Achillea millefolium Essential Oil Mitigates Peptic Ulcer in Rats through Nrf2/HO-1 Pathway

Extreme ethanol ingestion is associated with developing gastric ulcers. Achillea millefolium (yarrow) is one of the most commonly used herbs with numerous proven pharmacological actions. The goal of the hereby investigation is to explore the gastroprotective action of yarrow essential oil against ethanol-induced gastric ulcers and to reveal the unexplored mechanisms. Rats were distributed into five groups (n = 6); the control group administered 10% Tween 20, orally, for two weeks; the ethanol group administered absolute ethanol (5 mL/kg) to prompt gastric ulcer on the last day of the experiment. Yarrow essential oil 100 or 200 mg/kg + ethanol groups pretreated with yarrow oil (100 or 200 mg/kg, respectively), orally, for two weeks prior to gastric ulcer induction by absolute ethanol. Lanso + ethanol group administered 20 mg/kg lansoprazole, orally, for two weeks prior to gastric ulcer induction by ethanol. Results of the current study showed that ethanol caused several macroscopic and microscopic alterations, amplified lipid peroxidation, pro-inflammatory cytokines, and apoptotic markers, as well as diminished PGE₂, NO, and antioxidant enzyme activities. On the other hand, animals pretreated with yarrow essential oil exhibited fewer macroscopic and microscopic modifications, reduced ulcer surface, and increased Alcian blue binding capacity, pH, and pepsin activity. In addition, yarrow essential oil groups exhibited reduced pro-inflammatory cytokines, apoptotic markers, and MDA, restored the PGE₂ and NO levels, and recovered the antioxidant enzyme activities. Ethanol escalated Nrf2 and HO-1 expressions, whereas pretreatment of yarrow essential oil caused further intensification in Nrf2 and HO-1. To conclude, the current study suggested yarrow essential oil as a gastroprotective agent against ethanol-induced gastric lesions. This gastroprotective effect could be related to the antioxidant, anti-inflammatory, and anti-apoptotic actions of the essential oil through the instigation of the Nrf2/HO-1 pathway.

Essential Oil of the Plants Growing in the Brazilian Amazon: Chemical Composition, Antioxidants, and Biological Applications

Essential oils are biosynthesized in the secondary metabolism of plants, and in their chemical composition, they can be identified different classes of compounds with potential antioxidant and biological applications. Over the years in the Amazon, several species of aromatic plants were discovered and used in traditional medicine. The literature has shown that essential oils extracted from amazon species have several biological activities, such as antioxidant, antibacterial, antifungal, cytotoxic, and antiprotozoal activities. These activities are related to the diversified chemical composition found in essential oils that, by synergism, favors its pharmacological action. In light of this vital importance, this study aimed at performing a review of the literature with particular emphasis on the chemical composition and biological activities in studies conducted with species collected in the Amazon, taking into consideration in particular the last 10 years of collection and research.

Effect of essential oils on Leishmania amazonensis: a systematic review

This systematic review investigated the evidence for the therapeutic potential of essential oils (EOs) against Leishmania amazonensis. We searched available scientific publications from 2005 to 2019 in the PubMed and Web of Science electronic databases, according to PRISMA statement. The search strategy utilized descriptors and free terms. The EOs effect of 35 species of plants identified in this systematic review study, 45.7% had half of the maximal inhibitory concentration (IC50) 10 < IC50 ⩽ 50 μg mL−1 and 14.3% had a 10 < IC50μg mL−1 for promastigote forms of L. amazonensis. EOs from Cymbopogon citratus species had the lowest IC50 (1.7 μg mL−1). Among the plant species analyzed for activity against intracellular amastigote forms of L. amazonensis, 39.4% had an IC50 10 < IC50 ⩽ 50 μg mL−1, and 33.3% had an IC50 10 < IC50μg mL−1. Aloysia gratissima EO showed the lowest IC50 (0.16 μg mL−1) for intracellular amastigotes. EOs of Chenopodium ambrosioides, Copaifera martii and Carapa guianensis, administered by the oral route, were effective in reducing parasitic load and lesion volume in L. amazonensis-infected BALB/c mice. EOs of Bixa orellana and C. ambrosioides were effective when administered intraperitoneally. Most of the studies analyzed in vitro and in vivo for the risk of bias showed moderate methodological quality. These results indicate a stimulus for the development of new phytotherapy drugs for leishmaniasis treatment.

