Chemical characteristics of poplar type propolis of different geographic origin

Abstract

-Validated spectrophotometric procedures were used to quantify three main groups of bioactive substances (phenolics, flavones/flavonols, flavanones/dihydroflavonols) in 114 samples of poplar-type propolis from different geographic origins. From the results, we characterized raw poplar propolis in terms of minimum content of its bioactive components (antimicrobial and antioxidant) as follows: 45% resin, 21% total phenolics, 4% total flavones/flavonols; 4% total flavanones/dihydroflavonols, and a maximum Minimum Inhibitory Concentration (MIC) against S. aureus of 250 µg/mL. A significant negative correlation was observed between the amount of total phenolics and MIC. The results indicate that measuring the concentrations of groups of active compounds, rather than individual components, is an appropriate approach in developing quality standards for propolis. poplar propolis / chemical characteristics / antibacterial activity / standardization

Color, phenolic and flavonoid content, and antioxidant activity of honey from Roraima, Brazil

“…The flavonoid results in this study were lower than the results obtained for honey from the northeast of Brazil, which ranged from 2.5 to 83.8 mg of quercetin kg -1 of honey (Liberato et al, 2011). (Chang et al, 2002;Popova et al, 2005Popova et al, , 2007Tylkowski et al, 2010). The principle of this method is that the 2,4-dinitrophenylhydrazine reagent reacts with the carbonyl of ketones and aldehydes to form 2,4-dinitrophenylhydrazone, resulting in a red color (Chang et al, 2002).…”

“…Data on the antioxidant activity of honey from Malaysia suggest that the phenolics are responsible for free-radical scavenging and antioxidant activity. Another important class of compounds in products derived from bees are flavonoids (Chang et al, 2002;Popova et al, 2004Popova et al, , 2007Lebranc et al, 2009;Tylkowski et al, 2010). The total flavonoid content is generally determined using a spectrophotometric assay based on the formation of an aluminum chloride complex, which has been applied for quantification of flavones and flavonols in honey (Meda et al, 2005;Liberato et al, 2011).…”

“…The total flavonoid content is generally determined using a spectrophotometric assay based on the formation of an aluminum chloride complex, which has been applied for quantification of flavones and flavonols in honey (Meda et al, 2005;Liberato et al, 2011). Although the flavonone and dihydroflavonol content has not yet been determined in honey, these compounds have largely been determined in propolis and pollen using the 2,4-dinitrophenylhydrazine method (Chang et al, 2002;Popova et al, 2004Popova et al, , 2007Lebranc et al, 2009;Tylkowski et al, 2010). An important parameter of honey is its color, which reflects the floral source (Bertoncelj et al, 2007) and can be determined by spectrophotometric measurement of the absorbance of a 50% honey solution at 635 nm and classified according to the Pfund scale (Ferreira et al, 2009;Lacerda et al, 2010).…”

“…The absorbance of the supernatant solution was measured at 486 nm against a methanol blank. A standard curve of pinocembrin was drawn within a concentration range of 5.0 x 10 -4 to 4.0 x 10 -3 mg/mL (Chang et al, 2002;Popova et al, 2004Popova et al, , 2007Tylkowski et al, 2010;Gómez-Caravaca et al, 2006).…”

Chiral Analysis of Monoterpenes in Volatile Oils From Propolis

“…4 So, the geographical location and associated flora can determine the propolis composition. 5 Considering that some factors (e.g. ; rainfall and variations in temperature), could affect the chemical composition of propolis, investigations on the chemical composition and biological properties are important not only for academic interest, but also for the chemical and biological standardization of a particular type of propolis.…”