Screening of strains for producing Saussurea involucrata polysaccharide with skincare efficacy

Abstract:

[Objective] The microbial fermentation of plant can increase the yield of polysaccharide and transform the original plant polysaccharide into a new fermentative polysaccharide with higher activity. According to the viable count, yield of Saussurea involucrata polysaccharide, and skincare efficacy, we conducted strain screening, aiming to obtain a strain suitable for the production of S. involucrata polysaccharide. [Methods] Different strains were used to produce S. involucrata polysaccharide. The viable count was determined by plate colony counting method, and the content of polysaccharide in the fermentation broth was determined by anthrone colorimetry. The cell models of barrier damage and inflammation were used to evaluate the skincare efficacy of the polysaccharide in cells, with the cell viability measured by MTT method and NO content measured by Griess method. The mouse model of atopic dermatitis was used to evaluate the efficacy of the polysaccharide in animals in terms of skin appearance, trans-epidermal water loss, skin pathology, changes in epidermal thickness, and the barrier protein filaggrin of skin tissue. [Results] There were significant differences in the viable count and yield of crude polysaccharide after fermentation by different strains. The viable counts of Bacillus subtilis CCFM1162, B. subtilis 165-M1, Lactobacillus casei CCFM1073, L. reuteri CCFM8631, and L. sakei GD17-9 were no less than 2.0×10⁸ CFU/mL and higher than those of the other strains. However, Saccharomyces cerevisiae HN7-A5, L. casei CCFM1073, L. reuteri CCFM8631, and L. sakei GD17-9 produced more than 1.37 g/L polysaccharide. On the basis of the polysaccharide yield and the viable count, the skincare efficacy of crude polysaccharide from S. involucrata fermented by L. casei CCFM1073, L. reuteri CCFM8631, L. sakei GD17-9, and S. cerevisiae HN7-A5 was evaluated with cell models. The results showed that the polysaccharides produced by the selected strains had little effect on the survival rate of HaCaT cells induced by sodium lauryl sulfate, while the polysaccharides decreased the NO content in the RAW264.7 cells exposed to lipopolysaccharide (LPS). The polysaccharides produced by L. sakei GD17-9 and L. reuteri CCFM8631 had better effect, reducing the NO content by 81% and 71%, respectively. According to the viable count, polysaccharide yield, and the skincare efficacy in cell models, we selected the crude polysaccharides from S. involucrata fermented by L. sakei GD17-9 and L. reuteri CCFM8631 to validate the skincare efficacy in the animal model. The results showed that the crude polysaccharides from S. involucrata fermented by L. reuteri CCFM8631 had better skincare efficacy. [Conclusion] L. reuteri CCFM8631 was the most suitable strain for the production of crude polysaccharide from S. involucrata, considering the viable count, the polysaccharide yield, and the skincare efficacy in cell and animal models.