Study On Extraction And Purification Process Of Total Flavonoids From Litchi Seeds

Objective: To study the preparation process of the effective fraction of total flavonoids in litchi seeds,determine the optimal process conditions for the extraction and purification of effective parts,and the preparation design work before the formulation was preliminarily studied.In order to prepare the total flavonoids of litchi seeds in accordance with the requirements of effective parts of traditional Chinese medicine,and lay the foundation for the development of the total flavonoids of litchi seeds into five new drugs of traditional Chinese medicine.Methods: 1.The content of total flavonoids in litchi seeds was determined by UV spectrophotometry.The total flavonoids in litchi seeds were extracted by ethanol extraction.The extraction process of total flavonoids from litchi seeds was studied by four factors: solid-liquid ratio,ethanol concentration,extraction time and extraction times.2.The best macroporous resin for purifying the total flavonoids of litchi seeds by static adsorption-elution test was used.Based on single factor test and the comprehensive score of total flavonoids content and purity of litchi seeds as indicators,the effects of ethanol volume fraction,sample concentration,diameter-to-height ratio,sample flow rate,sample volume,eluent volume and elution flow rate on the purification process were investigated.3.The equilibrium solubility of total flavonoids in litchi seeds in phosphate buffer at different p H was determined by saturated solution method.At the same time,the apparent oil-water partition coefficient of total flavonoids in litchi seeds in 1-octanol-water/phosphate buffer solution was determined by shake flask method.The fluidity of total flavonoids in litchi seeds was measured by measuring the angle of repose and the degree of compression.The critical relative humidity and its influencing factors were investigated.Results: 1.Through the investigation of the extraction and purification parameters of total flavonoids from litchi seeds,the optimal extraction conditions were as follows: 100 g litchi seeds with 12 times the amount of60% ethanol,reflux extraction 2 times,each time 30 min.2.The purification process of total flavonoids from litchi seeds was as follows: AB-8 type macroporous adsorption resin was selected,the mass ratio of resin to medicinal material is 1∶3,the concentration of sample liquid is 5.26mg/m L,the loading volume is 2BV,and the loading flow rate is1 m L/min,the aspect ratio is 1 ∶ 12.When eluting,the impurity is first removed by 20% ethanol 3BV,and then eluted with 60% ethanol 3BV,and the elution flow rate is 4 m L/min.3.The total flavonoids of litchi seeds have higher solubility in alkaline phosphate buffer.When p H=10,the solubility is 11.74mg/m L;the partition coefficient of oil-water is between-0.08～0.29;the angle of repose is 35.83°,the compression degree is 19.50%,the bulk density is 1.20g/m L,the tap density is 1.49g/m L;the relative critical humidity is 75.29%.The results of influencing factors of total flavonoids in litchi seeds showed that the total flavonoids of litchi seeds had good thermal stability at 60 °C,good wet stability at 75% RH,and the content decreased by <5%.The color will be deepened under strong light irradiation.The content is reduced by <5%,and the light stability is good.Conclusion: 60% ethanol extract of litchi seeds is the main effective part of total flavonoids in litchi seeds;its content determination method is stable,extraction and purification process is simple and feasible,suitable for process production;The pre-prescription study of total flavonoids from litchi seeds has laid a foundation for the development of total flavonoids from litchi seeds into five types of new drugs of traditional Chinese medicine.