Monday, April 25, 2011
J Agric Food Chem, 2011 Apr 18
Seven bee pollen samples with different palynological sources were harvested from Pindamonhangaba municipality (Southeast Brazil). Methanol extracts of untreated samples (control), samples freezed to -18oC and samples freezed and then dried were analyzed by HPLC/DAD/ESI/MS/MS.
Glycosides of quercetin, kaempferol, isorhamnetin and patuletin were detected. The main constituent found in all samples C1-C7 (seven collections of bee pollen along 21 days) was N',N",N'"-tris-p-feruloylspermidine, together N',N",N'"-tris-p-coumaroylspermidine. Distinct phenolic profiles characterize the samples analyzed, but no differences were noted as resulting from different treatments.
Total phenolic ranged from 1.7 to 2.2%. Antioxidant activities above 75% (based on the DPPH method) were observed for all extracts, not correlated with total phenolic content.
Among samples from the same origin, those freezed were more active than samples untreated (control), and the samples freezed and dried were the most active.