Antileishmanial activity of a linalool-rich essential oil from Croton cajucara

Unveiling of the antileishmanial activities of Linalool loaded zinc oxide nanocomposite through its potent antioxidant and immunomodulatory effects

This study aimed to produce linalool loaded zinc oxide nanocomposite (LZNPs) and assess its in vitro and in vivo antileishmanial effects against Leishmania major. LZNPs was produced through the synthesis of an ethanolic solution containing polyvinyl alcohol. The average size of LZNPs was determined to be 105 nm. The findings indicated that LZNPs displayed significant (p < 0.01) antileishmanial effects on promastigotes and amastigotes. Following exposure of promastigotes to LZNPs, there was a notable rise in the percentage of early and late apoptotic cells from 9.0 to 57.2 %. The gene expression levels of iNOS, IFN-γ, and TNF-α in macrophages were upregulated in a dose-dependent approach following exposure to LZNPs. LZNPs alone and in conjunction with glucantime (Glu) resulted in a reduction in the diameter and parasite load of CL lesions in infected mice. Treatment of the CL-infected mice with LZNPs at 25 and 50 mg/kg mainly in combination with Glu-reduced the tissue level of malondialdehyde (MDA), increased both gene and protein expression of the antioxidant enzymes as well as raised the expression level of IFN-γ and IL-12 cytokines, whereas caused a significant reduction in the expression level of IL-4. The present study shows that LZNPs has potent antileishmanial effects and controls CL in a mice model through its antioxidant and immunomodulatory properties. Further investigation, especially in clinical trials, could explore the potential use of this nanocomposite in managing and treating CL.

Investigating the effects of essential oils and pure botanical compounds against Eimeria tenella in vitro

Essential oils (EO) and natural bioactive compounds are well-known antibacterial and anti-inflammatory factors; however, little is known about their anticoccidial activity and mode of action. EO deriving from basil (BEO), garlic (GAR), oregano (OEO), thyme (TEO), and their main bioactive compounds were investigated for their anticoccidial proprieties and compared to salinomycin (SAL) and amprolium (AMP) in vitro. The invasion of Eimeria tenella sporozoites was studied on 2 cell models: Madin-Darby Bovine Kidney (MDBK) cells and primary chicken epithelial cells (cIEC). Invasion efficiency was evaluated at 2 and 24 h postinfection (hpi) with counts of extracellular sporozoites and by detection of intracellular E. tenella DNA by PCR. Results show that at both timepoints, the EO were most effective in preventing the invasion of E. tenella with an average reduction of invasion at 24 hpi by 36% in cIEC and 55% in MDBK. The study also examined cytokine gene expression in cIEC at 24 hpi and found that AMP, BEO, OEO, TEO, carvacrol (CAR), and thymol (THY) significantly reduced interleukin (IL)8 expression, with CAR also reducing expression of IL1β and IL6 compared to the infected control. In addition, this work investigated the morphology of E. tenella sporozoites treated with anticoccidial drugs and EO using a scanning electron microscope. All the treatments induced morphological anomalies, characterized by a reduction of area, perimeter and length of sporozoites. SAL had a significant impact on altering sporozoite shape only at 24 h, whereas CAR and THY significantly compromised the morphology already at 2 hpi, compared to the untreated control. OEO and GAR showed the most significant alterations among all the treatments. The findings of this study highlight the potential of EO as an alternative to traditional anticoccidial drugs in controlling E. tenella invasion and in modulating primary immune response.

Study on Morphological Changes and Interference in the Development of Aedes aegypti Caused by Some Essential Oil Constituents

Dengue, Chikungunya and Zika are arboviruses, transmitted by the mosquito Aedes aegypti, that cause high mortality and serious health consequences in human populations. Efforts to control Ae. aegypti are important for preventing outbreaks of these diseases. Essential oil constituents are known to exhibit many activities, such as their use as larvicides. Given their potential, the present study aimed to characterize the larvicidal effect of dihydrojasmone, p-cymene, carvacrol, thymol, farnesol and nerolidol on the larvae of Ae. aegypti and their interference over the morphology of the mosquitos. The essential oil constituents were dissolved in dimethylsulfoxide at concentrations of 1-100 μg/mL and were applied in the breeding environment of third-stage larvae. The larvae from bioassays were fixed, dehydrated and embedded. Ultrathin sections were contrasted using 5% uranyl acetate and 1% lead citrate for observation through transmission electron microscopy. The oil with the highest larvicidal efficiency was found to be nerolidol, followed by farnesol, p-cymene, carvacrol, thymol and dihydrojasmone, with an LC50 of 11, 21, 23, 40, 45 and 66 µg/mL, respectively. The treated Ae. aegypti larvae caused alteration to the tegument or internal portions of larvae. The present study demonstrated which of these oils-dihydrojasmone, farnesol, thymol, p-cymene, carvacrol and nerolidol-have effective larvicidal activity.

Validated High-Performance Thin-Layer Chromatography-Mass Spectrometry Method and Stability Study of Linalool in the Volatile Oil of the Rhizomes of Homalomena aromatica Schott

Homalomena aromatica is a herb of tremendous ethnomedicinal importance to various communities residing in northeast India. In this study, a high-performance thin-layer chromatography-based densitometric method was developed for identification, quantification and stability study of linalool. Mass spectrometry was hyphenated to HPTLC for streamlining the method. The stability of linalool was studied by analyzing the effect of acid, base, UV, sunlight, thermal stress and H2O2 on linalool. The chromatographic plates were developed to a height of 70 mm in toluene:ethyl acetate solvent system at a ratio of 9.5:0.5 and visualized with p-anisaldehyde reagent. The developed method was found to be precise, accurate and reproducible according to International Conference on Harmonization guidelines, and compact bands of linalool were observed at Rf of 0.351 ± 0.001. The content of linalool in the volatile oil of H. aromatica was found to be 58% v/v. By application of the hyphenated MS technique, linalool was identified at m/z 137, (M + H)+. It was observed that acidic pH has the highest effect on linalool with a percentage degradation of 65. The developed method can be used in the analysis and quality control of herbal materials and volatile oils containing linalool and quality control of rhizomes of H. aromatica.

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.

Antileishmanial Effects of Bunium Persicum Crude Extract, Essential Oil, and Cuminaldehyde on Leishmania Major: In Silico and In Vitro Properties

PURPOSE

Cuminaldehyde (CA), an oxidized aldehyde monoterpene, is a major essential oil component in cumin seeds, which has shown different promising medical effects. In this study, we comprehensively evaluated the antileishmanial potential of Bunium persicum (Boiss) B. Fedtsch (Apiaceae) and one of its main essential oil constituents, CA, focus on the mechanisms of action.

METHODS

We used a molecular docking approach to examine the capability of CA for binding to IL-12P40 and TNF-α. The colorimetric assay was performed to assess the effect of B. persicum crude extract, essential oil, and CA, against Leishmania major promastigotes and intracellular amastigotes. The expression of IFN-γ, IL-12P40, TNF-α, and IL-10 genes was detected using quantitative real-time polymerase chain reaction qPCR.

RESULTS

Docking analyses in the current study indicated CA binds to IL-12P40 and TNF-α. These products were safe, extremely antileishmanial, and significantly promoted Th1-related cytokines (IFN-γ, IL-12P40, TNF-α), while downregulating the Th2 phenotype (IL-10).

CONCLUSION

Cumin essential oil and its major component, CA, possessed powerful antileishmanial activity. The primary mechanism of activity involves an immunomodulatory role toward Th1 cytokine response. Therefore, cumin essential oil and CA deserve further explorations as promising medications for treating leishmaniasis.

Antifungal Effect and Inhibition of the Virulence Mechanism of D-Limonene against Candida parapsilosis

Yeasts from the Candida parapsilosis complex are clinically relevant due to their high virulence and pathogenicity potential, such as adherence to epithelial cells and emission of filamentous structures, as well as their low susceptibility to antifungals. D-limonene, a natural compound, emerges as a promising alternative with previously described antibacterial, antiparasitic, and antifungal activity; however, its mechanisms of action and antivirulence activity against C. parapsilosis complex species have not been elucidated. Therefore, in the present study, we aimed to evaluate the antifungal and antivirulence action, as well as the mechanism of action of D-limonene against isolates from this complex. D-limonene exhibited relevant antifungal activity against C. parapsilosis complex yeasts, as well as excellent antivirulence activity by inhibiting yeast morphogenesis and adherence to the human epithelium. Furthermore, the apoptotic mechanism induced by this compound, which is not induced by oxidative stress, represents an important target for the development of new antifungal drugs.

