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PC-16

Chemical characterization, GLP-1 secretion effect and gut microbial

fermentation of Polygonatum polysaccharides

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1
Fu-Hsuan Yang, #,1 Shoei-Sheng Lee, Chia-Chuan Chang*

1 Department of Pharmacy, College of Medicine, National Taiwan University, Taipei 100025,
Taiwan
* E-mail: chiachang@ntu.edu.tw

Abstract
Polygonatum, a traditional Chinese herb, contains polysaccharides with hypoglycemic,
antioxidant, anti-inflammatory, and antidepressant activities. Multiple studies confirm that its
hypoglycemic effects were related to the interaction among the polysaccharides, gut microbes,
and the host. Moreover, previous studies have reported that Polygonatum polysaccharides
remarkably promoted the growth of Bifidobacterium and Lactobacillus as a sole carbon source,
highlighting their prebiotic potential. However, limited investigations have examined
oligosaccharides derived from fermentation by specific gut microbes. Therefore, this study
aimed to isolate Polygonatum polysaccharides, assess their degradability by specific gut
microbes, and explore the bioactivity of the resulting oligosaccharides. Crude polysaccharide
from wine-processed Polygonatum was fractionated by DEAE-Sephacel chromatography into
neutral (PSP-A) and acidic (PSP-B & PSP-C) fractions. Monosaccharide analysis showed
galactose predominance with glucose and mannose in smaller amounts, at ratios of 12.7:2.8:1.0
1
(PSP-A), 3.8:1.4:1.0 (PSP-B), and 7.6:0.8:1.0 (PSP-C). Their H NMR spectra resembled a
reported pectin galactan, which has a main β-1,4 skeleton. Furthermore, PSP-A~PSP-C
enhanced GLP-1 secretion by 1.0-, 1.7-, and 1.3-fold (10 µg/mL), positively correlated to a
lower galactose ratio. To evaluate their fermentative activity, commercial pectin galactan was
fermented by five Lactobacillus and Bifidobacterium strains for 24 h. Increased turbidity
indicated their utilization, and these strains may possess enzymes capable of degrading the β-
1,4-galactan main chain. Since PSPs share this β-1,4 skeleton, they are likely fermentable into
bioactive oligosaccharides with prebiotic activity, offering protection against diabetes.
Subsequent research will characterize degradation-derived oligosaccharides and assess their
antidiabetic activity, for exploring applications in functional foods and gut health.

Keywords: Polygonatum; Gut microbiota; Oligosaccharides; Glucogalactomannan; GLP-1