Spatialized Metabolomic Annotation Combining MALDI Imaging and Molecular Networks

MALDI mass spectrometry imaging has gained major interest in the field of chemical imaging. This technique makes it possible to locate tens to hundreds of ionic signals on the sample surface without any a priori. One of the current challenges is still the limited ability to annotate signals in order to convert m/z values into probable chemical structures. At the same time, data obtained by LC-MS/MS have benefited from the development of numerous chemoinformatics tools, in particular molecular networks, for their efficient annotation. For the first time, we present here the combination of MALDI-FT-ICR imaging with molecular networks from MALDI-MS/MS data directly acquired on plant tissue sections. Annotation improvements are demonstrated, paving the way for new annotation pipelines for MALDI imaging.

Sphingolipidoses in Morocco: Chemical profiling for an affordable and rapid diagnosis strategy

Sphingolipidoses are a group of metabolic diseases in which lysosomal hydrolases dysfunction disrupt normal sphingolipids' metabolism, leading to excess accumulation in cellular compartments and excretion in urine. These pathologies represent a significant burden among Moroccan population, for which an easy access to enzymatic assays and genetic tests is not guaranteed. Parallel analytical methods thus have to be developed for preliminary screening. In this study, 107 patients were addressed to the metabolic platform of the Marrakesh Faculty of Medicine for diagnosis confirmation. Thin-Layer Chromatography was used as a first step to perform chemical profiling of the patients' urinary lipids, allowing 36% of the patients to be efficiently oriented towards the adequate enzymatic assay. UPLC-MS/MS analyses of urinary sulfatides excreted in urines patient had been used to control the reliability of TLC analysis and to obtain more accurate information related to the sulfatides isoforms. This analytical process combining TLC with UPLC-MS/MS has enabled rapid and appropriate patient management in a reduced time and with reduced resources.

Treating leishmaniasis in Amazonia, part 2: Multi-target evaluation of widely used plants to understand medicinal practices

ETHNOPHARMACOLOGICAL RELEVANCE

Leishmaniasis are widely distributed among tropical and subtropical countries, and remains a crucial health issue in Amazonia. Indigenous groups across Amazonia have developed abundant knowledge about medicinal plants related to this pathology.

AIM OF THE STUDY

We intent to explore the weight of different pharmacological activities driving taxa selection for medicinal use in Amazonian communities. Our hypothesis is that specific activity against Leishmania parasites is only one factor along other (anti-inflammatory, wound healing, immunomodulating, antimicrobial) activities.

MATERIALS AND METHODS

The twelve most widespread plant species used against leishmaniasis in Amazonia, according to their cultural and biogeographical importance determined through a wide bibliographical survey (475 use reports), were selected for this study. Plant extracts were prepared to mimic their traditional preparations. Antiparasitic activity was evaluated against promastigotes of reference and clinical New-World strains of Leishmania (L. guyanensis, L. braziliensis and L. amazonensis) and L. amazonensis intracellular amastigotes. We concurrently assessed the extracts immunomodulatory properties on PHA-stimulated human PBMCs and RAW264.7 cells, and on L. guyanensis antigens-stimulated PBMCs obtained from Leishmania-infected patients, as well as antifungal activity and wound healing properties (human keratinocyte migration assay) of the selected extracts. The cytotoxicity of the extracts against various cell lines (HFF1, THP-1, HepG2, PBMCs, RAW264.7 and HaCaT cells) was also considered. The biological activity pattern of the extracts was represented through PCA analysis, and a correlation matrix was calculated.

