In vitro susceptibility of Trypanosoma brucei brucei to selected essential oils and their major components

Seseli tortuosum L. subsp. tortuosum Essential Oils and Their Principal Constituents as Anticancer Agents

Seseli tortuosum L. subsp. tortuosum, belonging to the Apiaceae family, is a species that grows in Europe, mainly in the Mediterranean regions. The history of its application in traditional medicine highlights its various biological properties. Trying to explore the phytochemistry and pharmacological aspects of this species, the essential oils (EOs) extracted from flowers, stems, and roots of a locally wild accession, never previously investigated, growing in Sicily, Italy, were investigated. The chemical composition of all EOs, obtained by the hydrodistillation method, was evaluated by GC-MS. The most abundant class of all investigated samples was that of monoterpene hydrocarbons (79.98-91.21%) with p-cymene, α-pinene, β-pinene, and β-ocimene as major compounds. These EOs, and their main components, were tested for their possible anticancer activity. Obtained data provided evidence that among the different EOs tested, at the dose of 100 μg/mL, those extracted from stems and roots were particularly effective, already at 24 h of treatment, in reducing the cell viability of 42% and 95%, respectively, in HCT116 colon cancer cell line. These EOs also exerted a remarkable cytotoxic effect that was accompanied by morphological changes represented by cell shrinkage as well as a reduction in residual cell population. Differently, modest effects were found when EOs extracted from flowers were tested in the same experimental conditions. The evaluation of the phytocompounds mainly represented in the EOs extracted from different parts of the plant and tested in a range of concentrations between 20 and 200 μg/mL, revealed that α-pinene, β-pinene, and p-cymene exerted only modest effects on cell viability. Differently, a remarkable effect was found when β-ocimene, the most abundant phytocomponent in EOs from roots, was tested on colon cancer cells. This phytocompound, among those identified in EOs from Seseli tortuosum L. subsp. tortuosum, was found to be the most effective in reducing colon cancer cell viability with IC50 = 64.52 μg/mL at 24 h of treatment. All together, these data suggest that β-ocimene could be responsible for the effects observed in colon cancer cells.

Chemistry and Bioactivity of Croton Essential Oils: Literature Survey and Croton hirtus from Vietnam

Using essential oils to control vectors, intermediate hosts, and disease-causing microorganisms is a promising approach. The genus Croton in the family Euphorbiaceae is a large genus, with many species containing large amounts of essential oils, however, essential oil studies are limited in terms of the number of Croton species investigated. In this work, the aerial parts of C. hirtus growing wild in Vietnam were collected and analyzed by gas chromatography/mass spectrometry (GC/MS). A total of 141 compounds were identified in C. hirtus essential oil, in which sesquiterpenoids dominated, comprising 95.4%, including the main components β-caryophyllene (32.8%), germacrene D (11.6%), β-elemene (9.1%), α-humulene (8.5%), and caryophyllene oxide (5.0%). The essential oil of C. hirtus showed very strong biological activities against the larvae of four mosquito species with 24 h LC50 values in the range of 15.38-78.27 μg/mL, against Physella acuta adults with a 48 h LC50 value of 10.09 μg/mL, and against ATCC microorganisms with MIC values in the range of 8-16 μg/mL. In order to provide a comparison with previous works, a literature survey on the chemical composition, mosquito larvicidal, molluscicidal, antiparasitic, and antimicrobial activities of essential oils of Croton species was conducted. Seventy-two references (seventy articles and one book) out of a total of two hundred and forty-four references related to the chemical composition and bioactivity of essential oils of Croton species were used for this paper. The essential oils of some Croton species were characterized by their phenylpropanoid compounds. The experimental results of this research and the survey of the literature showed that Croton essential oils have the potential to be used to control mosquito-borne and mollusk-borne diseases, as well as microbial infections. Research on unstudied Croton species is needed to search for species with high essential oil contents and excellent biological activities.

Anti-Trichomonas gallinae activity of essential oils and main compounds from Lamiaceae and Asteraceae plants

