Flavonoids, phenolic content, and antioxidant activity of propolis from various areas of Guanajuato, Mexico

Abstract Propolis is a resin gathered by honey bees from trees and shrubs but it used in the beehive as building material or as an antibiotic paste. The aim of this study was to determine the content of flavonoids and phenols, as well as the antioxidant capacity of propolis from various regions of Guanajuato, Mexico. The content of flavonoids and phenols was determined by the aluminum nitrate method and the Folin-Ciocalteu method. The antioxidant capacity was determined using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) method and the ferric reduction of Fe3+ to Fe2+ (FRAP•) assay. The flavonoid content varied from 13 to 379 mg of quercetin equivalents (QE) per g of propolis and the phenolic content ranged from 68 to 500 mg of caffeic acid equivalents (CAE) per g of propolis. The trolox equivalent antioxidant capacity (TEAC) per g of propolis varied from 39.8 to 54.4 for the DPPH• method and from 50 to 2000 for the FRAP• assay. Propolis rich in flavonoids and phenols possesses a low antioxidant capacity. The results show that propolis from different areas of Guanajuato are rich in flavonoids and phenolics compounds while their antioxidant capacity is variable.

摘要：蜂胶（Propolis）是蜜蜂从树木和灌木上采集的树脂，可被用于蜂箱中作为构筑材料或抗菌膏剂。本研究旨在测定墨西哥瓜纳华托州不同区域蜂胶的黄酮类、酚类物质含量及其抗氧化能力。黄酮类与酚类物质含量分别采用硝酸铝法与福林-酚（Folin-Ciocalteu）法测定；抗氧化能力则通过自由基2,2-二苯基-1-苦基肼（2,2-diphenyl-1-picrylhydrazyl, DPPH•）法与三价铁还原为二价铁（FRAP•）实验进行评估。实验结果显示，蜂胶中黄酮类物质含量范围为每克蜂胶含13~379 mg槲皮素当量（quercetin equivalents, QE），酚类物质含量范围为每克蜂胶含68~500 mg咖啡酸当量（caffeic acid equivalents, CAE）。以Trolox当量抗氧化能力（TEAC）计，采用DPPH•法测得的每克蜂胶抗氧化能力范围为39.8~54.4，FRAP•实验测得的范围为50~2000。富含黄酮类与酚类物质的蜂胶，其抗氧化能力较低。本研究结果表明，墨西哥瓜纳华托州不同区域的蜂胶均富含黄酮类与酚类化合物，但其抗氧化能力存在差异。