Polysaccharide from Atractylodes macrocephala Koidz binding with zinc oxide nanoparticles: Characterization, immunological effect and mechanism

Ruonan Bo; Xiaopan Liu; Jing Wang; Simin Wei; Xinyue Wu; Ya Tao; Shuya Xu; Mingjiang Liu; Jingui Li; Huan Pang

doi:10.3389/fnut.2022.992502

Polysaccharide from Atractylodes macrocephala Koidz binding with zinc oxide nanoparticles: Characterization, immunological effect and mechanism

Front Nutr. 2022 Sep 15:9:992502. doi: 10.3389/fnut.2022.992502. eCollection 2022.

Authors

Ruonan Bo^{1

2

3}, Xiaopan Liu¹, Jing Wang¹, Simin Wei¹, Xinyue Wu⁴, Ya Tao¹, Shuya Xu¹, Mingjiang Liu^{1

2

3}, Jingui Li^{1

2

3}, Huan Pang⁴

Affiliations

¹ College of Veterinary Medicine, Yangzhou University, Yangzhou, China.
² Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.
³ Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China.
⁴ School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, China.

Abstract

Atractylodes macrocephala Koidz (A. macrocephala) has been used both as a traditional medicine and functional food for hundreds of years in Asia. And it has a variety of biological activities, such as enhancing the ability of immunity and modulating effect on gastrointestinal motility. In this study, a water-soluble polysaccharide with molecular weight of 2.743 × 10³ Da was isolated from the root of A. macrocephala. Polysaccharide from A. macrocephala (AMP) consisted of arabinose, galactose, glucose, xylose, mannose, ribose, galactose uronic acid, glucose uronic acid, with a percentage ratio of 21.86, 12.28, 34.19, 0.43, 0.92, 0.85, 28.79, and 0.67%, respectively. Zinc plays an important role in immune system. Therefore, we supposed that AMP binding with zinc oxide (ZnO) nanoparticles (AMP-ZnONPs) might be an effective immunostimulator. AMP-ZnONPs was prepared by Borch reduction, and its structural features were characterized by Scanning Electron Microscope (SEM), Transmission electron microscope (TEM), TEM-energy dispersive spectroscopy mapping (TEM-EDS mapping), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectrometer (XPS), X-ray diffraction (XRD), particle size and zeta-potential distribution analysis. Then, its immunostimulatory activity and the underlying mechanism were evaluated using RAW264.7 cells. The results showed that AMP-ZnONPs remarkably promoted cell proliferation, enhanced phagocytosis, the release of nitric oxide (NO), cytokines (IL-6 and IL-1β) and the expression of co-stimulatory molecules (CD80, CD86 and MHCII). Moreover, AMP-ZnONPs could promote the expression of Toll-like receptor 4 (TLR4), Myeloid differentiation factor 88 (MyD88), TNF receptor associated factor 6 (TRAF6), phospho-IκBα (P-IκBα) and phospho-p65 (P-p65), and TLR4 inhibitor (TAK242) inhibited the expression of these proteins induced by AMP-ZnONPs. Therefore, AMP-ZnONPs activated macrophages by TLR4/MyD88/NF-κB signaling pathway, indicating that AMP-ZnONPs could act as a potential immunostimulator in medicine and functional food.

Keywords: TLR4 signaling pathways; immunostimulatory activity; polysaccharide from Atractylodes macrocephala Koidz; potential immunostimulator; zinc oxide nanoparticles.