Untargeted LC-MS metabolomic studies of Asteraceae species to discover inhibitors of Leishmania major dihydroorotate dehydrogenase

INTRODUCTION

Interesting data about the family Asteraceae as a new source of Leishmania major dihydroorotate dehydrogenase (LmDHODH) inhibitors are presented. This key macromolecular target for parasites causing neglected diseases catalyzes the fourth reaction of the de novo pyrimidine biosynthetic pathway, which takes part in major cell functions, including DNA and RNA biosynthesis.

OBJECTIVES

We aimed to (1) determine LmDHODH inhibitor candidates, revealing the type of chemistry underlying such bioactivity, and (2) predict the inhibitory potential of extracts from new untested plant species, classifying them as active or inactive based on their LC-MS based metabolic fingerprints.

METHODS

Extracts from 150 species were screened for the inhibition of LmDHODH, and untargeted UHPLC-(ESI)-HRMS metabolomic studies were carried out in combination with in silico approaches.

RESULTS

The IC₅₀ values determined for a subset of 59 species ranged from 148 µg mL^-1 to 9.4 mg mL^-1. Dereplication of the metabolic fingerprints allowed the identification of 48 metabolites. A reliable OPLS-DA model (R² > 0.9, Q² > 0.7, RMSE_CV < 0.3) indicated the inhibitor candidates; nine of these metabolites were identified using data from isolated chemical standards, one of which-4,5-di-O-E-caffeoylquinic acid (IC₅₀ 73 µM)-was capable of inhibiting LmDHODH. The predictive OPLS model was also effective, with 60% correct predictions for the test set.

CONCLUSION

Our approach was validated for (1) the discovery of LmDHODH inhibitors or interesting starting points for the optimization of new leishmanicides from Asteraceae species and (2) the prediction of extracts from untested species, classifying them as active or inactive.

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.

Ultrastructural and physiological changes induced by different stress conditions on the human parasite Trypanosoma cruzi

Trypanosoma cruzi is the etiological agent of Chagas disease. The life cycle of this protozoan parasite is digenetic because it alternates its different developmental forms through two hosts, a vector insect and a vertebrate host. As a result, the parasites are exposed to sudden and drastic environmental changes causing cellular stress. The stress response to some types of stress has been studied in T. cruzi, mainly at the molecular level; however, data about ultrastructure and physiological state of the cells in stress conditions are scarce or null. In this work, we analyzed the morphological, ultrastructural, and physiological changes produced on T. cruzi epimastigotes when they were exposed to acid, nutritional, heat, and oxidative stress. Clear morphological changes were observed, but the physiological conditions varied depending on the type of stress. The maintenance of the physiological state was severely affected by heat shock, acidic, nutritional, and oxidative stress. According to the surprising observed growth recovery after damage by stress alterations, different adaptations from the parasite to these harsh conditions were suggested. Particular cellular death pathways are discussed.

Effects of linalool and eugenol on the survival of Leishmania (L.) infantum chagasi within macrophages

The most commonly used drugs against visceral leishmaniasis are based on pentavalent antimonial compounds, which have played a fundamental role in therapy for over 70 years. However, the treatment is painful and has severe toxic side effects that can be fatal. Antimonial resistance is spreading and reaching alarming proportions. Linalool and eugenol have been shown to kill Leishmania (L.) amazonensis and Trypanosoma cruzi at low doses. In the present study, we demonstrate the effects of linalool and eugenol, components of essential oils, on Leishmania (L.) infantum chagasi, one of the causative agents of visceral leishmaniasis. We compared the effects of those compounds to the effects of glucantime, a positive control. In L. infantum chagasi killing assays, the LD₅₀ for eugenol was 220μg/ml, and that for linalool was 550μg/ml. L. infantum chagasi was added to cultures of peritoneal mouse macrophages for four hours prior to drug treatment. Eugenol and linalool significantly decreased the number of parasites within the macrophages. Eugenol and linalool enhanced the activities of the L. infantum chagasi protein kinases PKA and PKC. Linalool also decreased L. infantum chagasi oxygen consumption. In conclusion, both linalool and eugenol promoted a decrease in the proliferation and viability of L. infantum chagasi. These effects were more pronounced during the interaction between the parasites and peritoneal mouse macrophages.