Trichomonas gallinae is a flagellated protozoan that parasitizes the upper digestive tract of various bird species and causes avian trichomonosis. The emergence of resistant strains to the standard treatment, based on nitroimidazoles, increases the need to find alternative therapies. In this study, 36 essential oils (EOs) from Lamiaceae and Asteraceae plant families were tested against T. gallinae trophozoites using the 3-(4,5-dimethylthiazol-2-yl-)-2,5-dipheniltetrazolium bromide (MTT) reduction assay. Among them, EOs from distinct species of Lamiaceae, including the genera Lavandula, Salvia, Thymus, Origanum, and Satureja were the ones reporting better anti-trichomonal activity, and were selected for further analysis, including chemical composition and in vitro assays. The chemical composition of the selected EOs was determined by gas chromatography followed by mass spectrometry and 19 pure compounds were tested against the protozoa, according to their higher abundance in the active EOs. Pure compounds which displayed the highest activity against T. gallinae trophozoites, ordered by highest to lowest activity, were α and β-thujones, camphene, β-pinene, linalyl acetate, thymol, 4-terpineol, γ-terpinene, α-pinene, p-cymene, D-fenchone and β-caryophyllene. A dose dependent effect was observed in most of the EOs and pure compounds tested. The toxicity test conducted in eukaryotic cell cultures with the anti-trichomonal active pure compounds showed that β-caryophyllene, camphene, α-pinene, and β-pinene were slightly toxic for Vero cells, and the selectivity index was calculated. Based on the anti-trichomonal activity and the absence of cytotoxicity results, natural products from Lamiaceae plants could be useful as alternative therapy against avian trichomonosis, mainly those containing linalyl acetate, thymol, 4-terpinenol, γ-terpinene, p-cymene and D-fenchone.

Evaluation of the In Vitro Antiparasitic Effect of the Essential Oil of Cymbopogon winterianus and Its Chemical Composition Analysis

Cymbopogon winterianus, known as “citronella grass”, is an important aromatic and medicinal tropical herbaceous plant. The essential oil of C. winterianus (EOCw) is popularly used to play an important role in improving human health due to its potential as a bioactive component. The present study aimed to identify the components of the essential oil of C. winterianus and verify its leishmanicidal and trypanocidal potential, as well as the cytotoxicity in mammalian cells, in vitro. The EOCw had geraniol (42.13%), citronellal (17.31%), and citronellol (16.91%) as major constituents. The essential oil only exhibited significant cytotoxicity in mammalian fibroblasts at concentrations greater than 250 μg/mL, while regarding antipromastigote and antiepimastigote activities, they presented values considered clinically relevant, since both had LC50 < 62.5 μg/mL. It can be concluded that this is a pioneer study on the potential of the essential oil of C. winterianus and its use against the parasites T. cruzi and L. brasiliensis, and its importance is also based on this fact. Additionally, according to the results, C. winterianus was effective in presenting values of clinical relevance and low toxicity and, therefore, an indicator of popular use.

Lavandula viridis L´Hér. Essential Oil Inhibits the Inflammatory Response in Macrophages Through Blockade of NF-KB Signaling Cascade

Lavandulaviridis L´Hér. is an endemic Iberian species with a high essential oil yield and a pleasant lemon scent. Despite these interesting features, this species remains unrecognized and poorly explored by the food and pharmaceutical industries. Nevertheless, it has been valued in traditional medicine being used against flu, circulatory problems and to relieve headaches. Since these disorders trigger inflammatory responses, it is relevant to determine the anti-inflammatory potential of L. viridis L´Hér. essential oil in an attempt to validate its traditional use and concomitantly to increment its industrial exploitation. Therefore, in the present study the chemical composition of this volatile extract as well as the effect on ROS production, inflammatory response and proteasome activity on LPS-stimulated macrophages were disclosed. Also, its safety profile on keratinocytes, hepatocytes and alveolar epithelial cells was depicted, envisioning a future human administration. The essential oil was characterized by high quantities of 1,8-cineole, camphor and α-pinene. From a pharmacological point of view, the essential oil showed a potent antioxidant effect and inhibited nitric oxide production through down-modulation of nuclear factor kappa B-dependent Nos2 transcription and consequently iNOS protein expression as well as a decrease in proteasomal activity. The anti-inflammatory activity was also evidenced by a strong inhibition of LPS-induced Il1b and Il6 transcriptions and downregulation of COX-2 levels. Overall, bioactive safe concentrations of L. viridis L´Hér. essential oil were disclosed, thus corroborating the traditional usage of this species and paving the way for the development of plant-based therapies.

