title: Antiplasmodial and Cytotoxic Activities of Toad Venoms from Southern Amazon, Brazil.
abstract: The drug-resistance of malaria parasites is the main problem in the disease control. The huge Brazilian biodiversity promotes the search for new compounds, where the animal kingdom is proving to be a promising source of bioactive compounds. The main objective of this study was to evaluate the antiplasmodial and cytotoxic activity of the compounds obtained from the toad venoms of Brazilian Amazon. Toad venoms were collected from the secretion of Rhinella marina and Rhaebo guttatus in Mato Grosso State, Brazil. The powder was extracted at room temperature, yielding 2 extracts (RG and RM) and a substance ('1') identified as a bufadienolide, named telocinobufagin. Growth inhibition, intraerythrocytic development, and parasite morphology were evaluated in culture by microscopic observations of Giemsa-stained thin blood films. Cytotoxicity was determined against HepG2 and BGM cells by MTT and neutral red assays. The 2 extracts and the pure substance ('1') tested were active against chloroquine-resistant Plasmodium falciparum strain, demonstrating lower IC50 values. In cytotoxic tests, the 2 extracts and substance '1' showed pronounced lethal effects on chloroquine-resistant P. faciparum strain and low cytotoxic effect, highlighting toad parotoid gland secretions as a promising source of novel lead antiplasmodial compounds.
authors.affiliation: Universidade Federal de Mato Grosso, Instituto de Ciências da Saúde, Sinop, MT, Brazil.
authors.forename: Felipe Finger
authors.initials: FF
authors.lastname: Banfi
authors.affiliation: Universidade Federal de Mato Grosso, Instituto de Ciências da Saúde, Sinop, MT, Brazil.
authors.forename: Karla de Sena
authors.initials: Kde S
authors.lastname: Guedes
authors.affiliation: Universidade Federal de Mato Grosso, Instituto de Ciências da Saúde, Sinop, MT, Brazil.
authors.forename: Carla Regina
authors.initials: CR
authors.lastname: Andrighetti
authors.affiliation: Laboratório de Química Medicinal e Experimental, Universidade de São Paulo, São Carlos, SP, Brazil.
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Aguiar
authors.affiliation: Universidade Federal de Mato Grosso, Instituto de Ciências Naturais, Humanas e Sociais, Sinop, MT, Brazil.
authors.forename: Bryan Wender
authors.initials: BW
authors.lastname: Debiasi
authors.affiliation: Universidade Federal de Mato Grosso, Instituto de Ciências Naturais, Humanas e Sociais, Sinop, MT, Brazil.
authors.forename: Janaina da Costa
authors.initials: Jda C
authors.lastname: Noronha
authors.affiliation: Universidade Federal de Mato Grosso, Instituto de Ciências Naturais, Humanas e Sociais, Sinop, MT, Brazil.
authors.forename: Domingos de Jesus
authors.initials: Dde J
authors.lastname: Rodrigues
authors.affiliation: Universidade Federal do Piauí, Departamento de Química, Teresina, PI, Brazil.
authors.forename: Gerardo Magela Vieira
authors.initials: GM
authors.lastname: Júnior
authors.affiliation: Universidade Federal de Mato Grosso, Instituto de Ciências da Saúde, Sinop, MT, Brazil.
authors.forename: Bruno Antonio Marinho
authors.initials: BA
authors.lastname: Sanchez
mesh_terms: D000664:Amphibian Venoms / Q000737:chemistry* / Q000302:isolation & purification; D000818:Animals; D000981:Antiprotozoal Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity*; D001688:Biological Products / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity*; D001938:Brazil; D002025:Bufonidae; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D020128:Inhibitory Concentration 50; D010963:Plasmodium falciparum / Q000187:drug effects*
chemical_list: D000664:Amphibian Venoms; D000981:Antiprotozoal Agents; D001688:Biological Products
keywords: Plasmodium falciparum; antiplasmodial effect; bufadienolide; malaria chemotherapy; toad venom