Chemical Composition and In Vitro and In Silico Antileishmanial Evaluation of the Essential Oil from Croton linearis Jacq. Stems

Croton linearis Jacq. is an aromatic shrub that has been utilized in traditional medicine in the Bahamas, Jamaica, and Cuba. Recent studies have revealed the antiprotozoal potential of its leaves. The present work is aimed to identify the volatile constituents of essential oil from the stems of C. linearis (CLS-EO) and evaluate its in vitro antileishmanial activity. In addition, an in silico study of the molecular interactions was performed using molecular docking. A gas chromatographic-mass spectrometric analysis of CLS-EO identified 1,8-cineole (27.8%), α-pinene (11.1%), cis-sabinene (8.1%), p-cymene (5.7%), α-terpineol (4.4%), epi-γ-eudesmol (4.2%), linalool (3.9%), and terpinen-4-ol (2.6%) as major constituents. The evaluation of antileishmanial activity showed that CLS-EO has good activity on both parasite forms (IC_{50Promastigote} = 21.4 ± 0.1 μg/mL; IC_50Amastigote = 18.9 ± 0.3 μg/mL), with a CC₅₀ of 49.0 ± 5.0 μg/mL on peritoneal macrophages from BALB/c mice (selectivity index = 2 and 3 using the promastigote and amastigote results). Molecular docking showed good binding of epi-γ-eudesmol with different target enzymes of Leishmania. This study is the first report of the chemical composition and anti-Leishmania evaluation of CLS-EO. These findings provide support for further studies of the antileishmanial effect of this product.

Sustainable Extraction, Chemical Profile, Cytotoxic and Antileishmanial Activities In-Vitro of Some Citrus Species Leaves Essential Oils

Anti-leishmanial drugs extracted from natural sources have not been sufficiently explored in the literature. Until now, leishmaniasis treatments have been limited to synthetic and expensive drugs. This study investigated, for the first time, the anti-leishmanial efficacy of essential oils (EOs) from the leaves of Citrus species (C. sinensis, C. limon, and C. clementina). Essential oils were extracted from three species by solvent free microwave extraction (SFME); in addition, lemon oil was also isolated by hydro-distillation (HD). These were investigated using gas chromatography coupled with mass spectrometry (GC–MS) and evaluated against Leishmania species, namely Leishmania major and Leishmania infantum, using a mitochondrial tetrazolium test (MTT) assay. The chemical compositions of Citrus limon EOs obtained by HD and SFME showed some differences. The identified peaks of C. limon (SFME) represented 93.96%, where linalool was the major peak (44.21%), followed by sabinene (14.22%) and ocimene (6.09%). While the hydro-distilled oil of C. limon contained geranial (30.08%), limonene (27.09%), and neral (22.87%) in the identified peaks (96.67%). The identified components of C. clementina leaves oil (68.54%) showed twenty-six compounds, where the predominant compound was geranial (42.40%), followed by neral (26.79%) and limonene (14.48%). However, 89.82% C. sinensis oil was identified, where the major peaks were for neral (27.52%), linalool (25.83%), and geranial (23.44%). HD oil of lemon showed the highest activity against L. major, with moderate toxicity on murine macrophage (RAW 264.7) cells, and possessed the best selectivity index on both Leishmanial species (SI: 3.68; 6.38), followed by C. clementina oil and C. limon using SFME (0.9 ± 0.29, 1.03 ± 0.27, and 1.13 ± 0.3), respectively. C. clementina oil induced the greatest activity on Leishmania infantum, followed by HD lemon and SFME lemon oils (0.32 ± 0.18, 0.52 ± 0.15, and 0.57 ± 0.09, respectively) when compared to Amphotericin B (0.80 ± 0.18 and 0.23 ± 0.13) as a positive control, on both species, respectively. Our study suggests a potent anti-leishmanial activity of lemon oil (HD) on L. major, followed by C. clementina. With the same potency on L. infantum shown by C. clementina oil, followed by HD lemon oil. This effect could be attributed to the major compounds of limonene, citral, and neral, as well as the synergistic effect of other different compounds. These observations could be a starting point for the building of new anti-leishmanial drugs from natural origins, and which combine different EOs containing Citrus cultivars.

In silico and in vitro antileishmanial effects of gamma-terpinene: Multifunctional modes of action

INTRODUCTION

Leishmaniasis denotes a significant health challenge worldwide with no ultimate treatment. The current study investigated the biological effects of gamma-terpinene (GT) on Leishmania major in putative antileishmanial action, cytotoxicity, apoptosis induction, gene expression alteration, antioxidant activity, hemolysis, and ROS generation.

METHODS

GT and meglumine antimoniate (MA) were probed alone and in combination (GT/MA) for their anti-leishmanial potentials using the MTT biochemical colorimetric assay and a model macrophage cell. In addition, their immunomodulatory properties were assessed by analyzing their effect on the transcription of cytokines related to Th1 and Th2 responses. GT and MA, alone and in combination, were also assessed for their potential to alter metacaspase gene expression in L. major promastigotes by real-time RT-PCR. The hemolytic potential of GT and MA-treated promastigotes were also measured by routine UV absorbance reading. Electrophoresis on agarose gel was employed to analyze genomic DNA fragmentation.

RESULTS

GT demonstrated notable dose-dependent antileishmanial effects towards promastigotes and amastigotes of L. major. The IC₅₀ values for GT against L. major promastigotes and amastigotes were 46.76 mM and 25.89 mM, respectively. GT was considerably safer towards murine macrophages than L. major amastigotes with an SI value of 3.17. Transcriptional expression of iNOS, JAK-1, Interleukin (IL-10), and TGF-β was meaningfully decreased, while the levels of metacaspase mRNA were increased. Results also confirmed GT antioxidant activities. Also, increased levels of intracellular ROS were observed upon treatment of promastigotes with GT. The gel electrophoresis result indicated slight DNA fragmentation in the treated promastigotes by both drugs. A weak hemolytic effect was also observed for GT.

CONCLUSION

The results demonstrated that GT showed potent activity against L. major stages. It seems that its mechanism of action involves representing an immunomodulatory role towards upregulation of iNOS and JAK-1, while downregulation of IL-10 and TGF- β. Moreover, GT has an antioxidative potential and exerts its action through activating macrophages to kill the organism. Further in vivo and clinical studies are essential to explore its effect in future programs.

An Update on Natural Antileishmanial Treatment Options from Plants, Fungi and Algae

Efficient drugs for the treatment of leishmaniasis, which is classified as a neglected tropical disease, are sought for. This review covers potential drug candidates from natural plant, fungus and algae sources, which were described over the last six years. The identification of these natural antileishmanials often based on the knowledge of traditional medicines. Crucial insights into the activities of these natural remedies against Leishmania parasites and against infections caused by these parasites in laboratory animals or patients are provided and compared with selected former active examples published more than six years ago. In addition, immuno-modulatory natural antileishmanials and recent developments on combination therapies including natural products and approved antileishmanials are discussed. The described natural products revealed promising data warranting further efforts on the discovery and development of new antileishmanials based on patterns from nature.

Antiviral, Antibacterial, Antifungal, and Antiparasitic Properties of Propolis: A Review

Propolis is a complex phytocompound made from resinous and balsamic material harvested by bees from flowers, branches, pollen, and tree exudates. Humans have used propolis therapeutically for centuries. The aim of this article is to provide comprehensive review of the antiviral, antibacterial, antifungal, and antiparasitic properties of propolis. The mechanisms of action of propolis are discussed. There are two distinct impacts with regards to antimicrobial and anti-parasitic properties of propolis, on the pathogens and on the host. With regards to the pathogens, propolis acts by disrupting the ability of the pathogens to invade the host cells by forming a physical barrier and inhibiting enzymes and proteins needed for invasion into the host cells. Propolis also inhibits the replication process of the pathogens. Moreover, propolis inhibits the metabolic processes of the pathogens by disrupting cellular organelles and components responsible for energy production. With regard to the host, propolis functions as an immunomodulator. It upregulates the innate immunity and modulates the inflammatory signaling pathways. Propolis also helps maintain the host's cellular antioxidant status. More importantly, a small number of human clinical trials have demonstrated the efficacy and the safety of propolis as an adjuvant therapy for pathogenic infections.