Evaluation of Origanum vulgare Essential Oil and Its Active Ingredients as Potential Drugs for the Treatment of Toxoplasmosis

Toxoplasma gondii is a serious hazard to public health and animal husbandry. Due to the current dilemma of treatment of toxoplasmosis, it is urgent to find new anti-T. gondii drugs to treat toxoplasmosis. In this study, the anti-T. gondii activity of Origanum vulgare essential oil (Ov EO) was firstly studied, and then, carvanol (Ca), the main ingredient of Ov EO was evaluated using the MTT assay on human foreskin fibroblast (HFF) cells in vitro. The cytotoxicity was evaluated using the MTT assay on HFF cells. The CC₅₀ of Ov EO and Ca was 134.9 and 43.93 μg/ml, respectively. Both of them exhibited anti-parasitic activity, and inhibited the growth of T. gondii in a dose-dependent manner. For the inhibition effect, Ca was better than Ov EO at the same concentration, the IC₅₀ of Ov EO and Ca was 16.08 and 7.688 μg/ml, respectively. In addition, treatment with Ca, was found to change the morphology of T. gondii tachyzoites and made their shapes curl up. These results showed that Ca was able to inhibit the proliferation of T. gondii by reducing invasion, which may be due to its detrimental effect on the mobility of tachyzoites. Our results indicated that Ca could be a potential new and effective drug for treating toxoplasmosis.

In Vitro Evaluation of Lavandula angustifolia Essential Oil on Anti-Toxoplasma Activity

The current methods of treating toxoplasmosis have a number of side effects, and these therapies are only effective against the acute stage of the disease. Thus, development of new low toxicity and efficient anti-Toxoplasma drugs is extremely important. Natural products are important sources for screening new drugs; among them, essential oils (EOs) have efficacy in anti-bacterial, anti-inflammatory, anti-insect, and other aspects. In this study, 16 EOs were screened for their anti-T. gondii activity. Lavandula angustifolia essential oil (La EO)was found to have an anti-parasitic effect on T. gondii. The cytotoxicity of La EO was firstly evaluated using the MTT assay on human foreskin fibroblast (HFF) cells, and then the anti-T. gondii activity was evaluated by plaque assay. Finally, the invasion experiment and electron microscope observation were used to study the mechanism of La EO in anti-toxoplasma activity. The results indicated that the CC₅₀ of La EO was 4.48 mg/ml and that La EO had activity against T. gondii and the inhibition was in a dose-dependent manner under safe concentrations. La EO was able to reduce T. gondii invasion, which may be due to its detrimental effect on changes of the morphology of tachyzoites. These findings indicated that La EO could be a potential drug for treating toxoplasmosis.

GC-MS Characterization of Antibacterial, Antioxidant, and Antitrypanosomal Activity of Syzygium aromaticum Essential Oil and Eugenol

Syzygium aromaticum has a diversity of biological activities due to the chemical compounds found in its plant products such as total phenolic compounds and flavonoids. The present work describes the chemical analysis and antimicrobial, antioxidant, and antitrypanosomal activity of the essential oil of S. aromaticum. Eugenol (53.23%) as the major compound was verified by gas chromatography-mass spectrometry. S. aromaticum essential oil was more effective against S. aureus (MIC 50 μg/mL) than eugenol (MIC 250 μg/mL). Eugenol presented higher antioxidant activity than S. aromaticum essential oil, with an EC₅₀ of 12.66 and 78.98 µg/mL, respectively. S. aromaticum essential oil and eugenol exhibited Trypanosoma cruzi inhibitory activity, with IC₅₀ of 28.68 ± 1.073 and 31.97 ± 1.061 μg/mL against epimastigotes and IC₅₀ of 64.51 ± 1.658 and 45.73 ± 1.252 μg/mL against intracellular amastigotes, respectively. Both compounds presented low cytotoxicity, with S. aromaticum essential oil displaying 15.5-fold greater selectivity for the parasite than the cells. Nitrite levels in T. cruzi-stimulated cells were reduced by essential oil (47.01%; p = 0.002) and eugenol (48.05%; p = 0.003) treatment. The trypanocidal activity of S. aromaticum essential oil showed that it is reasonable to use it in future research in the search for new therapeutic alternatives for trypanosomiasis.

In vitro Anti-parasitic Activity of Pelargonium X. asperum Essential Oil Against Toxoplasma gondii

Toxoplasmosis is a global zoonotic disease, and one-third of the human population is chronically infected by Toxoplasma gondii. Due to the limited effectiveness and prominent side effects of the existing drugs, there is a dire need for the discovery of new therapeutic options in the treatment of toxoplasmosis. In this study, five essential oils (EO) were screened for their anti-parasitic activity against T. gondii. The cytotoxicity of essential oils was evaluated using the MTT assay on human foreskin fibroblast cells. The CC₅₀ values of Eucalyptus globulus EO, Cupressus sempervirens EO, Citrus aurantifolia EO, Melaleuca alternifolia EO, and Pelargonium X. asperum (Pa) EO were found to be 22.74, 7.25, 15.01, 6.26, and 4.77 mg/mL, respectively. Only PaEO exhibited anti-parasitic activity, and inhibited the growth of T. gondii in a dose-dependent manner. In addition, treatment with PaEO, was found to reduce the volume of T. gondii tachyzoites and make their membrane surfaces rough. These results showed that PaEO was able to inhibit the growth of T. gondii by reducing invasion, which may be due to its detrimental effect on the ability of tachyzoites to move. These findings suggest that PaEO could be a potential anti-T. gondii drug, which may facilitate the development of new and effective treatments against toxoplasmosis.

