Optimization of astilbin extraction from the rhizome of Smilax glabra, and evaluation of its anti-inflammatory effect and probable underlying mechanism in lipopolysaccharide-induced RAW264.7 macrophages.

Chuan-Li Lu,Dong-Mei Wang,Yan-Fang Zhu,Chuan-Jian Lu,Xiao-Jie Xu,Meng-Mei Hu,Wei Zhu

doi:10.3390/molecules20010625

Abstract

Astilbin, a dihydroflavonol derivative found in many food and medicine plants, exhibited multiple pharmacological functions. In the present study, the ethanol extraction of astilbin from the rhizome of smilax glabra Roxb was optimized by response surface methodology (RSM) using Box-Behnken design. Results indicated that the obtained experimental data was well fitted to a second-order polynomial equation by using multiple regression analysis, and the optimal extraction conditions were identified as an extraction time of 40 min, ethanol concentration of 60%, temperature of 73.63 °C, and liquid-solid ratio of 29.89 mL/g for the highest predicted yield of astilbin (15.05 mg/g), which was confirmed through validation experiments. In addition, the anti-inflammatory efficiency of astilbin was evaluated in lipopolysaccharide (LPS)-induced RAW 264.7 cells. Results showed that astilbin, at non-cytotoxicity concentrations, significantly suppressed the production of nitric oxide (NO) and tumor necrosis factor-α (TNF-α), as well as the mRNA expression of inducible nitric oxide synthase (iNOS) and TNF-α in LPS-induced RAW 264.7 cells, but did not affect interleukin-6 (IL-6) release or its mRNA expression. These effects may be related to its up-regulation of the phosphorylation of p65, extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK).

Highlights

IntroductionInflammation is an important component of innate immunity and the host response to pathogens [1]
Inflammation is an important component of innate immunity and the host response to pathogens [1].uncontrolled excessive inflammation may be detrimental, and contribute to the pathogenesis of many diseases [2]
In order to study the combined effect of independent variables on the extraction yield of astilbin (EYA), 29 experiments were carried out for different combinations of the extraction parameters using

Summary

Introduction

Inflammation is an important component of innate immunity and the host response to pathogens [1]. Uncontrolled excessive inflammation may be detrimental, and contribute to the pathogenesis of many diseases [2]. Pro-inflammatory cells, mainly activated macrophages, mediate most of the cellular and molecular pathophysiology of inflammation by producing cytokines and other pro-inflammatory molecules, including prostaglandins, enzymes and free radicals [3]. LPS is a compound derived from Gram negative bacterial cell walls, which has been proposed as a potent inducer of inflammatory cytokines. In response to LPS, the RAW264.7 cells become potent secretary cells that release various pro-inflammatory mediators, including IL-1β, IL-6, TNF-α, and NO [4]. LPS-activated RAW264.7 macrophages have been broadly used for evaluating the anti-inflammatory activity of natural products

Methods

Results

Conclusion