RESUMO
Background: Infectious diseases are the worst problem in tropical and subtropical regions of the world. The Nupe ethnic group from Nigeria has been using the leaves of Abrus precatorius for treatment of malaria and various forms of cancers. However studies have shown that the plant has antimicrobial and anti-cancer activities. In this study the crude methanolic extract, methanolic, ethyl acetate, chloroform and n-hexane fractions of Abrus precatorius leaf were tested In vitro against chloroquine and pyrimethamine resistant Plasmodium falciparum K1, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovoni and rat skeletal myoblasts (L-6 cells). Methods: The leaf ingredients were extracted and separated via methanol, ethyl acetate, chloroform and n-hexane solvents using column chromatography. In vitro activity against erythrocytic stages of P. falciparum was determined by a modified [3H]-hypoxanthine incorporation assay. In vitro activities against T. brucei rhodesiense, T. cruzi and L. donovoni and cytotoxicity against L6 cells line were assayed. Regression analysis was adopted for computation of the 50% inhibitory concentrations. The antiprotozoan activity of the extracts was qualified as active when IC50 value was less than 50 g/ml. The extract that showed selectivity index higher than 3.29 was considered to have potential for safer therapy. Results: n-hexane fraction showed the best antiplasmodial activity with inhibitory concentration (IC50) value of 12.1 g/ml followed by chloroform fraction (23.0 g/ml), crude methanolic extract (30.4 g/ml) and ethyl acetate fraction (45.9 g/ml) with selectivity index of 3.66, 1.90, 2.18 and 3.29 respectively. Chloroform fraction showed the best activity against T. brucei rhodesiense with IC50 value of 17.9 g/ml and selectivity index of 2.44 and followed by n-hexane fraction with IC50 (34.5 g/ml) and selectivity index of 1.28. Conclusion: Since leaf extract has significant antiplasmodial, antitrypanosomal and antileshmanial activities in vitro, bioassay guided isolation of the active principles can be done with a view to discovering novel drugs for the treatment of malaria, trypanosomiasis and leishmaniasis.
RESUMO
Aim: Malaria is a very serious deadly disease that has attracted the attention of many researchers all over the world. Because a lot of work has been done in the area of malariology, there is need to understand its advance pattern and therapeutic regimens. Methods: Past and recent literatures on malaria were searched for information on history, global situation, classification, biology, pathology, pathogenesis, diagnosis, treatment and control of malaria to assess the progress made so far in the area of malariology. Results: Malaria is an ancient disease recognized by Hippocrates over 2413 years ago, caused by Plasmodium species, first identified by Charles-laveran 123 years ago affect 300–500 millions human worldwide, responsible for 3 deaths in every 30 seconds. The knowledge of classification, biology, pathology, pathogenesis, diagnosis and treatment of malaria is a tremendous achievement towards the control of the disease. Conclusion: But complete elimination of malaria perhaps will still take another time, since lots need to be known about the molecular biology of antigenic shift and drift, nature and mechanisms of action of the parasite toxin, in order to have basis for definite vaccine development. By so doing, radical cure and total eradication of malaria can be achieved.