Compounds with potentialities as novel chemotherapeutic agents in leishmaniasis at preclinical level.

Leishmaniasis are neglected infectious diseases caused by kinetoplastid protozoan parasites from the genus Leishmania. These sicknesses are present mainly in tropical regions and almost 1 million new cases are reported each year. The absence of vaccines, as well as the high cost, toxicity or resistance to the current drugs determines the necessity of new treatments against these pathologies. In this review, several compounds with potentialities as new antileishmanial drugs are presented. The discussion is restricted to the preclinical level and molecules are organized according to their chemical nature, source and molecular targets. In this manner, we present antimicrobial peptides, flavonoids, withanolides, 8-aminoquinolines, compounds from Leish-Box, pyrazolopyrimidines, and inhibitors of tubulin polymerization/depolymerization, topoisomerase IB, proteases, pteridine reductase, N-myristoyltransferase, as well as enzymes involved in polyamine metabolism, response against oxidative stress, signaling pathways, and sterol biosynthesis. This work is a contribution to the general knowledge of these compounds as antileishmanial agents.

Antileishmanial Anthracene Endoperoxides: Efficacy In Vitro, Mechanisms and Structure-Activity Relationships.

Leishmaniasis is a vector-borne disease caused by protozoal Leishmania parasites. Previous studies have shown that endoperoxides (EP) can selectively kill Leishmania in host cells. Therefore, we studied in this work a set of new anthracene-derived EP (AcEP) together with their non-endoperoxidic analogs in model systems of Leishmania tarentolae promastigotes (LtP) and J774 macrophages for their antileishmanial activity and selectivity. The mechanism of effective compounds was explored by studying their reaction with iron (II) in chemical systems and in Leishmania. The correlation of structural parameters with activity demonstrated that in this compound set, active compounds had a LogPOW larger than 3.5 and a polar surface area smaller than 100 Å2. The most effective compounds (IC50 in LtP < 2 µM) with the highest selectivity (SI > 30) were pyridyl-/tert-butyl-substituted AcEP. Interestingly, also their analogs demonstrated activity and selectivity. In mechanistic studies, it was shown that EP were activated by iron in chemical systems and in LtP due to their EP group. However, the molecular structure beyond the EP group significantly contributed to their differential mitochondrial inhibition in Leishmania. The identified compound pairs are a good starting point for subsequent experiments in pathogenic Leishmania in vitro and in animal models.

Machine Learning Analysis of Essential Oils from Cuban Plants: Potential Activity against Protozoa Parasites.

Essential oils (EOs) are a mixture of chemical compounds with a long history of use in food, cosmetics, perfumes, agricultural and pharmaceuticals industries. The main object of this study was to find chemical patterns between 45 EOs and antiprotozoal activity (antiplasmodial, antileishmanial and antitrypanosomal), using different machine learning algorithms. In the analyses, 45 samples of EOs were included, using unsupervised Self-Organizing Maps (SOM) and supervised Random Forest (RF) methodologies. In the generated map, the hit rate was higher than 70% and the results demonstrate that it is possible find chemical patterns using a supervised and unsupervised machine learning approach. A total of 20 compounds were identified (19 are terpenes and one sulfur-containing compound), which was compared with literature reports. These models can be used to investigate and screen for bioactivity of EOs that have antiprotozoal activity more effectively and with less time and financial cost.

In Vitro Pharmacological Screening of Essential Oils from Baccharis parvidentata and Lippia origanoides Growing in Brazil.

In this study, the in vitro antimicrobial, antiparasitic, antiproliferative and cytotoxic activities of essential oil from Baccharis parvidentata Malag. (EO-Bp) and Lippia origanoides Kunth (EO-Lo) were explored. The relevant effects were observed against the parasitic protozoans Plasmodium falciparum, Trypanosoma cruzi, Trypanosoma brucei and Leishmania amazonensis (ranging 0.6 to 39.7 µg/mL) and malignant MCF-7, MCF-7/HT, 22Rv1, and A431 cell lines (ranging 6.1 to 31.5 µg/mL). In parallel, EO-Bp showed better selective indexes in comparison with EO-Lo against peritoneal macrophages from BALB/c mice and MRC-5 cell line. In conclusion, EO-Lo is known to show a wide range of health benefits that could be added as another potential use of this oil with the current study. In the case of EO-Bp, the wide spectrum of its activities against protozoal parasites and malignant cells, as well as its selectivity in comparison with non-malignant cells, could suggest an interesting candidate for further tests as a new therapeutic alternative.