Trypanocidal Essential Oils: A Review

Trypanosomiases are diseases caused by parasitic protozoan trypanosomes of the genus Trypanosoma. In humans, this includes Chagas disease and African trypanosomiasis. There are few therapeutic options, and there is low efficacy to clinical treatment. Therefore, the search for new drugs for the trypanosomiasis is urgent. This review describes studies of the trypanocidal properties of essential oils, an important group of natural products widely found in several tropical countries. Seventy-seven plants were selected from literature for the trypanocidal activity of their essential oils. The main chemical constituents and mechanisms of action are also discussed. In vitro and in vivo experimental data show the therapeutic potential of these natural products for the treatment of infections caused by species of Trypanosoma.

Biological Evaluation of Essential Oils from Selected Medicinal Plants and Their Main Components against Phytomonas davidi (Kinetoplastea: Trypanosomatidae)

Eight essential oils (EOs) from selected medicinal plants have been tested for their activity against Phytomonas davidi, a plant trypanosomal parasite. In the present research, the EOs have been tested on promastigote forms of P. davidi ATCC^® 30287™ strain, along with their major components, both separately and in binary combinations, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. The EOs with the highest antipromastigote activity were from Origanum virens and Salvia lavandulifolia. Thymol and β-pinene were the most active pure compounds. The study of the activity of the pure compounds in combination indicated the existence of antagonistic and synergistic effects depending on the concentration tested. In general, the combinations at low concentrations favored the activity.

Antiprotozoal Activity of Turkish Origanum onites Essential Oil and Its Components

Essential oil of Origanum species is well known for antimicrobial activity, but only a few have been evaluated in narrow spectrum antiprotozoal assays. Herein, we assessed the antiprotozoal potential of Turkish Origanum onites L. oil and its major constituents against a panel of parasitic protozoa. The essential oil was obtained by hydrodistillation from the dried herbal parts of O. onites and analyzed by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography coupled with Mass Spectrometry (GC-MS). The in vitro activity of the oil and its major components were evaluated against Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani, and Plasmodium falciparum. The main component of the oil was identified as carvacrol (70.6%), followed by linalool (9.7%), p-cymene (7%), γ-terpinene (2.1%), and thymol (1.8%). The oil showed significant in vitro activity against T. b. rhodesiense (IC₅₀ 180 ng/mL), and moderate antileishmanial and antiplasmodial effects, without toxicity to mammalian cells. Carvacrol, thymol, and 10 additional abundant oil constituents were tested against the same panel; carvacrol and thymol retained the oil’s in vitro antiparasitic potency. In the T. b. brucei mouse model, thymol, but not carvacrol, extended the mean survival of animals. This study indicates the potential of the essential oil of O. onites and its constituents in the treatment of protozoal infections.

Supercritical Carbon Dioxide Antisolvent Fractionation for the Sustainable Concentration of Lavandula luisieri (Rozeira) Riv.- Mart Antimicrobial and Antioxidant Compounds and Comparison with Its Conventional Extracts

Lavandula stoechas subsp. luisieri is a Spanish subspecies from the Lamiaceae family. Its essential oil has been traditionally used for several medical applications though little is known about other extracts. Similar to many other studies aiming to obtain traditional plant extracts to be used in different applications, this work evaluated the antioxidant and antimicrobial activities of Lavandula luisieri extracts and the correlation with their composition. Traditional hydrodistillation and ethanolic maceration were used to obtain the essential oil and the maceration extract, respectively. A green and sustainable methodology was applied to the maceration extract that was under a Supercritical Antisolvent Fractionation process to obtain a fine solid enriched in rosmarinic acid and the terpenes oleanolic and ursolic acids. Antimicrobial activities of all extracts and pure identified compounds (rosmarinic and ursolic acids) were evaluated against five bacterial strains; Listeria monocytogenes, Enterococcus faecium, Staphylococcus aureus, Salmonella Typhimurium and Escherichia coli and were compared with the pure compounds identified, rosmarinic and ursolic acids. All strains were sensitive against L. luisieri essential oil. The solid product obtained from the supercritical process was concentrated in the identified actives compared to the maceration extract, which resulted in higher antimicrobial and DPPH scavenging activities. The supercritical sustainable process provided L. luisieri compounds, with retention of their antimicrobial and antioxidant activities, in a powder exemptof organic solvents with potential application in the clinical, food or cosmetic fields.