The Potential of Traditional Knowledge to Develop Effective Medicines for the Treatment of Leishmaniasis

Leishmaniasis is a neglected tropical disease that affects people living in tropical and subtropical areas of the world. There are few therapeutic options for treating this infectious disease, and available drugs induce severe side effects in patients. Different communities have limited access to hospital facilities, as well as classical treatment of leishmaniasis; therefore, they use local natural products as alternative medicines to treat this infectious disease. The present work performed a bibliographic survey worldwide to record plants used by traditional communities to treat leishmaniasis, as well as the uses and peculiarities associated with each plant, which can guide future studies regarding the characterization of new drugs to treat leishmaniasis. A bibliographic survey performed in the PubMed and Scopus databases retrieved 294 articles related to traditional knowledge, medicinal plants and leishmaniasis; however, only 20 were selected based on the traditional use of plants to treat leishmaniasis. Considering such studies, 378 quotes referring to 292 plants (216 species and 76 genera) that have been used to treat leishmaniasis were recorded, which could be grouped into 89 different families. A broad discussion has been presented regarding the most frequent families, including Fabaceae (27 quotes), Araceae (23), Solanaceae and Asteraceae (22 each). Among the available data in the 378 quotes, it was observed that the parts of the plants most frequently used in local medicine were leaves (42.3% of recipes), applied topically (74.6%) and fresh poultices (17.2%). The contribution of Latin America to studies enrolling ethnopharmacological indications to treat leishmaniasis was evident. Of the 292 plants registered, 79 were tested against Leishmania sp. Future studies on leishmanicidal activity could be guided by the 292 plants presented in this study, mainly the five species Carica papaya L. (Caricaceae), Cedrela odorata L. (Meliaceae), Copaifera paupera (Herzog) Dwyer (Fabaceae), Musa × paradisiaca L. (Musaceae), and Nicotiana tabacum L. (Solanaceae), since they are the most frequently cited in articles and by traditional communities.

Monoterpenes: Essential Oil Components with Valuable Features

Medicinal plants have a wide range of secondary metabolites including monoterpene. These volatile compounds are the main components of essential oils, belonging to the isoprenoid group and possessing valuable features for plants and humans. This review provides comprehensive information on chemical structures and classification of monoterpenes. It describes their biosynthesis pathways and introduces plant families and species rich in noteworthy monoterpenes. Bio-activities, pharmacological and pesticide effects as well as their mechanism of action are reported. Applications of these compounds in various industries are also included.

Determination of chemical structure and anti-Trypanosoma cruzi activity of extracts from the roots of Lonchocarpus cultratus (Vell.) A.M.G. Azevedo & H.C. Lima

Trypanosoma cruzi is the agent of Chagas disease, an infection that affects around 8 million people worldwide. The search for new anti-T. cruzi drugs are relevant, mainly because the treatment of this disease is limited to two drugs. The objective of this study was to investigate the trypanocidal and cytotoxic activity and elucidate the chemical profile of extracts from the roots of the Lonchocarpus cultratus. Roots from L. cultratus were submitted to successive extractions with hexane, dichloromethane, and methanol, resulting in LCH, LCD, and LCM extracts, respectively. Characterization of extracts was done using 1H-RMN, 13C-RMN, CC and TLC. Treatment of T. cruzi forms (epimastigotes, trypomastigotes, and amastigotes) with crescent concentrations of LCH, LCD, and LCM was done for 72, 48, and 48 h, respectively. After this, the percentage of inhibition and IC50/LC50 were calculated. Benznidazole was used as a positive control. Murine macrophages were treated with different concentrations of both extracts for 48 h, and after, the cellular viability was determined by the MTT method and CC50 was calculated. The chalcones derricin and lonchocarpine were identified in the hexane extract, and for the first time in the genus Lonchocarpus, the presence of a dihydrolonchocarpine derivative was observed. Other chalcones such as isocordoin and erioschalcone B were detected in the dichloromethane extract. The dichloromethane extract showed higher activity against all tested forms of T. cruzi than the other two extracts, with IC50 values of 10.98, 2.42, and 0.83 µg/mL, respectively; these values are very close to those of benznidazole. Although the dichloromethane extract presented a cytotoxic effect against mammalian cells, it showed selectivity against amastigotes. The methanolic extract showed the lowest anti-T. cruzi activity but was non-toxic to peritoneal murine macrophages. Thus, the genus Lonchocarpus had demonstrated in the past action against epimastigotes forms of T. cruzi but is the first time that the activity against infective forms is showed, which leading to further studies with in vivo tests.

Aniba rosaeodora (Var. amazonica Ducke) Essential Oil: Chemical Composition, Antibacterial, Antioxidant and Antitrypanosomal Activity

Aniba rosaeodora is one of the most widely used plants in the perfumery industry, being used as medicinal plant in the Brazilian Amazon. This work aimed to evaluate the chemical composition of A. rosaeodora essential oil and its biological activities. A. rosaeodora essential oil presented linalool (93.60%) as its major compound. The A. rosaeodora essential oil and linalool showed activity against all the bacteria strains tested, standard strains and marine environment bacteria, with the lower minimum inhibitory concentration being observed for S. aureus. An efficient antioxidant activity of A. rosaeodora essential oil and linalool (EC₅₀: 15.46 and 6.78 µg/mL, respectively) was evidenced by the inhibition of the 2,2-azinobis- (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical. The antitrypanosomal activity of A. rosaeodora essential oil and linalool was observed at high concentrations against epimatigote forms (inhibitory concentration for 50% of parasites (IC₅₀): 150.5 ± 1.08 and 198.6 ± 1.12 µg/mL, respectively), and even higher against intracellular amastigotes of T. cruzi (IC₅₀: 911.6 ± 1.15 and 249.6 ± 1.18 µg/mL, respectively). Both A. rosaeodora essential oil and linalool did not exhibit a cytotoxic effect in BALB/c peritoneal macrophages, and both reduced nitrite levels in unstimulated cells revealing a potential effect in NO production. These data revealed the pharmacological potential of A. rosaeodora essential oil and linalool, encouraging further studies.

Ethanolic extract of Croton blanchetianus Ball induces mitochondrial defects in Leishmania amazonensis promastigotes

Leishmaniasis is a neglected disease caused by Leishmania. Chemotherapy remains the mainstay for leishmaniasis control; however, available drugs fail to provide a parasitological cure, and are associated with high toxicity. Natural products are promising leads for the development of novel chemotherapeutics against leishmaniasis. This work investigated the leishmanicidal properties of ethanolic extract of Croton blanchetianus (EECb) on Leishmania infantum and Leishmania amazonensis, and found that EECb, rich in terpenic compounds, was active against promastigote and amastigote forms of both Leishmania species. Leishmania infantum promastigotes and amastigotes presented IC50 values of 208.6 and 8.8 μg/mL, respectively, whereas Leishmania amazonensis promastigotes and amastigotes presented IC50 values of 73.6 and 3.1 μg/mL, respectively. Promastigotes exposed to EECb (100 µg/mL) had their body cellular volume reduced and altered to a round shape, and the flagellum was duplicated, suggesting that EECb may interfere with the process of cytokinesis, which could be the cause of the decline in the parasite multiplication rate. Regarding possible EECb targets, a marked depolarization of the mitochondrial membrane potential was observed. No cytotoxic effects of EECb were observed in murine macrophages at concentrations below 60 µg/mL, and the CC50 obtained was 83.8 µg/mL. Thus, the present results indicated that EECb had effective and selective effects against Leishmania infantum and Leishmania amazonensis, and that these effects appeared to be mediated by mitochondrial dysfunction.

