| The financial grant of this work has been supported by the R&D Special Fund for Public Welfare Industry from State Ocean Administration P.R.China(No.200709005).This project focuses on finding the antioxidant activity and analysing the active components of Mactra veneriformis.Through the analysis of those components,the efficacious material basis of Mactra veneriformis would be figured out,which can be used as basic material for functional health products.The main contents of this paper consist of three parts as follow:1.Literature studyBy reviewing to the related literatures of antioxidant substance to know the composition,properties,content as well as the mechanism of antioxidant effect,which are systematic summarized at this capter.By referring to the literatures on the purification and analysis method of natural micromolecule with antioxidant activity,chemical characteristics and basic parameters of pharmacology of this kind of substance are revealed.The follow-up experimental works are on the basis of these literature researches.2.The antioxidant efffect screening of the major fractions from the flesh of Mactra veneriformis.According to the Chinese medicine theory,"water extracting-alcohol precipitating" was used,and the extract of Mactra veneriformis was roughly divided into there extracting fractions:crude polysaccharide,water soluble ointment and total extract.Antioxdation activity of three parts is proved in anti-aging mouse.The results showed that the effect of water soluble ointment was significantly better than the other two groups.This part further was extracted to other four parts with organic solvents with different polarities.The experiments of scavenging free radical were toke to investigate the capacity of antioxidant.Results show that the water part show the best scavenging effect for DPPH and superoxide radical;the ethyl acetate extract not only owed the strongest chelating ability with metal elements but also has the strongest restore capability.This shows that the active substances of water soluble ointment present in the water parts and ethyl acetate.3.The composition analysis of small molecular of Mactra veneriformis1.Composition analysis of nucleosideTen kinds of nucleoside are determined in Mactra veneriformis by HPLC-Q-TOF-MS,which are uridine,xanthine,thymine,hypoxanthine,inosine,guanosine,2-deoxyguanosine,2-deoxidation inosine,thymidine and adenosine.Biobasic-C 18 column was used to separate those nucleosides.To inspect the instrument conditions of the mobile phase,column temperature as well as flow rate are examined,water and methanol was selected as the final mobile phase with column temperature 30?,flow rate of 0.5ml/min.HPLC-Q-TOF-MS was used to identified the structure of nucleosides.Samples from different regions in different months were detected.Further,different extraction methods,different extraction solvent and different extraction time were investigated under former instrument condition.The preferred optimum extraction condition was set as ultrasonic extraction for 2 hours with 50%methanol as solvent.Best extraction method and instrument conditions were set,than stability and repeatability of the instrument were also investigated for determining samples from four different origins in different months.Results show:the content of nucleoside of Mactra veneriformis in the sample had a great degree of correlation with the origins and seasons,which shows us a quality standard of Mactra veneriformis by the appropriate extract method of the nucleoside composition.2.Composition analysis of amino acidsAutomatic amino acid analyzer was used to analysis the composition of free amino acid in Mactra veneriformis,which showed that:there is 10.22%alanine in the sofeware,which accounted 1/3of total aminoacids.The content of glutamate(Glu)is 4.06%and the content of glycine(Gly)is 4.73%.Because of the total fresh amino acids,which are account for 77%of the total amino acids,the Mactra veneriformis is very delicious.3.Composition analysis of fatty acidsImproved Bligh-Dyer method and petroleum ether extraction method were used to extract the fatty acids,GC-MS analysis was use to analysis the composition of fatty acids.Results showed that the content of unsaturated fatty acids in total fatty acids of about 50%by both methods,which EPA and DHA are nealy 10%.Other unsaturated fatty acids as Hexadecanoic acid,10.13-Eicosadienoic acid,9,12,15-Octadecatrienoic acid etc.were also found in Mactra veneriformis.4.Composition analysis of sterid slcoholsThe exteact method of sterols is simiar to the method of fatty acids.Adding methyl reagent after getting the fatty acids,which makes the fatty acids into salt,then separates the oil and water,mixed-steroidal alcohol exsits in oil.Mixed-steroidal alcohol can recrystallizate,GC-MS was used to analysis the composition of sterid slcohols.Ten of sterols compositions were determined in Mactra veneriformis in which the content of three cholesteryls are close to 70%as the highest concentration,among which Cholesta-5,22-dien-3-ol is nearly 10%.The content of three ergostas is nearly 18%;the content of two stigmasterols is nearly 6%.Androsten is the least one,which is only 1.48%.5.Composition analysis of inorganic elementICP was used to determine the metal elements of the software of Mactra veneriformis and water soluble ointment,which showed that the software are rich in trace elements like Ca,Mg,Fe as well as trace Zn.The content of heave metals is all below the national food standards.4.The composition analysis of water soluble ointment in Mactra veneriformisThe composition analysis of water soluble ointment in Mactra veneriformis was detected,which results the total kinds of composition in water souble ointment are less than software,but there is no huge different in total content.Total number of fatty acid has increase more than ten kinds;the content of amino acid is increase nearly 10%.As to nucleoside,there has no adenosine in water soluble ointment.Kinds of sterols have no different.Result of inorganicelements in water soluble ointment reminds us to control the consumption of Mcctra veneriformis. |
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