Trypanocidal action of Lippia alba and Lippia origanoides essential oils against Trypanosoma evansi in vitro and in vivo used mice as experimental model

Parasitic diseases have an enormous health and economic impact and are a particular problem in tropical regions of the world. Disease caused by protozoa, such as trypanosomiasis, are the cause of most parasite related morbidity and mortality. Thus, the aim of this study was to verify the trypanocidal effectiveness of Lippia alba and Lippia origanoides against Trypanosoma evansi in vitro and in vivo. L. alba and L. origanoides were used in vitro on trypomastigotes at different concentrations (0.5, 1.0 and 2.0 %) and exposure times (0, 1, 3, 6 and 9 h). The three concentrations tested showed trypanocidal activity in vitro, completely eliminating the parasites in small concentration after 6 h of assay. In vivo tests were performed using mice as the experimental model. T. evansi infected mice were treated with L. alba and L. origanoides with dose of 1.5 mL kg^-1 during 5 days. These protocols did not provide curative efficacy, however the mice treated with L. origanoides showed a significant increase in the longevity when compared to control group. Active compounds present in essential oils, such as L. origanoides, may potentiate the treatment of trypanosomosis when associated with other trypanocidal drugs.

Evaluation of Antileishmanial Activity of Albaha Medicinal Plants against Leishmania amazonensis

Sixteen methanolic extracts obtained from thirteen plant species, selected either from ethnobotanical or chemotaxonomical data, were screened for their antileishmanial activity against Leishmania amazonensis. The cytotoxic activity against normal peritoneal macrophages from normal BALB/c mice was also determined. Eight extracts had IC50 values ranging from <12.5 to 37.8 µg/mL against promastigotes. Achillea biebersteinii flower, Euphorbia helioscopia, and Solanum incanum leaf extracts showed antileishmanial activities with IC50 between <12.5-26.9 µg/mL and acceptable selectivity indices of 8-5. The other leishmanicidal plant extracts, with IC50 ranging from 18.0 to 29.5 µg/mL, exhibited low selectivity indices.

Chemical composition, leishmanicidal and cytotoxic activities of the essential oils from Mangifera indica L. var. Rosa and Espada

The essential oils from Mangifera indica var. Rosa and Espada latex were obtained by hydrodistillation and analyzed using GC-FID and GC-MS. Twenty-seven components were identified. The main compound in the essential oil from M. indica var. Espada (EOMiE) was terpinolene (73.6%). The essential oil of M. indica var. Rosa (EOMiR) was characterized by high amounts of β-pinene (40.7%) and terpinolene (28.3%). In the test for leishmanicidal activity against promastigotes forms of L. amazonensis, EOMiR and EOMiE showed IC₅₀ (72 h) of 39.1 and 23.0 μg/mL, respectively. In macrophages, EOMiR and EOMiE showed CC₅₀ of 142.84 and 158.65 μg/mL, respectively. However, both were more specific to the parasite than macrophages, with values of selectivity index of 6.91 for EOMiE and 3.66 for EOMiR. The essential oils were evaluated for their cytotoxicity against the human tumor cells HEp-2, HT-29, NCI-H292, and HL-60. The EOMiR and EOMiE were most effective against the HL-60, with IC₅₀ values of 12.3 and 3.6 μg/mL, respectively. The results demonstrated that the essential oils of M. indica can destroy L. amazonensis and inhibit tumor cell growth. These findings contribute to the knowledge of the Brazilian biodiversity as a source of potential therapeutic agents.

Activity of Thymus capitellatus volatile extract, 1,8-cineole and borneol against Leishmania species

In the search for new leishmanicidal agents, Thymus capitellatus Hoffmanns. & Link (family Lamiaceae) volatile extract and its major compounds, 1,8-cineole and borneol, were tested against Leishmania infantum, Leishmania tropica and Leishmania major. Plant volatile extract (essential oil) was analysed by GC and GC-MS and the activity of essential oil on Leishmania promastigotes viability was assessed using tetrazolium-dye colorimetric method (MTT). The MTT test was also used to assess the cytotoxicity of essential oil on macrophages and bovine aortic endothelial cells. Effects on parasites were also analyzed by flow cytometry in order to assess mitochondrial transmembrane electrochemical gradient (JC-1), analyze phosphatidylserine externalization (annexin V-FITC, propidium iodide) and evaluate cell cycle (DNase-free, RNase, PI). Morphological and ultrastructural studies were performed by light, scanning and transmission electron microscopy. T. capitellatus volatile extract exhibited anti-parasite activity on Leishmania species, with IC50 values ranging from 35 to 62 μg/ml. However, major compounds 1,8-cineole and borneol did not showed biological activity suggesting that these monoterpenes are not responsible for the antileishmanial activity of T. capitellatus essential oil. Appearance of aberrant-shaped cells, mitochondrial swelling and autophagosomal structures were some of the ultrastructural alterations exhibited among treated promastigote cells. T. capitellatus promoted leishmanicidal effect by triggering a programmed cell death as evidenced by externalization of phosphatidylserine, loss of mitochondrial membrane potential, and cell-cycle arrest at the G(0)/G(1) phase. The volatile extract did not induced cytotoxic effects on mammalian cells. Taken together, these results suggest that T. capitellatus may represent a valuable source for therapeutic control of leishmaniasis in humans and animals.