Salvia ceratophylla L. from South of Jordan: new insights on chemical composition and biological activities

In Jordan, Salvia ceratophylla L. is traditionally used in the treatment of cancer, microbial infections, and urinary disorders. This study aimed: (1) to chemically characterize S. ceratophylla essential oil (EO) from South Jordan, by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS); and (2) to evaluate in vitro the cytotoxic, anti-inflammatory, and antiprotozoal activities of the EO, it's predominant components, and the hexane (A), ethyl acetate (B), methanol (C) and crude-methanol extracts (D). The analysis revealed that the EO has 71 compounds, with linalool (54.8%) as main constituent. Only the hexane extract (A) showed some cytotoxic activity against SK-MEL, KB, BT-549, SK-OV-3, LLC-PK1 and VERO cells lines with IC₅₀ between 60 and > 100 µg/mL. The EO inhibited NO production (IC₅₀ 90 µg/mL) and NF-κB activity (IC₅₀ 38 µg/mL). The extracts A, B, and D inhibited NO production and NF- κB activity with IC₅₀ between 32 and 150 µg/mL. Linalool considerably inhibited NO production (IC₅₀ 18 µg/mL). The extracts tested did not exhibit antileishmanial activity. Regarding antitrypanosomal activity, the EO exhibited significant results with IC₅₀ 2.65 µg/mL. In conclusion, Jordan S. ceratophylla EO represents a rich source of linalool and bears a promising therapeutic potential for further antitrypanosomal drug development.

Dual transcriptome analysis reveals differential gene expression modulation influenced by Leishmania arginase and host genetic background

The outcome of Leishmania infection is strongly influenced by the host's genetic background. BALB/c mice are susceptible to Leishmania infection, while C57BL/6 mice show discrete resistance. Central to the fate of the infection is the availability of l-arginine and the related metabolic processes in the host and parasite. Depending on l-arginine availability, nitric oxide synthase 2 (NOS2) of the host cell produces nitric oxide (NO) controlling the parasite growth. On the other hand, Leishmania can also use host l-arginine for the production of polyamines through its own arginase activity, thus favouring parasite replication. Considering RNA-seq data, we analysed the dual modulation of host and parasite gene expression of BALB/c or C57BL/6 mouse bone marrow-derived macrophages (BMDMs) after 4 h of infection with Leishmania amazonensis wild-type (La-WT) or L. amazonensis arginase knockout (La-arg-). We identified 12 641 host transcripts and 8282 parasite transcripts by alignment analysis with the respective Mus musculus and L. mexicana genomes. The comparison of BALB/c_La-arg-versus BALB/c_La-WT revealed 233 modulated transcripts, with most related to the immune response and some related to the amino acid transporters and l-arginine metabolism. In contrast, the comparison of C57BL/6_La-arg-vs. C57BL/6_La-WT revealed only 30 modulated transcripts, including some related to the immune response but none related to amino acid transport or l-arginine metabolism. The transcriptome profiles of the intracellular amastigote revealed 94 modulated transcripts in the comparison of La-arg-_BALB/c vs. La-WT_BALB/c and 45 modulated transcripts in the comparison of La-arg-_C57BL/6 vs. La-WT_C57BL/6. Taken together, our data present new insights into the impact of parasite arginase activity on the orchestration of the host gene expression modulation, including in the immune response and amino acid transport and metabolism, mainly in susceptible BALB/c-infected macrophages. Moreover, we show how parasite arginase activity affects parasite gene expression modulation, including amino acid uptake and amastin expression.

Recent researches in effective antileishmanial herbal compounds: narrative review

Leishmaniasis are neglected diseases and a public health problem; they are caused by protozoan species belonging to the genus Leishmania and mostly influences the poor populations in many developing countries. The lack of effective medications, and an approved vaccine, high toxicity and life-threatening side effects and many cases of drug resistance reported in different countries have resulted in the necessity to discover new, efficient, inexpensive, and safe antileishmanial compounds with less or no toxicity. This increase in consumer demand of natural herbal-derived plant extracts as alternative medicines continues despite the low scientific information to establish their efficacy and safety profiles. Various studies have been conducted so far concerning the application of herbal medicines for the treatment of leishmaniasis, but research on relatively effective and low toxic substances is still needed. In this review, we have summarized recent developments and reported studies concerning about herbal and naturally derived therapeutics in the treatment of leishmaniasis, conducted by several researchers worldwide. Some of these medical herbs with promising results have undergone prospective clinical researches, but many others have either not yet been explored. Recent articles described these medical herbs and their active and important molecules, including quinones, phenolic derivatives, lignans, tannins, terpenes, and oxylipins. We searched ISI Web of Science, PubMed, SID, Scholar, Scopus, and Science Direct, and articles published up to 2019 were included. The keywords of leishmaniasis and some words associated with herbal medicines and natural products were used in our search. This review can serve as a quick reference database for researchers.

A Review on Applications and Uses of Thymus in the Food Industry

Thyme is one of the most important medicinal plants because of its ethnopharmacological relevance and high content of bioactive compounds. This review focuses particularly on thyme as an alternative natural antioxidant and antimicrobial with potential use in the food industry. This is in line with the preferences of the current consumer, who demands healthier and more natural products. Different studies have concluded that the use of thyme increases stability and reduces lipid oxidation during the shelf-life period of foods (meat, meat products, milk, fish or fish products), which makes thyme a promising source of natural additives. Despite these findings, the use of Thymus extracts or essential oils as natural additives in foods is reduced in comparison with other natural preservative extracts. This review provides an overview of the most important information on the positive effect of the bioactive compounds of thyme and its uses as a preservative in foods, taking into account its origin (from plants, plant extracts or essential oils).

Chemical Compositions of Commercial Essential Oils From Coriandrum sativum Fruits and Aerial Parts

Coriander and cilantro, the fruit and herb of Coriandrum sativum, are popular additives in various cuisines worldwide. The essential oils derived from coriander and cilantro are also popular and have shown some remarkable biological properties and health benefits. In this report, we have analyzed the essential oil compositions of 19 commercial coriander and 28 commercial cilantro essential oil samples by gas chromatography–mass spectrometry (GC–MS) techniques. In addition, 5 coriander and 4 cilantro commercial essential oil samples were analyzed by chiral GC–MS. Commercial coriander essential oil is dominated by linalool (62.2%-76.7%) with lesser quantities of α-pinene (0.3%-11.4%), γ-terpinene (0.6%-11.6%), and camphor (0.0%-5.5%). Commercial cilantro essential oil is composed largely of (2 E)-decenal (16.0%-46.6%), linalool (11.8%-29.8%), (2 E)-decen-1-ol (0.0%-24.7%), decanal (5.2%-18.7%), (2 E)-dodecenal (4.1%-8.7%), and 1-decanol (0.0%-9.5%). The enantiomeric distribution of linalool was 87% (+)-linalool:13% (−)-linalool in both coriander and cilantro essential oils, while α-pinene was 93% (+):7% (−) in coriander, 90% (+):10% (−) in cilantro; and (+)-camphor:(−)-camphor was 13%:87% in both essential oils. Chiral GC–MS analysis was able to detect an adulterated coriander essential oil sample. The data provided in this study serves to establish a baseline for future evaluations of these essential oils as well as a screen for authenticity or adulteration.

An investigation of the antileishmanial properties of semi-synthetic saponins

Leishmaniasis is a neglected tropical disease caused by insect-vector borne protozoan parasites of the, Leishmania species. Whilst infection threatens and affects millions of the global poor, vaccines are absent and drug therapy limited. Extensive efforts have recently been made to discover new leads from small molecule synthetic compound libraries held by industry; however, the number of new chemical entities identified and entering development as anti-leishmanials has been very low. This has led to increased interest in the possibility of discovering naturally derived compounds with potent antileishmanial activity which may be developed towards clinical applications. Plant-derived triterpenoid and steroidal saponins have long been considered as anti-microbials and here we describe an investigation of a library of 137 natural (9) and semi-synthetic saponins (128) for activity against Leishmania mexicana, a causative agent of cutaneous leishmaniasis. The triterpenoid sapogenin, hederagenin, readily obtained in large quantities from Hedera helix (common ivy), was converted into a range of 128 derivatives. These semi-synthetic compounds, as well as saponins isolated from ivy, were examined with a phenotypic screening approach to identify potent and selective anti-leishmanial hits. This led to the identification of 12 compounds, including the natural saponin gypsogenin, demonstrating high potency (ED50 < 10.5 μM) against axenic L. mexicana amastigotes, the mammalian pathogenic form. One of these, hederagenin disuccinate, was sufficiently non-toxic to the macrophage host cell to facilitate further analyses, selectivity index (SI) > 10. Whilst this was not active in an infected cell model, the anti-leishmanial properties of hederagenin-derivatives have been demonstrated, and the possibility of improving the selectivity of natural hederagenin through chemical modification has been established.

