ABSTRACT
The Coumarin (1,2-benzopyrone) is the main secondary metabolite of Mikania laevigata Sch. Beep ex Baker and Mikania glomerata Spreng., which are popularly known as guaco. These plants have been used mainly in traditional medicine in the treatment of respiratory diseases because their bronchodilator effect. However, there are around 200 species of Mikania, which are quite similar in appearance. From these, only M.leavigata and M. glomerata have high concentrations of coumarins. In this line, the falsification of products Mikania based has been frequent. In this sense, this work demonstrated the application of the easy, fast, e not destructive method based in Nuclear Magnetic Resonance in quantitative mode (qNMR) for the determination of coumarin in both commercial and homemade guaco products. Thus, in the first step the compounds were extract from guaco leaves and syrups using chloroform (CHCl3), with or without ultrasound. About the method, was linear with a R2 = 0.9947 for 1,2-benzopyrone, with detection and quantification limits with were 0.11 and 0.36 mg mL-1 respectively. In the same line, the method was safe with RSD <0.3% and with recovery ranging from 93-101%. To confirm the applicability of the method, in the last step was applied to 10 real samples (6 from leaves and 4 from syrups). The content of the coumarin in the leaf extract ranged from 0.62 to 1.30 mg mL-1 . For syrups I, II and IV, the content of coumarin was in accordance with the manufacturers. However, for de Syrup III, the concentration was 155% higher. In summary, the qNMR is a rapid method with minimal sample preparation that can be used to quantify coumarin in home-made plant extracts as well as in commercial samples as syrup for instance. This method is applicable for quality control of different plants-based products.
ABSTRACT
The Coumarin (1,2-benzopyrone) is the main secondary metabolite of Mikania laevigata Sch. Beep ex Baker and Mikania glomerata Spreng., which are popularly known as guaco. These plants have been used mainly in traditional medicine in the treatment of respiratory diseases because their bronchodilator effect. However, there are around 200 species of Mikania, which are quite similar in appearance. From these, only M.leavigata and M. glomerata have high concentrations of coumarins. In this line, the falsification of products Mikania based has been frequent. In this sense, this work demonstrated the application of the easy, fast, e not destructive method based in Nuclear Magnetic Resonance in quantitative mode (qNMR) for the determination of coumarin in both commercial and homemade guaco products. Thus, in the first step the compounds were extract from guaco leaves and syrups using chloroform (CHCl3), with or without ultrasound. About the method, was linear with a R2 = 0.9947 for 1,2-benzopyrone, with detection and quantification limits with were 0.11 and 0.36 mg mL-1 respectively. In the same line, the method was safe with RSD <0.3% and with recovery ranging from 93-101%. To confirm the applicability of the method, in the last step was applied to 10 real samples (6 from leaves and 4 from syrups). The content of the coumarin in the leaf extract ranged from 0.62 to 1.30 mg mL-1 . For syrups I, II and IV, the content of coumarin was in accordance with the manufacturers. However, for de Syrup III, the concentration was 155% higher. In summary, the qNMR is a rapid method with minimal sample preparation that can be used to quantify coumarin in home-made plant extracts as well as in commercial samples as syrup for instance. This method is applicable for quality control of different plants-based products.
ABSTRACT
Propolis has been used worldwide for years in folk medicine and currently marketed by the pharmaceutical industry. In Brazil, propolis was classified into 13 groups based on their organoleptics and physicochemical characteristics. The 13th type named red propolis has been an important source of investigation since late 90s. Their property comes from the countless compounds, including terpenes, pterocarpans, prenylated benzophenones and especially the flavonoids. This last compound class has been indicated as the responsible for its potent pharmacological actions, highlighting the antimicrobial, anti-inflammatory, antioxidant, healing and antiproliferative activities. The red propolis can also be found in other countries, especially Cuba, which has similar features as the Brazilian. Therefore, with the compilation of 80 papers, this review aims to provide a key reference for researchers interested in natural products and discovery of new active compounds, such as from propolis.
ABSTRACT
Objective To investigate the antidiabetic effect of Rourea cuspidata hydroalcoholic stem extract in normal and streptozotocin-induced diabetic rats. Methods In order to evaluate the chemical composition, different extracts from stem in ascending solvent order of polarity were prepared. The extracts were analyzed by high resolution mass spectrometry and 7 compounds were identified, including hyperin, an important and already reported active compound in the literature. Hyperin was also quantified by HPLC-UV in all the extracts. The hydroalcoholic stem extract (Ss5), which showed the highest concentration of hyperin, was administered to STZ-induced diabetes rats to evaluate the potential hypoglycemic activity. Total cholesterol, HDL, triglycerides, ALT and AST were also evaluated. In the present study, the effects of oral administration of hydroalcoholic stem extract (200 mg/kg b. wt.) for 28 days on the level of serum glucose, total cholesterol, HDL, triglycerides, aspartate amino transferase (AST) and alanine amino transferase (ALT) in normal and streptozotocin-induced diabetic rats were evaluated. Histopathological changes in diabetic rats' pancreas were also studied. Results The extract exposition demonstrated hypoglycemic effect like the drug control glibenclamide. The extract was able to increase the HDL levels. Histopathological study on diabetic rats' pancreas after extract treatment showed morphological alterations in STZ-induced diabetes rats, which were apparently restored after extract treatment. Conclusions This work demonstrates the potential use of R. cuspidata as hypoglycemic agent in the treatment of diabetes.
ABSTRACT
As cianobactérias apresentam, distribuição variada e podem ocorrer desde as regiões frias do ártico até os trópicos, em corpos d'água doce e no ambiente marinho. Algumas espécies de cianobactérias produzem compostos com conhecida toxidade, podendo causar efeitos deletérios em seres humanos e animais. Entre estes compostos estão os com atividade neurotóxica devido aos mais variados mecanismos de ação. O objetivo geral deste projeto é a obtenção por via sintética de algumas neurotoxinas e variantes, entre elas a β-N-metil-L-alanina (L-BMAA), anatoxina-a e anatoxina-a(s), bem como algumas aplicações. Para a L-BMAA, foi buscada a determinação de rotas sintéticas viáveis para a obtenção deste aminoácido modificado sob a forma racêmica e enantiomericamente pura, além de um possível produto cíclico que pode ser gerado naturalmente a partir da L-BMAA. Algumas rotas estratégicas foram determinadas com êxito para a síntese destes compostos. Entre as aplicações dos produtos obtidos podem ser citados: (i) a determinação de um método analítico para a determinação deste aminoácido por RMN de 1H; (ii) um método analítico por LC-MS utilizando D3-L-BMAA como padrão interno e (iii) a indicação de um possível mecanismo de neurotoxidade ligado a neurodegeneração via um intermediário produzido naturalmente do equilíbrio entre L-BMAA e íons bicarbonato...