title: Antileishmanial activity of meroditerpenoids from the macroalgae Cystoseira baccata.
abstract: The development of novel drugs for the treatment of leishmaniases continues to be crucial to overcome the severe impacts of these diseases on human and animal health. Several bioactivities have been described in extracts from macroalgae belonging to the Cystoseira genus. However, none of the studies has reported the chemical compounds responsible for the antileishmanial activity observed upon incubation of the parasite with the aforementioned extracts. Thus, this work aimed to isolate and characterize the molecules present in a hexane extract of Cystoseira baccata that was found to be bioactive against Leishmania infantum in a previous screening effort. A bioactivity-guided fractionation of the C. baccata extract was carried out and the inhibitory potential of the isolated compounds was evaluated via the MTT assay against promastigotes and murine macrophages as well as direct counting against intracellular amastigotes. Moreover, the promastigote ultrastructure, DNA fragmentation and changes in the mitochondrial potential were assessed to unravel their mechanism of action. In this process, two antileishmanial meroditerpenoids, (3R)- and (3S)-tetraprenyltoluquinol (1a/1b) and (3R)- and (3S)-tetraprenyltoluquinone (2a/2b), were isolated. Compounds 1 and 2 inhibited the growth of the L. infantum promastigotes (IC50= 44.9 ± 4.3 and 94.4 ± 10.1 μM, respectively), inducing cytoplasmic vacuolization and the presence of coiled multilamellar structures in mitochondria as well as an intense disruption of the mitochondrial membrane potential. Compound 1 decreased the intracellular infection index (IC50= 25.0 ± 4.1 μM), while compound 2 eliminated 50% of the intracellular amastigotes at a concentration > 88.0 μM. This work identified compound 2 as a novel metabolite and compound 1 as a biochemical isolated from Cystoseira algae displaying antileishmanial activity. Compound 1 can thus be an interesting scaffold for the development of novel chemotherapeutic molecules for canine and human visceral leishmaniases studies. This work reinforces the evidence of the marine environment as source of novel molecules.
authors.affiliation: Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
authors.forename: Carolina
authors.initials: C
authors.lastname: Bruno de Sousa
authors.affiliation: Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, Faro, Portugal; Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Katkam N
authors.initials: KN
authors.lastname: Gangadhar
authors.affiliation: Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brazil.
authors.forename: Thiago R
authors.initials: TR
authors.lastname: Morais
authors.affiliation: Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brazil.
authors.forename: Geanne A A
authors.initials: GA
authors.lastname: Conserva
authors.affiliation: Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Vizetto-Duarte
authors.affiliation: Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Pereira
authors.affiliation: Laboratório de Patologia das Moléstias Infecciosas (LIM-50), Departamento de Patologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Márcia D
authors.initials: MD
authors.lastname: Laurenti
authors.affiliation: Global Health and Tropical Medicine Centre, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal; Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
authors.forename: Lenea
authors.initials: L
authors.lastname: Campino
authors.affiliation: Laboratório de Genética e Hematologia Molecular (LIM-31), Departamento de Clinica Médica, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Debora
authors.initials: D
authors.lastname: Levy
authors.affiliation: Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brazil.
authors.forename: Miriam
authors.initials: M
authors.lastname: Uemi
authors.affiliation: Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
authors.forename: Luísa
authors.initials: L
authors.lastname: Barreira
authors.affiliation: Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, Faro, Portugal.
authors.forename: Luísa
authors.initials: L
authors.lastname: Custódio
authors.affiliation: São Paulo State University (UNESP), Institute of Biosciences, São Vicente, Praça Infante Dom Henrique, s/n, 11330-900 São Vicente, SP, Brazil.
authors.forename: Luiz Felipe D
authors.initials: LF
authors.lastname: Passero
authors.affiliation: Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brazil. Electronic address: joao.lago@unifesp.br.
authors.forename: João Henrique G
authors.initials: JH
authors.lastname: Lago
authors.affiliation: Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, Faro, Portugal. Electronic address: jvarela@ualg.pt.
authors.forename: João
authors.initials: J
authors.lastname: Varela
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018533:Biomass; D053938:DNA Fragmentation; D016054:DNA, Protozoan / Q000187:drug effects; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D018314:Leishmania infantum / Q000187:drug effects* / Q000235:genetics / Q000648:ultrastructure; D017737:Macrophages, Peritoneal / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism; D000459:Phaeophyceae / Q000737:chemistry*; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000494:pharmacology; D011174:Portugal; D013053:Spectrophotometry / Q000379:methods
chemical_list: D000981:Antiprotozoal Agents; D016054:DNA, Protozoan; D004224:Diterpenes; D010767:Phosphorylcholine; D009569:Nitric Oxide; C039128:miltefosine
keywords: Cystoseira baccata; Leishmania infantum; Macroalgae; Meroterpenoids; Tetraprenyltoluquinol; Tetraprenyltoluquinone