| Consenescence can cause many diseases of human, and oxidative stress can be the most important factor that bring on the Consenescence. It is a major part in the genesis of illness,from cancer to cardiovascular and degenerative diseases. Most of anti-ageing medicine are synthetic, they are not from nature. It has been proved that taking too much synthetic anti-ageing medicine can cause many side effects on human being. Therefore, it has great significance to find out novel natural antioxidant and anti-ageing medicines.Alga is a rich and comprehensive resource of the sea, has many nutriment elements. Antioxidant properties has been distilled from alga resources have many merits: high scavenging free radicals activity, kinds of sorts, low side effect. The research has shows that Spirulina and C-phycocyanin , which distilled from Spirulina , can act as a scavenger of reactive oxygen species and they can restrain the accumulation of free radical in the body. Otherwise, many overseas biologists have find active peptides from the alga hydrolysate which hydrolyzed by enzymes, and these peptides proved to have high scavenging free radicals activity, high ACE inhibitory activity, anti-tumor activity and anti-proliferation activity,they can postpone the body caducity, restrain forming tumour with deducing hypertension. In this paper, we used Spirulina platensis total protein hydrolysate to achieve peptide with high activities of scavenging free radicals.The results of this dissertation includes the following sections.The Spirulina is cultured in the laboratory , the maturational alga is collected and cleaned by distill water. The alga is mixed with phosphate buffer solution. The mixture solution is freezed and thawed by several times. The crude extract of Spirulina was digested by protease SM98011 , and chalked up properties with high scavenging free radicals activity. Treated crude extract by protease SM98011, phosphate buffer solution, and total protein of Spirulina. The mixture of broken alga protein and protease solution was incubated with constant agitation at 50℃for 5h. Then, the reaction was ended by 15 min incubation at 90℃. After centrifugation at 10,000×g,4℃for 20 min, According to our research, the hydrolysate obtained by digestion of algae protein with protease SM98011 showed much higher scavenging free radicals activity (SA% =33.28% ), comparing to the untreated algae protein slurry (SA% = 12.15 mg/mL) . Additionally, the hydrolysate and control are dealed by salicylsulfonic acid and hydrochloric acid. The productions are carried through amino acid analysis, the amino acid formations have many differences.The hydrolysate was separated with gel permeation chromatography on a Sephadex G-15 column, and 5 fractions were collected. The scavenging free radicals activity of each fraction was assayed. Fraction 3 showed remarkably higher scavenging free radicals activity (SA% = 26.82%) than other fractions. Therefore, Fraction 3 went through further purification using RP-HPLC, and 10 fractions were got and named a-j, respectively. The scavenging free radicals activity of all the fractions separated by RP-HPLC were assayed. Among them, fraction d showed higher scavenging free radicals activity and its scavenging free radicals activity is 13.42%. The other fractions showed no or very lower scavenging free radicals activity. The sequences of the scavenging free radicals peptide was identified by mass spectrometry. The ion peak of each peptide appeared at m/z of the theoretical value in the ESI-MS/MS. Additionally, the ion peak of each peptide went through second ion mass spectrometry using the same ESI-MS/MS system. According to the results, the sequences of peptide is considerd to be LAHICGVP.Proteins of alga are potential resources of natural drugs and food additives, and the Spirulina platensis is one of the raw material alga which used usually. There are many reports about Spirulina platensis for food and medicine. Many previous results showed that Spirulina platensis hydrolysate obtained with pepsin or other proteases digestion showed high angiotensin-I-converting enzyme (ACE) inhibitory activity or other activities, whereas there are a fat lot reports about its antioxidant activity . In this article, antioxidant peptides were separated from Spirulina platensis hydrolysate and identified. They may have potential in the treatment of consenescence or in clinical nutrition. This research may provide an efficient utilization of Spirulina platensis . This study also proposes an alternative method for usage of the by-product of the algae essence extraction process, which is normally employed as a low-value animal feed. |
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