Biogenic metal nanoparticles as a potential class of antileishmanial agents: mechanisms and molecular targets

Leishmaniasis, a category 1 disease, has remained neglected for decades, and therefore, has developed into a severe health problem worldwide. Unfortunately, the available antileishmanial drugs are limited, and the parasites have shown an inevitable resistance toward most of these drugs. All these factors pose a barrier to control the parasite at present. Hence, new strategies are needed to develop more effective and less toxic nanomedicines that could treat and manage the Leishmania parasite. One of these effective strategies is to construct nanometals with biologically active molecules that could possess dynamic antileishmanial activities with desirable biocompatibility. In this review paper, antileishmanial potencies of different metal nanoparticles, with particular emphasis on biogenic metal nanoparticles from 2011 to 2019, are summarized. The mechanisms by which metal-based nanomedicines kill Leishmania are also discussed.

Differential immune response modulation in early Leishmania amazonensis infection of BALB/c and C57BL/6 macrophages based on transcriptome profiles

The fate of Leishmania infection can be strongly influenced by the host genetic background. In this work, we describe gene expression modulation of the immune system based on dual global transcriptome profiles of bone marrow-derived macrophages (BMDMs) from BALB/c and C57BL/6 mice infected with Leishmania amazonensis. A total of 12,641 host transcripts were identified according to the alignment to the Mus musculus genome. Differentially expressed genes (DEGs) profiling revealed a differential modulation of the basal genetic background between the two hosts independent of L. amazonensis infection. In addition, in response to early L. amazonensis infection, 10 genes were modulated in infected BALB/c vs. non-infected BALB/c macrophages; and 127 genes were modulated in infected C57BL/6 vs. non-infected C57BL/6 macrophages. These modulated genes appeared to be related to the main immune response processes, such as recognition, antigen presentation, costimulation and proliferation. The distinct gene expression was correlated with the susceptibility and resistance to infection of each host. Furthermore, upon comparing the DEGs in BMDMs vs. peritoneal macrophages, we observed no differences in the gene expression patterns of Jun, Fcgr1 and Il1b, suggesting a similar activation trends of transcription factor binding, recognition and phagocytosis, as well as the proinflammatory cytokine production in response to early L. amazonensis infection. Analysis of the DEG profile of the parasite revealed only one DEG among the 8,282 transcripts, indicating that parasite gene expression in early infection does not depend on the host genetic background.

Quantification of Nitric Oxide and Reactive Oxygen Species in Leishmania-infected J774A.1 Macrophages as a Response to the in vitro treatment with a Natural Product Compound

Leishmaniasis is a parasitic disease caused by the obligatory intracellular protozoa Leishmania spp. Current therapeutic options are limited and thus, drug discovery against leishmaniasis is very important. Nevertheless, there is a great difficulty to develop therapeutic strategies against the disease because the parasite deploys various mechanisms to evade the immune system and multiply inside the host. Among the main factors of the immunity that are recruited to confront the Leishmania infection are the macrophages (MΦs) that produce effector molecules such as Nitric Oxide (NO) and Reactive Oxygen Species (ROS). Therefore, efficient drug agents should combine the antileishmanial effect of these gaseous transmitters along with the enhancement of the host's adaptive immunity. In the quest of therapeutic alternatives, natural products have been extensively studied and are considered as candidate antileishmanial agents since they exhibit specific properties in modulating the host's immune response towards an effective anti-leishmanial cell-mediated immunity capable to eliminate parasitic dissemination. In the current protocol, Leishmania-infected MΦs (J774A.1 cell line) that have been treated with various increasing concentrations of a natural compound, are tested for the production of the aforementioned molecules. In order to detect NO production, we employ the Griess colorimetric nitrite assay and quantification relies on the construction of an accurate standard curve using appropriate standards of known concentration. ROS detection and quantification is achieved by flow cytometry and relies on the use of carboxy-H₂DCFDA, an indicator that converts to a fluorescent form when interacts with ROS molecules.

Medicinal Properties of Cannabinoids, Terpenes, and Flavonoids in Cannabis, and Benefits in Migraine, Headache, and Pain: An Update on Current Evidence and Cannabis Science

BACKGROUND

Comprehensive literature reviews of historical perspectives and evidence supporting cannabis/cannabinoids in the treatment of pain, including migraine and headache, with associated neurobiological mechanisms of pain modulation have been well described. Most of the existing literature reports on the cannabinoids Δ⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD), or cannabis in general. There are many cannabis strains that vary widely in the composition of cannabinoids, terpenes, flavonoids, and other compounds. These components work synergistically to produce wide variations in benefits, side effects, and strain characteristics. Knowledge of the individual medicinal properties of the cannabinoids, terpenes, and flavonoids is necessary to cross-breed strains to obtain optimal standardized synergistic compositions. This will enable targeting individual symptoms and/or diseases, including migraine, headache, and pain.

OBJECTIVE

Review the medical literature for the use of cannabis/cannabinoids in the treatment of migraine, headache, facial pain, and other chronic pain syndromes, and for supporting evidence of a potential role in combatting the opioid epidemic. Review the medical literature involving major and minor cannabinoids, primary and secondary terpenes, and flavonoids that underlie the synergistic entourage effects of cannabis. Summarize the individual medicinal benefits of these substances, including analgesic and anti-inflammatory properties.

CONCLUSION

There is accumulating evidence for various therapeutic benefits of cannabis/cannabinoids, especially in the treatment of pain, which may also apply to the treatment of migraine and headache. There is also supporting evidence that cannabis may assist in opioid detoxification and weaning, thus making it a potential weapon in battling the opioid epidemic. Cannabis science is a rapidly evolving medical sector and industry with increasingly regulated production standards. Further research is anticipated to optimize breeding of strain-specific synergistic ratios of cannabinoids, terpenes, and other phytochemicals for predictable user effects, characteristics, and improved symptom and disease-targeted therapies.

Mining for natural product antileishmanials in a fungal extract library

Leishmaniasis is a Neglected Tropical Disease caused by the insect-vector borne protozoan parasite, Leishmania species. Infection affects millions of the World's poorest, however vaccines are absent and drug therapy limited. Recently, public-private partnerships have developed to identify new modes of controlling leishmaniasis. Most of these collaborative efforts have relied upon the small molecule synthetic compound libraries held by industry, but the number of New Chemical Entities (NCE) identified and entering development as antileishmanials has been very low. In light of this, here we describe a public-private effort to identify natural products with activity against Leishmania mexicana, a causative agent of cutaneous leishmanaisis (CL). Utilising Hypha Discovery's fungal extract library which is rich in small molecule (<500 molecular weight) secondary metabolites, we undertook an iterative phenotypic screening and fractionation approach to identify potent and selective antileishmanial hits. This led to the identification of a novel oxidised bisabolane sesquiterpene which demonstrated activity in an infected cell model and was shown to disrupt multiple processes using a metabolomic approach. In addition, and importantly, this study also sets a precedent for new approaches for CL drug discovery.

The protective and therapeutic effects of linalool against doxorubicin-induced cardiotoxicity in Wistar albino rats

The aim of the present study was to determine the protective and therapeutic effects of linalool (LIN) against doxorubicin (DOX)-induced cardiotoxicity in rats histologically and biochemically. In experiments, 64 male Wistar albino rats were randomly divided into eight groups ( n = 8). These groups were control (C) (0.9% saline solution), DOX (20 mg/kg DOX), LIN50 (50 mg/kg LIN), LIN100 (100 mg/kg LIN), DOX + LIN50 (20 mg/kg DOX and 50 mg/kg LIN), DOX + LIN100 (20 mg/kg DOX and 100 mg/kg LIN), LIN50 + DOX (50 mg/kg LIN and 20 mg/kg DOX), and LIN100 + DOX (100 mg/kg LIN and 20 mg/kg DOX). It was determined that necrosis and extensive inflammatory cell infiltration were observed in the DOX group. It was determined that histopathological changes significantly decreased in groups treated with LIN after DOX administration. While the caspase-3 immunostaining was highly evident in DOX group apoptotic cells ( p < 0.001, for all), the intensity of caspase-3 immunostaining in the treatment groups decreased ( p < 0.05). While DOX administration resulted in a significant increase in malondialdehyde (MDA) levels and plasma Creatine kinase (CK) and lactate dehydrogenase (LDH) levels in cardiac tissue when compared to the C groups, it was observed that DOX + LIN administration led to a significant decrease in MDA, plasma CK and LDH levels and a significant increase in glutathione (GSH), superoxide dismutase, and catalase enzyme levels. Finally, it was concluded that DOX led to heavy cardiotoxicity and DOX + LIN administration could remove cardiomyopathy symptoms.

