| Laminaria japonica is a kind of large-scale economic algae,which has extremely high edible value and medicinal value because it is rich in various nutrients.Fucoidan,as a biologically active ingredient in kelp,is a complex water-soluble sulfate heteropolysaccharide present in the intercellular space,which has physiological activities such as lowering blood sugar,lowering blood fat,antioxidant,antibacterial,antitumor,regulating body immunity,etc.Although less content in kelp,but because of its wide range of pharmacological health effects,it has become a hot research of marine drug,great research value,broad application prospects.In this paper,Shandong Rongcheng Xunshan kelp is used as a raw material,and the changes of the content of kelp components in different growth periods,different breeding areas,and different parts of the head and tail are tracked and analyzed for three consecutive years.The crude kelp fucoidan is separated and purified to obtain three components H-1,H-2,H-3,and study its purity,molecular weight and antioxidant activity.The main research contents and results are as follows:1.Track and analyze the kelp in the high,medium and low breeding areas from March to June for three consecutive years from 2017 to 2019.By measuring the content of water,ash,crude fiber,alginate,crude polysaccharide,total fucose,sulfate,and fucoxanthin,the changes in kelp at different growth periods,cultivation areas and parts were studied.The specific results are as follows:(1)The average content of each component in the maturity of Xunshan kelp in Rongcheng,Shandong is: fresh weight and middle water 90.27%;dry weight and middle ash 43.48%,crude fiber 4.54%,alginate 22.22%,crude polysaccharide17.23%,fucoxanthin 0.04 mg/g;in fucoidan,total fucose 70.62%,sulfate 17.47%.(2)The results of the comparison of the content of kelp components in different regions during the same period showed that the water content was the highest in the central region for three consecutive years,the crude fiber content was the highest in the high region for three consecutive years,and alginate had the highest content in the high,middle and low regions within three years.Most of the remaining ingredients are concentrated in the high and middle regions.(3)The results of the comparison of the contents of the kelp components in different periods in the same region show that the highest values of the composition in the kelp in the high area are: crude polysaccharide in March,water,ash,fucoxanthin in April,crude fiber,alginate,total fucose and sulfate in June.In the middle and low areas,because there was no sampling in June,the water content did not change much in March and April.The contents of ash,alginate,and fucoxanthin were April> March,and the sulfate content was March> April.(4)The results of the comparison of the content of various components of kelp in different parts of the same area show that the content of water,ash,crude fiber and fucoxanthin in the kelp in the high area is mainly head> tail,and the content of alginate,crude polysaccharide and total fucose tail> head;In the kelp in the central area,except for the ash content tail> head,the other components are mainly head> tail;In the low zone kelp,the total fucose,sulfate,fucoxanthin content tail> head.(5)The results of the comparison of the contents of the kelp components in different periods of the same strain showed that the water,ash and fucoxanthin contents firstly increased and then decreased from March to June,and all reached the highest value in April.The contents of crude fiber,alginate,total fucose,and sulfate basically showed an upward trend,and the content reached the highest value in June.The content of crude polysaccharides showed a declining and rising trend for three consecutive years,and the lowest value in April.2.Separation and purification of kelp fucoidan crude by three different methods of thin layer chromatography,DEAE-Sepharose FF weak anion exchange column chromatography and high performance liquid gel chromatography.The results show that ion exchange chromatography and high performance liquid Phase gel chromatography separation method is more ideal,the results are highly consistent,all three components H-1,H-2 and H-3 were separated.(1)DEAE-Sepharose FF weak anion exchange column chromatography results: H-1 is the elution peak,H-2 and H-3 are the salt elution peak,H-2 salt concentration is 0-0.5 mol/L,H-3 salt concentration It is 1-1.25 mol/L.(2)The retention time of the three components H-1,H-2 and H-3 separated by high performance liquid gel chromatography were 8.107 min,9.594 min and 10.397 min,respectively.3.Determine the purity and molecular weight of fucoidan components by HPGFC method(high performance liquid gel filtration chromatography).The results prove that the three components H-1,H-2,and H-3 have higher purity,and the corresponding molecular weights are 193.148 KD,74.407 KD,and 44.452 KD,respectively.4.DPPH(1,1-diphenyl-2-trinitrophenylhydrazine)free radical and ·OH(Hydroxyl free radical)were removed from the three components H-1,H-2 and H-3after separation and purification of crude fucoidan Of determination.Using BHT and Vc as controls,the differences in antioxidant activity of fucoidan with different molecular weights were analyzed.The results showed that fucoidan showed strong scavenging ability to DPPH free radical and ·OH,and the scavenging rate increased with the increase of concentration.The antioxidant activities of the three components with different molecular weights showed a consistent rule: H-3> H-2> H-1,that is,the smaller the molecular weight,the stronger the scavenging ability and the higher the antioxidant activity. |
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