Structural characterisation and antioxidant activities in vitro and in vivo of a novel polysaccharide from <i>Salvia miltiorrhiza</i>
Yongshuai Jing, Jinying Hu, Ziteng Su, Wenjing Cheng, Yuwei Zhang, Xiaosheng Yang, Danshen Zhang, Lanfang Wu
Abstract
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.