Antimicrobial activity of triterpene acids against phytopathogens / Atividade antimicrobiana de triterpenos ácidos contra fitopatógenos

Phytopathogenic microorganisms, responsible for causing diseases in various types of plantations, have an immense impact on crops, reducing food production, which is one of the main problems of agriculture. Antibiotics in association with cupric fungicides have been commonly used to solve this problem, but result in toxic residues to humans, animals and the environment, in addition to not being as effective as expected. Natural products, such as triterpenes, have become an important source of new substances to fight pathogens. In this study, the triterpenes ursolic acid, oleanolic acid and gypsogenic acid were re-isolated from Miconia stenostachya. The identification of all substances was carried out based on data obtained from 1H NMR, 13C-NMR and/or comparison with authentic standards. In the assays of antimicrobial activity against nine phytopathogenic bacteria, the triterpene gypsogenic acid was the most effective with a MIC value of 3.12; 25 and 100 µg/mL, for bacteria Ralstonia solanacearum, Pseudomonas syringae and Streptmyces scabiei, respectively. The cytotoxic activity results of gypsogenic acid in GM7492A cells (human fibroblasts) indicated that the substance promoted toxic effects in the strain only at higher concentrations (above of 500 µg/mL – 1,027.3 µM)

In Vitro Schistosomicidal Activity of Some Brazilian Cerrado Species and Their Isolated Compounds

, Struthanthus syringifolius (Mart.) (Loranthaceae), and Schefflera vinosa (Cham. & Schltdl.) Frodin (Araliaceae) are plant species from the Brazilian Cerrado whose schistosomicidal potential has not yet been described. The crude extracts, fractions, the triterpenes betulin, oleanolic acid, ursolic acid and the flavonoids quercetin 3- Schistosoma mansoni adult worms and the bioactive n-hexane fractions of the mentioned species were also analyzed by GC-MS. Betulin was able to cause worm death percentage values of 25% after 120 h (at 100 μM), and 25% and 50% after 24 and 120 h (at 200 μM), respectively; besides the flavonoid quercetin 3-O-β-d-rhamnoside promoted 25% of death of the parasites at 100 μM. Farther the flavonoids quercetin 3-O-β-d-glucoside and quercetin 3-O-β-d-rhamnoside at 100 μM exhibited significantly reduction in motor activity, 75% and 87.5%, respectively. Biological results indicated that crude extracts of R. montana, S. vinosa, and M. langsdorffii and some n-hexane and EtOAc fractions of this species were able to induce worm death to some extent. The results suggest that lupane-type triterpenes and flavonoid monoglycosides should be considered for further antiparasites studies

In Vitro Schistosomicidal Activity of Some Brazilian Cerrado Species and Their Isolated Compounds

Miconia langsdorffii Cogn. (Melastomataceae), Roupala montana Aubl. (Proteaceae), Struthanthus syringifolius (Mart.) (Loranthaceae), and Schefflera vinosa (Cham. & Schltdl.) Frodin (Araliaceae) are plant species from the Brazilian Cerrado whose schistosomicidal potential has not yet been described. The crude extracts, fractions, the triterpenes betulin, oleanolic acid, ursolic acid and the flavonoids quercetin 3-O-beta-D-rhamnoside, quercetin 3-O-beta-D-glucoside, quercetin 3-O-beta-D-glucopyranosyl-(1-2)-alpha-L-rhamnopyranoside and isorhamnetin 3-O-beta-D-glucopyranosyl-(1-2)-alpha-L-rhamnopyranoside were evaluated in vitro against Schistosoma mansoni adult worms and the bioactive n-hexane fractions of the mentioned species were also analyzed by GC-MS. Betulin was able to cause worm death percentage values of 25% after 120 h (at 100 mu M), and 25% and 50% after 24 and 120 h (at 200 mu M), respectively; besides the flavonoid quercetin 3-O-beta-D-rhamnoside promoted 25% of death of the parasites at 100 mu M. Farther the flavonoids quercetin 3-O-beta-D-glucoside and quercetin 3-O-beta-D-rhamnoside at 100 mu M exhibited significantly reduction in motor activity, 75% and 87.5%, respectively. Biological results indicated that crude extracts of R. montana, S. vinosa, and M. langsdorffii and some n-hexane and EtOAc fractions of this species were able to induce worm death to some extent. The results suggest that lupane-type triterpenes and flavonoid monoglycosides should be considered for further antiparasites studies.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2006/60132-4, 2008/01268-9, 2009/00604-8]Coordenadoria de Aperfeicoamento de Pessoal do Ensino Superior (CAPES)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq

Natural products and Chagas’ disease: the action of triterpenes acids isolated from Miconia species

The protozoan Trypanosoma cruzi causes Chagas’ disease, a neglected illness that remains a relevant public health concern in Latin America. In Brazil, Benznidazole is available for its treatment. This compound is effective against circulating forms of the parasite in the acute phase of the disease, but its efficacy during the chronic stage is debatable. The search for new medications that can treat Chagas’ disease is therefore mandatory. Natural sources display a wide range of secondary metabolites and may play an important role in the discovery of new potential drugs. Miconia is one of the largest genus of the family Melastomataceae and includes approximately 1,000 plant species; Brazil alone is home to approximately 250 of these species, which exist in forests and savannas. Studies on the various biological activities of the Miconia species have reported promising results. Several researchers have screened these plants as well as their extracts in vitro against trypomastigote forms of T. cruzi, which displayed significant trypanocidal activity. It has been demonstrated that the presence of ursolic and oleanolic determines this biological activity

Natural products and Chagas’ disease: the action of triterpenes acids isolated from Miconia species

The protozoan Trypanosoma cruzi causes Chagas’ disease, a neglected illness that remains a relevant public health concern in Latin America. In Brazil, Benznidazole is available for its treatment. This compound is effective against circulating forms of the parasite in the acute phase of the disease, but its efficacy during the chronic stage is debatable. The search for new medications that can treat Chagas’ disease is therefore mandatory. Natural sources display a wide range of secondary metabolites and may play an important role in the discovery of new potential drugs. Miconia is one of the largest genus of the family Melastomataceae and includes approximately 1,000 plant species; Brazil alone is home to approximately 250 of these species, which exist in forests and savannas. Studies on the various biological activities of the Miconia species have reported promising results. Several researchers have screened these plants as well as their extracts in vitro against trypomastigote forms of T. cruzi, which displayed significant trypanocidal activity. It has been demonstrated that the presence of ursolic and oleanolic determines this biological activity