Purification characterization and anti-aging activity of sika deer antler polysaccharide
Authors: Zhang jiaqi , Wang lulu , He yuan , Guo chunyang , Zhang jing , Wang jing 
Published: October 2022

Abstract
As a traditional Chinese medicine, sika deer antler is widely distributed in Northeast China. It is rich in protein, polysaccharide and other substances, and has a wide range of physiological activities such as nourishing, anti-oxidation and anti-aging. The content of sika deer antler polysaccharides are rich and related to the efficacy of sika deer antler. Therefore, the extraction, purification, structural characterization and anti-aging activity analysis of sika deer antler polysaccharide (SDAPO) could clarify the pharmacodynamic substances of anti-aging effect of sika deer antler. The SDAPO was extracted with hot water and precipitated with ethanol. The purity of SDAPO was determined as 83.62% by phenol-sulfuric acid method, and the content was 33.20 mg/g. The structural morphology, functional groups, monosaccharide composition, glycosidic bond configuration and glycosidic bond connection order of SDAPO were characterized and analysed. Fourier transform infrared spectroscopy (FT-IR) analysis showed that SDAPO had a typical polysaccharide structure, whcih contained amide group and sulfate radical groups. Detection of polysaccharide hydrolysates showed that SDAPO was an acidic mucopolysaccharide, which was composed of mannose, glucosamine hydrochloride, ribose, glucuronic acid, galacturonic acid, galactosamine hydrochloride, glucose and galactose. The molar ratio was 9.3:7.5:9.1:12.6:1.8:1:33.5:42.3. Methylation analysis showed that SDAPO contained more galactosamine hydrochloride residues as →3)-GalA-HCIp-(1→. 1H nuclear magnetic resonance (1H NMR) analysis showed that SDAPO contained a β-Pyranose configuration. At the same time, detection of morphological characteristics showed that the SDAPO was honeycomb. According to the results of free radical scavenging activity in vitro, the maximum scavenging rates of DPPH, OH and ABTS free radicals by SDAPO were 73.68%, 75.30% and 71.97% respectively, which indicated that it had significant antioxidant activity in vitro. Furthermore, according to the analysis of anti-aging model of Caenorhabditis elegans, compared with the blank control group, in the dose 800μg/mL, SDAPO could prolong the average life span of C. elegans under normal environment by 25.46%. Compared with the oxidative stress model group established by paraquat, in the dose 800μg/mL, SDAPO reduced the ROS fluorescence intensity of C. elegans by 23.67 RFU/worm. The swallowing frequency and the ability to maintain normal movement of C. elegans in SDAPO treatment group were significantly better than those in control group. It was worth noting that SDAPO could prolong the average lifespan and downregulate ROS level and upregulated the swallowing and locomotor abilities in C. elegans. In summary, our research showed that SDAPO was a β-Pyran based acidic mucopolysaccharide which had antioxidant activity and anti-aging ability, but also for the sika deer antler polysaccharide further research provided a reference.
Practical applications
The sika deer antler polysaccharide is rich in polysaccharides and has high edible and medicinal value. This study showed that SDAPO had anti-aging ability, which will enhance public awareness regarding sika deer antler polysaccharide, and provide new directions for the research and development of new products derived from sika deer antler.