Improved antimutagenic effect of Pyrostegia venusta (Ker Gawl. ) Miers nanostructured extract in liposome and polymeric nanoparticle

Abstract Pyrostegia venusta (Ker Gawl.) Miers, popularly known as "Cipó-de São-João", has been used in traditional medicine for its therapeutic properties. Nanotechnology is able to enhance the pharmacological activity of plant extracts. In this context, liposomes and polymeric nanoparticles containing P. venusta ethanolic extract were developed and then physico-chemically characterized to evaluate the mutagenic/antimutagenic effects of P. venusta. In addition, transaminases and serum creatinine were biochemically analyzed for liver and renal damage, respectively. The micronucleus test was performed with male Swiss mice treated orally for 15 consecutive days with free extracts and nanostructured with P. venusta, and then intraperitoneally with N-ethyl-N-nitrosurea (50 mg/kg) on the 15th day of treatment. Micronucleated polychromatic erythrocytes (MNPCE) were evaluated in bone marrow. There was a significant reduction in the frequency of MNPCE (LPEPV = 183% and NPEPV = 114%, p < 0.001), indicating antimutagenic potential of the nanostructured extracts with P. venusta. The groups treated with only nanostructured extract did not show an increase in MNPCE frequency, and biochemical analyzes showed no significant difference between treatments. The liposomes and polymeric nanoparticles containing Pyrostegia venusta ethanolic extract showed biological potential in preventing the first step of carcinogenesis under the experimental conditions

Dehydrobufotenin extracted from the Amazonian toad Rhinella marina (Anura: Bufonidae) as a prototype molecule for the development of antiplasmodial drugs

he resistance against antimalarial drugs represents a global challenge in the fight and control of malaria. The Brazilian biodiversity can be an important tool for research and development of new medicinal products. In this context, toxinology is a multidisciplinary approach on the development of new drugs, including the isolation, purification, and evaluation of the pharmacological activities of natural toxins. The present study aimed to evaluate the cytotoxicity, as well as the antimalarial activity in silico and in vitro of four compounds isolated from Rhinella marina venom as potential oral drug prototypes. Methods: Four compounds were challenged against 35 target proteins from P. falciparum and screened to evaluate their physicochemical properties using docking assay in Brazilian Malaria Molecular Targets (BraMMT) software and in silico assay in OCTOPUS® software. The in vitro antimalarial activity of the compounds against the 3D7 Plasmodium falciparum clones were assessed using the SYBR Green I based assay (IC50). For the cytotoxic tests, the LD50 was determined in human pulmonary fibroblast cell line using the [3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay. Results: All compounds presented a ligand-receptor interaction with ten Plasmodium falciparum-related protein targets, as well as antimalarial activity against chloroquine resistant strain (IC50 = 3.44 µM to 19.11 µM). Three of them (dehydrobufotenine, marinobufagin, and bufalin) showed adequate conditions for oral drug prototypes, with satisfactory prediction of absorption, permeability, and absence of toxicity. In the cell viability assay, only dehydrobufotenin was selective for the parasite. Conclusions: Dehydrobufotenin revealed to be a potential oral drug prototype presenting adequate antimalarial activity and absence of cytotoxicity, therefore should be subjected to further studies.(AU)

Chemical constituents from Casearia spp. (Flacourtiaceae/Salicaceae sensu lato)

ABSTRACT Chemical investigation of the leaves of Casearia gossypiosperma Briq., Salicaceae, led to the isolation of two known flavonoids, (+)-taxifolin and quercetin, the leaves of Casearia decandra Jacq. have afforded hydroquinone, the leaves of Casearia rupestris Eichler and Casearia lasiophylla Eichler have afforded a diterpene, (E)-phytol, and the leaves of C. rupestris and Casearia obliqua Spreng. have afforded sitosterol. The twigs of Casearia lasiophylla Eichler led to the isolation of two compounds (+)-pinoresinol, and N-trans-feruloyltyramine, and the twigs of C. obliqua have afforded N-trans-feruloyltyramine, N-trans-cumaroyltyramine, and cinamic acid. This is the first report of the compounds (+)-taxifolin, quercetin, hydroquinone, (+)-pinoresinol and N-trans-cumaroyltyramine from the Casearia genus.

Protease inhibition activity of extracts from Salicaceae species from Brazilian Cerrado and Atlantic Rain Forest and of an enriched fraction of clerodane diterpenes (casearins) / Atividade biológica de uma fração enriquecida de diterpenos clerodânicos (casearinas) e de extratos de espécies de Salicaceae do Cerrado e Mata Atlântica em um ensaio de inibição de proteases

Considering the traditional use of Casearia sylvestris Sw., Salicaceae, to threat gastric injuries and the pre-clinical studies showing its efficacy we aimed to screen other species to explore the biological activity of some species of this family. For this, we used a protease inhibition assay as a model for searching gastric anti-ulcer plant extracts. The ethanolic and aqueous extracts from branches and leafs of C. gossypiosperma, C. decandra and C. rupestris showed high percentage inhibition of pepsin, approximately 50 percent, with 1 μg/mL concentration. Curiously, C. obliquoa and Flacourtia ramontchi did not inhibit pepsin, but its most apolar extract showed inhibitory activity in the subtilisin assay. The enriched fraction of clerodane diterpenes inhibited the activity (42.75 percent) of pepsin with 1 ug/mL, but it did not inhibit subtilisin (23.76 percent). The results obtained with apolar and polar extracts from branches and leaves of some species of Salicaceae showed a different pattern of inhibition of two proteases, the aspartic pepsin and the serinic subtilisin, related with different biological activities. The results with the enriched fraction of clerodane diterpenes suggests that the activity observed with the C. sylvestris may be related with the presence of these substances in the crude extract.

Considerando o uso popular de Casearia sylvestris Sw., Salicaceae, para o tratamento de problemas gástricos e resultados pré-clínicos que mostraram potencial atividade anti-ulcerogênica, foi realizado um screening farmacológico para avaliar a atividade biológica de outras espécies de Salicaceae. Para isso, foi utilizado um ensaio de inibição de proteases como um modelo farmacológico molecular para screening de extratos com atividade anti-ulcerogênica. Os extratos etanólico e aquoso dos galhos e folhas de C. gossypiosperma, C. decandra e C. rupestris mostraram inibição da atividade da pepsina em aproximadamente 50 por cento com a concentração de 1 μg/mL. Curiosamente, C. obliquoa e Flacourtia ramontchi não apresentaram atividade sobre a pepsina, mas seus extratos mais apolares mostraram atividade inibitória sobre a subtilisina. A fração enriquecida de diterpenos clerodânicos mostrou atividade inibitória (42,75 por cento) sobre a pepsina com a concentração de 1 μg/mL, mas não sobre a subtilisina (23,76 por cento). Os resultados obtidos com os extratos e folhas das espécies testadas mostraram um padrão de atividade diferente sobre os dois tipos de proteases, a pepsina e a subtilisina, as quais estão relacionadas com diferentes tipos de atividades biológicas. Ainda mais, os resultados com a fração enriquecida de diterpenos clerodânicos sugerem que estas substâncias podem estar relacionadas com a atividade do extrato bruto de C. sylvestris.