Purification, characterisation and antioxidant properties of a novel polysaccharide from Physalis pubescens L. fruits

Summary Considering the medicinal and edible properties of Physalis pubescens L. fruit, the plant has a long history of cultivation in China. In the current study, a novel polysaccharide (PPL‐1) was successfully obtained from P. pubescens fruits using multi‐column techniques. The chemical characterisation of the polysaccharide was achieved by acid hydrolysis, determination of weight average molecular mass, thermogravimetric and Smith degradation analyses, in addition to ultraviolet, Fourier transform infrared spectroscopy, one‐ and two‐dimensional nuclear magnetic resonance spectroscopy. According to the structural analyses, PPL‐1 consisted of rhamnose, arabinose, fructose, mannose and glucose with a relative molar ratio of 0.39:0.12:0.02:0.03:0.44. The average molecular weight of PPL‐1 was 7.3 kDa and it was mainly composed of (1 → 3) and (1 → 6) linkages. PPL‐1 exhibited not only scavenging effects on 2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) free radicals but also hydrogen peroxide‐induced oxidative stress in SH‐SY5Y cells effectively by decreasing malondialdehyde content and increasing total antioxidant capacity, superoxide dismutase and glutathione peroxidase activity levels.