Acridine and acridinones: old and new structures with antimalarial activity.

Since emergence of chloroquine-resistant Plasmodium falciparum and reports of parasite resistance to alternative drugs, there has been renewed interest in the antimalarial activity of acridines and their congeners, the acridinones. This article presents literature compilation of natural acridinone alkaloids and synthetic 9-substituted acridines, acridinediones, haloalcoxyacridinones and 10-N-substituted acridinones with antimalarial activity. The review also provides an outlook to antimalarial modes of action of some described compounds.

[Antimalarial activity and cytotoxicity of hydroalcoholic extracts from six plant species used in Cuban traditional medicine]. / Actividad antimalárica y citotoxicidad de extractos hidroalcohólicos de seis especies de plantas usadas en la medicina tradicional cubana.

INTRODUCTION: Malaria is the most important parasitic disease for global health. Lack of the structural diversity in current antimalarials demands the urgent search for new therapeutic alternatives. The plants have shown their potential to provide effective antimalarials, therefore, a large sample of Cuban medicinal plants is being studied. OBJECTIVES: To evaluate antimalarial activity of extracts from six plant species and to determine their selectivity by meassuring cytotoxicity against human cells. METHODS: Hydroalcoholic extracts from Annona glabra L., Bidens pilosa L., Cecropia peltata L., Curcuma longa L., Hura crepitans L. and Pluchea odorata (L.) Cass. were prepared. Their activity was evaluated in vitro against Plasmodium falciparum and human fibroblasts MRC-5. The mean inhibitory concentration, the mean cytotoxic concentration and the selectivity index were estimated. A preliminary phytochemical screening of the most active extract was made. RESULTS: H. cre-pitans extract was the only one that showed good antiplasmodial activity (mean inhibitory concentration of 5,7 microg/mL) with excellent selectivity (selectivity index of 18,8). Phytochemical screening revealed the presence of phenolic compounds, triterpenoids, alkaloids, quinones, flavonoids and anthocyanidins. CONCLUSIONS: One extract with potent antimalarial activity in vitro was obtained. This result is an incentive to continue studying this vegetal preparation.

In vitro antimalarial activity and cytotoxicity of some selected cuban medicinal plants / Actividad antimalárica in vitro y citotoxicidad de algunas plantas medicinales Cubanas seleccionadas

Terrestrial plants have been demonstrated to be sources of antimalarial compounds. In Cuba, little is known about antimalarial potentials of plant species used as medicinals. For that reason, we evaluated the antimalarial activity of 14 plant species used in Cuba as antimalarial, antipyretic and/or antiparasitic. Hydroalcoholic extracts were prepared and tested in vitro for the antimalarial activity against Plasmodium falciparum Ghana strain and over human cell line MRC-5 to determine cytotoxicity. Parasite multiplication was determined microscopically by the direct count of Giemsa stained parasites. A colorimetric assay was used to quantify cytotoxicity. Nine extracts showed IC50 values lower than 100 µg/mL against P. falciparum, four extracts were classified as marginally active (SI < 4), one as partially active (Parthenium hysterophorus) exhibiting SI equal to 6.2 and two extracts as active (Bambusa vulgaris and Punica granatum), showing SI > 10. B. vulgaris showed the most potent and specific antiplasmodial action (IC50 = 4.7 µg/mL, SI = 28.9). Phytochemical characterization of active extracts confirmed the presence of triterpenoids in B. vulgaris and polar compounds with phenol free groups and fluorescent metabolites in both extracts as major phytocompounds, by thin layer chromatography. In conclusion, antimalarial use of B. vulgaris and P. hysterophorus was validated. B. vulgaris and P. granatum extracts were selected for follow-up because of their strong antimalarial activity.