RESULTS

Spondias mombin L. bark and Anacardium occidentale L. stem and leaves extracts displayed high anti-promatigotes activity, with IC₅₀ ≤ 32 μg/mL against L. guyanensis promastigotes for S. mombin and IC₅₀ of 67 and 47 μg/mL against L. braziliensis and L. guyanensis promastigotes, respectively, for A. occidentale. In addition to the antiparasitic effect, antifungal activity measured against C. albicans and T. rubrum (MIC in the 16-64 μg/mL range) was observed. However, in the case of Leishmania amastigotes, the most active species were Bixa orellana L. (seeds), Chelonantus alatus (Aubl.) Pulle (leaves), Jacaranda copaia (Aubl.) D. Don. (leaves) and Plantago major L. (leaves) with IC₅₀ < 20 μg/mL and infection rates of 14-25% compared to the control. Concerning immunomodulatory activity, P. major and B. orellana were highlighted as the most potent species for the wider range of cytokines in all tested conditions despite overall contrasting results depending on the model. Most of the species led to moderate to low cytotoxic extracts except for C. alatus, which exhibited strong cytotoxic activity in almost all models. None of the tested extracts displayed wound healing properties.

CONCLUSIONS

We highlighted pharmacologically active extracts either on the parasite or on associated pathophysiological aspects, thus supporting the hypothesis that antiparasitic activities are not the only biological factor useful for antileishmanial evaluation. This result should however be supplemented by in vivo studies, and attracts once again the attention on the importance of the choice of biological models for an ethnophamacologically consistent study. Moreover, plant cultural importance, ecological status and availability were discussed in relation with biological results, thus contributing to link ethnobotany, medical anthropology and biology.

The Effect of Secondary Metabolites Produced by Serratia marcescens on Aedes aegypti and Its Microbiota

Serratia marcescens is a bacterial species widely found in the environment, which very efficiently colonizes mosquitoes. In this study, we isolated a red-pigmented S. marcescens strain from our mosquito colony (called S. marcescens VA). This red pigmentation is caused by the production of prodigiosin, a molecule with antibacterial properties. To investigate the role of prodigiosin on mosquito-S. marcescens interactions, we produced two white mutants of S. marcescens VA by random mutagenesis. Whole genome sequencing and chemical analyses suggest that one mutant has a nonsense mutation in the gene encoding prodigiosin synthase, while the other one is deficient in the production of several types of secondary metabolites including prodigiosin and serratamolide. We used our mutants to investigate how S. marcescens secondary metabolites affect the mosquito and its microbiota. Our in vitro tests indicated that S. marcescens VA inhibits the growth of several mosquito microbiota isolates using a combination of prodigiosin and other secondary metabolites, corroborating published data. This strain requires secondary metabolites other than prodigiosin for its proteolytic and hemolytic activities. In the mosquito, we observed that S. marcescens VA is highly virulent to larvae in a prodigiosin-dependent manner, while its virulence on adults is lower and largely depends on other metabolites.

Ecology, evolution, and epidemiology of zoonotic and vector-borne infectious diseases in French Guiana: Transdisciplinarity does matter to tackle new emerging threats

French Guiana is a European ultraperipheric region located on the northern Atlantic coast of South America. It constitutes an important forested region for biological conservation in the Neotropics. Although very sparsely populated, with its inhabitants mainly concentrated on the Atlantic coastal strip and along the two main rivers, it is marked by the presence and development of old and new epidemic disease outbreaks, both research and health priorities. In this review paper, we synthetize 15 years of multidisciplinary and integrative research at the interface between wildlife, ecosystem modification, human activities and sociodemographic development, and human health. This study reveals a complex epidemiological landscape marked by important transitional changes, facilitated by increased interconnections between wildlife, land-use change and human occupation and activity, human and trade transportation, demography with substantial immigration, and identified vector and parasite pharmacological resistance. Among other French Guianese characteristics, we demonstrate herein the existence of more complex multi-host disease life cycles than previously described for several disease systems in Central and South America, which clearly indicates that today the greater promiscuity between wildlife and humans due to demographic and economic pressures may offer novel settings for microbes and their hosts to circulate and spread. French Guiana is a microcosm that crystallizes all the current global environmental, demographic and socioeconomic change conditions, which may favor the development of ancient and future infectious diseases.

