Abstract:

The optimal procedure for the ultrasonic-assisted solvent extraction of Acanthopanacis senticosi polysaccharides (ASP) was investigated using orthogonal array design. The effects of different geographic origins and different harvesting times on polysaccharide content and antioxidant activity of crude ASPs from the leaves of Acanthopanacis senticosi were addressed. The phenol-sulfuric acid method was used for polysaccharide determination and the antioxidant activity of the ASP extract was tested by FRAP assay, pyrogallol autoxidation method and DPPH radical scavenging assay. The optimum conditions for the ultrasonic-assisted solvent extraction of ASP were found to be: extraction temperature 70 ℃ and ultrasonic power 500 W for 3- time extraction for 90 min each time. The polysaccharide contents of crude ASPs from different geographic origins were obviously different and decreased in the following order: Ershenchang ＞ Dahu ＞ Xinglong. With the harvesting time prolonged from June to August, crude ASPs from the same geographic origin exhibited an increasing trend in polysaccharide content; beyond September, an opposite pattern was observed. Antioxidant activity testing revealed that a total of 12 samples of crude ASPs from 3 geographic origins harvested during June-September, respectively were all strong antioxidants. The strongest antioxidant was the ASP extract from Ershenchang harvested in August.

Key words: Acanthopanacis senticosi, polysaccharides, extraction, antioxidant activity