Key Laboratory of Marine Drugs of Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
Marine Biomedical Research Institute of Qingdao, Qingdao 266237, China.
Mar Drugs. 2023 Apr 26;21(5):270. doi: 10.3390/md21050270.
Marine microorganisms often produce exopolysaccharides with novel structures and diverse biological activities due to their specific marine environment. The novel active exopolysaccharides from marine microorganisms have become an important research area in new drug discovery, and show enormous development prospects. In the present study, a homogeneous exopolysaccharide from the fermented broth of the mangrove endophytic fungus N29, designated as PJ1-1, was obtained. The results of chemical and spectroscopic analyses showed that PJ1-1 was a novel galactomannan with a molecular weight of about 10.24 kDa. The backbone of PJ1-1 was composed of →2)-α-d-Man-(1→, →4)-α-d-Man-(1→, →3)-β-d-Gal-(1→ and →2)-β-d-Gal-(1→ units with partial glycosylation at C-3 of →2)-β-d-Gal-(1→ unit. PJ1-1 had a strong hypoglycemic activity in vitro, evaluated using the assay of α-glucosidase inhibition. The anti-diabetic effect of PJ1-1 in vivo was further investigated using mice with type 2 diabetes mellitus induced by a high-fat diet and streptozotocin. The results indicated that PJ1-1 markedly reduced blood glucose level and improved glucose tolerance. Notably, PJ1-1 increased insulin sensitivity and ameliorated insulin resistance. Moreover, PJ1-1 significantly decreased the levels of serum total cholesterol, triglyceride and low-density lipoprotein cholesterol, enhanced the level of serum high-density lipoprotein cholesterol and alleviated dyslipidemia. These results revealed that PJ1-1 could be a potential source of anti-diabetic agent.
海洋微生物由于其特殊的海洋环境，经常产生具有新颖结构和多样生物活性的胞外多糖。新型活性海洋微生物胞外多糖已成为新药发现的一个重要研究领域，具有巨大的发展前景。本研究从红树林内生真菌 N29 的发酵液中获得了一种均一的胞外多糖，命名为 PJ1-1。化学和光谱分析结果表明，PJ1-1 是一种新型半乳甘露聚糖，分子量约为 10.24 kDa。PJ1-1 的主链由→2)-α-d-Man-(1→、→4)-α-d-Man-(1→、→3)-β-d-Gal-(1→和→2)-β-d-Gal-(1→单元组成，部分在→2)-β-d-Gal-(1→单元的 C-3 位发生糖苷化。PJ1-1 在体外具有很强的α-葡萄糖苷酶抑制活性，可降低血糖水平。进一步研究了 PJ1-1 在高脂饮食和链脲佐菌素诱导的 2 型糖尿病小鼠体内的抗糖尿病作用。结果表明，PJ1-1 可显著降低血糖水平，改善葡萄糖耐量。值得注意的是，PJ1-1 可增加胰岛素敏感性，改善胰岛素抵抗。此外，PJ1-1 可显著降低血清总胆固醇、甘油三酯和低密度脂蛋白胆固醇水平，提高血清高密度脂蛋白胆固醇水平，改善血脂异常。这些结果表明 PJ1-1 可能是一种潜在的抗糖尿病药物来源。