In-Vitro Evaluation of 52 Commercially-Available Essential Oils Against Leishmania amazonensis

Leishmaniasis is a neglected tropical disease caused by members of the Leishmania genus of parasitic protozoa that cause different clinical manifestations of the disease. Current treatment options for the cutaneous disease are limited due to severe side effects, poor efficacy, limited availability or accessibility, and developing resistance. Essential oils may provide low cost and readily available treatment options for leishmaniasis. In-vitro screening of a collection of 52 commercially available essential oils has been carried out against promastigotes of Leishmania amazonensis. In addition, cytotoxicity has been determined for the essential oils against mouse peritoneal macrophages in order to determine selectivity. Promising essential oils were further screened against intracellular L. amazonensis amastigotes. Three essential oils showed notable antileishmanial activities: frankincense (Boswellia spp.), coriander (Coriandrum sativum L.), and wintergreen (Gualtheria fragrantissima Wall.) with IC₅₀ values against the amastigotes of 22.1 ± 4.2, 19.1 ± 0.7, and 22.2 ± 3.5 μg/mL and a selectivity of 2, 7, and 6, respectively. These essential oils could be explored as topical treatment options for cutaneous leishmaniasis.

Clerodane Diterpenes from Croton Species: Distribution and a Compilation of their 13C NMR Spectral Data

The present work is a review of the literature of clerodane diterpenes from Croton species. It contains a compilation of 13C NMR data of 83 of these diterpenoids and their biological activities. This review covers a period from 1969 to October 2005 and 224 references are cited.

Chemical Composition and Cruzain Inhibitory Activity of Croton draco Bark Essential Oil from Monteverde, Costa Rica

American trypanosomiasis, Chagas disease, is a great cause of human morbidity and mortality in the Neotropics. Although there is currently no effective treatment for this parasitic disease, a number of potential biochemical targets have been identified, including the cysteine protease cruzain. Croton draco Cham. & Schldl. (Euphorbiaceae), commonly known as sangre de drago, is used in traditional medicine for a number of maladies. In this study, Croton draco bark essential oil has been shown to inhibit the activity of cruzain. The bark oil has been analyzed by GC-MS and the major components found to be β-caryophyllene (31.9%), caryophyllene oxide (22.0%), 1,8-cineole (6.2%), and α-humulene (5.6%). The major components have been tested for cruzain inhibitory activity, but show minimal activity, so it is not clear if the activity of Croton draco bark oil is due to a synergistic effect of the essential oil components or due to very active minor components. Croton draco bark oil has also been tested for cytotoxic activity against a panel of human tumor cell lines, but shows little activity.

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.

Nigella sativa oil entrapped polycaprolactone nanoparticles for leishmaniasis treatment

This study is the first to investigate the antileishmanial activities of Nigella sativa oil (NSO) entrapped poly-ɛ-caprolactone (PCL) nanoparticles on Leishmania infantum promastigotes and amastigotes in vitro. NSO molecules with variable initial doses of 50, 100, 150, and 200 mg were successfully encapsulated into PCL nanoparticles identified as formulations NSO1, NSO2, NSO3, and NSO4, respectively. This process was characterised by scanning electron microscope, dynamic light scattering, Fourier transform infrared, encapsulation efficiency measurements, and release profile evaluations. The resulting synthetised nanoparticles had sizes ranging between 200 and 390 nm. PCL nanoparticles encapsulated 98% to 80% of initial doses of NSO and after incubation released approximately 85% of entrapped oil molecules after 288 h. All investigated formulations demonstrated strong antileishmanial effects on L. infantum promastigotes by inhibiting up to 90% of parasites after 192 h. The tested formulations decreased infection indexes of macrophages in a range between 2.4- and 4.1-fold in contrast to control, thus indicating the strong anti-amastigote activities of NSO encapsulated PCL nanoparticles. Furthermore, NSO-loaded PCL nanoparticles showed immunomodulatory effects by increasing produced nitric oxide amounts within macrophages by 2-3.5-fold in contrast to use of free oil. The obtained data showed significant antileishmanial effects of NSO encapsulated PCL nanoparticles on L. infantum promastigotes and amastigotes.

Benzimidazole derivatives endowed with potent antileishmanial activity

Two sets of benzimidazole derivatives were synthesised and tested in vitro for activity against promastigotes of Leishmania tropica and L. infantum. Most of the tested compounds resulted active against both Leishmania species, with IC50 values in the low micromolar/sub-micromolar range. Among the set of 2-(long chain)alkyl benzimidazoles, whose heterocyclic head was quaternised, compound 8 resulted about 100-/200-fold more potent than miltefosine, even if the selectivity index (SI) versus HMEC-1 cells was only moderately improved. In the set of 2-benzyl and 2-phenyl benzimidazoles, bearing a basic side chain in position 1, compound 28 (2-(4-chlorobenzyl)-1-lupinyl-5-trifluoromethylbenzimidazole) was 12-/7-fold more potent than miltefosine, but exhibited a further improved SI. Therefore, compounds 8 and 28 represent interesting hit compounds, susceptible of structural modification to improve their safety profiles.

Identification of highly effective antitrypanosomal compounds in essential oils from the Apiaceae family

The Apiaceae family encompasses aromatic plants of economic importance employed in foodstuffs, beverages, perfumery, pharmaceuticals and cosmetics. Apiaceae are rich sources of essential oils because of the wealth of secretory structures (ducts and vittae) they are endowed with. The Apiaceae essential oils are available on an industrial level because of the wide cultivation and disposability of the bulky material from which they are extracted as well as their relatively cheap price. In the fight against protozoal infections, essential oils may represent new therapeutic options. In the present work, we focused on a panel of nine Apiaceae species (Siler montanum, Sison amomum, Echinophora spinosa, Kundmannia sicula, Crithmum maritimum, Helosciadium nodiflorum, Pimpinella anisum, Heracleum sphondylium and Trachyspermum ammi) and their essential oils as a model for the identification of trypanocidal compounds to be used as alternative/integrative therapies in the treatment of Human African trypanosomiasis (HAT) and as starting material for drug design. The evaluation of inhibitory effects of the Apiaceae essential oils against Trypanosoma brucei showed that some of them (E. spinosa, S. amomum, C. maritimum and H. nodiflorum) were active, with EC₅₀ in the range 2.7-10.7 μg/mL. Most of these oils were selective against T. brucei, except the one from C. maritimum that was highly selective against the BALB/3T3 mammalian cells. Testing nine characteristic individual components (α-pinene, sabinene, α-phellandrene, p-cymene, limonene, β-ocimene, γ-terpinene, terpinolene, and myristicin) of these oils, we showed that some of them had much higher selectivity than the oils themselves. Terpinolene was particularly active with an EC₅₀ value of 0.035 μg/mL (0.26 µM) and a selectivity index (SI) of 180. Four other compounds with EC₅₀ in the range 1.0-6.0 μg/mL (7.4-44 µM) had also good SI: α-pinene (>100), β-ocimene (>91), limonene (>18) and sabinene (>17). In conclusion, these results highlight that the essential oils from the Apiaceae family are a reservoir of substances to be used as leading compounds for the development of natural drugs for the treatment of HAT.

Leishmanicidal activity of α-bisabolol from Tunisian chamomile essential oil

According to the World Health Organization, leishmaniasis is considered as a major neglected tropical disease causing an enormous impact on global public health. Available treatments were complicated due to the high resistance, toxicity, and high cost. Therefore, the search for novel sources of anti-leishmania agents is an urgent need. In the present study, an in vitro evaluation of the leishmanicidal activity of the essential oil of Tunisian chamomile (Matricaria recutita L.) was carried out. Chamomile essential oil exhibits a good activity on promastigotes forms of L. amazonensis and L. infantum with a low inhibitory concentration at 50% (IC₅₀) (10.8 ± 1.4 and 10.4 ± 0.6 μg/mL, respectively). Bio-guided fractionation was developed and led to the identification of (-)-α-bisabolol as the most active molecule with low IC₅₀ (16.0 ± 1.2 and 9.5 ± 0.1 μg/mL for L. amazonensis and L. infantum, respectively). This isolated sesquiterpene alcohol was studied for its activity on amastigotes forms (IC₅₀ = 5.9 ± 1.2 and 4.8 ± 1.3 μg/mL, respectively) and its cytotoxicity (selectivity indexes (SI) were 5.4 and 6.6, respectively). The obtained results showed that (-)-α-bisabolol was able to activate a programmed cell death process in the promastigote stage of the parasite. It causes phosphatidylserine externalization and membrane damage. Moreover, it decreases the mitochondrial membrane potential and total ATP levels. These results highlight the potential use of (-)-α-bisabolol against both L. amazonensis and L. infantum, and further studies should be undertaken to establish it as novel leishmanicidal therapeutic agents.

