Structure and Antioxidant Activity of Extracellular Polysaccharides from Antarctic Marine Filamentous Fungi

The structure and antioxidant activity of extracellular polysaccharides derived from filamentous fungi from Antarctic marine were studied. Methods The extracellular polysaccharides produced by the strains were separated and purified by ethanol precipitation, strong anion exchange chromatography column and gel permeation chromatography column. High performance liquid chromatography, infrared spectroscopy, gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy were carried out by PMP pre-column derivatization. The structure of polysaccharides was characterized. The antioxidant activities of extracellular polysaccharides were studied by measuring DPPH free radicals, superoxide anion radicals, hydroxyl radicals, ABTS free radical scavenging activity and Fe2+ chelation ability. The polysaccharide HDN-51 was isolated from the fermentation product of the Antarctic marine filamentous fungus Lecanicillium kalimantanense HDN13-339. Its molecular weight was 16.3kDa, which was mainly composed of mannose and galactose. The sugar chain was composed of (1 ->)-Galf. (1 -> 2)-Manp, (1 -> 5)-Galf, (1.6)-Manp, (1 -> 6) - Galf and (1 -> 2,6) - Manp, HDN - 51 has good Antioxidant activity, especially hydroxyl radical scavenging ability. HDN - 51 with a certain structure has been isolated from the Antarctic marine filamentous fungus Lecanicillium kalimantanense HDN13 - 339 for the first time, and it was a novel galactomannan with antioxidant ability.