Structural characterization of a novel polysaccharide from tremella fuciformis and its interaction with gut microbiota.

BACKGROUND: Due to their diverse biological activities, polysaccharides derived from Tremella fuciformis have received growing attention. This study aimed to investigate the structural characterization of a purified polysaccharide (designated as PTP-3a) derived from Tremella fuciformis and explore its interaction with gut microbiota in vitro.

RESULTS: The findings revealed that PTP-3a had a molecular weight of 1.22 × 103  kDa and consisted of fucose, glucose, xylose, mannose, and glucuronic acid in a molar ratio of 0.271:0.016:0.275:0.400:0.038. The primary linkage types identified in PTP-3a were 1,3-linked-manp, 1,4-linked-xylp, and 1,2,3-linked-fucp, with corresponding ratios of 0.215:0.161:0.15. In addition, PTP-3a demonstrated notable thermal stability and exhibited a triple helical structure. Moreover, following in vitro fermentation for 48 h, PTP-3a was efficiently utilized, resulting in a reduction in carbohydrate levels, the production of short-chain fatty acids (SCFAs), and pH adjustment. Furthermore, during in vitro fecal microbial fermentation, PTP-3a decreased the relative abundance of Firmicutes while increasing the proportions of Bacteroidetes and Proteobacteria, resulting in a significantly reduced Firmicutes/Bacteroidetes ratio. Additionally, PTP-3a stimulated the growth of beneficial bacteria such as Parabacteroides merdae, Gordonibacter pamelaeae, Bifidobacterium pseudolongum, and Parabacteroides distasonis. Importantly, a strong correlation was observed between the production of SCFAs and specific microorganisms.

CONCLUSION: These findings suggested that PTP-3a held potential as a prebiotic for modulating the gut microbiota. This article is protected by copyright. All rights reserved.