Towards the optimization of botanical insecticides research: Aedes aegypti larvicidal natural products in French Guiana

Natural products have proven to be an immeasurable source of bioactive compounds. The exceptional biodiversity encountered in Amazonia, alongside a rich entomofauna and frequent interactions with various herbivores is the crucible of a promising chemodiversity. This prompted us to search for novel botanical insecticides in French Guiana. As this French overseas department faces severe issues linked to insects, notably the strong incidence of vector-borne infectious diseases, we decided to focus our research on products able to control the mosquito Aedes aegypti. We tested 452 extracts obtained from 85 species originating from 36 botanical families and collected in contrasted environments against an Ae. aegypti laboratory strain susceptible to all insecticides, and a natural population resistant to both pyrethroid and organophosphate insecticides collected in Cayenne for the most active of them. Eight species (Maytenus oblongata Reissek, Celastraceae; Costus erythrothyrsus Loes., Costaceae; Humiria balsamifera Aubl., Humiriaceae; Sextonia rubra (Mez) van der Werff, Lauraceae; Piper hispidum Sw., Piperaceae; Laetia procera (Poepp.) Eichl., Salicaceae; Matayba arborescens (Aubl.) Radlk., Sapindaceae; and Cupania scrobitulata Rich., Sapindaceae) led to extracts exhibiting more than 50% larval mortality after 48 h of exposition at 100 µg/mL against the natural population and were considered active. Selectivity and phytochemistry of these extracts were therefore investigated and discussed, and some active compounds highlighted. Multivariate analysis highlighted that solvents, plant tissues, plant family and location had a significant effect on mortality while light, available resources and vegetation type did not. Through this case study we highlighted that plant defensive chemistry mechanisms are crucial while searching for novel insecticidal products.

The antifungal potential of (Z)-ligustilide and the protective effect of eugenol demonstrated by a chemometric approach

Mankind is on the verge of a postantibiotic era. New concepts are needed in our battle to attenuate infectious diseases around the world and broad spectrum plant-inspired synergistic pharmaceutical preparations should find their place in the global fight against pathogenic microorganisms. To progress towards the discovery of potent antifungal agents against human pathologies, we embarked upon developing chemometric approach coupled with statistical design to unravel the origin of the anticandidal potential of a set of 66 essential oils (EOs). EOs were analyzed by GC-MS and tested against Candida albicans and C. parapsilosis (Minimal Inhibitory Concentration, MIC). An Orthogonal Partial Least Square (OPLS) analysis allowed us to identify six molecules presumably responsible for the anticandidal activity of the oils: (Z)-ligustilide, eugenol, eugenyl acetate, citral, thymol, and β-citronellol. These compounds were combined following a full factorial experimental design approach in order to optimize the anticandidal activity and selectivity index (SI = IC₅₀(MRC₅ cells)/MIC) through reconstituted mixtures. (Z)-Ligustilide and citral were the most active compounds, while (Z)-ligustilide and eugenol were the two main factors that most contributed to the increase of the SI. These two terpenes can, therefore, be used to construct bioinspired synergistic anticandidal mixtures.

Biosynthetic investigation of γ-lactones in Sextonia rubra wood using in situ TOF-SIMS MS/MS imaging to localize and characterize biosynthetic intermediates

Molecular analysis by parallel tandem mass spectrometry (MS/MS) imaging contributes to the in situ characterization of biosynthetic intermediates which is crucial for deciphering the metabolic pathways in living organisms. We report the first use of TOF-SIMS MS/MS imaging for the cellular localization and characterization of biosynthetic intermediates of bioactive γ-lactones rubrynolide and rubrenolide in the Amazonian tree Sextonia rubra (Lauraceae). Five γ-lactones, including previously reported rubrynolide and rubrenolide, were isolated using a conventional approach and their structural characterization and localization at a lateral resolution of ~400 nm was later achieved using TOF-SIMS MS/MS imaging analysis. 2D/3D MS imaging at subcellular level reveals that putative biosynthetic γ-lactones intermediates are localized in the same cell types (ray parenchyma cells and oil cells) as rubrynolide and rubrenolide. Consequently, a revised metabolic pathway of rubrynolide was proposed, which involves the reaction between 2-hydroxysuccinic acid and 3-oxotetradecanoic acid, contrary to previous studies suggesting a single polyketide precursor. Our results provide insights into plant metabolite production in wood tissues and, overall, demonstrate that combining high spatial resolution TOF-SIMS imaging and MS/MS structural characterization offers new opportunities for studying molecular and cellular biochemistry in plants.

