An enzyme-based enhanced extraction and structural characterization of pectic polysaccharides from Panax notoginseng marc

Panax notoginseng (Burkill) is a traditional herb in Chinese medicine. This study has established a green and efficient α-amylase-assisted extraction method for the secondary utilization of Panax notoginseng marc post hot water-extraction. This process has produced a polysaccharide fraction (PNPE) with an extraction level of 6.5 %. PNPE was further separated into one neutral and six pectin fractions using a combination of anion-exchange and gel permeation chromatography. Structural characterization demonstrates that PNPEA-1A and PNPEA-2A are composed primarily of arabinogalactans (AG) that are rich in α-1,5- L -Ara f and β-1,4- D -Gal p linkages. PNPEA-1B and PNPEA-3A were identified as type I rhamnogalacturonan (RG-I) that features a backbone of disaccharide repeating units −2)-α- L -Rha p -(1,4)-α- D -Gal p A-(1-, substituted with side chains of β-1,4- D -Gal p and α-1,5/1,3,5- L -Ara f . PNPEA-2B and PNPEA-3B are homogalacturonan (HG)-type pectins with low molecular weights and low degrees of methyl-esterification. Overall, this investigation reports an efficient process for polysaccharide extraction from Panax notoginseng marc that offers a potential strategy for high-value integrated utilization of the by-product from Panax notoginseng marc.