Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
Add more filters










Database
Language
Publication year range
1.
PLoS Negl Trop Dis ; 11(9): e0005929, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28945741

ABSTRACT

Four sesquiterpene lactones, mikanolide, deoxymikanolide, dihydromikanolide and scandenolide, were isolated by a bioassay-guided fractionation of Mikania variifolia and Mikania micrantha dichloromethane extracts. Mikanolide and deoxymikanolide were the major compounds in both extracts (2.2% and 0.4% for Mikania variifolia and 21.0% and 6.4% for Mikania micrantha respectively, calculated on extract dry weight). Mikanolide, deoxymikanolide and dihydromikanolide were active against Trypanosoma cruzi epimastigotes (50% inhibitory concentrations of 0.7, 0.08 and 2.5 µg/mL, for each compound respectively). These sesquiterpene lactones were also active against the bloodstream trypomastigotes (50% inhibitory concentrations for each compound were 2.1, 1.5 and 0.3 µg/mL, respectively) and against amastigotes (50% inhibitory concentrations for each compound were 4.5, 6.3 and 8.5 µg/mL, respectively). By contrast, scandenolide was not active on Trypanosoma cruzi. Besides, mikanolide and deoxymikanolide were also active on Leishmania braziliensis promastigotes (50% inhibitory concentrations of 5.1 and 11.5 µg/mL, respectively). The four sesquiterpene lactones were tested for their cytotoxicity on THP 1 cells. Deoxymikanolide presented the highest selectivity index for trypomastigotes (SI = 54) and amastigotes (SI = 12.5). In an in vivo model of Trypanosoma cruzi infection, deoxymikanolide was able to decrease the parasitemia and the weight loss associated to the acute phase of the parasite infection. More importantly, while 100% of control mice died by day 22 after receiving a lethal T. cruzi infection, 70% of deoxymikanolide-treated mice survived. We also observed that this compound increased TNF-α and IL-12 production by macrophages, which could contribute to control T. cruzi infection.


Subject(s)
Lactones/pharmacology , Leishmania braziliensis/drug effects , Mikania/chemistry , Plant Extracts/pharmacology , Sesquiterpenes/pharmacology , Trypanosoma cruzi/drug effects , Animals , Chagas Disease/drug therapy , Chagas Disease/parasitology , Drug Discovery , Interleukin-12/biosynthesis , Interleukin-12/immunology , Lactones/administration & dosage , Lactones/chemistry , Lactones/isolation & purification , Lactones/therapeutic use , Life Cycle Stages/drug effects , Male , Mice , Mice, Inbred BALB C , Plant Extracts/chemistry , Sesquiterpenes/chemistry , Sesquiterpenes/isolation & purification , Sesquiterpenes, Germacrane/administration & dosage , Sesquiterpenes, Germacrane/isolation & purification , Sesquiterpenes, Germacrane/pharmacology , Sesquiterpenes, Germacrane/therapeutic use , Trypanosoma cruzi/isolation & purification , Tumor Necrosis Factor-alpha/biosynthesis , Tumor Necrosis Factor-alpha/immunology
2.
Pharm Biol ; 54(10): 2188-95, 2016 Oct.
Article in English | MEDLINE | ID: mdl-26983579

ABSTRACT

Context Chagas' disease and leishmaniasis produce significant disability and mortality with great social and economic impact. The genus Stevia (Asteraceae) is a potential source of antiprotozoal compounds. Objective Aerial parts of four Stevia species were screened on Trypanosoma cruzi. Stevia satureiifolia (Lam.) Sch. Bip. var. satureiifolia (Asteraceae) dichloromethane extract was selected for a bioassay-guided fractionation in order to isolate its active compounds. Additionally, the antileishmanial activity and the cytotoxicity of these compounds on mammalian cells were assessed. Materials and methods The dichloromethane extract was fractionated by column chromatography. The isolated compounds were evaluated using concentrations of 0-100 µg/mL on T. cruzi epimastigotes and on Leishmania braziliensis promastigotes for 72 h, on trypomastigotes and amastigotes of T. cruzi for 24 h and 120 h, respectively. The compounds' cytotoxicity (12.5-500 µg/mL) was assessed on Vero cells by the MTT assay. The structure elucidation of each compound was performed by spectroscopic methods and HPLC analysis. Results The dichloromethane extracts of Stevia species showed significant activity on T. cruzi epimastigotes. The flavonoids eupatorin (1.3%), cirsimaritin (1.9%) and 5-desmethylsinensetin (1.5%) were isolated from S. satureiifolia var. satureiifolia extract. Eupatorin and 5-desmethylsinensetin showed IC50 values of 0.2 and 0.4 µg/mL on T. cruzi epimastigotes and 61.8 and 75.1 µg/mL on trypomastigotes, respectively. The flavonoid 5-desmethylsinensetin showed moderate activity against T. cruzi amastigotes (IC50 value = 78.7 µg/mL) and was the most active compound on L. braziliensis promastigotes (IC50 value = 37.0 µg/mL). Neither of the flavonoids showed cytotoxicity on Vero cells, up to a concentration of 500 µg/mL.