Tandem Mass Spectrometry Imaging and in Situ Characterization of Bioactive Wood Metabolites in Amazonian Tree Species Sextonia rubra

Driven by a necessity for confident molecular identification at high spatial resolution, a new time-of-flight secondary ion mass spectrometry (TOF-SIMS) tandem mass spectrometry (tandem MS) imaging instrument has been recently developed. In this paper, the superior MS/MS spectrometry and imaging capability of this new tool is shown for natural product study. For the first time, via in situ analysis of the bioactive metabolites rubrynolide and rubrenolide in Amazonian tree species Sextonia rubra (Lauraceae), we were able both to analyze and to image by tandem MS the molecular products of natural biosynthesis. Despite the low abundance of the metabolites in the wood sample(s), efficient MS/MS analysis of these γ-lactone compounds was achieved, providing high confidence in the identification and localization. In addition, tandem MS imaging minimized the mass interferences and revealed specific localization of these metabolites primarily in the ray parenchyma cells but also in certain oil cells and, further, revealed the presence of previously unidentified γ-lactone, paving the way for future studies in biosynthesis.

Treating leishmaniasis in Amazonia: A review of ethnomedicinal concepts and pharmaco-chemical analysis of traditional treatments to inspire modern phytotherapies

ETHNOPHARMACOLOGICAL RELEVANCE

Cutaneous and mucocutaneous leishmaniasis are neglected tropical diseases that occur in all intertropical regions of the world. Amazonian populations have developed an abundant knowledge of the disease and its remedies. Therefore, we undertook to review traditional antileishmanial plants in Amazonia and have developed new tools to analyze this somewhat dispersed information.

MATERIAL AND METHODS

A literature review of traditional remedies for cutaneous/mucocutaneous leishmaniasis in the Amazon was conducted and the data obtained was used to calculate distribution indexes designed to highlight the most relevant uses in Amazonia. The cultural distribution index represents the distribution rate of a given taxon among different cultural groups and was calculated as the ratio of the number of groups using the taxon to the total number of groups cited. The geographical distribution index allowed us to quantify spatial distribution of a taxon's uses in Amazonia and was calculated geometrically by measuring the average distance between the points where uses have been reported and the barycenter of those points. The general distribution index was defined as an arithmetic combination of the previous two and provides information on both cultural and spatial criteria.

RESULTS

475 use reports, concerning 291 botanical species belonging to 83 families have been gathered depicted from 29 sources. Uses concern 34 cultural groups. While the use of some taxa appears to be Pan-Amazonian, some others are clearly restricted to small geographical regions. Particular attention has been paid to the recipes and beliefs surrounding treatments. Topical application of the remedies dominated the other means of administration and this deserves particular attention as the main treatments against Neotropical leishmaniasis are painful systemic injections. The data set was analyzed using the previously defined distribution indexes and the most relevant taxa were further discussed from a phytochemical and pharmacological point of view.

CONCLUSIONS

The Amazonian biodiversity and cultural heritage host a fantastic amount of data whose systematic investigation should allow a better large-scale understanding of the dynamics of traditional therapies and the consequent discovery of therapeutic solutions for neglected diseases. Distribution indices are indeed powerful tools for emphasizing the most relevant treatments against a given disease and should be very useful in the meta-analysis of other regional pharmacopeia. This focus on renowned remedies that have not yet benefitted from extended laboratory studies, could stimulate future research on new treatments of natural origin for leishmaniasis.