Cedrus deodara: In vitro antileishmanial efficacy & immumomodulatory activity

Background & objectives

The existing antileishmanial drugs for complete cure of visceral leishmaniasis (kala-azar) are limited. The available drugs are either toxic or less effective leading to disease relapse or conversion to post-kala-azar dermal leishmaniasis. Several herbal extracts have been shown to have antileishmanial activity, but a herbal drug may not always be safe. In the present study, the extract of Cedrus deodara leaves has been standardized and tested for immunomodulatory antileishmanial activities.

Methods

The extracts of C. deodara leaves with different solvents such as benzene, chloroform, ethyl acetate and methanol were made by soxhlation process. Solvents were removed under reduced pressure and temperature using rotary evaporator. The antileishmanial bioassay test was performed with in vitro maintained parasites. Immunomodulatory activity of different extracts was tested by flow cytometry. Standardization of the effective fraction was performed with Linalool as a marker compound through reverse-phase high-performance liquid chromatography.

Results

The extract with the use of benzene solvent showed strong antileishmanial activities within a dose 25-200 μg/ml culture with non-significant haemolytic activities and significant immunomodulant activities against the host cells. Linalool was found to be 1.29 per cent in the effective extract of C. deodara.

Interpretation & conclusions

The antileishmanial activity of C. deodara, as assessed by bioassay testing on.

Leishmania donovani

parasites and immunomodulatory effect of benzene extract of leaves on host cells indicated that it might be a potential new safe therapeutic target to cure the visceral leishmaniasis.

Exploration of antiplasmodial activity in Acalypha wilkesiana Müller Argoviensis, 1866 (family: Euphorbiaceae) and its GC-MS fingerprint

The plant kingdom continues to hold great promise for the eradication of Malaria infection following the challenges of insecticide resistance by the vector mosquito, drug resistance by the parasite, and the development of a vaccine still being a mirage. Acalypha wilkesiana Muller Argoviensis, 1866 (family: Euphorbiaceae) leaves have the ethnopharmacological reputation for use as a remedy against dermal microbial infections in Nigeria. Here, we have studied the antiplasmodial potential of the extract of the leaves of this ornamental plant. Aqueous methanol crude extract (70%) and Prep reversed-phase high-performance liquid chromatography (RPHPLC) fractions were tested in vitro against blood stage Plasmodium falciparum 3D7 strain parasites for antiplasmodial activity using the SYBR Green assay. Results obtained were validated through Giemsa stained microscopic blood smeared slides. An IC₅₀ of < 0.39 μg/ml for fractions of the RPHPLC together with TC₅₀ of > 100 μg/ml against mammalian HUH-7 cell lines and a HC₅₀ of > 100 μg/ml against red blood cells indicate a high selectivity of this plant against Plasmodium. This is the first report of the antiplasmodial activity of this plant and a GC-MS fingerprinting of the same, opening the possibilities of identifying novel pharmacophores against the malaria parasite.

In vitro antileishmanial and cytotoxicity activities of essential oils from Haplophyllum tuberculatum A. Juss leaves, stems and aerial parts

BACKGROUND

Plants used for traditional medicine produce diverse and complex secondary metabolites exhibiting various medicinal properties. The medicinal plant Haplophyllum tuberculatum is used by native people against malaria and parasitic infections.

METHODS

In this study and in order to contribute for the search of new natural drugs for leishmaniasis, the essential oils of H. tuberculatum leaves, stems and aerial parts (leaves+stems) collected in two different periods, 2013 and 2015, and their components by GC/FID and GC/MS analyses were investigated. Those collected in 2013 were also re-analyzed two years later. The extracted oils were screened in vitro for anti-leishmanial activity on Leishmania mexicana mexicana (L.m.m.) promastigotes and cytotoxicity on the Chinese Hamster Ovary (CHO) cell line. Limonene (1.5 - 8%), its isomers (R- (+)-limonene and S-(-)-limonene), linalool and octanol were also tested.

RESULTS

Results showed that the chemical composition varied according to the year of collection. Though major compounds remain almost the same, qualitative and quantitative variations in the composition of the EOs can be observed between the two years of collection, with some minor compounds identified only in one type of samples. Variation in the composition were also observed in the re-analyzed volatile oils, showing stability concerns. The essential oils and R-(+)-limonene showed moderate anti-leishmanial activity. Their IC50 range from 6.48 to 50.28 μg/ml. Cytotoxicity assays for theses volatile extracts, R- (+)-limonene and S- (-)-limonene on CHO cells showed relatively potent cytotoxicity with a selectivity index <10. Their CC50 range from 27.79 to 82.56 μg/ml.

CONCLUSIONS

The findings of the present study demonstrated that H. tuberculatum might not be considered as a natural source for production of new anti-leishmanial agents without further analyzing its eventual in vivo toxicity as well as that of major pure compounds.

Repurposing as a strategy for the discovery of new anti-leishmanials: the-state-of-the-art

Leishmaniasis is a vector-borne neglected tropical disease caused by protozoan parasites of the genus Leishmania for which there is a paucity of effective viable non-toxic drugs. There are 1·3 million new cases each year causing considerable socio-economic hardship, best measured in 2·4 million disability adjusted life years, with greatest impact on the poorest communities, which means that desperately needed new antileishmanial treatments have to be both affordable and accessible. Established medicines with cheaper and faster development times may hold the cure for this neglected tropical disease. This concept of using old drugs for new diseases may not be novel but, with the ambitious target of controlling or eradicating tropical diseases by 2020, this strategy is still an important one. In this review, we will explore the current state-of-the-art of drug repurposing strategies in the search for new treatments for leishmaniasis.

Antiparasitic Activity and Essential Oil Chemical Analysis of the Piper Tuberculatum Jacq Fruit

With the increase of neglected diseases such as leishmaniasis and Chagas disease, there was a need for the search for new therapeutic alternatives that reduce the harm caused by medicine available for treatment. Thus, this study was performed to investigate the antiparasitic activity of the essential oil from the fruits of Piper tuberculatum Jacq, against lines of Leishmania braziliensis (MHOM/CO/88/UA301), Leishmania infantum (MHOM/ES/92/BCN83) and Trypanosoma cruzi (LC-B5 clone). Before running protocols, an analysis of the chemical composition of essential oil was conducted, which presented monoterpenes and sesquiterpenes. As major constituents, β-pinene and α-pinene were identified. Regarding to antiparasitic activity, the essential oil had an EC₅₀ values of 133.97 µg/mL and 143.59 µg/mL against variations promastigotes of L. infantum and L. braziliensis, respectively. As for trypanocidal activity, the oil showed EC₅₀ value of 140.31 µg/mL against epimastigote form of T. cruzi. Moreover, it showed moderate cytotoxicity in fibroblasts with LC₅₀ value of 204.71 µg/mL. The observed effect may be related to the presence of terpenes contained in the essential oil, since it has its antiparasitic activity proven in the literature.

Volatile oil profile of some lamiaceous plants growing in Saudi Arabia and their biological activities

A comparative investigation of hydro-distilled essential oils from aerial parts of Mentha longifolia L. (ML), Mentha microphylla K.Koch (MM), Mentha australis R.Br. (MA), and Teucrium polium L. (TP) growing in Al Madinah Al Munawwarah, Saudi Arabia, was carried out. The total numbers of identified constituents were 22, 23, 14, and 20 in ML, MM, MA, and TP oils, representing 93.0, 99.3, 78.1, and 81.1% of the total oil composition, respectively. Pulegone (40.7%) and cineole (33.4%) were the major components in ML, whereas carvone (64.6%) was the major one in MM. Furthermore, β-linalool (22.9%) and α-terpineol (12%) were the major components in MA, whereas, (E)-3-caren-2-ol accounted for 12.1% in TP. The essential oils of TP and MA exhibited promising activities against Leishmania donovani promastigotes with IC50 values of 2.3 and 3.7 μg/mL, respectively. In contrast, MA essential oils exhibited antifungal activities towards Candida krusei and C. glabrata with IC50 values of 1 and 1.2 μg/mL, respectively.

