Optimization of Accelerated Solvent Extraction of Polysaccharides from Gracilaria lemaneiformis Using Response Surface Methodology and Anti-inflammatory Activity

Abstract

The aim of this work was to apply response surface methodology (RSM) to model and optimize the accelerated solvent extraction (ASE) technique for extracting the crude polysaccharides (GLP-K) from Gracilaria lemaneiformis. In terms of the yield of polysaccharide, single factor tests and Box-Behnken design response surface method were developed. The structure of the prepared polysaccharides was characterized by Fourier transform infrared (FT-IR) and high performance liquid chromatography (HPLC). And the anti-inflammatory potential of GLP-K in lipopolysaccharide (LPS)-induced RAW264.7 macrophages was also explored. Briefly, the optimal extraction conditions for GLP-K were as follows: 70 °C of extraction temperature, 8.5 min of extraction time, and 4 extraction cycles. Under the condition, the experimental yield of polysaccharide was 9.58%±0.31%. FT-IR showed that the polysaccharide contained uronic acid, and the weight-average molecular weight ranged from 4.4 to 747.1 kDa. GLP-K had no significant cytotoxic effects at or below the concentrations of 1000 μg/mL (P<0.001). Compared with the model group, GLP-K administration group (50, 100, 200, 300, 400, 500 μg/mL) displayed remarkable inhibitory effects on the release level of NO (P<0.001), which decreased by 43.76%~69.47%. This paper enriched the research on the extraction of polysaccharides by accelerated solvent extraction technology, and provided experimental basis for the development and utilization of Gracilaria lemaneiformis polysaccharides.

Keywords

• gracilaria lemaneiformis polysaccharides
• technique optimization
• accelerated solvent extraction
• structural characterization
• anti-inflammatory