Inhibition of Bacterial Adhesion and Biofilm Formation by Seed-Derived Ethanol Extracts from Persea americana Mill.

The increase in antibiotic resistance demands innovative strategies to combat microorganisms. The current study evaluated the antibacterial and antivirulence effects of ethanol extracts from Persea americana seeds obtained by the Soxhlet (SE) and maceration (MaE) methods. The UHPLC-DAD-QTOF analysis showed mainly the presence of polyphenols and neolignan. Ethanol extracts were not cytotoxic to mammalian cells (CC50 > 500 µg/mL) and displayed a moderate antibacterial activity against Pseudomonas aeruginosa (IC50 = 87 and 187 µg/mL) and Staphylococcus aureus (IC50 = 144 and 159 µg/mL). Interestingly, no antibacterial activity was found against Escherichia coli. SE and MaE extracts were also able to significantly reduce the bacterial adhesion to A549 lung epithelial cells. Additionally, both extracts inhibited the biofilm growth at 24 h and facilitated the release of internal cell components in P. aeruginosa, which might be associated with cell membrane destabilization. Real-time PCR and agarose electrophoresis gel analysis indicated that avocado seed ethanol extracts (64 µg/mL) downregulated virulence-related factors such as mexT and lasA genes. Our results support the potential of bioproducts from P. americana seeds as anti-adhesive and anti-biofilm agents.

Essential Oil from Melaleuca leucadendra: Antimicrobial, Antikinetoplastid, Antiproliferative and Cytotoxic Assessment.

Essential oils (EOs) are known for their use in cosmetics, food industries, and traditional medicine. This study presents the chemical composition and therapeutic properties against kinetoplastid and eukaryotic cells of the EO from Melaleucaleucadendra (L.) L. (Myrtaceae). Forty-five compounds were identified in the oil by GC-MS, containing a major component the 1,8-cineole (61%). The EO inhibits the growth of Leishmania amazonensis and Trypanosoma brucei at IC50 values <10 µg/mL. However, 1,8 cineole was not the main compound responsible for the activity. Against malignant (22Rv1, MCF-7, EFO-21, including resistant sublines MCF-7/Rap and MCF-7/4OHTAMO) and non-malignant (MCF-10A, J774A.1 and peritoneal macrophage) cells, IC50 values from 55 to 98 µg/mL and from 94 to 144 µg/mL were obtained, respectively. However, no activity was observed on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Aspergillus niger, Candida parapsilosis, Microsporum canis, or Trypanosoma cruzi. The EO was able to control the lesion size and parasite burden in the model of cutaneous leishmaniasis in BALB/c mice caused by L. amazonensis compared to untreated animals (p < 0.05) and similar with those treated with Glucantime® (p > 0.05). This work constitutes the first evidence of antiproliferative potentialities of EO from M. leucadendra growing in Cuba and could promote further preclinical investigations to confirm the medical value of this plant, in particular for leishmaniasis treatment.

Techniques to study phagocytosis and uptake of Leishmania tarentolae by J774 macrophages.

Leishmaniasis is a vector borne parasitic disease affecting millions of people worldwide and is spreading into further areas because of global warming. The development of new active substances against these single-cell eukaryotic parasites is of great importance. Leishmania tarentolae promastigotes (LtP) are non-pathogenic for mammals and serve as model organisms for pathogenic Leishmania in basic research. However, it is important to refine methods to study the process of the infection of mammalian macrophages by LtP and pathogenic Leishmania. Important stages of the infection are phagocytosis by macrophages and multiplication of Leishmania amastigotes in the phagolysosome of macrophages. In this study, advanced methods using electron spin resonance (ESR) spectroscopy and genetically manipulated LtP were used to monitor the infection of adherent J774 macrophages with LtP. An ESR method was established to detect the formation of superoxide radicals directly in adherent J774 cells and to investigate the effect of LtP on this activity. J774 cells responded with a burst of superoxide radicals in the presence of phorbol myristate acetate as positive control. In contrast, challenging J774 cells with LtP resulted in a much lower burst of superoxide radicals. To facilitate LtP detection in the phagolysosome of J774 macrophages, LtP expressing enhanced green fluorescent protein (EGFP-LtP) were constructed. After different infection times with EGFP-LtP, the J774 cells were visualized by phase contrast microscopy and the cell number was determined. The intramacrophage Leishmania tarentolae amastigotes (LtA) expressing EGFP were detected by fluorescence microscopy and then counted with ImageJ. These experiments showed that LtP are taken up by J774 cells and form intraphagolysosomal amastigotes. LtA under our conditions multiplied intracellularly and were able to persist about 48 h in J774 cells. These experiments showed that ESR spectroscopy of attached macrophages and the use of the EGFP-LtP are suitable methods to study the initial phase of Leishmania infection in vitro.