Active Essential Oils and Their Components in Use against Neglected Diseases and Arboviruses

The term neglected diseases refers to a group of infections caused by various classes of pathogens, including protozoa, viruses, bacteria, and helminths, most often affecting impoverished populations without adequate sanitation living in close contact with infectious vectors and domestic animals. The fact that these diseases were historically not considered priorities for pharmaceutical companies made the available treatments options obsolete, precarious, outdated, and in some cases nonexistent. The use of plants for medicinal, religious, and cosmetic purposes has a history dating back to the emergence of humanity. One of the principal fractions of chemical substances found in plants are essential oils (EOs). EOs consist of a mixture of volatile and hydrophobic secondary metabolites with marked odors, composed primarily of terpenes and phenylpropanoids. They have great commercial value and were widely used in traditional medicine, by phytotherapy practitioners, and in public health services for the treatment of several conditions, including neglected diseases. In addition to the recognized cytoprotective and antioxidative activities of many of these compounds, larvicidal, insecticidal, and antiparasitic activities have been associated with the induction of oxidative stress in parasites, increasing levels of nitric oxide in the infected host, reducing parasite resistance to reactive oxygen species, and increasing lipid peroxidation, ultimately leading to serious damage to cell membranes. The hydrophobicity of these compounds also allows them to cross the membranes of parasites as well as the blood-brain barrier, collaborating in combat at the second stage of several of these infections. Based on these considerations, the aim of this review was to present an update of the potential of EOs, their fractions, and their chemical constituents, against some neglected diseases, including American and African trypanosomiasis, leishmaniasis, and arboviruses, specially dengue.

Essential Oils of Five Baccharis Species: Investigations on the Chemical Composition and Biological Activities

This paper provides a comparative account of the essential oil chemical composition and biological activities of five Brazilian species of Baccharis (Asteraceae), namely B. microdonta, B. pauciflosculosa, B. punctulata, B. reticularioides, and B. sphenophylla. The chemical compositions of three species (B. pauciflosculosa, B. reticularioides, and B. sphenophylla) are reported for the first time. Analyses by GC/MS showed notable differences in the essential oil compositions of the five species. α-Pinene was observed in the highest concentration (24.50%) in B. reticularioides. Other major compounds included α-bisabolol (23.63%) in B. punctulata, spathulenol (24.74%) and kongol (22.22%) in B. microdonta, β-pinene (18.33%) and limonene (18.77%) in B. pauciflosculosa, and β-pinene (15.24%), limonene (14.33%), and spathulenol (13.15%) in B. sphenophylla. In vitro analyses for antimalarial, antitrypanosomal, and insecticidal activities were conducted for all of the species. B. microdonta and B. reticularioides showed good antitrypanosomal activities; B. sphenophylla showed insecticidal activities in fumigation bioassay against bed bugs; and B. pauciflosculosa, B. reticularioides, and B. sphenophylla exhibited moderate antimalarial activities. B. microdonta and B. punctulata showed cytotoxicity. The leaves and stems of all five species showed glandular trichomes and ducts as secretory structures. DNA barcoding successfully determined the main DNA sequences of the investigated species and enabled authenticating them.

The Current Status of the Pharmaceutical Potential of Juniperus L. Metabolites

Background: Plants and their derived natural compounds possess various biological and therapeutic properties, which turns them into an increasing topic of interest and research. Juniperus genus is diverse in species, with several traditional medicines reported, and rich in natural compounds with potential for development of new drugs. Methods: The research for this review were based in the Scopus and Web of Science databases using terms combining Juniperus, secondary metabolites names, and biological activities. This is not an exhaustive review of Juniperus compounds with biological activities, but rather a critical selection taking into account the following criteria: (i) studies involving the most recent methodologies for quantitative evaluation of biological activities; and (ii) the compounds with the highest number of studies published in the last four years. Results: From Juniperus species, several diterpenes, flavonoids, and one lignan were emphasized taking into account their level of activity against several targets. Antitumor activity is by far the most studied, being followed by antibacterial and antiviral activities. Deoxypodophyllotoxin and one dehydroabietic acid derivative appears to be the most promising lead compounds. Conclusions: This review demonstrates the Juniperus species value as a source of secondary metabolites with relevant pharmaceutical potential.