Comparing the Polyphenolic and Flavonoid Content, Antioxidant and Radical Scavenging Capacity of Widely Consumed Berries

Abstract

Abstract Objectives To determine and compare the phenolic and flavonoid content as well as antioxidant and radical scavenging capacity of blackberry, blueberry, raspberry, and strawberry extracts. Methods Polyphenol extractions from berries were performed using 80% ethanol. Crude extracts were then purified with chloroform followed by fractionation with ethyl acetate. Total polyphenol content (TPC) was assessed using the Folin-Ciocalteu reagent and total flavonoid content (TFC) was assessed using aluminum chloride. Antioxidant capacity was measured using trolox equivalent antioxidant capacity (TEAC) and ferric-reducing antioxidant power (FRAP) assay while 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to determine radical scavenging capacity. Results Blackberry had the highest TPC followed by raspberry, blueberry and strawberry (149 ± 1.1 > 116 ± 0.6 > 112 ± 0.6 > 88 ± 1.3 μmol GAE/L, respectively). Blackberry had the highest TFC followed by blueberry, raspberry, and strawberry (2.6 ± 0.1 > 1.8 ± 0.1 > 1.6 ± 0.2 > 0.5 ± 0.2 μg QE/ml, respectively). Blackberry extracts had the highest TEAC followed by blueberry, strawberry and raspberry (287 ± 8 > 253 ± 4 > 211 ± 6 > 153 ± 10 μmol TE/L, respectively). Similarly, blackberry had significantly higher FRAP than the other berries. Raspberry and blackberry had similar DPPH radical scavenging activity (109 ± 0.0 and 106 ± 0.7 μmol TE/L, respectively), which was significantly higher than blueberry and strawberry (99 ± 4 and 69 ± 1 μmol TE/L, respectively). Conclusions Our results indicate that among the berries examined, blackberry is the best source of polyphenols and antioxidants. Further investigations are warranted to compare the antioxidant capacity of polyphenol-rich berries, including blackberry, in vivo. Funding Sources Georgia State University Honors College.