SUMMARYTerrestrial 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 IC 50 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 (IC 50 = 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.
Bromelia pinguin L. is a plant broadly distributed in Central America and Caribbean islands. The fruits have been used in traditional medicine as anthelmintic, probably owed to the presence of a mixture of cysteine endopeptidases, initially termed pinguinain. This work deals with the purification and characterization of the four main components of that mixture, two of them showing acid pI and the other two alkaline pI. Molecular masses (SDS-PAGE and MALDI-TOF), N-terminal sequence and the reactivity and kinetic parameters versus synthetic substrates (p-nitrophenyl-N-alpha-CBZ-amino acid esters, PFLNA, Z-Arg-Arg-p-NA, and Z-Phe-Arg-p-NA) of the studied peptidases are given, as well as the N-terminal sequences of the enzymes and the homology degree with other plant endopeptidases.
Preliminary phytochemical study of methanol extracts from Vernonanthura patens's leaves located in Marcabelí (El Oro province), Ecuador. The methodology consisted of chromatographic column separations with increasing polarity solvents and the analysis of fractions by Gas Chromatography-Mass Spectrometry coupled system (GC-MS). The structure of 53 compounds was proposed. Analyzed V. patens species showed the presence of terpene and aliphatic hydrocarbons, free fatty acids and their methyl and ethyl esters, oxygen sesqui, triterpenoids and sugars. For ecuadorian species, there are no records of chemical studies.
Recent research suggests that marine organisms may produce compounds with activity against malaria parasites. Of a total of 27 aqueous extracts from different marine species, collected on the northwest Cuban coast, 20 were considered as showing no significant activity against Plasmodium falciparum F32, with minimum inhibitory concentrations (MIC) >500 microg/ml, while seven extracts (MIC < or =500 microg/ml) were selected for further investigation by determining their selectivity indices and in vivo antimalarial activity. Three species of tunicates were chosen, as more than 50% reduction of P. berghei parasitaemia was produced after administration of 250 or 500 mg/kg of their crude extracts into infected mice. The aqueous extracts of Microcosmus goanus, Ascidia sydneiensis and Phallusia nigra were partitioned between water and n-butanol; the organic phases inhibited P. falciparum growth by 50% at concentrations of 17.5 microg/ml, 20.9 microg/ml and 29.4 microg/ml respectively. In general, these results are similar to those of most ethnobotanical surveys. Further chemical studies are being undertaken in order to isolate new antimalarial compounds from these Caribbean tunicates.
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