Optimization of Polyphenol Extraction From Pu’er Tea Flowers and Evaluation of Their Antioxidant and Hypoglycemic-Hypolipidemic Activities

Abstract

Objective In order to enhance the application value of polyphenolic compounds in Pu’er tea flowers, the extraction methods and physiological activities of these compounds were studied. Methods Ultrasonic-assisted extraction was utilized to isolate polyphenolic compounds from Pu’er tea flowers, and the extraction process was systematically optimized using response surface methodology (RSM). Results The optimal conditions were determined as follows: ethanol concentration of 55%, solid-liquid ratio of 1:45 (g/mL), extraction temperature of 55 °C, extraction time of 90 min, and ultrasonic power of 480 W. Under these optimal conditions, the total polyphenol yield reached 4.95±0.08 mg/g. The extracted polyphenols exhibited notable in vitro bioactivities. They demonstrated strong antioxidant capacity, with IC 50 values of 0.068 mg/mL for DPPH• scavenging and 0.093 mg/mL for ABTS• + scavenging. In addition, the polyphenols showed significant hypoglycemic potential via inhibition of α-glucosidase, with an IC 50 value of 0.73 mg/mL. Moreover, their hypolipidemic effect was evidenced by bile salt binding capacity, with IC 50 values of 2.49 mg/mL for sodium taurocholate and 4.40 mg/mL for sodium glycocholate. Conclusion In summary, polyphenols derived from Pu’er tea flowers possess remarkable antioxidant, hypoglycemic, and hypolipidemic properties. These findings highlight their potential as a multi-functional natural ingredient for use in functional foods and nutraceuticals, supporting further development and value-added utilization of Pu’er tea flowers.