Aedes aegypti Larvicidal Sesquiterpene Alkaloids from Maytenus oblongata

Four new sesquiterpene alkaloids (1-4) with a β-dihydroagrofuran skeleton and a new triterpenoid (5) were isolated from an ethyl acetate extract of Maytenus oblongata stems. Their structures were elucidated using 1D and 2D NMR spectroscopy as well as MS and ECD experiments. The M. oblongata stem EtOAc extract and the pure compounds isolated were tested for larvicidal activity against Aedes aegypti under laboratory conditions, and compounds 2 and 3 were found to be active.

Assessment of A Simple Compound-Saving Method To Study Insecticidal Activity of Natural Extracts and Pure Compounds Against Mosquito Larvae

Research on natural insecticides has intensified with the spread of resistance to chemicals among insects, particularly disease vectors. To evaluate compounds, the World Health Organization (WHO) has published standardized procedures. However, those may be excessively compound-consuming when it comes to assessing the activity of natural extracts and pure compounds isolated in limited amount. As part of our work on the discovery of new mosquito larvicides from Amazonian plants, we developed a compound-saving assay in 5-ml glass tubes instead of WHO larval 100-ml cups. Comparing activity of synthetic and natural chemicals validated the glass tube assay. Raw data, lethal doses that kill 50% (LD₅₀) and 90% (LD₉₀) at 24 and 48 h, were highly correlated (0.68 < R² < 0.96, P < 0.001, Pearson test) between cups and tubes. It was also established that 10 tubes (N = 50 larvae) provided the same level of sensitivity as 20 tubes (N = 100). This method proved suitable for rapid screening of natural extracts and molecules, identifying active compounds using 10 times less material than in the WHO protocol.

Wayanin and guaijaverin, two active metabolites found in a Psidium acutangulum Mart. ex DC (syn. P. persoonii McVaugh) (Myrtaceae) antimalarial decoction from the Wayana Amerindians

ETHNOPHARMACOLOGICAL RELEVANCE

Psidium acutangulum Mart. ex DC is a small tree used by the Wayana Amerindians from the Upper-Maroni in French Guiana for the treatment of malaria.

AIM OF THE STUDY

In a previous study, we highlighted the in vitro antiplasmodial, antioxidant and anti-inflammatory potential of the traditional decoction of P. acutangulum aerial parts. Our goal was then to investigate on the origin of the biological activity of the traditional remedy, and eventually characterize active constituents.

MATERIALS AND METHODS

Liquid-liquid extractions were performed on the decoction, and the antiplasmodial activity evaluated against chloroquine-resistant FcB1 ([(3)H]-hypoxanthine bioassay) and 7G8 (pLDH bioassay) P. falciparum strains, and on a chloroquine sensitive NF54 ([(3)H]-hypoxanthine bioassay) P. falciparum strain. The ethyl acetate fraction (D) was active and underwent bioguided fractionation. All the isolated compounds were tested on P. falciparum FcB1 strain. In vitro anti-inflammatory activity (IL-1β, IL-6, IL-8, TNFα) of the ethyl acetate fraction and of an anti-Plasmodium active compound, was concurrently assessed on LPS-stimulated human PBMC and NO secretion inhibition was measured on LPS stimulated RAW murine macrophages. Cytotoxicity of the fractions and pure compounds was measured on VERO cells, L6 mammalian cells, PBMCs, and RAW cells.

RESULTS

Fractionation of the ethyl acetate soluble fraction (IC50 ranging from 3.4 to <1µg/mL depending on the parasite strain) led to the isolation of six pure compounds: catechin and five glycosylated quercetin derivatives. These compounds have never been isolated from this plant species. Two of these compounds (wayanin and guaijaverin) were found to be moderately active against P. falciparum FcB1 in vitro (IC50 5.5 and 6.9µM respectively). We proposed the name wayanin during public meetings organized in June 2015 in the Upper-Maroni villages, in homage to the medicinal knowledge of the Wayana population. At 50µg/mL, the ethyl acetate fraction (D) significantly inhibited IL-1β secretion (-46%) and NO production (-21%), as previously observed for the decoction. The effects of D and guiajaverin (4) on the secretion of other cytokines or NO production were not significant.