Las plantas terrestres han demostrado ser fuentes de compuestos antimaláricos. En Cuba, el conocimiento sobre el potencial antimalárico de las plantas medicinales es escaso. Por esta razón, evaluamos la actividad antimalárica de 14 especies de plantas usadas en Cuba como antimaláricas, antipiréticas y/o antiparasitarias. Se prepararon extractos hidroalcohólicos y se probaron in vitro frente a la cepa Ghana de Plasmodium falciparum para la actividad antimalárica y frente a la línea celular humana MRC-5 para determinar citotoxicidad. La multiplicación de los parásitos se determinó microscópicamente mediante el conteo directo de los parásitos teñidos con Giemsa. Un ensayo colorimétrico se utilizó para cuantificar la citotoxicidad. Nueve extractos mostraron valores de CI50 frente a Plasmodium falciparum por debajo de 100 µg/mL; cuatro extractos se clasificaron como marginalmente activos (IS < 4), uno parcialmente activo (Parthenium hysterophorus) exhibiendo IS de 6.2 y dos activos (Bambusa vulgaris y Punica granatum) mostrando IS>10. B. vulgaris, mostró la acción más potente y específica (CI50 = 4,7 µg/mL, IS = 28,9). La caracterización fitoquímica de los extractos más activos; confirmó la presencia de triterpenoides en B. vulgaris y de compuestos polares con grupos fenólicos libres y metabolitos fluorescentes en ambos extractos como fitocompuestos principales mediante cromatografía en capa delgada. En conclusión, se validó el uso antimalárico de B. vulgaris y P. hysterophorus. Los extractos de B. vulgaris y P. granatum se seleccionaron para seguimiento por su potente actividad antimalárica.

In vitro antimalarial activity and cytotoxicity of some selected cuban medicinal plants.

Terrestrial plants have been demonstrated to be sources of antimalarial compounds. In Cuba, little is known about antimalarial potentials of plant species used as medicinals. For that reason, we evaluated the antimalarial activity of 14 plant species used in Cuba as antimalarial, antipyretic and/or antiparasitic. Hydroalcoholic extracts were prepared and tested in vitro for the antimalarial activity against Plasmodium falciparum Ghana strain and over human cell line MRC-5 to determine cytotoxicity. Parasite multiplication was determined microscopically by the direct count of Giemsa stained parasites. A colorimetric assay was used to quantify cytotoxicity. Nine extracts showed IC50 values lower than 100 µg/mL against P. falciparum, four extracts were classified as marginally active (SI < 4), one as partially active (Parthenium hysterophorus) exhibiting SI equal to 6.2 and two extracts as active (Bambusa vulgaris and Punica granatum), showing SI > 10. B. vulgaris showed the most potent and specific antiplasmodial action (IC50 = 4.7 µg/mL, SI = 28.9). Phytochemical characterization of active extracts confirmed the presence of triterpenoids in B. vulgaris and polar compounds with phenol free groups and fluorescent metabolites in both extracts as major phytocompounds, by thin layer chromatography. In conclusion, antimalarial use of B. vulgaris and P. hysterophorus was validated. B. vulgaris and P. granatum extracts were selected for follow-up because of their strong antimalarial activity.

In vitro anti-microbial activity of the Cuban medicinal plants Simarouba glauca DC, Melaleuca leucadendron L and Artemisia absinthium L.

In the present study, an extensive in vitro antimicrobial profiling was performed for three medicinal plants grown in Cuba, namely Simarouba glauca, Melaleuca leucadendron and Artemisia absinthium. Ethanol extracts were tested for their antiprotozoal potential against Trypanosoma b. brucei, Trypanosoma cruzi, Leishmania infantum and Plasmodium falciparum. Antifungal activities were evaluated against Microsporum canis and Candida albicans whereas Escherichia coli and Staphylococcus aureus were used as test organisms for antibacterial activity. Cytotoxicity was assessed against human MRC-5 cells. Only M. leucadendron extract showed selective activity against microorganisms tested. Although S. glauca exhibited strong activity against all protozoa, it must be considered non-specific. The value of integrated evaluation of extracts with particular reference to selectivity is discussed.

Actividad semejante a catepsina L en la hemolinfa de hembras repletas de Boophilus microplus / Cathepsin L-like activity in hemolymph of females crammed with Boophilus microplus

The cysteine-proteinase activity present in the hemolymph of females crammed with Boophilus microplus at the second oviposition was proved. The enzyme assay was performed using the synthetic N-carbobenzoxi-phenilalanyl-arginil-4-metoxibetan++ +-naphthylamide substrate, and hydrolysis in both raw ovarim extract and hemolymph were observed. The activity was 100 inhibited by trans-epoxisuscinyl-L-leucidamide (4-guadinine) butane, an specific inhibitor for cysteine-proteinase. Polyacrylamide and gelatin-gel electrophoresis showed the existence of only one active band in both samples tested with the same electrophoretic sliding (approximately 38 kDa).