Polyethylene glycol-based ultrasonic-assisted enzymatic extraction, characterization, and antioxidant activity in vitro and in vivo of polysaccharides from Lonicerae japonica leaves.

In this paper, polyethylene glycol (PEG)-based ultrasonic-assisted enzymatic extraction (UAEE) was employed in polysaccharides extraction from Lonicerae japonica leaves (LJLP). The optimal extraction conditions (extraction time of 33 min, PEG concentration of 30%, and ultrasonic power of 191 W) were obtained by Box-Behnken design (BBD). Under this condition, the LJLP yield was 14.76%. Furthermore, LJLP was identified as a typical heteropolysaccharide considering the main constitutive monosaccharides include galactose (32.3%), glucose (20.9%), and ribose (15.2%). Moreover, LJLP exhibited high total reducing power and considerable scavenging activities on superoxide radicals, in a concentration-dependent manner in vitro. In addition, antioxidant analysis in vivo revealed that for the LJLP-treated mice, the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) activities, and total antioxidant capacity (TAOC) were significantly increased, while the level of malondialdehyde (MDA) was decreased in both serum and liver.