CONCLUSIONS

The confirmed antiplasmodial activity of the ethyl acetate soluble fraction of the decoction and of the isolated compounds support the previous results obtained on the P. acutangulum decoction. The antiplasmodial activity might be due to a mixture of moderately active non-toxic flavonoids. The anti-inflammatory activities were less marked for ethyl acetate fraction (D) than for the decoction.

Antiplasmodial and anti-inflammatory effects of an antimalarial remedy from the Wayana Amerindians, French Guiana: takamalaimë (Psidium acutangulum Mart. ex DC., Myrtaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Field investigations highlighted the use of Psidium acutangulum Mart. ex DC (syn. P. persoonii McVaugh), a small tree used by the Wayana Amerindians in Twenke-Taluhwen and Antecume-Pata, French Guiana, for the treatment of malaria, and administered either orally in the form of a decoction or applied externally over the whole body. This use appears limited to the Wayana cultural group in French Guiana and has never been reported anywhere else. Our goal was to evaluate the antimalarial and anti-inflammatory activities of a P. acutangulum decoction to explain the good reputation of this remedy.

MATERIALS AND METHODS

Interviews with the Wayana inhabitants of Twenke-Taluhwen and Antecume-Pata were conducted within the TRAMAZ project according to the TRAMIL methodology, which is based on a quantitative and qualitative analysis of medicinal plant uses. A decoction of dried aerial parts of P. acutangulum was prepared in consistency with the Wayana recipe. In vitro antiplasmodial assays were performed on chloroquine-resistant FcB1 ([(3)H]-hypoxanthine bioassay) and 7G8 (pLDH bioassay) P. falciparum strains and on chloroquine sensitive NF54 ([(3)H]-hypoxanthine bioassay) P. falciparum strain. In vitro anti-inflammatory activity (IL-1β, IL-6, IL-8, TNFα) was evaluated on LPS-stimulated human PBMC and NO secretion inhibition was measured on LPS stimulated RAW murine macrophages. Cytotoxicity of the decoction was measured on L6 mammalian cells, PBMCs, and RAW cells. A preliminary evaluation of the in vivo antimalarial activity of the decoction, administered orally twice daily, was assessed by the classical four-day suppressive test against P. berghei NK65 in mice.

RESULTS

The decoction displayed a good antiplasmodial activity in vitro against the three tested strains, regardless to the bioassay used, with IC50 values of 3.3µg/mL and 10.3µg/mL against P. falciparum FcB1 and NF54, respectively and 19.0µg/mL against P. falciparum 7G8. It also exhibited significant anti-inflammatory activity in vitro in a dose dependent manner. At a concentration of 50µg/mL, the decoction inhibited the secretion of the following pro-inflammatory cytokines: TNFα (-18%), IL-1β (-58%), IL-6 (-32%), IL-8 (-21%). It also exhibited a mild NO secretion inhibition (-13%) at the same concentration. The decoction was non-cytotoxic against L6 cells (IC50>100µg/mL), RAW cells and PBMC. In vivo, 150µL of the decoction given orally twice a day (equivalent to 350mg/kg/day of dried extract) inhibited 39.7% average parasite growth, with more than 50% of inhibition in three mice over five. The absence of response for the two remaining mice, however, induced a strong standard deviation.

CONCLUSIONS

This study highlighted the in vitro antiplasmodial activity of the decoction of P. acutangulum aerial parts, used by Wayana Amerindians from the Upper-Maroni in French Guiana in case of malaria. Its antioxidant and anti-inflammatory potential, which may help to explain its use against this disease, was demonstrated using models of artificially stimulated cells.

