Tuesday, May 17, 2011
J Agric Food Chem, 2011 May 13
The antioxidant capacity of propolis from the southern region of Uruguay was evaluated using in vitro as well as cellular assays. Free radical scavenging capacity was assessed by ORAC, obtaining values significantly higher than other natural products (8000 µmol trolox equivalents/g propolis).
ORAC values correlated well with total polyphenol content (determined by Folin-Ciocalteau method) and UV absorption. Total polyphenol content (150 mg gallic acid equivalents/g propolis) and flavonoids (45 mg quercetin equivalents/g propolis) were similar to values reported for southern Brazilian (group 3) and Argentinean propolis.
Flavonoid composition determined by RP-HPLC indicates a strong poplar-tree origin. Samples high in polyphenols efficiently inhibit low density lipoprotein lipoperoxidation and tyrosine nitration.
In addition, we found that Uruguayan propolis were able to induce the expression of endothelial nitric oxide synthase and inhibit endothelial NADPH oxidase suggesting a potential cardiovascular benefit by increasing nitric oxide bioavailability in the endothelium.