Chemical Constituents with Leishmanicidal Activity from a Pink-Yellow Cultivar of Lantana camara var. aculeata (L.) Collected in Central Mexico.

Lantana camara (L.) is employed by several ethnical groups to treat numerous diseases. Although there are no ethnomedical reports on its use against leishmaniasis, organic extracts prepared from L. camara were shown to display leishmanicidal activity. In the present study, we carried out a bioassay-guided fractionation of the dichloromethane extract from Mexican L. camara in order to identify the compounds responsible for the leishmanicidal activity. Eighteen chromatographic fractions (FI⁻FXVIII) were evaluated in vitro against Leishmania mexicana and L. amazonensis. FII, FX, FXI, FXV, and FXVI showed significant activity against both Leishmania strains, the most potent of which was FXV. Eicosane (1), squalene (2), ß-ionone (3), caryophyllene oxide (4), ß-caryophyllene (5), hexanoic acid (6), tiglic acid (7), a mixture of lantanilic (8) and camaric (9) acids, and lantadene B (10) were identified and obtained from the active fractions and evaluated for their leishmanicidal activity. The mixture of lantanilic (8) and camaric (9) acids (79%/21%) was the most potent one (half maximal inhibitory concentration (IC50) = 12.02 ± 0.36 µM). This study indicates that this cultivar of L. camara has high potential for the development of phytomedicines or as a source of natural products, which might represent lead compounds for the design of new drugs against leishmaniasis.

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.

Bixa orellana L. (Bixaceae) and Dysphania ambrosioides (L.) Mosyakin & Clemants (Amaranthaceae) Essential Oils Formulated in Nanocochleates against Leishmania amazonensis.

Leishmaniasis is a group of neglected tropical diseases caused by protozoan parasites of the Leishmania genus. The absence of effective vaccines and the limitations of current treatments make the search for effective therapies a real need. Different plant-derived essential oils (EOs) have shown antileishmanial effects, in particular from Bixa orellana L. (EO-Bo) and Dysphania ambrosioides (L.) Mosyakin & Clemants (EO-Da). In the present study, the EO-Bo and EO-Da, formulated in nanocochleates (EO-Bo-NC and EO-Da-NC, respectively), were evaluated in vitro and in vivo against L. amazonensis. The EO-Bo-NC and EO-Da-NC did not increase the in vitro inhibitory activity of the EOs, although the EO-Bo-NC showed reduced cytotoxic effects. In the animal model, both formulations (30 mg/kg/intralesional route/every 4 days/4 times) showed no deaths or weight loss greater than 10%. In the animal (mouse) model, EO-Bo-NC contributed to the control of infection (p < 0.05) in comparison with EO-Bo treatment, while the mice treated with EO-Da-NC exhibited larger lesions (p < 0.05) compared to those treated with EO-Da. The enhanced in vivo activity observed for EO-Bo-NC suggests that lipid-based nanoformulations like nanocochleates should be explored for their potential in the proper delivery of drugs, and in particular, the delivery of hydrophobic materials for effective cutaneous leishmaniasis treatment.

Chemical Composition, Antimicrobial and Antiparasitic Screening of the Essential Oil from Phania matricarioides (Spreng.) Griseb.

Essential oils (EOs) have gained increasing attention due to their pharmacological effectiveness, and they also constitute some of the most popular natural products. In this study, we present the chemical characterization of the EO from Phania matricarioides and the in vitro activity/selectivity against a wide panel of bacteria, fungi and parasitic protozoa. Forty-five compounds were identified in the studied EO, of which lavandulyl acetate (40.1%) and thymyl isobutyrate (13.9%) were the major components. The EO did not inhibit bacterial or fungal growth at the maximum concentration tested (64 µg/mL), although it displayed activity on all evaluated protozoa (IC50 values ranging from 2.2 to 56.6 µg/mL). In parallel, the EO demonstrated a noteworthy cytotoxic activity against peritoneal macrophages (CC50 values of 28.0 µg/mL). The most sensitive microorganism was Trypanosoma cruzi, which had a superior activity (IC50 = 2.2 µg/mL) and selectivity (SI = 13) in respect to other parasitic protozoa and the reference drug (p < 0.05). Further in vivo studies are needed to evaluate the potential use of this EO and the main compounds as antitrypanosomal agents. To our knowledge, this is the first report of chemical characterization and antimicrobial assessment of the EO from P. matricarioides.