Therapeutic switching: from antidermatophytic essential oils to new leishmanicidal products

This study examined whether the antidermatophytic activity of essential oils (EOs) can be used as an indicator for the discovery of active natural products against Leishmania amazonensis. The aerial parts of seven plants were hydrodistilled. Using broth microdilution techniques, the obtained EOs were tested against three strains of dermatophytes (Trichophyton mentagrophytes, Microsporum gypseum and Microsporum canis). To compare the EOs antifungal and antiparasitic effects, the EOs activities against axenic amastigotes of L. amazonensis were concurrently evaluated. For the most promising EOs, their antileishmanial activities against parasites infecting peritoneal macrophages of BALB/c mice were measured. The most interesting antifungal candidates were the EOs from Cymbopogon citratus, Otacanthus azureus and Protium heptaphyllum, whereas O. azureus, Piper hispidum and P. heptaphyllum EOs exhibited the lowest 50% inhibitory concentration (IC₅₀) values against axenic amastigotes, thus revealing a certain correspondence between both activities. The P. hispidum EO was identified as the most promising product in the results from the infected macrophages model (IC₅₀: 4.7 µg/mL, safety index: 8). The most abundant compounds found in this EO were sesquiterpenes, notably curzerene and furanodiene. Eventually, the evaluation of the antidermatophytic activity of EOs appears to be an efficient method for identifying new potential drugs for the treatment of L. amazonensis.

In vitro antidermatophytic activity of Otacanthus azureus (Linden) Ronse essential oil alone and in combination with azoles

AIMS

We determined the chemical composition and investigated the antifungal activity of Otacanthus azureus (Linden) Ronse essential oil (EO) against a range of dermatophytes alone or in combination with azole antifungals.

METHODS AND RESULTS

Aerial parts of the plant were steam-distilled and the obtained oil was analysed by gas chromatography/mass spectrometry and (1) H-NMR. It was shown to be largely composed of sesquiterpenes, with the main component being β-copaen-4-α-ol. Using broth microdilution techniques, this oil was found to have remarkable in vitro antifungal activities. Minimum inhibitory concentrations as low as 4 μg ml(-1) were recorded. The analysis of the combined effect of the O. azureus EO with azoles using chequerboard assays revealed a synergism between the EO and ketoconazole, fluconazole or itraconazole against Trichophyton mentagrophytes. Notably, the O. azureus essential oil showed low cytotoxicity to VERO cells.

CONCLUSIONS

The O. azureus essential oil alone or in combination with azoles is a promising antifungal agent in the treatment for human dermatomycoses caused by filamentous fungi.

SIGNIFICANCE AND IMPACT OF THE STUDY

There is much interest in the study of essential oils for the discovery of new antimicrobial drugs. This study has highlighted the antidermatophytic activity of the O. azureus EO.

New findings on Simalikalactone D, an antimalarial compound from Quassia amara L. (Simaroubaceae)

Quassia amara L. (Simaroubaceae) is a species widely used as tonic and is claimed to be an efficient antimalarial all over the Northern part of the Amazon basin. Quassinoid compound Simalikalactone D (SkD) has been shown to be one of the molecules responsible for the antiplasmodial activity of a watery preparation made out of juvenile fresh leaves of this plant. Because of its strong antimalarial activity, we decided to have a further insight of SkD pharmacological properties, alone or in association with classical antimalarials. At concentrations of up to 200μM, we showed herein that SkD did not exert any apoptotic or necrotic activities in vitro on lymphoblastic cells. However, an antiproliferative effect was evident at concentrations higher than 45nM. SkD was inefficient at inhibiting heme biomineralization and the new permeability pathways induced by the parasite in the host erythrocyte membrane. With respect to Plasmodium falciparum erythrocytic stages, SkD was almost inactive on earlier and later parasite stages, but potently active at the 30th h of parasite cycle when DNA replicates in mature trophozoites. In vitro combination studies with conventional antimalarial drugs showed that SkD synergizes with atovaquone (ATO). The activity of ATO on the Plasmodium mitochondrial membrane potential was enhanced by SkD, which on its own had a poor effect on this cellular parameter.

