Physicochemical Characteristics, Anti-Lipase and Antioxidant Activities of Polysaccharide Extracted from Astragalus spinosis Grown in the Northern Region of Saudi Arabia

Abstract

Introduction: Northern border region of Saudi Arabia is one of the richest areas of traditional plants. This study was designed with an interest to work on the polysaccharide extracted from Astragalus spinosis leaves (PLAS) collected from rafha province. Methods: Polysaccharide was isolated by hot water extraction, followed by ethanol precipitation. The isolated crude polysaccharide contains 62.43% ±2.09% carbohydrate and 0.29 ± 0.07% protein. The physicochemical characteristics, such as chemical composition, humidity, foaming capacity, solubility as well as water and oil holding capacity were evaluated. The structural feature of polysaccharide was studied through Fourier transform infrared (FT-IR) analysis and scanning electron microscopy. Results: Polysaccharide extracted from Astragalus spinosis leaves showed good inhibitory lipase and antioxidant activities. It was observed that the total antioxidant capacity, the 1,1- diphenyl-2-picrylhydrazyl (DPPH) and the 2,2 -azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ATBS) radical scavenging activities were high at 2.0 mg/ml (97 µmol eq tocopherol ± 1.4, 73% ± 2.1 and 93% ± 0.9 respectively).  Conclusion: the crude polysaccharide extract demonstrated good emulsion stabilizing capacities, with various hydrophobic compounds. It could be a potential source of natural antioxidants and emulsifiers.