Interaction of ascaridole, carvacrol, and caryophyllene oxide from essential oil of Chenopodium ambrosioides L. with mitochondria in Leishmania and other eukaryotes.

The antileishmanial activity of the essential oil (EO) from Chenopodium ambrosioides L. has been demonstrated in vitro and in animal models, attributed to the major components of the EO. This study focused on the effects of the three major EO compounds carvacrol, caryophyllene oxide (Caryo), and the antileishmanial endoperoxide ascaridole (Asc) on mitochondrial functions in Leishmania tarentolae promastigotes (LtP). EO and Caryo were able to partially inhibit the leishmanial electron transport chain, whereas other components failed to demonstrate a direct immediate effect. Caryo demonstrated inhibition of complex III activity in LtP and in isolated complex III from other species. The formation of superoxide radicals was studied in Leishmania by electron spin resonance spectroscopy in the presence of iron chelators wherein selected compounds failed to trigger a significant immediate additional superoxide production in LtP. However, upon prolonged incubation of Leishmania with Asc and especially in the absence of iron chelators (allowing the activation of Asc), an increased superoxide radical production and significant impairment of mitochondrial coupling in Leishmania was observed. Prolonged incubation with all EO components resulted in thiol depletion. Taken together, the major components of EO mediate their leishmanicidal activity via different mitochondrial targets and time profiles. Further studies are required to elucidate possible synergistic effects of carvacrol and Asc and the influence of minor compounds.

Activation of Anthracene Endoperoxides in Leishmania and Impairment of Mitochondrial Functions.

Leishmaniasis is a vector-borne disease caused by protozoal Leishmania. Because of resistance development against current drugs, new antileishmanial compounds are urgently needed. Endoperoxides (EPs) are successfully used in malaria therapy, and experimental evidence of their potential against leishmaniasis exists. Anthracene endoperoxides (AcEPs) have so far been only technically used and not explored for their leishmanicidal potential. This study verified the in vitro efficiency and mechanism of AcEPs against both Leishmania promastigotes and axenic amastigotes (L. tarentolae and L. donovani) as well as their toxicity in J774 macrophages. Additionally, the kinetics and radical products of AcEPs' reaction with iron, the formation of radicals by AcEPs in Leishmania, as well as the resulting impairment of parasite mitochondrial functions were studied. Using electron paramagnetic resonance combined with spin trapping, photometry, and fluorescence-based oximetry, AcEPs were demonstrated to (i) show antileishmanial activity in vitro at IC50 values in a low micromolar range, (ii) exhibit host cell toxicity in J774 macrophages, (iii) react rapidly with iron (II) resulting in the formation of oxygen- and carbon-centered radicals, (iv) produce carbon-centered radicals which could secondarily trigger superoxide radical formation in Leishmania, and (v) impair mitochondrial functions in Leishmania during parasite killing. Overall, the data of different AcEPs demonstrate that their structures besides the peroxo bridge strongly influence their activity and mechanism of their antileishmanial action.

The antileishmanial activity of xanthohumol is mediated by mitochondrial inhibition.

Xanthohumol (Xan) is a natural constituent of human nutrition. Little is known about its actions on leishmanial parasites and their mitochondria as putative target. Therefore, we determined the antileishmanial activity of Xan and resveratrol (Res, as alternative compound with antileishmanial activity) with respect to mitochondria in Leishmania amazonensis promastigotes/amastigotes (LaP/LaA) in comparison with their activity in peritoneal macrophages from mouse (PMM) and macrophage cell line J774A.1 (J774). Mechanistic studies were conducted in Leishmania tarentolae promastigotes (LtP) and mitochondrial fractions isolated from LtP. Xan and Res demonstrated antileishmanial activity in LaA [half inhibitory concentration (IC50): Xan 7 µ m, Res 14 µ m]; while they had less influence on the viability of PMM (IC50: Xan 70 µ m, Res >438 µ m). In contrast to Res, Xan strongly inhibited oxygen consumption in Leishmania (LtP) but not in J774 cells. This was based on the inhibition of the mitochondrial electron transfer complex II/III by Xan, which was less pronounced with Res. Neither Xan nor Res increased mitochondrial superoxide release in LtP, while both decreased the mitochondrial membrane potential in LtP. Bioenergetic studies showed that LtP mitochondria have no spare respiratory capacity in contrast to mitochondria in J774 cells and can therefore much less adapt to stress by mitochondrial inhibitors, such as Xan. These data show that Xan may have antileishmanial activity, which is mediated by mitochondrial inhibition.

