Alkali treated antioxidative crude polysaccharide from Russula alatoreticula potentiates murine macrophages by tunning TLR/NF-\u03baB pathway

Somanjana Khatua,Krishnendu Acharya

doi:10.1038/s41598-018-37998-2

Abstract

In our previous research, Russula alatoreticula was demonstrated as a novel species, ethnic myco-food and reservoir of hot water extractable polysaccharides. However, residue after the hydrothermal process still offer plenty of medicinal carbohydrates that could easily be extracted by using alkali solvent. Thus, the present work was attempted to prepare crude polysaccharide using remainder of the conventional method and subsequently a β-glucan enriched fraction, RualaCap, was isolated. The bio-polymers displayed pronounced therapeutic efficacy as evident by radical scavenging, chelating ability, reducing power and total antioxidant capacity. In addition, strong immune-enhancing potential was also observed indicated by augmentation in macrophage viability, phagocytic uptake, nitric oxide (NO) production and reactive oxygen species (ROS) synthesis. Alongside, the polysaccharides effectively triggered transcriptional activation of Toll like receptor (TLR)-2, TLR-4, nuclear factor kappa B (NF-κB), cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-α, Iκ-Bα, interferon (IFN)-γ and interleukin (IL)-10 genes explaining mode of action. Taken together, our results signify possibility of RualaCap as a potent nutraceutical agent and enhance importance of R. alatoreticula especially in the field of innate immune stimulation.

Highlights

Russula alatoreticula has recently been established as a new species (Russulaceae, Basidiomycota) after thorough micro and macro-morphological studies followed by molecular systematics aspect
To prepare polysaccharidic fraction from R. alatoreticula a quite distinct extraction procedure was followed that involved leftover residue of hot water process and alkali as extractant solvent
Spectroscopic outcome implied that β-glucan was the dominant component of polysaccharide backbone while α-linked glucose was presented in trace

Summary

Introduction

Russula alatoreticula has recently been established as a new species (Russulaceae, Basidiomycota) after thorough micro and macro-morphological studies followed by molecular systematics aspect. Antioxidant Assays Scavenging ability of hydroxyl radicals Scavenging ability of DPPH radicals EC50 value (μg/ml) Scavenging ability of ABTS radicals Chelating ability of ferrous ion Reducing power Total antioxidant activity by phosphomolybdenum method (μg ascorbic acid equivalent/mg of dry polysaccharide) Standard 69 ± 1b 4.5 ± 0.5b 2.58 ± 0.09b 2.54 ± 0.5b 14.5 ± 5b activity was determined and result showed that reducing capacity of 1 mg of the extract was equivalent to 1.47 μg of ascorbic acid.

Results

Conclusion