RNA-seq transcriptional profiling of Leishmania amazonensis reveals an arginase-dependent gene expression regulation

Background

Leishmania is a protozoan parasite that alternates its life cycle between the sand-fly vector and the mammalian host. This alternation involves environmental changes and leads the parasite to dynamic modifications in morphology, metabolism, cellular signaling and regulation of gene expression to allow for a rapid adaptation to new conditions. The L-arginine pathway in L. amazonensis is important during the parasite life cycle and interferes in the establishment and maintenance of the infection in mammalian macrophages. Host arginase is an immune-regulatory enzyme that can reduce the production of nitric oxide by activated macrophages, directing the availability of L-arginine to the polyamine pathway, resulting in parasite replication. In this work, we performed transcriptional profiling to identify differentially expressed genes in L. amazonensis wild-type (La-WT) versus L. amazonensis arginase knockout (La-arg^-) promastigotes and axenic amastigotes.

Methodology/Principal findings

A total of 8253 transcripts were identified in La-WT and La-arg^- promastigotes and axenic amastigotes, about 60% of them codifying hypothetical proteins and 443 novel transcripts, which did not match any previously annotated genes. Our RNA-seq data revealed that 85% of genes were constitutively expressed. The comparison of transcriptome and metabolome data showed lower levels of arginase and higher levels of glutamate-5-kinase in La-WT axenic amastigotes compared to promastigotes. The absence of arginase activity in promastigotes increased the levels of pyrroline 5-carboxylate reductase, but decreased the levels of arginosuccinate synthase, pyrroline 5-carboxylate dehydrogenase, acetylornithine deacetylase and spermidine synthase transcripts levels. These observations can explain previous metabolomic data pointing to the increase of L-arginine, citrulline and L-glutamate and reduction of aspartate, proline, ornithine and putrescine. Altogether, these results indicate that arginase activity is important in Leishmania gene expression modulation during differentiation and adaptation to environmental changes. Here, we confirmed this hypothesis with the identification of differential gene expression of the enzymes involved in biosynthesis of amino acids, arginine and proline metabolism and arginine biosynthesis.

Conclusions/Significance

All data provided information about the transcriptomic profiling and the expression levels of La-WT and La-arg^- promastigotes and axenic amastigotes. These findings revealed the importance of arginase in parasite survival and differentiation, and indicated the existence of a coordinated response in the absence of arginase activity related to arginine and polyamine pathways.

Leishmania are auxotrophic for many essential nutrients, including amino acids. In this way, the parasite needs to uptake the amino acids from the environment. The uptake of amino acids is mediated by amino acid transporters that are unique for Leishmania. As part of polyamine pathway, the arginase converts L-arginine to ornithine and furthermore to putrescine, products which are essential for parasite growth. On the other hand, the absence of arginase activity could alter the metabolism of the parasite to surpass the external signals during the life cycle and the fate of infection. The transcriptional profiling of La-WT and La-arg^- promastigotes and axenic amastigotes revealed 8253 transcripts, 60% encoding hypothetical proteins and 443 novel transcripts. In addition, our data revealed that 85% of the genes were constitutively expressed. Among the 15% (1268 genes) of the differentially expressed genes, we identified genes up- and down-regulated comparing the transcript abundance from different life cycle stages of the parasite and in the presence or absence of arginase. We also combined the transcriptional with metabolic profile that revealed a proportional correlation between enzyme and metabolites in the polyamine pathway. The differentiation of promastigotes to amastigotes alters the expression of enzymes from polyamines biosynthesis, which modulates ornithine, L-glutamate, proline and putrescine levels. In addition, the absence of arginase activity increased the levels of L-arginine, citrulline and L-glutamate and decreased the levels of aspartate, proline, ornithine and putrescine in promastigotes by differential modulation of genes involved in its metabolism. Altogether these data provided additional insights into how Leishmania is able to modulate its biological functions in the presence or absence of arginase activity to survive during environmental changes.

L-arginine availability and arginase activity: Characterization of amino acid permease 3 in Leishmania amazonensis

BACKGROUND

Leishmania uses the amino acid L-arginine as a substrate for arginase, enzyme that produces urea and ornithine, last precursor of polyamine pathway. This pathway is used by the parasite to replicate and it is essential to establish the infection in the mammalian host. L-arginine is not synthesized by the parasite, so its uptake occurs through the amino acid permease 3 (AAP3). AAP3 is codified by two copies genes (5.1 and 4.7 copies), organized in tandem in the parasite genome. One copy presents the expression regulated by L-arginine availability.

METHODOLOGY/PRINCIPAL FINDINGS

RNA-seq data revealed 14 amino acid transporters differentially expressed in the comparison of La-WT vs. La-arg- promastigotes and axenic amastigotes. The 5.1 and 4.7 aap3 transcripts were down-regulated in La-WT promastigotes vs. axenic amastigotes, and in La-WT vs. La-arg- promastigotes. In contrast, transcripts of other transporters were up-regulated in the same comparisons. The amount of 5.1 and 4.7 aap3 mRNA of intracellular amastigotes was also determined in sample preparations from macrophages, obtained from BALB/c and C57BL/6 mice and the human THP-1 lineage infected with La-WT or La-arg-, revealing that the genetic host background is also important. We also determined the aap3 mRNA and AAP3 protein amounts of promastigotes and axenic amastigotes in different environmental growth conditions, varying pH, temperature and L-arginine availability. Interestingly, the increase of temperature increased the AAP3 level in plasma membrane and consequently the L-arginine uptake, independently of pH and L-arginine availability. In addition, we demonstrated that besides the plasma membrane localization, AAP3 was also localized in the glycosome of L. amazonensis promastigotes and axenic amastigotes.

CONCLUSIONS/SIGNIFICANCE

In this report, we described the differential transcriptional profiling of amino acids transporters from La-WT and La-arg- promastigotes and axenic amastigotes. We also showed the increased AAP3 levels under amino acid starvation or its decrease in L-arginine supplementation. The differential AAP3 expression was determined in the differentiation of promastigotes to amastigotes conditions, as well as the detection of AAP3 in the plasma membrane reflecting in the L-arginine uptake. Our data suggest that depending on the amino acid pool and arginase activity, Leishmania senses and could use an alternative route for the amino acid transport in response to stress signaling.

Cannabis Pharmacology: The Usual Suspects and a Few Promising Leads

The golden age of cannabis pharmacology began in the 1960s as Raphael Mechoulam and his colleagues in Israel isolated and synthesized cannabidiol, tetrahydrocannabinol, and other phytocannabinoids. Initially, THC garnered most research interest with sporadic attention to cannabidiol, which has only rekindled in the last 15 years through a demonstration of its remarkably versatile pharmacology and synergy with THC. Gradually a cognizance of the potential of other phytocannabinoids has developed. Contemporaneous assessment of cannabis pharmacology must be even far more inclusive. Medical and recreational consumers alike have long believed in unique attributes of certain cannabis chemovars despite their similarity in cannabinoid profiles. This has focused additional research on the pharmacological contributions of mono- and sesquiterpenoids to the effects of cannabis flower preparations. Investigation reveals these aromatic compounds to contribute modulatory and therapeutic roles in the cannabis entourage far beyond expectations considering their modest concentrations in the plant. Synergistic relationships of the terpenoids to cannabinoids will be highlighted and include many complementary roles to boost therapeutic efficacy in treatment of pain, psychiatric disorders, cancer, and numerous other areas. Additional parts of the cannabis plant provide a wide and distinct variety of other compounds of pharmacological interest, including the triterpenoid friedelin from the roots, canniprene from the fan leaves, cannabisin from seed coats, and cannflavin A from seed sprouts. This chapter will explore the unique attributes of these agents and demonstrate how cannabis may yet fulfil its potential as Mechoulam's professed "pharmacological treasure trove."