Effect of extraction methods on property and bioactivity of water-soluble polysaccharides from Amomum villosum

In the present study, effect of different extraction methods on property and bioactivity of water-soluble polysaccharides (WSP) from the seeds of Amomum villosum were investigated. Firstly, four different extraction methods were used to extract WSP, which include hot water extraction (HWE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE) and enzyme-assisted extraction (EAE). As a result, four WSP samples, WSPH, WSPU, WSPM and WSPE were acquired. Then, the difference of four WSP samples in yield, characterization and antioxidant activities in vitro were further compared. Experimental results showed that the four WSP samples had the same monosaccharide composition, but mere difference in the content; they all had typical IR spectra characteristic of polysaccharides. WSPU contained the highest contents of uronic acid and sulfate. The yield of WSPU was the highest and its antioxidant activity was the best. These results suggested that ultrasonic-assisted extraction was the best extraction method for WSP.