Extraction, purification, structural characterization, and antioxidant activity of a novel polysaccharide from Lonicera japonica Thunb.
Feiyu An, Guangyu Ren, Junrui Wu, Kaixin Cao, Mo Li, Yumeng Liu, Yanfeng Liu, Xinyu Hu, Meijun Song, Rina Wu
Abstract
A novel water-soluble polysaccharide (HEP-4) with a molecular weight of 1.98 × 10 5 Da was extracted from honeysuckle. Structural characterization was performed using high-performance liquid chromatography (HPLC), gas chromatography, Fourier transform-infrared (FT-IR) spectrum, nucleus magnetic resonance (NMR) spectra, and scanning electron microscopy. The results showed that HEP-4 is primarily composed of mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose with a mole ratio of 6.74:1.56:1.04:14.21:4.31:5.4, and the major types of the glycosidic bond types of HEP-4 were 1-α-D-Glc p , 1,4-β-D-Glc p , 1-β-D-Ara p , 1,3,4-β-D-Ara p , and 1,3,6-β-D-Man p . The results of bioactivity experiments revealed that HEP-4 had antioxidant in vitro . In addition, HEP-4 inhibited H 2 O 2 -induced oxidative damage and increased the activity of HepG2 cells by reducing MDA levels and inhibiting ROS production. Meanwhile, HEP-4 significantly enhanced the activities of GSH-Px and CAT, indicating that HEP-4 exerts a protective effect on H 2 O 2 -induced oxidative stress. These results indicate that HEP-4 could be a potential natural antioxidant.