Chemical Structure and Immunomodulating Activities of an α-Glucan Purified from Lobelia chinensis Lour.
A neutral α-glucan, named BP1, with a molecular mass of approximately 9.45 kDa, was isolated from Lobelia chinensis by hot-water extraction, a Q-Sepharose Fast Flow column and Superdex-75 column chromatography. Its chemical structure was characterized by monosaccharide analysis, methylation analysis and analysis of its FT-IR, high performance gel permeation chromatography (HPGPC) and 1D/2D-NMR spectra data. The backbone of BP1 consists of →₆α-d-Glcp¹→6,3α-d-Glcp¹→(₆α-d-Glcp¹)x-6,3α-d-Glcp¹-(₆α-d-Glcp¹)y→. The side chains were terminal α-d-Glcp¹→ and α-d-Glcp¹→ (₆α-d-Glcp¹)z→₄α-d-Glcp¹→₃α-d-Glcp¹→₄α-d-Glcp¹→ (x + y + z = 5), which are attached to the backbone at O-3 of 3,6α-d-Glcp¹. The results of the effect of BP1 on mouse macrophage cell line RAW 264.7 indicate that BP1 enhances the cell proliferation, phagocytosis, nitric oxide production and cytokine secretion in a dose-dependent manner. Because the inhibitor of Toll-like receptor 4 blocks the BP1-induced secretion of TNF-α and IL-6, we hypothesize that α-glucan BP1 activates TLR4, which mediates the above-mentioned immunomodulating effects.
Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. lixiaojun@hkbu.edu.hk.|School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China. lixiaojun@hkbu.edu.hk.
Xiao-Jun
XJ
Li
School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China. wanrong@hkbu.edu.hk.
Wan-Rong
WR
Bao
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China. duncanleung@umac.mo.
Chung-Hang
CH
Leung
Department of Chemistry, Hong Kong Baptist University, Hong Kong 999077, China. edmondma@hkbu.edu.hk.
Dik-Lung
DL
Ma
School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China. zhangge@hkbu.edu.hk.
Ge
G
Zhang
School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China. aipinglu@hkbu.edu.hk.
Ai-Ping
AP
Lu
Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. shunchunwang@126.com.
Shun-Chun
SC
Wang
School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China. simonhan@hkbu.edu.hk.
Quan-Bin
QB
Han
D000818:Animals; D005786:Gene Expression Regulation / Q000187:drug effects; D005936:Glucans / Q000008:administration & dosage / Q000737:chemistry* / Q000302:isolation & purification; D056747:Immunomodulation; D015850:Interleukin-6 / Q000096:biosynthesis*; D029746:Lobelia / Q000737:chemistry*; D008745:Methylation; D051379:Mice; D009005:Monosaccharides / Q000737:chemistry / Q000302:isolation & purification; D010587:Phagocytosis / Q000187:drug effects; D000067996:RAW 264.7 Cells / Q000187:drug effects; D017550:Spectroscopy, Fourier Transform Infrared; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D005936:Glucans; D015850:Interleukin-6; D009005:Monosaccharides; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha
Lobelia chinensis; NMR; RAW 264.7; TLR4; immunomodulating