In vitro cytocidal effects of the essential oil from Croton cajucara (red sacaca) and its major constituent 7- hydroxycalamenene against Leishmania chagasi

BACKGROUND

Visceral leishmaniasis is the most serious form of leishmaniasis and can be lethal if left untreated. Currently available treatments for these parasitic diseases are frequently associated to severe side effects. The leaves of Croton cajucara are used as an infusion in popular medicine to combat several diseases. Previous studies have demonstrated that the linalool-rich essential oil from C. cajucara (white sacaca) is extremely efficient against the tegumentary specie Leishmania amazonensis. In this study, we investigated the effects of the 7-hydroxycalamenene-rich essential oil from the leaves of C. cajucara (red sacaca) against Leishmania chagasi, as well as on the interaction of these parasites with host cells.

METHODS

Promastigotes were treated with different concentrations of the essential oil for determination of its minimum inhibitory concentration (MIC). In addition, the effects of the essential oil on parasite ultrastructure were analyzed by transmission electron microscopy. To evaluate its efficacy against infected cells, mouse peritoneal macrophages infected with L. chagasi promastigotes were treated with the inhibitory and sub-inhibitory concentrations of the essential oil.

RESULTS

The minimum inhibitory concentrations of the essential oil and its purified component 7-hydroxycalamenene against L. chagasi were 250 and 15.6 μg/mL, respectively. Transmission electron microscopy analysis revealed important nuclear and kinetoplastic alterations in L. chagasi promastigotes. Pre-treatment of macrophages and parasites with the essential oil reduced parasite/macrophage interaction by 52.8%, while it increased the production of nitric oxide by L. chagasi-infected macrophages by 80%.

CONCLUSION

These results indicate that the 7-hydroxycalamenene-rich essential oil from C. cajucara is a promising source of leishmanicidal compounds.

Recent advances in leishmaniasis treatment

About 1.5 million new cases of cutaneous leishmaniasis and 500,000 new cases of visceral leishmaniasis occur each year around the world. For over half a century, the clinical forms of the disease have been treated almost exclusively with pentavalent antimonial compounds. In this review, we describe the arsenal available for treating Leishmania infections, as well as recent advances from research on plants and synthetic compounds as source drugs for treating the disease. We also review some new drug-delivery systems for the development of novel chemotherapeutics. We observe that the pharmaceutical industry should employ its modern technologies, which could lead to better use of plants and their extracts, as well as to the development of synthetic and semi-synthetic compounds. New studies have highlighted some biopharmaceutical technologies in the design of the delivery strategy, such as nanoparticles, liposomes, cochleates, and non-specific lipid transfer proteins. These observations serve as a basis to indicate novel routes for the development and design of effective anti-Leishmania drugs.

Comparative Chemical, Cytotoxicity and Antileishmanial Properties of Essential Oils from Chenopodium ambrosioides

In countries where leishmaniasis is endemic, there are not very many treatment alternatives and most options have problems associated with their use. Plants and their natural products constitute good sources of interesting lead compounds that could be potentially active against Leishmania. Chenopodium ambrosioides is a plant that is widely used in popular medicine and its antiparasitic effects have been documented, including the antileishmanial potentialities of Chenopodium oil. The objective of this study was to determine the chemical composition, in-vitro cytotoxicity and antileishmanial activity of essential oils extracted from C. ambrosioides, which received different treatments prior to extraction. The chemical characterization by GC-MS of the three essential oil samples showed similar composition and the major components were α-terpinene (17.0-20.7%), p-cymene (20.2-21.1%) and ascaridole (30.5-47.1%). The essential oils exhibited similar antileishmanial activities against intracellular amastigote form, with IC50 values between 4.7 and 12.4 μg/mL. However, a lower cytotoxicity was displayed by the essential oil extracted from fresh green vegetable material, which was statistically different ( P < 0.05) from the other samples. This study demonstrated that the prior treatment of plant material did not interfere with the antiparasitic activity of essential oils from C. ambrosioides but did change their cytotoxicity, which should be taken into account in further studies.