Subject(s)
Leishmania braziliensis/drug effects , Plant Extracts/pharmacology , Stevia , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/drug effects , Animals , Cell Survival/drug effects , Chemical Fractionation , Chlorocebus aethiops , Chromatography, High Pressure Liquid , Dose-Response Relationship, Drug , Inhibitory Concentration 50 , Leishmania braziliensis/growth & development , Methylene Chloride/chemistry , Parasitic Sensitivity Tests , Phytotherapy , Plant Components, Aerial , Plant Extracts/isolation & purification , Plant Extracts/toxicity , Plants, Medicinal , Solvents/chemistry , Stevia/chemistry , Trypanocidal Agents/isolation & purification , Trypanocidal Agents/toxicity , Trypanosoma cruzi/growth & development , Vero Cells
3.
ScientificWorldJournal ; 2012: 121253, 2012.
Article in English | MEDLINE | ID: mdl-22919289

ABSTRACT

The aim of this study was to investigate the antiprotozoal and antiviral activities of four Argentinean Mikania species. The organic and aqueous extracts of Mikania micrantha, M. parodii, M. periplocifolia, and M. cordifolia were tested on Trypanosoma cruzi epimastigotes, Leishmania braziliensis promastigotes, and dengue virus type 2. The organic extract of M. micrantha was the most active against T. cruzi and L. braziliensis exhibiting a growth inhibition of 77.6 ± 4.5% and 84.9 ± 6.1%, respectively, at a concentration of 10 µg/ml. The bioguided fractionation of M. micrantha organic extract led to the identification of two active fractions. The chromatographic profile and infrared analysis of these fractions revealed the presence of sesquiterpene lactones. None of the tested extracts were active against dengue virus type 2.


Subject(s)
Antiprotozoal Agents/pharmacology , Antiviral Agents/pharmacology , Mikania/chemistry , Plant Extracts/pharmacology , Chromatography, High Pressure Liquid , Dengue Virus/drug effects , In Vitro Techniques , Leishmania braziliensis/drug effects , Spectroscopy, Fourier Transform Infrared , Trypanosoma cruzi/drug effects
4.
Am J Bot ; 92(2): 352-69, 2005 Feb.
Article in English | MEDLINE | ID: mdl-21652411

ABSTRACT

In order to clarify the relationships among southern South American (sSA) representatives of the genus Ilex, an amplified fragment length polymorphism (AFLP) analysis was accomplished. In addition, the phylogenetic relationships of the species were studied using ribosomal internal transcribed spacer (ITS) sequence data alone and in combination with AFLP data, taking into account the possible existence of paralogous sequences and the influence of alignment parameters. To explore stability of phylogenetic hypotheses, a sensitivity analysis was performed using 15 indel-substitution models. Within each species assayed, the AFLPs allowed the recognition of several diagnostic bands. Furthermore, the AFLP analysis revealed that individuals belonging to the same morpho-species formed coherent clades. In addition, some cases of geographical association were noted. Studies on ITS sequences revealed divergence between data obtained herein and sequence data downloaded from GenBank. The sensitivity analyses yielded different interspecific hypotheses of relationships. Notwithstanding, analyses of the ITS data alone and in combination with AFLPs, rendered clades stable to variation in the analytical parameters. Topologies obtained for the AFLPs, the ITS data alone and the combined analyses, demonstrated the existence of a group formed by I. argentina, I. brasiliensis, I. brevicuspis, I. integerrima, and I. theezans, and that I. dumosa and I. paraguariensis were distantly related to the former. Incongruence with traditional taxonomical treatments was found.

SELECTION OF CITATIONS
SEARCH DETAIL
...