Structure elucidation of arabinogalactan and arabinogalacturonan from the root of Scutellaria baicalensis Georgi and evaluation on their immunoregulating effects via TLR2 pathway

• Published in: Chemical and Biological Technologies in Agriculture
• Main Authors: Xiaojun Li, Rui Zhang, Huizi Tang, Yu Kou, Yuan Yin, Haiyang Guo, Xue Zhang
• Format: Article
• Language: English
• Published: SpringerOpen 2025-03-01
• Subjects: Scutellaria baicalensis Georgi; Polysaccharides; Chemical structure; Arabinogalactan; Arabinogalacturonan; Immunomodulations
• Online Access: https://doi.org/10.1186/s40538-025-00755-5

Abstract Background Polysaccharides were extracted from the roots of Scutellaria baicalensis Georgi using hot water and ethanol precipitation method. The SBP-1 and SBP-2, were obtained after eluting from DE-52 column. The molecular weight, monosaccharide composition and linkage types of SBP-1 and SBP-2 were determined by the high performance gel permeation chromatography, high-performance anion exchange chromatography, gas chromatography–mass spectroscopy and NMR spectra. Results SBP-1 and SBP-2 were characterized as a homogenous polysaccharide with Mw of 80.5 and 25.8 kDa, respectively. Moreover, there were seven linkage types in the SBP-1 and it was a type II arabinogalactan formed by a (1→6)-linked β-d-Galp main chain. Whereas, except for the linkage types of α-l-Araf-(1→, →5)-α-l-Araf-(1→ and →3,5)-α-l-Araf-(1→, the SBP-2 enriched with →3,4)-α-d-GalpA-(1→, →4)-α-d-GalpA-(1→ and →4)-α-d-GalpA(OMe)-(1→, indicating the pectic type arabinogalacturonan structure. Moreover, both SBP-1 and SBP-2 exhibited immunoregulatory effects on RAW 264.7 cells by modulating the toll-like receptor (TLR) signaling pathway, as demonstrated through RNA-seq analysis, western blotting, immunoprecipitation (IP) experiments, and surface plasmon resonance (SPR) analysis. Conclusions These findings suggest an immunological basis for the therapeutic potential of S. baicalensis. Graphical Abstract