Antitrypanosomal and cytotoxic activities of 22-Hydroxyclerosterol, a new sterol from Allexis cauliflora (Violaceae)

Antileishmanial and Antiplasmodial Activities of Secondary Metabolites from the Root of Antrocaryon klaineanum Pierre (Anacardiaceae)

Antrocaryon klaineanum is traditionally used for the treatment of back pain, malaria, female sterility, chlamydiae infections, liver diseases, wounds, and hemorrhoid. This work aimed at investigating the bioactive compounds with antileishmanial and antiplasmodial activities from A. klaineanum. An unreported glucocerebroside antroklaicerebroside (1) together with five known compounds (2-6) were isolated from the root barks of Antrocaryon klaineanum using chromatographic techniques. The NMR, MS, and IR spectroscopic data in association with previous literature were used for the characterization of all the isolated compounds. Compounds 1-4 are reported for the first time from A. klaineanum. The methanol crude extract (AK-MeOH), the n-hexane fraction (AK-Hex), the dichloromethane fraction (AK-DCM), the ethyl acetate fraction (AK-EtOAc), and compounds 1-6 were all evaluated for their antiparasitic effects against Plasmodium falciparum strains susceptible to chloroquine (3D7), resistant to chloroquine (Dd2), and promastigotes of Leishmania donovani (MHOM/SD/62/1S). The AK-Hex, AK-EtOAc, AK-MeOH, and compound 2 were strongly active against Dd2 strain with IC50 ranging from 2.78 ± 0.06 to 9.30 ± 0.29 µg/mL. Particularly, AK-MeOH was the most active-more than the reference drugs used-with an IC50 of 2.78 ± 0.06 µg/mL. The AK-EtOAc as well as all the tested compounds showed strong antileishmanial activities with IC50 ranging from 4.80 ± 0.13 to 9.14 ± 0.96 µg/mL.

Compounds from African Medicinal Plants with Activities Against Selected Parasitic Diseases: Schistosomiasis, Trypanosomiasis and Leishmaniasis

Parasitic diseases continue to represent a threat on a global scale, particularly among the poorest countries in the world. This is particularly because of the absence of vaccines, and in some cases, resistance against available drugs, currently being used for their treatment. In this review emphasis is laid on natural products and scaffolds from African medicinal plants (AMPs) for lead drug discovery and possible further development of drugs for the treatment of parasitic diseases. In the discussion, emphasis has been laid on alkaloids, terpenoids, quinones, flavonoids and narrower compound classes of compounds with micromolar range activities against Schistosoma, Trypanosoma and Leishmania species. In each subparagraph, emphasis is laid on the compound subclasses with most promising in vitro and/or in vivo activities of plant extracts and isolated compounds. Suggestions for future drug development from African medicinal plants have also been provided. This review covering 167 references, including 82 compounds, provides information published within two decades (1997-2017).

Ergosterol isolated from the basidiomycete Pleurotus salmoneostramineus affects Trypanosoma cruzi plasma membrane and mitochondria

Background

Major drawbacks of the available treatment against Chagas disease (American trypanosomiasis) include its toxicity and therapeutic inefficiency in the chronic phase of the infection, which makes it a concern among neglected diseases. Therefore, the discovery of alternative drugs for treating chronic Chagas disease requires immediate action. In this work, we evaluated the mushroom Pleurotus salmoneostramineus in the search for potential antiparasitic compounds.

Methods

Fruit bodies of the basidiomycete Pleurotus salmoneostramineus were triturated and submitted to organic solvent extraction. After liquid-liquid partition of the crude extract, three fractions were obtained and the bioguided fractionation study was conducted to isolate the active metabolites. The elucidation of the chemical structure was performed using GC-MS and NMR techniques. The biological assays for antiparasitic activity were carried out using trypomastigotes of Trypanosoma cruzi and murine macrophages for mammalian cytotoxicity. The mechanism of action of the isolated compound used different fluorescent probes to evaluate the plasma membrane permeability, the potential of the mitochondrial membrane and the intracellular levels of reactive oxygen species (ROS).

Results

The most abundant fraction showing the antiparasitic activity was isolated and chemically elucidated, confirming the presence of ergosterol. It showed anti-Trypanosoma cruzi activity against trypomastigotes, with an IC₅₀ value of 51.3 μg/mL. The compound demonstrated no cytotoxicity against mammalian cells to the maximal tested concentration of 200 μg/mL. The mechanism of action of ergosterol in Trypanosoma cruzi trypomastigotes resulted in permeabilization of the plasma membrane, as well as depolarization of mitochondrial membrane potential, leading to parasite death. Nevertheless, no increase in ROS levels could be observed, suggesting damages to plasma membrane rather than an induction of oxidative stress in the parasite.

Conclusions

The selection of naturally antiparasitic secondary metabolites in basidiomycetes, such as ergosterol, may provide potential scaffolds for drug design studies against neglected diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s40409-017-0120-0) contains supplementary material, which is available to authorized users.

New Bioactive Semisynthetic Derivatives of 31-Norlanostenol and Obtusifoliol from Euphorbia Officinarum

Fifteen semisynthetic terpenoid derivatives from the major latex components of Euphorbia officinarum have been evaluated against the insect pest Spodoptera littoralis, two species of protozoan parasites, Trypanosoma cruzi and Leishmania infantum, and also against insect Sf9 and mammalian CHO cells to test their selective cytotoxicity. Our results showed that 40% of the test substances were postingestive toxicants to S. littoralis. All the tested derivatives had cytotoxic effects on insect-derived Sf9 cells, whereas mammalian CHO cells were affected by a lower number of compounds (47%). Furthermore, 87% of the test compounds had antiparasitic effects on bothi. infantum and T. cruzi, with some of them being selective parasite toxicants.