title: The in vitro biological activity of the Brazilian brown seaweed Dictyota mertensii against Leishmania amazonensis.
abstract: Seaweeds present a wide variety of interesting bioactive molecules. In the present work we evaluated the biological activity of the dichloromethane/methanol (2:1) extract (DME) from the brown seaweed Dictyota mertensii against Leishmania amazonensis and its cytotoxic potential on mammalian cells. The extract showed significant inhibitory effect on the growth of promastigote forms (IC50=71.60 μg/mL) and low toxicity against mammalian cells (CC50=233.10 μg/mL). The DME was also efficient in inhibiting the infection in macrophages, with CC50 of 81.4 μg/mL and significantly decreased the survival of amastigote forms within these cells. The selectivity index showed that DME was more toxic to both promastigote (SI=3.25) and amastigote (SI=2.86) forms than to macrophages. Increased NO production was observed in treated macrophages suggesting that besides acting directly on the parasites, the DME also shows an immunomodulatory effect on macrophages. Drastic ultrastructural alterations consistent with loss of viability and cell death were observed in treated parasites. Confocal microscopy and cytometry analyzes showed no significant impairment of plasma membrane integrity, whereas an intense depolarization of mitochondrial membrane could be observed by using propidium iodide and rhodamine 123 staining, respectively. The low toxicity to mammalian cells and the effective activity against promastigotes and amastigotes, point to the use of DME as a promising agent for the treatment of cutaneous leishmaniasis.
authors.affiliation: Departamento de Microbiologia, Centro de Pesquisa Aggeu Magalhães (CPqAM-FIOCRUZ), Av. Moraes Rego s/n Cidade Universitária, Campus da UFPE, Recife 50670-420, Brazil. Amanda_alianca@yahoo.com.br.
authors.forename: Amanda Silva
authors.initials: AS
authors.lastname: dos Santos Aliança
authors.affiliation: Departamento de Microbiologia, Centro de Pesquisa Aggeu Magalhães (CPqAM-FIOCRUZ), Av. Moraes Rego s/n Cidade Universitária, Campus da UFPE, Recife 50670-420, Brazil. keicyanne1@yahoo.com.br.
authors.forename: Keicyanne Fernanda Lessa
authors.initials: KF
authors.lastname: dos Anjos
authors.affiliation: Departamento de Oceanografia, Universidade Federal de Pernambuco (UFPE), Recife 50740-550, Brazil. reistnv@gmail.com.
authors.forename: Thiago Nogueira
authors.initials: TN
authors.lastname: de Vasconcelos Reis
authors.affiliation: Departamento de Microbiologia, Centro de Pesquisa Aggeu Magalhães (CPqAM-FIOCRUZ), Av. Moraes Rego s/n Cidade Universitária, Campus da UFPE, Recife 50670-420, Brazil. taciana@cpqam.fiocruz.br.
authors.forename: Taciana Mirely Maciel
authors.initials: TM
authors.lastname: Higino
authors.affiliation: Departamento de Imunologia Centro de Pesquisa Aggeu Magalhães (CPqAM-FIOCRUZ), Av. Moraes Rego s/n Cidade Universitária, Campus da UFPE, Recife 50670-420, Brazil. carolina.brelaz@gmail.com.
authors.forename: Maria Carolina Accioly
authors.initials: MC
authors.lastname: Brelaz-de-Castro
authors.affiliation: Programa de Pós-graduação em Química, Fundação Universidade Regional de Blumenau (FURB), Campus 1, Rua Antonio da Veiga, 140, Blumenal 89012-900, Brazil. ebianco@chemist.com.
authors.forename: Éverson Miguel
authors.initials: ÉM
authors.lastname: Bianco
authors.affiliation: Departamento de Microbiologia, Centro de Pesquisa Aggeu Magalhães (CPqAM-FIOCRUZ), Av. Moraes Rego s/n Cidade Universitária, Campus da UFPE, Recife 50670-420, Brazil. bressan@cpqam.fiocruz.br.
authors.forename: Regina Celia Bressan Queiroz
authors.initials: RC
authors.lastname: de Figueiredo
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002478:Cells, Cultured; D004353:Drug Evaluation, Preclinical; D020128:Inhibitory Concentration 50; D007891:Leishmania / Q000187:drug effects*; D007896:Leishmaniasis / Q000188:drug therapy*; D017737:Macrophages, Peritoneal / Q000378:metabolism / Q000469:parasitology; D008807:Mice, Inbred BALB C; D051336:Mitochondrial Membranes / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism; D000459:Phaeophyceae / Q000737:chemistry*
chemical_list: D000981:Antiprotozoal Agents; D009569:Nitric Oxide