Chemical and cytological evaluation of honeybee pollen antioxidant ability.

The crude flavonoid extract of pollen (CFP) of four species of honeybee pollens were extracted with ethanol, and the total flavonoid contents ranged from 3.4 to 14.5 mg rutin/g dry weight. The antioxidant activities of the CFPs were evaluated from both chemical and cytological aspects. Comprehensive antioxidant scores were determined based on these two evaluation systems. The results showed that canola CFP had the highest antioxidant capacity among the four CFPs. A cytotoxicity assay was conducted to assess the safety threshold of the CFPs, and canola CFP was proved to be the least toxic to vascular endothelial cell. Of the four tested CFPs, this research suggests that canola CFP is the most promising natural antioxidant. In addition, high-performance liquid chromatography (HPLC) analysis detected seven flavonoid glycosides in the hydrolysates of the four CFPs. Among them, quercetin and kaempferol were present in all four honeybee pollen extracts, but there were significant differences between their contents. A correlation analysis revealed a strong correlation between the content of quercetin in the pollen extract and the extract's antioxidant activity. PRACTICAL APPLICATION: Many varieties of honeybee pollen are commercially available. The results of this study help guide consumers to choose honeybee pollens that have a better antioxidant effect. This report can also provide guidance and data in support of the development of honeybee pollen health products.