ABSTRACT
Multidrug resistance of cancer cells and pathogenic microorganisms leading to the treatment failure of some forms of cancer or life-threatening bacterial or fungal infections is often caused by the overexpression of multidrug efflux pumps belonging to the ATP-binding cassette transporters superfamily. The multidrug resistance of fungal cells often involves the overexpression of efflux pumps belonging to the pleiotropic drug resistance (PDR) family of ABC transporters. Possibly the best-studied fungal PDR transporter is the multidrug resistance transporter Pdr5p of Saccharomyces cerevisiae. Some research groups have been searching for new inhibitors of these efflux pumps in order to alleviate resistance. Natural products are a great source for the discovery of new compounds with biological activity. Propolis is a complex resinous material collected by honeybees from exudates and buds of certain plant sources and this material is thought to serve as a defense substance for bee hives. Propolis is widely used in traditional medicine and is reported to have a broad spectrum of pharmacological properties. Literature reported some biological functionalities of propolis, such as antibacterial, antiviral, fungicidal, anti-inflammatory and anti-carcinogenic activities. The chemical composition of propolis is qualitatively and quantitatively variable. Components isolated from methanolic extract of red Brazilian propolis (Alagoas, Northeast of Brazil) are isoflavonoids (including pterocarpans, isoflavans, isoflavones), flavanones and polyprenylated benzophenones. In this work we demonstrated the effects of five different isolated compounds on the ATPase activity of Pdr5p. Out of all five substances tested, only BRP-1 was able to completely abolish the enzymatic activity while others worked as positive modulators of the enzyme activity. BRP-1also inhibited the efflux of Rhodamine 6G from yeast cells overexpressing Pdr5p. Taken together, these results demonstrate that Brazilian propolis could be a source of promising compounds that can alleviate the MDR phenomenon, particularly in some fungi, where it could be used as an adjuvant for the treatment with azoles.
ABSTRACT
Wendtia calycina (Griseb.) Griseb., Vivianiaceae, is a Paraguayan herbaceous plant commonly known as burrito. Our previous study indicated that burrito leaves are a very good source of phenylpropanoid glycosides, principally verbascoside. From W. calycina leaves, a standardized, water-soluble extract rich in phenylpropanoid glycosides (WSE) has been developed on an industrial scale to be used as a food supplement, cosmetic, phytomedicine, and ingredient of different formulations. In this study, we investigated the effect of the WSE on human platelet aggregation in vitro induced by adenosine diphosphate (ADP), epinephrine (EPN), collagen (COL) or arachidonic acid (AA). WSE, concentration-dependently, inhibited ADP and EP-induced human platelet aggregation (IC50 were 0.82±0.15 mg/mL and 0.41±0.02 mg/mL, respectively). It did not inhibit collagen-induced platelet aggregation, thus suggesting a selectivity for the ADP-induced platelet activation pathways.
ABSTRACT
Objetivos: aislar e identificar los componentes principales presentes en el extracto metanólico de la resina de la especie Calophyllum pinetorum Bisse.Métodos: la cromatografía líquida de alta resolución se utilizó para la separación de los compuestos. Para la caracterización estructural se emplearon las técnicas de resonancia magnética nuclear y la espectrometría de masas.Resultados: el proceso de separación permitió el aislamiento de 3 compuestos que fueron reconocidos como derivados de cromonas. Los compuestos 1-3 fueron identificados como: ácido calolóngico, ácido apetálico y ácido isoapetálico.Conclusiones: la presencia de cromonas se corresponde con los estudios realizados con otras especies de este género, pero es la primera vez que estos compuestos se aíslan e identifican desde una misma especie. Por otra parte, es la primera vez que se informa la presencia de cromonas en la resina de este género.
Objectives: to isolate and identify the main components in the methanolic extract of the resin of the species Calophyllum pinetorum Bisse.Methods: high resolution liquid chromatography was used for the separation of the compounds. Magnetic resonance imaging and mass spectrometry were used for the structural characterization.Results: the separation process allowed the isolation of 3 compounds that were recognized as derivatives of chromans. The compounds 1-3 were identified as calolongic acid, apetalic acid and isoapetalic acid.Conclusions: the presence of chromans corresponds with the studies conducted with other species of this genus, but it is the first time that these compounds are isolated and identified from the same species. On the other hand, it is reported for the first time, too, the presence of chromans in the resin of this genus.