Chemical Structure and Immunomodulating Activities of an α-Glucan Purified from Lobelia chinensis Lour.

Xiao-Jun Li,Dik-Lung Ma,Ai-Ping Lu,Shun-Chun Wang,Ge Zhang,Quan-Bin Han,Wan-Rong Bao,Chung-Hang Leung

doi:10.3390/molecules21060779

Abstract

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.

Highlights

Lobelia chinensis, commonly known as Chinese lobelia, Herba Lobellae Chinensis, aze mushiro and mizo kakushi, grows wild throughout East Asia
The present study aims to analyze the chemistry of polysaccharides purified fromfrom the water water extract of Lobelia chinensis and to explore their immune modulating effects on the RAW 264.7 extract of Lobelia chinensis and to explore their immune modulating effects on the RAW 264.7 cell cell line
A neutral α-glucan, named BP1, with a molecular mass of approximately 9.45 kDa was isolated from Lobelia chinensis

Summary

Introduction

Commonly known as Chinese lobelia, Herba Lobellae Chinensis, aze mushiro and mizo kakushi, grows wild throughout East Asia. It is one of the most used anti-cancer herbs in Chinese. The current phytochemical studies have found various types of chemical components, including piperidine alkaloids, coumarins, terpenoids and saponins [2,3]. These chemicals show various biological activities, including anti-bacterial, anti-venom, anticancer, anti-viral and anti-inflammatory activities [4,5,6,7,8]. Little is known about the chemistry and bioactivity of the polysaccharides of this herb

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Results

Conclusion