Study On Extraction Of Antioxidant Bio-active Components From Chlorellaand Its Anti-aging Effect

Aging is a physiological process that occurs naturally in the body and is inevitable.The birth rate of the modern population has plummeted,and the average life expectancy of people has increased,leading to a more serious trend of population aging.How to solve the related diseases caused by old age and aging has become a research hotspot in the current era.One of the causes of human aging is the inability of the body to maintain the balance of free radicals and antioxidants.The production of excessive free radicals will oxidatively damage cells and cause damage to intracellular structures,protein inactivation,and tissue and organ dysfunction.Recent studies have found that polysaccharides and peptides,the active ingredients of marine microalgae,have antibacterial and anti-inflammatory effects,regulate gastrointestinal absorption and promote the excretion of toxins,but there are still few studies on anti-aging.Chlorella pyrenoidesa is an anti-inflammatory,improves constipation and enhances immunity.It has various active substances such as polysaccharides,peptides,vitamins and minerals.In this thesis,chlorella is used as the raw material to extract two active substances,polysaccharides and peptides,and C.elegans as the main model for antioxidant activity testing and anti-aging verification analysis.Objective:Polysaccharides and peptides with antioxidant activity are extracted from the Chlorella.Carry out anti-aging research on the extracted polysaccharides and peptides.Purification and identification of chlorella peptides to further explore the anti-oxidation mechanism.Methods:Chlorella powder was used as the raw material.Chlorella polysaccharide was purified by boiled alcohol precipitation and Sevag method to remove protein,and then analyzed for polysaccharide content and monosaccharide composition.Using chlorella powder as raw material,antioxidant peptides were extracted by three enzymatic hydrolysis methods,which were applied to the C.elegans model to detect the anti-oxidative stress ability of C.elegans to evaluate the antioxidant capacity.The peptides were separated and purified by ultrafiltration to obtain ﹤ 3kDa,3 ～ 10 kDa,﹤ 10 KDa,﹥10kDa,a total of 4 components,and then tested the antioxidant activity to get the best component.Paraquat was used to test the oxidative damage of C.elegans,and the anti-aging effects of C.elegans on food clearance rate,body length,resistance to high temperature stress,lipofuscin detection and exerciseability were tested.The mechanism of anti-oxidation of chlorella peptides was explored by the change of ROS level and SOD activity.Result:Chlorella polysaccharides increased the survival time of C.elegans in the C.elegans antioxidative stress experiment.The survival time of the4 mg / mL component was 30.1% higher than that of the blank group.In the aging characterization experiment,the mortality rate in the anti-high temperature stress experiment was 33.91% lower than that in the blank group,which significantly improved the nematode heat resistance.When C.elegans reached senescence(day 15),the number of swings increased by 42.86% compared to the blank group,which improved the C.elegans ability to exercise.In the lipofuscin test,the lipofuscin aggregation was reduced by 33.30% compared with the control group.The papain-extracted protein Chlorella polypeptide has the most antioxidant activity,so this polypeptide was subjected to ultrafiltration separation and purification.C.elegans oxidative stress experiments showed that the <3kDa component had the most antioxidant activity.A peptide chain(PEP1)of 700 Da in amino acid sequence Leu-Asn-Gly-Asp-Val-Trp was selected for anti-aging studies.The experiment found that PEP1 has the ability of anti-oxidative stress on the C.elegans,and the survival time of 2mg / mL and 4mg/mL increased by33.82% and 39.17% compared with the blank group.Compared with theblank group,the 2mg/mL and 4mg/mL increased the survival rate by38.94% and 51.3% respectively in the high temperature stress experiment.PEP1 also reduced lipofuscin production,which was reduced by 28.39%compared with the blank group,while also improving exercise capacity and having anti-aging activity.In the experiment of ROS level and detection of SOD activity,it was found that it can reduce the ROS level of C.elegans due to paraquat oxidative stress and increase SOD activity.Conclusion:Chlorella polysaccharides show antioxidant capacity in the C.elegans model.Without affecting the normal growth and development of the nematode,it improves the ability to exercise during aging and reduces lipofuscin aggregation,and has the ability to delay aging.Chlorella peptides exhibit antioxidant capacity in the C.elegans model.Reduced the ROS level of C.elegans due to paraquat oxidative stress,and increased SOD vitality But the peptide group inhibited the feeding of nematodes.Chlorella polypeptide may affect the growth and development of Caenorhabditis elegans through a diet-restricted pathway.