Structural Characterization, Antioxidant and Antitumor Activities of the Two Novel Exopolysaccharides Produced by Debaryomyces hansenii DH-1

Exopolysaccharides produced by edible microorganisms exhibit excellent constructive physicochemical and significant biological activity, which provide advantages for the food or pharmaceutical industries. Two novel exopolysaccharides produced by Debaryomyces hansenii DH-1 were characterized, named S1 and S2, respectively. S1, with a molecular weight of 34.594 kDa, primarily consisted of mannose and glucose in a molar ratio of 12.19:1.00, which contained a backbone fragment of alpha-D-Manp-(1 -> 4)-alpha-D-Manp-(1 -> 2)-alpha-D-Glcp-(1 -> 3)-alpha-D-Manp-(1 -> 3)-beta-D-Glcp-(1 -> 4)-beta-D-Manp-(1 ->. S2, with a molecular weight of 24.657 kDa, was mainly composed of mannose and galactose in a molar ratio of 4.00:1.00, which had a backbone fragment of alpha-D-Manp-(1 -> 6)-beta-D-Manp-(1 -> 2)-alpha-D-Manp-(1 -> 4)-alpha-D-Galp-(1 -> 3)-beta-D-Manp-(1 -> 6)-alpha-D-Manp-(1 ->. Both S1 and S2 exhibited good thermal stability and potent hydroxyl radical scavenging activity, with similar to 98%. Moreover, S1 possessed an additional strong iron-reducing capacity. In vitro antitumor assays showed that S1 and S2 significantly inhibited the proliferation of Hela, HepG2, and PC-9 cancer cells. Moreover, PC-9 was more sensitive to S1 compared with S2. The above results indicate that S1 and S2 have great potential to be utilized as natural antioxidants and candidates for cancer treatment in the food and pharmaceutical industries.

Automated summary

Exopolysaccharides produced by edible microorganisms, such as S1 and S2, have excellent physicochemical properties and significant biological activity, making them advantageous for the food and pharmaceutical industries. Both S1 and S2 exhibited good thermal stability and potent hydroxyl radical scavenging activity, with S1 also possessing strong iron-reducing capacity. In vitro antitumor assays showed that S1 and S2 significantly inhibited the proliferation of Hela, HepG2, and PC-9 cancer cells, with PC-9 being more sensitive to S1. These findings suggest that S1 and S2 have great potential as natural antioxidants and candidates for cancer treatment in the food and pharmaceutical industries.