In Vitro Antiplasmodial and Cytotoxic Activities of Compounds from the Roots of Eriosema montanum Baker f. (Fabaceae)

Leaf hydroalcoholic extract and oleoresin from Copaifera multijuga control Toxoplasma gondii infection in human trophoblast cells and placental explants from third-trimester pregnancy

The conventional treatment of congenital toxoplasmosis is mainly based on the combination of sulfadiazine and pyrimethamine. However, therapy with these drugs is associated with severe side effects and resistance, requiring the study of new therapeutic strategies. There are currently many studies with natural products, including Copaifera oleoresin, showing actions against some pathogens, as Trypanosoma cruzi and Leishmania. In the present study, we investigated the effects of the leaf hydroalcoholic extract and oleoresin from Copaifera multijuga against Toxoplasma gondii in human villous (BeWo) and extravillous (HTR8/SVneo) trophoblast cells, as well as in human villous explants from third-trimester pregnancy. For this purpose, both cells and villous explants were infected or not with T. gondii, treated with hydroalcoholic extract or oleoresin from C. multijuga and analyzed for toxicity, parasite proliferation, cytokine and ROS production. In parallel, both cells were infected by tachyzoites pretreated with hydroalcoholic extract or oleoresin, and adhesion, invasion and replication of the parasite were observed. Our results showed that the extract and oleoresin did not trigger toxicity in small concentrations and were able to reduce the T. gondii intracellular proliferation in cells previously infected. Also, the hydroalcoholic extract and oleoresin demonstrated an irreversible antiparasitic action in BeWo and HTR8/SVneo cells. Next, adhesion, invasion and replication of T. gondii were dampened when BeWo or HTR8/SVneo cells were infected with pretreated tachyzoites. Finally, infected and treated BeWo cells upregulated IL-6 and downmodulated IL-8, while HTR8/SVneo cells did not change significantly these cytokines when infected and treated. Finally, both the extract and oleoresin reduced the T. gondii proliferation in human explants, and no significant changes were observed in relation to cytokine production. Thus, compounds from C. multijuga presented different antiparasitic activities that were dependent on the experimental model, being the direct action on tachyzoites a common mechanism operating in both cells and villi. Considering all these parameters, the hydroalcoholic extract and oleoresin from C. multijuga can be a target for the establishment of new therapeutic strategy for congenital toxoplasmosis.

Antiplasmodial, Antioxidant, and Cytotoxic Activity of Bridelia micrantha a Cameroonian Medicinal Plant Used for the Treatment of Malaria

Introduction

Resistance to common antimalarial drugs and persistence of the endemicity of malaria constitute a major public health problem in Cameroon. The aim of this study was to evaluate the in vitro antiplasmodial, antioxidant, and cytotoxic activities of aqueous and ethanol extracts of Bridelia micrantha used by Cameroonian traditional healers for the treatment of malaria.

Methods

Aqueous and ethanolic stem bark extracts were prepared according to standard procedures. The SYBR Green method was used for antiplasmodial activity on strains of Plasmodium falciparum sensitive to chloroquine (3D7) and resistant (Dd2). In vitro antioxidant activities of B. micrantha were determined using the scavenging activity of 2,2'-diphenyl-1-picrylhydrazyl, nitric oxide, ferric reducing power, and hydrogen peroxide as well as their cytotoxicity on RAW 264.7 macrophage cells and red blood cells (RBC).

Results

The aqueous and ethanol extracts of Bridelia micrantha showed antiplasmodial activity on the 3D7 strain with IC₅₀ of 31.65 ± 0.79 μg/ml and 19.41 ± 2.93 μg/ml, respectively, as well as 37.64 ± 0.77 μg/ml and 36.22 ± 1.04 μg/ml for the Dd2 strain, respectively. The aqueous and ethanol extracts showed free radical scavenging properties. The IC₅₀ aqueous and ethanol extract was approximately 0.0001737 μg/ml, 42.92 μg/ml, 1197 μg/ml, 63.78 μg/ml and 4.617 μg/ml, 429.9 μg/ml, 511 μg/ml, and 69.32 μg/ml for DPPH, NO, H2O2, and FRAP, respectively, which were compared to ascorbic acid (8.610e - 005 μg/ml, 2901 μg/ml, 3237 μg/ml, and 18.57 μg/ml). The aqueous and ethanol extracts of B. micrantha were found to be nontoxic with CC₅₀ values of 950 ± 6.6 μg/ml and 308.3 ± 45.4 μg/ml, respectively. Haemolysis test showed that the two extracts were not toxic.

Conclusion

These results suggest that B. micrantha can serve as an antimalarial agent. However, further studies are needed to validate the use of B. micrantha as an antimalarial.

Na2S-Mediated One-Pot Selective Deoxygenation of α-Hydroxyl Carbonyl Compounds including Natural Products

A practical method for the deoxygenation of α-hydroxyl carbonyl compounds under mild reaction conditions is reported here. The use of cheap and easy-to-handle Na₂S·9H₂O as the reductant in the presence of PPh₃ and N-chlorosuccinimide (NCS) enables the selective dehydroxylation of α-hydroxyl carbonyl compounds, including ketones, esters, amides, imides and nitrile groups. The synthetic utility is demonstrated by the late-stage deoxygenation of bioactive molecule and complex natural products.

Bioassay-Guided Fractionation, ESI-MS Scan, Phytochemical Screening, and Antiplasmodial Activity of Afzelia africana

Background. Afzelia africana is a plant species with reported numerous medicinal potentials and secondary metabolites. Various parts of the plant have been applied for the treatment of hernia, rheumatism, pain, lumbago, malaria, etc. The study seeks to evaluate the phytochemical constituents, antiplasmodial, and ESI-MS scan of bioassay-guided fractions from the methanol extract of the bark of the plant. Aims. The main aim of the study was to carry out bioassay-guided fractionation of the crude methanol extract of Afzelia africana in order to isolate fractions and to evaluate their antiplasmodial activities and ESI-MS fingerprints. Methods. The methods employed include column chromatographic fractionation, phytochemical screening, antiplasmodial activity (malaria SYBER green assay (MSF)), and ESI-MS profile (full ESI-MS scan). Results. The column chromatographic fractionation and phytochemical screening of the plant led to the separation of the following four fractions: 1 (flavonoids, phenolics, glycosides, terpenoids, and steroids), 2 (alkaloids, anthraquinones, flavonoids, phenolics, glycosides, terpenoids, and steroids), 3 (anthraquinones, flavonoids, phenolics, glycosides, terpenoids, and steroids), and 4 (alkaloids, flavonoids, phenolics, glycosides, terpenoids, and steroids). The antiplasmodial activities of the fractions were tested against the 3D7 strain of Plasmodium falciparum with reported stronger activities for 1 (IC50: 0.097 ± 0.034 μg/mL) and 3 (IC50: 1.43 ± 0.072 μg/mL), and weaker activities for 2 (IC50: >100 μg/mL) and 4 (IC50: 37.09 ± 6.14 μg/mL). The full ESI-MS fingerprint of fractions 1, 2, 3, and 4 revealed the presence of 14, 24, 34, and 37 major molecular ions or compounds in each fraction, respectively.