Phenolic Compounds and Antidiabetic Activity of Raspberry Ethanol Extract from Different Producing Areas

In this paper, phenolic compounds of raspberry from six producing areas (Guangdong, Guangxi, Anhui, Zhejiang, Jiangxi and Sichuan) were extracted by ethanol extraction method, and the phenolic compounds and their antidiabetic activities were compared and analyzed. The results showed that the content of polyphenol of raspberry from Guangdong was the highest (349.77 μg GAE/mg E), Zhejiang raspberry showed the highest total flavonoid content (202.55 μg QUE/mg E), while Sichuan raspberry showed the highest content of hydrolyzed tannin (125.07 mg GAE/g E). Thirty-four different phenolic compounds were identified from raspberry extracts, which were mainly ellagitannins, flavonoids and phenolic acids. Studies on antidiabetic activity showed that the DPPH· (IC₅₀=63.069 μg/mL) and ABTS⁺· scavenging capacities (IC₅₀=29.977 μg/mL) and the inhibitory effect on α-glycosidase (IC₅₀=0.086 mg/mL) of raspberry extracts from Sichuan were higher than those from other regions, whereas Anhui raspberry extract showed the strongest inhibitory ability of AGEs (81.91%). In summary, raspberry from Sichuan is a high-quality source of anti-diabetes drugs.