Avaliação da atividade antileishmania do extrato de Crinum scabrum e alcalóides da família Amaryllidaceae

Abstract

Leishmaniasis is a neglected parasitic disease that affects millions of people, mainly in tropical and subtropical regions. In Brazil, according to the Ministry of Health, there are approximately 14,000 people infected with the disease, with the North, Midwest and Northeast regions being the most affected. The disease is caused by protozoa of the genus Leishmania and is transmitted during blood transfusions by the female phlebotomine bug of the genus Lutzomyia, known as the straw mosquito. The disease can range from cutaneous and mucocutaneous lesions to visceral forms, with each clinical form correlating with the strain of Leishmania and the host's immune status. Currently, the drugs available to treat the disease consist basically of pentavalent antimonials and amphotericin B. However, due to the growing resistance to conventional treatments, the toxicity of the drugs, the limitation of available drugs and the social stigma caused by the disease, there is a need to search for new, more effective and safer therapies. In this context, natural products or their derivatives are important sources of study. Plants from the Amaryllidaceae family stand out for their diversity of secondary metabolites, including isoquinoline alkaloids, and previous studies have demonstrated various biological properties, including antiprotozoal activity for specific alkaloids from the family. In view of this, the aim of this work is to investigate the anti-leishmanial potential of Crinum scabrum extract and the alkaloids crinamine and haemantidine against the L. amazonensis protozoan through in vitro biological tests. The ethyl acetate fraction of the C. scabrum extract was the most active against promastigote forms, but the methanolic extract showed greater selectivity. Among the alkaloids isolated, haemantidine showed the greatest anti-leishmania activity and selectivity. It is hoped that these results can contribute significantly to the development of new drugs, improving the control and treatment of leishmaniasis.