Quassinoid constituents of Quassia amara L. leaf herbal tea. Impact on its antimalarial activity and cytotoxicity

AIM OF THE STUDY

Our objective was to assess whether it could be contemplated to recommend Quassia amara young leaf tea for treatment against malaria, and if yes, set up a standard protocol for preparing the herbal tea.

MATERIALS AND METHODS

The leaf tea was extracted with methylene chloride and the organic extract was fractionated with HPLC. Pure compounds were characterized and their in vitro cytotoxicity and antiplasmodial activity was determined.

RESULTS AND DISCUSSION

We discovered that antimalarial Quassia amara young leaf tea contains several quassinoids: simalikalactone D (SkD, 1), picrasin B (2), picrasin H (3), neoquassin (4), quassin (5), picrasin I (6) and picrasin J (7). These last two compounds are new. In addition, our experiments demonstrate that both biological activity and cytotoxicity of the remedy may be attributed solely to the presence of SkD.

CONCLUSION

In conclusion, this preparation should not be recommended for treatment of malaria until a clinical study in humans is performed with SkD.

Quassia amara L. (Simaroubaceae) leaf tea: effect of the growing stage and desiccation status on the antimalarial activity of a traditional preparation

In French Guiana, Quassia amara L. (Simaroubaceae) leaf tea is a well-known widely used traditional antimalarial remedy. Impact of the vegetal sampling condition on in vivo and in vitro antimalarial activity was assessed. Traditional infusions were prepared with juvenile or mature leaves, both either fresh or dried. Results showed that growing stage and freshness of vegetal material exert a striking effect on antimalarial activity, both in vitro and in vivo. By far, leaf tea made from fresh juvenile (FJ) Quassia amara leaves was the most active. In vitro, active component (simalikalactone D) concentration correlates biological activities, although unexplained subtle variations were observed. In vivo, tea made with dried juvenile (DJ) leaves displays a peculiar behavior, meaning that some components may help simalikalactone D delivery or may be active in vivo only, therefore enhancing the expected curative effect of the traditional preparation.

From Tonic-cups to Bitter-cups: Kwasi bita beker from Suriname Determination, past and present use of an ancient galenic artefact

In the main markets of Paramaribo (Suriname), many stands offer what is locally called "Bitter-cups", or "Kwasi bita beker", small footed-cups, roughly carved from a whitish wood. The use of these cups is strictly medicinal and it seems to be restricted to Suriname, as they are not found in neighbouring countries (Guyana, French Guiana). The aim of this study was to identify the botanical origin of Bitter-cups still in use in the Saramaka traditional medicine (as information from field people was controversial), and document the ethnopharmacology of this original galenical artefact. Microscopic and high performance liquid chromatography (HPLC) analyses were carried out on Bitter-cup, and anatomical criteria (marginal parenchyma band, size of intervessel and vessel-ray pits, rays width and rays composition, vessels clustering, frequency and size of parenchyma pits) together with HPLC profiles of the macerates showed that the wood cup was similar to Quassia amara L. (Simaroubaceae) wood. Ethnopharmacological investigation indicates that the use of these cups is simply due to the pharmacological properties attributed to "bitters", and is strongly linked to tradition and cultural attitudes. This study also emphasizes the long lasting use of these cups, now restricted to Suriname only, with almost no variation over one century.

Simalikalactone D is responsible for the antimalarial properties of an Amazonian traditional remedy made with Quassia amara L. (Simaroubaceae)

French Guiana (North-East Amazonia) records high malaria incidence rates. The traditional antimalarial remedy most widespread there is a simple tea made out from Quassia amara L. leaves (Simaroubaceae). This herbal tea displays an excellent antimalarial activity both in vitro and in vivo. A known quassinoid, simalikalactone D (SkD), was identified as the active compound, with an IC(50) value of 10nM against FcB1 Plasmodium falciparum chloroquine resistant strain in vitro. Lastly, it inhibits 50% of Plasmodium yoelii yoelii rodent malaria parasite at 3.7 mg/kg/day in vivo by oral route. These findings confirm the traditional use of this herbal tea.