Leishmaniose e doença de Chagas afetam milhões de pessoas em regiões tropicais e subtropicais. As drogas atualmente usadas para tratar estas doenças frequentemente apresentam efeitos colaterais indesejáveis e baixa eficiência. Este trabalho teve como objetivo encontrar extratos, frações e compostos isolados de espécies do gênero Lippia com atividades leishmanicida e tripanocida. Quinze extratos de diferentes partes de plantas do gênero Lippia, com composições químicas parcialmente conhecidas, quatro frações de partição, seis substâncias e uma mistura de quatro flavanonas interconversíveis isolados de Lippia salviaefolia e Lippia lupulina foram testados, in vitro, frente a formas epimastigotas de Trypanosoma cruzi e promastigotas de Leishmania amazonensis. O extrato etanólico das raízes de L. lupulina apresentou atividade potente contra T. cruzi e L. amazonensis (IC50 de 20,0 e 54,5 µg mL-1, respectivamente), enquanto que o ácido oleanônico mostrou as atividades mais fortes contra estes protozoários, com IC50 de 18,5 e 29,9 µM, respectivamente. Estes resultados indicam que espécies do gênero Lippia e seus derivados merecem investigações adicionais na busca por novas terapias antiprotozoárias, especialmente para o tratamento de leishmaniose e doença de Chagas.

ABSTRACT Leishmaniasis and Chagas disease affect millions of people in tropical and subtropical regions. Drugs used currently to treat such diseases often present undesirable side effects and low efficiency. The aim of this work was to identify extracts and isolated compounds from the genus Lippia with leishmanicidal and trypanocidal activity. Fifteen extracts from different plant parts of Lippia species with partially known chemical compositions, four partition fractions, six compounds and a mixture of four interconverting flavanones previously isolated from Lippia salviaefolia and Lippia lupulina were assayed in vitro towards epimastigote forms of Trypanosoma cruzi and promastigote forms of Leishmania amazonensis. The root extract of L. lupulina had potent activity against T. cruzi and L. amazonensis (IC50 of 20.0 and 54.5 µg mL-1, respectively). The triterpenoid oleanonic acid showed the strongest activity against these protozoans (IC50 of 18.5 and 29.9 µM, respectively). Our results indicate that Lippia plants and their derivatives deserve further investigation in the search for new antiprotozoal drugs, particularly for the treatment of leishmaniasis and Chagas disease.

The use of indigenous or remote popular knowledge to identify new drugs against diseases or infections is a well-known approach in medicine. The inhabitants of coastal regions are known to prepare algae extracts for the treatment of disorders and ailments such as wounds, fever and stomach aches, as for the prevention of arrhythmia. Recent trends in drug research from natural sources have indicated that marine algae are a promising source of novel biochemically active compounds, especially with antiprotozoal activity. Algae survive in a competitive environment and, therefore, developed defense strategies that have resulted in a significant level of chemical structural diversity in various metabolic pathways. The exploration of these organisms for pharmaceutical and medical purposes has provided important chemical candidates for the discovery of new agents against neglected tropical diseases, stimulating the use of sophisticated physical techniques. This current review describes the main substances biosynthesized by benthic marine algae with activity against Leishmaniaspp., Trypanosoma cruziand Trypanosoma brucei; the causative agents of leishmaniasis, Chagas disease and African trypanosomiasis, respectively. Emphasis is given to secondary metabolites and crude extracts prepared from marine algae.