Atividade anti-plasmodial do extrato hidroalcoólico de Libidibia ferrea mart. ex tul. var. ferrea

Abstract

Malaria is an infectious and parasitic disease that affects millions of people in the tropical and subtropical regions of the world. In Brazil, most cases are in the Legal Amazon, especially due to the favorable conditions for the existence of the vector. Malaria, a disease caused by protozoa of the genus Plasmodium, is the protozoan that kills most human beings in the world. The resistance described in Southeast Asia by Plasmodium falciparum, to artemisinin derivatives, a drug classically used to treat the disease, threatens malaria control, highlighting the need for the development of new drugs, especially natural products. Medicines from natural substances are able to treat about 80% of the diseases that affect humanity. Libidibia ferrea Mart. ex Tul. var. ferrea, is a tree that grows throughout Brazil, being found mainly in the North and Northeast regions, being commonly known as jucá. Jucá has been extensively investigated for its various biological properties (anti-inflammatory, analgesic, anticancer, antioxidant, antimicrobial and healing) but there are no studies on its action against Plasmodium parasites. In this context, the objective was to evaluate the in vitro anti-plasmodial activity of the hydroalcoholic extract of Jucá (L. ferrea) (EHJ). The preparation of the hydroalcoholic extract of Jucá was carried out using fruits, the fruits (1.5 kg) were sanitized with 70º Gl alcohol and dried at room temperature. After 48 hours, the fruits were placed in a forced air circulation oven at 40ºC for 72 hours. Subsequently, the fruits were crushed and placed for maceration in 96° Gl alcohol, in the proportion of 5 liters to 1 kg of fruit, for 7 days. Then, the macerate was filtered and the tincture was extracted using a rotary evaporator. For the cytotoxicity assay, the MTT method with WI- 26VA4 cells (ATCC CCL-75 lung fibroblast) was used. This test consists of the rapid colorimetric evaluation of the growth of cell lines in vitro. To obtain the intraerythrocyte phases of Plasmodium falciparum, parasites of the W2 strain (chloroquine-resistant) were cultured in human red blood cells in vitro under ideal conditions for growth. For the anti-plasmodial test, synchronized cultures of P. falciparum with 0.5% ring-stage parasitemia and 2% hematocrit were distributed in a 96-well plate (180μL per well). The tested compound was added (20μL) to the test plate, in triplicate, and in different serial concentrations from 50 to 0.20μg/mL. In the tests performed, cytotoxicity was recorded as the percentage of reduction in absorbance. The hydroalcoholic extract of Jucá did not show cytotoxic activity by MTT, with an IC50 value greater than 100 µg/ml. In the determination of IC50 by anti-plasmodial test, the value was 11.10 µg/ml. In addition, the selectivity index (SI) 9 was obtained, which corresponds to the relationship between the cytotoxic and anti-plasmodial activities of the hydroalcoholic extract of Jucá. The extract showed low hemolytic activity at the highest concentrations and did not show hemolytic activity at the lowest concentrations tested. Due to its anti-plasmodial activity at the concentrations tested and low toxicity, the Jucá extract is presented as a candidate for herbal medicine in the treatment of malaria, and may also potentiate its effect if associated with other herbal medicines.