OBJECTIVE To analyze the ethanol extracts, total phenols, total flavonoids contents and HPLC fingerprints of typical propolis samples from 6 foreign countries and 5 domestic regions, optimize the extraction process and evaluate the antioxidant activity, so as to provide data support for improving the quality control system of propolis.

METHODS The optimization of the propolis extraction process utilized flavonoid content as an indicator. Three flavonoid detection methods-namely, the aluminum trichloride method, aluminum nitrate method, and polyamide method-were compared. The content of ethanol extract, total phenol content, and the scavenging ability of DPPH free radicals for each sample were determined. Further analysis was conducted using HPLC fingerprint profiling.

RESULTS The propolis extract with the highest flavonoid content was obtained using 80% ethanol as the extraction solvent, operating at 50 ℃, with a stirring time of 3 h, ultrasonic power of 180 W, and ultrasonic time of 15 min. The aluminum trichloride method was proved to be the most effective for determining total flavonoids in propolis. While the ethanol extract, total flavonoids, and total phenols of propolis from Xinjiang, China were relatively low, their antioxidant activity exhibited superiority. HPLC analysis revealed, Brazilian red propolis lacked of chrysin, galangin, caffeic acid phenethyl ester and Brazilian green propolis lacked ferulic acid, apigenin, p-coumaric acid, chrysin, and pinocembrin. In contrast, the content of these four compounds in other samples varied, with the antioxidant capacity of the extracts not precisely corresponding to the compound content.

CONCLUSION Propolis exhibits a complex chemical composition with significant variations among varieties. Key quality control indexes must be comprehensively considered, encompassing physicochemical characteristics and biological activity. Establishing a multi-angle assessment system with a material basis-functional linkage is essential. This approach facilitates the realization of high quality and cost-effectiveness, thereby promoting the healthy development of the industry.