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Teles C.B.G.,Institute Pesquisas Em Patologias Tropicais Of Rondonia Ipepatro | Moreira L.S.,Federal University of Rondônia | Silva A.De.A.E.,Institute Pesquisas Em Patologias Tropicais Of Rondonia Ipepatro | Silva A.De.A.E.,Federal University of Rondônia | And 5 more authors.
Journal of the Brazilian Chemical Society | Year: 2011

This paper describes the activity of the ethanolic extract (EE), obtained from the fruits of Combretum leprosum, the triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene (1) and its synthetic derivatives la-ld on Leishmania amazonensis promastigotes. The EE displayed leishmanicidal activity and the IC50 was 24.8 μg mL-1. However, the triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene (1), at a concentration of 5.0 μg mL-1, showed a potent inhibitory activity on promastigotes proliferation (IC50 = 3.3 μg mL-1). Among the synthetic derivatives, only (1b) and (1d) were active against promastigotes (IC 50 = 3.48 μg mL-1and 5.8 μg mL-1, respectively). Moreover, the synthetic derivative la showed no activity on promastigotes of L. amazonensis. EE, (1) and the synthetic derivatives la-ld showed no cytotoxic effect on mice peritoneal macrophages. These results provide evidence that the ethanolic extract and the lupane isolated from C. leprosum was active against promastigotes of L. amazonensis, and may be used as a tool in the studies of new antileishmanial drugs. © 2011 Sociedade Brasileira de Química.

Azevedo Calderon L.D.,Federal University of Rondônia | Azevedo Calderon L.D.,Institute Pesquisas Em Patologias Tropicais Of Rondonia Ipepatro | Silva A.D.A.E.,Institute Pesquisas Em Patologias Tropicais Of Rondonia Ipepatro | Silva A.D.A.E.,Federal University of Rondônia | And 2 more authors.
Amino Acids | Year: 2011

Screening for new bioactive peptides in South American anurans has been pioneered in frogs of the genus Phyllomedusa. All frogs of this genus have venomous skin secretions, i.e., a complex mixture of bioactive peptides against potential predators and pathogens that presumably evolved in a scenario of predator-prey interaction and defense against microbial invasion. For every new anuran species studied new peptides are found, with homologies to hormones, neurotransmitters, antimicrobials, and several other peptides with unknown biological activity. From Vittorio Erspamer findings, this genus has been reported as a "treasure store" of bioactive peptides, and several groups focus their research on these species. From 1966 to 2009, more than 200 peptide sequences from different Phyllomedusa species were deposited in UniProt and other databases. During the last decade, the emergence of high-throughput molecular technologies involving de novo peptide sequencing via tandem mass spectrometry, cDNA cloning, pharmacological screening, and surface plasmon resonance applied to peptide discovery, led to fast structural data acquisition and the generation of peptide molecular libraries. Research groups on bioactive peptides in Brazil using these new technologies, accounted for the exponential increase of new molecules described in the last decade, much higher than in any previous decades. Recently, these secretions were also reported as a rich source of multiple antimicrobial peptides effective against multidrug resistant strains of bacteria, fungi, protozoa, and virus, providing instructive lessons for the development of new and more efficient nanotechnological-based therapies for infectious diseases treatment. Therefore, novel drugs arising from the identification and analysis of bioactive peptides from South American anuran biodiversity have a promising future role on nanobiotechnology. © 2010 Springer-Verlag.

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