Chemical Characterization, Antileishmanial Activity, and Cytotoxicity Effects of the Essential Oil from Leaves of Pluchea carolinensis (Jacq.) G. Don. (Asteraceae).

Current strategies to control leishmaniasis are mainly based on chemotherapy. However, none of the available drugs can be considered to be ideal to treat this disease. Because of the hydrophobic nature and bioactivities of their components, essential oils (EOs) can be considered as important sources for developing agents against intracellular pathogens, such as Leishmania parasites. In this study, we report the chemical characterization, antileishmanial activities, and cytotoxicity effect of the EO from Pluchea carolinensis (Jacq.) G. Don. (Asteraceae). Chemical analysis revealed that EO from aerial part from P. carolinensis is composed of 44 compounds. The main component was selin-11-en-4α-ol, which made up 51.0%. In vitro antileishmanial studies showed that P. carolinensis EO inhibited the growth of promastigotes (IC50  = 24.7 ± 7.1 µg/mL) and amastigotes (IC50  = 6.2 ± 0.1 µg/mL) of Leishmania amazonensis, while cytotoxicity evaluation revealed fivefold higher values than those for the parasites. In a model of experimental cutaneous leishmaniasis in BALB/c mice, five doses of EO at 30 mg/kg by intralesional route demonstrated smaller lesion size and parasite burden (p < 0.05) compared with animals treated with Glucantime® and untreated mice. In conclusion, in vitro and in vivo results showed the potentialities of EO from P. carolinensis with the future possibility of a new alternative in the treatment for leishmaniasis. Copyright © 2017 John Wiley & Sons, Ltd.

In Vitro Assessment of Plants Growing in Cuba Belonging to Solanaceae Family Against Leishmania amazonensis.

In this study, an in vitro antileishmanial assessment of plant extracts from 12 genera and 46 species growing in Cuba belonging to Solanaceae family was performed. A total of 226 extracts were screened against promastigotes of Leishmania amazonensis, and cytotoxicity of active extracts [median inhibitory concentration (IC50 ) promastigotes <100 µg/mL] was determined on peritoneal macrophage from BALB/c mice. Extracts that showed selective index >5 were then assayed against intracellular amastigote. Metabolomics analysis of promissory extracts was performed using chemical profile obtained by ultra performance liquid chromatography. Only 11 extracts (4.9%) from nine plants were selected as potentially actives: Brunfelsia cestroides A. Rich, Capsicum annuum L., Capsicum chinense Jacq., Cestrum nocturnum L., Nicotiana plumbaginifolia Viv., Solanum havanense Jacq., Solanum myriacanthum Dunal, Solanum nudum Dunal and Solanum seaforthianum And., with IC50 < 50 µg/mL and selectivity index >5. Metabolomics analysis demonstrated significant differences in the chemical profiles with an average of 42.8 (range 31-88) compounds from m/z 104 to 1477, which demonstrated the complex mixture of compounds. In addition, no common markers among active extracts were identified. The results demonstrate the importance of the Solanaceae family to search new antileishmanial agents, particularly in unexplored species of this family. Copyright © 2016 John Wiley & Sons, Ltd.

Chemodiversity Associated with Cytotoxicity and Antimicrobial Activity of Piper aduncum var. ossanum.

Chemical analysis, antimicrobial activity and cytotoxic effects of essential oils (EOs) from leaves of Piper aduncum var. ossanum from two localities Bauta (EO-B) and Ceiba (EO-C), Artemisa Province, Cuba, were determined. EOs were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. EO-B demonstrated higher activity against S. aureus and L. amazonensis; while a lower cytotoxicity on mammalian cells was observed. Both EOs displayed the same activity against Plasmodium falciparum, Trypanosoma cruzi, Trypanosoma brucei, and Leishmania infantum. Both EOs were inactive against Escherichia coli and Candida albicans.

