Extratos etanólicos de própolis obtidos a partir de diferentes concentrações de própolis e com álcool hidratado com diferentes teores de álcool/água foram analisados. A ação antioxidante destes extratos foi determinada através da captura do radical livre 1,1-difenil-2-picril-hidrazila (DPPH•) e do poder de redução férrico (FRAP) utilizando o complexo férrico-tripiridiltriazina (Fe 3+ -TPTZ). O teor de compostos fenólicos totais e a quantificação de flavonóides também foram verificados e obtidos por espectrometria de massas com ionização por electrospray (ESI(-)-MS) dos extratos. Observou-se que a composição química dos extratos de própolis e sua atividade antioxidante variam com a concentração de própolis e, principalmente, com o teor de álcool/água do etanol hidratado utilizado na extração. Foi possível perceber também que a atividade antioxidante dos extratos é significativamente dependente destes parâmetros de extração e que as composições de compostos fenólicos e flavonóides também variam muito. Os valores de FRAP não apresentaram, porém, boa correlação com o teor de flavonóides.Ethanolic extracts of propolis obtained with different concentrations of propolis and made using hydrous ethanol with various water/ethanol contents were analyzed. The antioxidant action of the extracts was determined by free radical 1,1-diphenyl-2-picryl-hydrazyl (DPPH•) scavenging and by ferric reducing ability power (FRAP), using the ferric-tripyridyl triazine (Fe 3+ -TPTZ) complex. The total phenolic and flavonoid contents were also determined, and the electrospray ionization mass spectrometry spectra (ESI(-)-MS) of the extracts were acquired. The chemical composition of propolis extracts and their antioxidant activity were observed to vary with the concentration of propolis, and especially with the water/ethanol contents of the hydrous ethanol used for extraction. The antioxidant activity of the extracts was also found to be significantly dependent on these extraction parameters, as well as on the composition of the phenolic compounds and flavonoids. FRAP values showed, however, poor correlation with the flavonoid content.
Keywords: total phenolic contents, antioxidant activity, ESI(-)-MS fingerprint, propolis extraction, flavonoids
IntroductionPropolis is a resin produced by honey bees by mixing wax, pollen, salivary secretions and collected natural resins. 1 The chemical composition of propolis is complex and varies with the vegetation visited by bees, as well as with bee species. [2][3][4][5][6] As propolis has characteristics that are beneficial to human health, such as antioxidant, anti-inflammatory, antifungal and anticancer activities, its chemical composition and properties have been extensively studied. [7][8][9][10] The antioxidant activity of ethanolic extracts of propolis has been evaluated by free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH • ) scavenging, 8 by the ferric reducing ability power (FRAP) using the ferric-tripyridyltriazine Antioxidant Activity and Composition of Propolis Obtained by Different Methods o...
