A Neutral Polysaccharide from Spores of <i>Ophiocordyceps gracilis</i> Regulates Oxidative Stress via NRF2/FNIP1 Pathway
<i>Ophiocordyceps gracilis</i> (<i>O. gracilis</i>) is a parasitic fungus used in traditional Chinese medicine and functional foods. In this study, a neutral heteropolysaccharide (GSP-1a) was isolated from spores of <i>O. gracilis</i>, and its structure and antiox...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-09-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/19/14721 |
| Summary: | <i>Ophiocordyceps gracilis</i> (<i>O. gracilis</i>) is a parasitic fungus used in traditional Chinese medicine and functional foods. In this study, a neutral heteropolysaccharide (GSP-1a) was isolated from spores of <i>O. gracilis</i>, and its structure and antioxidant capacities were investigated. GSP-1a was found to have a molecular weight of 72.8 kDa and primarily consisted of mannose (42.28%), galactose (35.7%), and glucose (22.02%). The backbone of GSP-1a was composed of various sugar residues, including →6)-α-D-Manp-(1→, →2,6)-α-D-Manp-(1→, →2,4,6)-α-D-Manp-(1→, →6)-α-D-Glcp-(1→, and →3,6)-α-D-Glcp-(1→, with some branches consisting of →6)-α-D-Manp-(1→ and α-D-Gal-(1→. In vitro, antioxidant activity assays demonstrated that GSP-1a exhibited scavenging effects on hydroxyl radical (<sup>•</sup>OH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS<sup>•+</sup>), and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH<sup>•</sup>). Moreover, GSP-1a was found to alleviate H<sub>2</sub>O<sub>2</sub>-induced oxidative stress in HepG2 cells by reducing the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), while enhancing the activities of superoxide dismutase (SOD). Furthermore, GSP-1a upregulated the mRNA expression of antioxidant enzymes such as <i>Ho-1</i>, <i>Gclm</i>, and <i>Nqo1</i>, and regulated the NRF2/KEAP1 and FNIP1/FEM1B pathways. The findings elucidated the structural types of GSP-1a and provided a reliable theoretical basis for its usage as a natural antioxidant in functional foods or medicine. |
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| ISSN: | 1661-6596 1422-0067 |