The Chemical Diversity of Lantana camara: Analyses of Essential Oil Samples from Cuba, Nepal, and Yemen.

The aerial parts of Lantana camara L. were collected from three different geographical locations: Artemisa (Cuba), Biratnagar (Nepal), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. A cluster analysis of 39 L. camara essential oil compositions revealed eight major chemotypes: ß-caryophyllene, germacrene D, ar-curcumene/zingiberene, γ-curcumen-15-al/epi-ß-bisabolol, (E)-nerolidol, davanone, eugenol/alloaromadendrene, and carvone. The sample from Cuba falls into the group dominated by (E)-nerolidol, the sample from Nepal is a davanone chemotype, and the sample from Yemen belongs to the ß-caryophyllene chemotype. The chemical composition of L. camara oil plays a role in the biological activity; the ß-caryophyllene and (E)-nerolidol chemotypes showed antimicrobial and cytotoxic activities.

Chemical composition along with anti-leishmanial and cytotoxic activity of Zataria multiflora.

CONTEXT: Natural products and their compounds are some of the most interesting sources of new drugs. Reviews have reported various pharmacological properties such as antimicrobial effects of Zataria multiflora Boiss (Lamiaceae). OBJECTIVE: The present study investigates the chemical composition of Z. multiflora essential oil and evaluates its cytotoxic effects and anti-leishmanial activities against Leishmania tropica in an in vitro model. MATERIALS AND METHODS: The components of Z. multiflora oil were identified by gas chromatography/mass spectroscopy (GC/MS) analysis. Anti-leishmanial effects of the essential oil (0-100 µL/mL) and methanol extract of Z. multiflora (0-100 µg/mL) on promastigote forms as well as their cytotoxic activities against J774 cells were evaluated using MTT assay for 72 h. The leishmanicidal activity against amastigote forms of L. tropica was evaluated at the concentrations of 0-50 µg/mL in a macrophage model for 48 h. RESULTS: The chemical analyses demonstrated that the main components of essential oil were thymol (41.81%), carvacrol (28.85%), and p-cymene (8.36%). Regarding leishmanicidal activity, the IC50 values for the essential oil and methanol extract were 3.2 µL/mL and 9.8 µg/mL against promastigote forms and 8.3 µL/mL and 34.6 µg/mL against amastigote forms, respectively. Essential oil (CC50 89.3 µL/mL) indicated a higher cytotoxic effect than the methanol extract (CC50 591.6 µg/mL) of Z. multiflora. CONCLUSION: The present study revealed the chemical composition of Z. multiflora that might be a natural source of new anti-leishmanial agents in terms of use against cutaneous leishmaniasis.

Role of mitochondria in the leishmanicidal effects and toxicity of acyl phloroglucinol derivatives: nemorosone and guttiferone A.

Nemorosone (Nem) and guttiferone A (GutA) are acyl phloroglucinol derivatives (APD) that are present in different natural products. For both compounds anti-cancer and anti-microbial properties have been reported. In particular, an anti-leishmanial activity of both compounds was demonstrated. The aim of this study was to explore the possible role of mitochondria in the anti-leishmanial activity of Nem and GutA in comparison with their action on mammalian mitochondria. Both APD inhibited the growth of promastigotes of Leishmania tarentolae (LtP) with half maximal inhibitory concentration (IC50) values of 0·67 ± 0·17 and 6·2 ± 2·6 µ m; while IC50 values for cytotoxicity against peritoneal macrophages from BALB/c mice were of 29·5 ± 3·7 and 9·2 ± 0·9 µ m, respectively. Nemorosone strongly inhibited LtP oxygen consumption, caused species-specific inhibition (P < 0·05) of succinate:ubiquinone oxidoreductase (complex II) from LtP-mitochondria and significantly increased (P < 0·05) the mitochondrial superoxide production. In contrast, GutA caused only a moderate reduction of respiration in LtP and triggered less superoxide radical production in LtP compared with Nem. In addition, GutA inhibited mitochondrial complex III in bovine heart submitochondrial particles, which is possibly involved in its mammalian toxicity. Both compounds demonstrated at low micromolar concentrations an effect on the mitochondrial membrane potential in LtP. The present study suggests that Nem caused its anti-leishmanial action due to specific inhibition of complexes II/III of mitochondrial respiratory chain of Leishmania parasites that could be responsible for increased production of reactive oxygen species that triggers parasite death.