| Sea-buckthorn is a natural product with homology of medicine and food.China has more than 95% of the sea-buckthorn distribution area in the world.Seabuckthorn flavonoids are a class of important active ingredient in sea-buckthorn,which have physiological functions such as antioxidant,anticancer,and hypoglycemic.Seabuckthorn flavonoids are mainly flavonols subclasses composed of aglycones such as isorhamnetin and quercetin and sugar residues,and the composition and content of flavonoid glycosides are closely related to the maturity and geographical location of sea-buckthorn.In this study,sea-buckthorn flavonoids were extracted from seabuckthorn fruits from three different regions and different maturity levels in Xinjiang as raw materials,and the differences in extraction rate and in vitro antioxidant capacity were investigated,and then the best experimental materials were screened.The crude extract of sea-buckthorn flavonoids was purified by AB-8 macroporous adsorption resin,and an HPLC method for the determination of quercetin,kaempferol,isorhamnetin and myricetin in sea-buckthorn flavonoids was established.Finally,the preparation process,characterization and physical stability of nanoliposomes encapsulating sea-buckthorn flavonoids were investigated.The specific experimental results are as follows:1.The total flavonoids in sea-buckthorn fruit were extracted by ultrasonic-assisted method.The best process obtained after optimization was ethanol concentration 55%,solid-liquid ratio 1:45,ultrasonic power 210 W,extraction time 50 min,and extraction temperature 50℃.The extraction rates of total flavonoids from sea-buckthorn A,B and C were(3.24±0.13)%,(1.86±0.01)% and(3.80±0.23)%,respectively,indicating that the extraction rate of total flavonoids from sea-buckthorn Aksu was higher than that in Tacheng,and the extraction rate of total flavonoids in sea-buckthorn fruit with higher maturity is lower.2.When the sample concentration was 0.04 mol/L,the DPPH free radical scavenging rates of the three crude extracts of total flavonoids from sea-buckthorn were as follows: sea-buckthorn C(95.28%)> ascorbic acid(94.95%)> sea-buckthorn B(87.47%),sea-buckthorn A(86.11%);the ABTS free radical scavenging rate of three crude extracts of total flavonoids of sea-buckthorn: sea-buckthorn C(92.50%)> seabuckthorn A(81.33%)> ascorbic acid(74.12%)> sea-buckthorn B(54.52%).At the same time,compared with the same concentration of ascorbic acid,the reducing ability of the three crude extracts of sea buckthorn total flavonoids is: sea-buckthorn C and sea-buckthorn A > sea-buckthorn B.In general,the antioxidant capacity and reducing ability of sea buckthorn C were stronger than those of sea buckthorn A and B.Combined with the difference in the extraction rate of sea-buckthorn total flavonoids,sea-buckthorn C from Aksu area of Xinjiang was selected as the best experimental sample.3.Purification of sea-buckthorn flavone crude extract by AB-8 macroporous adsorption resin.Through the single factor test results,it was found that when the sample volume was 30 m L,the sample loading speed was 1 m L/min,70% ethanol solution was selected as the eluent,the amount of eluent was 3 BV,and the elution speed was 1.8 m L/min.The maximum recovery rate of sea-buckthorn flavonoids was(78.05±3.46)%.The contents of isorhamnetin,quercetin,kaempferol and myricetin in the purified product were increased by 6.03,9.36,11.23 and 15.87 times respectively,and the total flavonoid aglycone content was increased by 7.29 times.4.Sea-buckthorn flavonoids nanoliposomes were successfully prepared by thin film dispersion method.The optimized process was as follows: drug concentration 0.2mg/m L,total amount of membrane 144 mg,hydration temperature 45°C,cholesterol to lipid ratio1:8.Sea-buckthorn flavonoid nanoliposomes are pale yellow turbid liquid,spherical vesicles,and evenly distributed.The encapsulation efficiency was 65.02%,the particle size was 213.6±6.21 nm,and the polydispersity index was 0.158±0.034.The stability was good after 20 days of storage,and the best storage temperature was4℃ without dark.In this study,the extraction and purification process of total flavonoids in Xinjiang sea-buckthorn fruit were optimized,the composition and content of flavonoid aglycones in Xinjiang sea-buckthorn flavonoids were clarified,and nanoliposomes encapsulating sea buckthorn flavonoids were successfully prepared to improve their stability.The purpose is to provide certain theoretical help for the comprehensive utilization of Xinjiang sea-buckthorn flavonoids. |
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