Structural Characterization, Simulated Digestion and Anti-Aging Activities of an Acidic Polysaccharide from Salvia Miltiorrhiza.

An acidic polysaccharide (SMP) with a molecular weight (Mw) of 1.28 × 106 Da was isolated from Salvia miltiorrhiza. The monosaccharide composition in molar percentages was rhamnose (Rha): galacturonic acid (GalA): galactose (Gal): arabinose (Ara) = 6.15: 55.98: 21.27: 16.69. The results of simulated digestion in vitro showed that SMP was not degraded in saliva, gastric juice or intestinal juice. The Y maze test and new object recognition test showed that SMP could improve the working memory impairment of aging mice. SMP could also increase the activity of superoxide dismutase (SOD) and catalase (CAT) in serum and brain tissue, decrease the content of malondialdehyde (MDA), decrease the levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in brain tissue, and increase the content of short-chain fatty acids (SCFA) in the intestine. In addition, SMP could also regulate the intestinal flora structure, including increasing the relative abundance of Firmicutes and Bacteroidetes and decreasing the relative abundance of Proteobacteria. This work lays a foundation for the development of functional foods related to Salvia miltiorrhiza.

Structural characterisation and antioxidant activities in vitro and in vivo of a novel polysaccharide from Salvia miltiorrhiza.

Polysaccharides have received extensive attention due to their multiple physiological functions, especially their remarkable antioxidant capacity. In this study, a novel acidic polysaccharide (PSMP-2) with a molecular weight (Mw) of 1.28 × 106 Da from Salvia miltiorrhiza Bunge was extracted and purified via DEAE-52 cellulose column and Sephadex G-100 column chromatography. The structure of PSMP-2 was characterised by high-performance gel permeation chromatography (HPGPC), high-performance liquid chromatography (HPLC), Fourier transforms infrared spectroscopy (FT-IR) and methylation analysis. The results showed that PSMP-2 was an acidic heteropolysaccharide composed of rhamnose (Rha) (6.15%), galacturonic acid (GalA) (55.98%), and galactose (Gal) (21.27%) and arabinose (Ara) (16.69%). PSMP-2 contained five major glycosidic linkages, (1→)-linked-Ara, (1→2, 4)-linked-Rha, (1→4)-linked-Gal, (1→6)-linked-Gal, (1→3, 6)-linked-Gal, in a molar ratio of 5.98: 1.45: 72.23: 16.40: 3.94. The IC50 of PSMP-2 on 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radical scavenging ability were 0.991 mg/mL and 4.007 mg/mL, respectively. It could regulate the activity of antioxidant enzymes in vivo and had good antioxidant activity. To sum up, a novel acidic polysaccharide (Mw of 1.28 × 106 Da) with antioxidant activity was isolated from S. miltiorrhiza, and its application prospect in the field of medicine and food was preliminarily revealed.