Preparation Of Ginkgo Flavonoids And Study On Its Antioxidant Activities

As one of the rare and ancient trees,Ginkgo has been recognized as a "living fossil" in the world,and the cultivated amount of ginkgo in China ranks the first in the whole world.Ginkgo biloba contains flavonoids,terpene lactones and other chemical constituents with biological functions: anti-inflammatory,anti-bacterial,anti-biological oxidation,etc.There are rich in nutritious in Ginkgo nuts,including sugar,protein and other ingredients.Flavonoids is an important functional factor in Ginkgo,and has strong scavenging activities of reactive oxygen free radicals and anti-lipid oxidation.In this paper,Ginkgo biloba and Ginkgo nuts as raw materials,and optimal conditions of preparation for total flavonoids from Ginkgo biloba nuts and Ginkgo biloba leaves were studied.And crude flavonoids from Ginkgo biloba leaves were purified.Then anti-bacterial and antioxidant activities of flavonoid were determined,which would lay the foundation for further development and utilization of Ginkgo resources.There are the conclusions: 1.Determination of the basic ingredients of Ginkgo biloba nuts and its emulsification,there were the results: the moisture content of Ginkgo biloba nuts was 8.76%,content of total sugar was 4.1%,content of crude fat was 3.82%,content of crude protein was 9.87% and content of flavonoids wass 0.784%.Ginkgo biloba nuts has a good emulsifying ability and emulsion stability.2.Total flavonoids from Ginkgo biloba nuts and Ginkgo biloba leaves were prepared by single factor and orthogonal experiments,technological conditions were optimized.The results were as follows:?1?The optimal process of flavonoids from Ginkgo biloba nuts was as follows: ratio of solid and liquid?1:50,g/mL?was carried out by 80% ethanol at 80 ? for 3h,the maximum yield of Ginkgo flavonoids reached 11.56mg/g.?2?The optimal process of flavonoids from Ginkgo biloba leaves was as follows: ratio of solid-liquid?1:35,g/mL?was carried out by 65% ethanol at 80 ? for 4h,the maximum yield of flavonoids was 45.21mg/g.3.Crude flavonoids Ginkgo biloba was purified by AB-8 macroporous resin,and the dynamic adsorption of macroporous resin for flavonoids in crude extracts-desorption conditions were studied.At flow rate of 1.5BV / h for the sample as a dynamic adsorption on injection volume of 12 BV,2.5BV / h as flow rate and 3.5BV 80% ethanol desorption,stored after freeze-dried.4.Ascorbic acid as a control,antioxidant activities of flavonoids in vitro were determined,the following conclusions were: flavones had a strong reducing power,and certain scavenging effect on DPPH · radical,· OH radical,O₂^-· radical,and the order of scavenging ability was: ascorbic acid> puried flavonoids> crude flavonoids,puried flavonoids have strong scavenging ability of DPPH,IC₅₀ value of ascorbic acid and flavonoids were 0.0145 mg/mL and 0.0209 mg/mL.5.Antibacterial activities of flavonoids on Escherichia coli,Bacillus subtilis,Staphylococcus aureus and Sarcina were tested,the results showed that different levels of antibacterial ability on the four bacteria,especially antibacterial ability on Bacillus subtilis was the most significant among of them.