RESUMO
Extracts from twelve samples of propolis collected from different regions of Libya were tested for their activity against Trypanosoma brucei, Leishmania donovani, Plasmodium falciparum, Crithidia fasciculata and Mycobacterium marinum and the cytotoxicity of the extracts was tested against mammalian cells. All the extracts were active to some degree against all of the protozoa and the mycobacterium, exhibiting a range of EC50 values between 1.65 and 53.6 µg/ml. The toxicity against mammalian cell lines was only moderate; the most active extract against the protozoan species, P2, displayed an IC50 value of 53.2 µg/ml. The extracts were profiled by using liquid chromatography coupled to high resolution mass spectrometry. The data sets were extracted using m/z Mine and the accurate masses of the features extracted were searched against the Dictionary of Natural Products (DNP). A principal component analysis (PCA) model was constructed which, in combination with hierarchical cluster analysis (HCA), divided the samples into five groups. The outlying groups had different sets of dominant compounds in the extracts, which could be characterised by their elemental composition. Orthogonal partial least squares (OPLS) analysis was used to link the activity of each extract against the different micro-organisms to particular components in the extracts.
Assuntos
Anti-Infecciosos/química , Antiprotozoários/química , Testes de Sensibilidade Microbiana , Própole/química , Animais , Anti-Infecciosos/farmacologia , Antiprotozoários/farmacologia , Produtos Biológicos/química , Cromatografia Líquida , Análise por Conglomerados , Crithidia fasciculata/efeitos dos fármacos , Feminino , Geografia , Humanos , Concentração Inibidora 50 , Análise dos Mínimos Quadrados , Leishmania donovani/efeitos dos fármacos , Líbia , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium marinum/efeitos dos fármacos , Extratos Vegetais/química , Plasmodium falciparum/efeitos dos fármacos , Análise de Componente Principal , Própole/farmacologia , Software , Trypanosoma brucei brucei/efeitos dos fármacos , Células U937RESUMO
Propolis is increasingly being explored as a source of biologically active compounds. Until now, there has been no study of Libyan propolis. Two samples were collected in North East Libya and tested for their activity against Trypanosoma brucei. Extracts from both samples had quite high activity. One of the samples was fractionated and yielded a number of active fractions. Three of the active fractions contained single compounds, which were found to be 13-epitorulosal, acetyl-13-epi-cupressic acid and 13-epi-cupressic acid, which have been described before in Mediterranean propolis. Two of the compounds had a minimum inhibitory concentration value of 1.56 µg/mL against T. brucei. The active fractions were also tested against macrophages infected with Leishmania donovani, and again moderate to strong activity was observed with the compounds having IC50 values in the range 5.1-21.9 µg/mL.
Assuntos
Antiprotozoários/farmacologia , Diterpenos/isolamento & purificação , Diterpenos/farmacologia , Própole/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Animais , Diterpenos/química , Concentração Inibidora 50 , Leishmania donovani/efeitos dos fármacos , Líbia , Macrófagos Peritoneais/parasitologia , Masculino , Camundongos Endogâmicos BALB CRESUMO
Preliminary investigation of the in vitro and in vivo efficacies of different extracts from the leaves of Vernonia amygdalina (VA), a plant widely used in Nigeria was evaluated in Balb/C mice infected with a laboratory strain of Leishmania major (L. major). The ability of the methanol, hexane and aqueous extracts of the plant to suppress the infection rate and its cytotoxicity on macrophages and L929 cells were determined in the in vitro study. The in vivo study evaluated time course of infection, lesion progression and the histopathology of cutaneous lesions, liver and spleen after inoculation with metacyclic promastigotes. Methanolic extract of VA containing high levels of flavanoids, was the most potent extract as it showed the highest suppression on infectivity and viability of intracellular amastigotes at a concentration lower than that which elicited cytotoxicity on macrophages. Treatment of infected mice with methanolic extract of VA showed delayed onset of disease with a significant reduction in lesion size and attenuation of the histopathological outcome characterised by intact epidermis and less tissue destruction in skin, spleen and liver. In conclusion, these results demonstrate that VA has potent antileishmanial properties which warrants further investigation into the immunological mechanism.