Natural Deep Eutectic Solvent-Assisted Extraction, Structural Characterization, and Immunomodulatory Activity of Polysaccharides from Paecilomyces hepiali

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 22; p. 8020
• Main Authors: Wang, Yanbin, Xu, Feijia, Cheng, Junwen, Wu, Xueqian, Xu, Juan, Li, Chunru, Li, Weiqi, Xie, Na, Wang, Yuqin, He, Liang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18.11.2022; MDPI
• Subjects: Biocompatibility; Carboxylic Acids; Choline; Conformation; Cytokines; deep eutectic solvent; Deep Eutectic Solvents; Efficiency; Functional foods & nutraceuticals; Fungi; Gene expression; Humans; Hydrogen bonds; IL-1β; Immunomodulation; immunomodulatory activity; Inflammation; Interleukin 6; Moisture content; Molecular conformation; Molecular weight; Natural & organic foods; Paecilomyces; Paecilomyces hepiali; physicochemical property; Polysaccharides; Polysaccharides - pharmacology; Saccharides; Solvents; Solvents - chemistry; Structural analysis; Succinic acid; Tumor necrosis factor-α; Uronic acid; Viscosity; Water - chemistry; Water content; deep eutectic solvent; polysaccharides; physicochemical property; Paecilomyces hepiali; immunomodulatory activity
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27228020

Polysaccharides, which can be affected by different preparations, play a crucial role in the biological function of (PHPS) as a health food. To explore high-valued polysaccharides and reduce the negative influence of human involvement, a green tailorable deep eutectic solvent (DES) was applied to optimize the extraction of polysaccharides (PHPS-D), followed by the evaluation of the structural properties and immunomodulation by comparison with the hot-water method (PHPS-W). The results indicated that the best system for PHPS-D was a type of carboxylic acid-based DES consisting of choline chloride and succinic acid in the molar ratio of 1:3, with a 30% water content. The optimal condition was as follows: liquid-solid ratio of 50 mL/g, extraction temperature of 85 °C, and extraction time of 1.7 h. The actual PHPS-D yield was 12.78 ± 0.17%, which was obviously higher than that of PHPS-W. The structural characteristics suggested that PHPS-D contained more uronic acid (22.34 ± 1.38%) and glucose (40.3 ± 0.5%), with a higher molecular weight (3.26 × 10 g/mol) and longer radius of gyration (78.2 ± 3.6 nm), as well as extended chain conformation, compared with PHPS-W, and these results were confirmed by AFM and SEM. Immunomodulatory assays suggested that PHPS-D showed better performance than PHPS-W regarding pinocytic activity and the secretion of NO and pro-inflammatory cytokines (IL-6, TNF-α and IL-1β) by activating the corresponding mRNA expression in RAW264.7 cells. This study showed that carboxylic acid-based DES could be a promising tailorable green system for acidic polysaccharide preparation and the valorization of in functional foods.