enables plants to defend themselves against predators, forcing them into adapting to these chemicals and becoming specialists, in a long-term chemo-evolutionary arm’s race....
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TL;DR: Recent evidence indicates that NF-κB and the signalling pathways that are involved in its activation are also important for tumour development.
Abstract: Nuclear factor of κB (NF-κB) is a sequence-specific transcription factor that is known to be involved in the inflammatory and innate immune responses. Although the importance of NF-κB in immunity is undisputed, recent evidence indicates that NF-κB and the signalling pathways that are involved in its activation are also important for tumour development. NF-κB should therefore receive as much attention from cancer researchers as it has already from immunologists.
2,436 citations