Research On The Accumulating And Removal Of Ginkgolic Acids In Ginkgo Biloba Leaves And Seeds

Ginkgo(Ginkgo biloba L.)is one of the oldest rare tree species in the world,and has the reputation of "living fossil".Ginkgo biloba is originated in China and has a special position in the field of medicinal plants in China,which is mainly due to the active ingredients in ginkgo leaves-ginkgo flavonoids.Ginkgo seeds are also rich in various kinds of trace elements and polysaccharides,as well as proteins and other beneficial ingredients.However,ginkgo leaves and seeds also contain harmful ingredients such as ginkgolic acids,which can cause serious adverse reactions in the body.Ginkgolic acids are special active ingredient contained in the leaves and seeds of Ginkgo biloba.It is a kind of derivatives from 6-alkylsalicylic acid or 6-alkenylsalicylic acid in the phenylalanine pathway.Recent studies have shown that ginkgolic acids belong to cytotoxin.The adverse reactions of excessive consumption are mainly abdominal pain,diarrhea,allergic dermatitis,and loss of consciousness.In severe cases,it can also cause cytotoxicity,embryo toxicity,immunotoxicity,mitochondrial DNA damage,mutagenicity and slight neurotoxicity.Further study on the methods of reducing the content of ginkgolic acids in Ginkgo biloba leaves and seeds has important theoretical and practical significance to promote the deep processing of Ginkgo biloba.In this paper,Ginkgo biloba leaves and seeds are used as materials to study the accumulation of ginkgolic acids in ginkgo leaves and seeds,as well as the influence of different treatment on the content of ginkgolic acids.Besides,the technology of low toxicity and safe detoxification of ginkgo leaves and seeds were also discussed.The main results were as follows:(1)By comparing the content of ginkgolic acids in ginkgo leaves at different developmental stages,it is found that in the ginkgo leaves harvested in different months,the ginkgolic acid content in the earlier leaves is higher,which needs further deacidification.The contents of ginkgolic acid and flavonoids in the leaves decreased with the increasing of the age of ginkgo trees,and the decreasing trend slowed down with the further increase of tree age of Ginkgo biloba.(2)Through the metabonomics detection of ginkgo leaves of different ages,the metabolites were qualitatively analyzed by positive and negative ion patterns,and a total of 492 metabolites were found,mainly including phenolic acids,flavonoids,nucleotides and amino acids.The number of metabolites in the phenylalanine pathway accounted for 9.38%of the total number of metabolites annotated,indicating that the metabolites are highly enriched under this pathway.A total of 151 differential metabolites were screened in 4-year-old and 1-year-old groups,203 differential metabolites were screened in 7-year-old and 1-year-old groups,and 82 differential metabolites were screened in 4-year-old and 7-year-old groups,of which phenolic acids accounted for 12%.Based on the analysis of all differential phenolic acid metabolites,63 substances were identified belonging to phenolic acids,5 substances belonged to ginkgolic acid,and all these 5 ginkgolic acids showed an upward trend.(3)Using different methods to treat ginkgo leaves,it was found that high density planting(80 plants/m2)could reduce the content of ginkgolic acid and increase the content of flavonoids in ginkgo leaves.After spraying different hormones,the ginkgolic acid content in ginkgo leaves decreased to a certain extent,but did not reach a significant level.In addition,irradiating with ultraviolet lamp at an intensity of 120 ?W·cm-2 could effectively reduce the content of ginkgolic acid and increase the flavonoids content.Furthermore,salt treatment with 150 mM could also reduce ginkgolic acid and increase the flavonoids content in leaves.(4)By comparing the ginkgolic acid content in different parts of ginkgo seed,it was found that the ginkgolic acid content in different parts of ginkgo seeds was embryo>inner seed coat>endosperm,while the ginkgolic acid content in finished seed powder was the lowest.A total of 855 metabolites were found based on metabonomic analysis of ginkgo seed powder,mainly including flavonoids,phenolic acids and alkaloids.(5)The effect of storage time on ginkgolic acid content in ginkgo seeds was studied.It was found that the longer the storage time,the longer the embryo growth was,and the higher the content of ginkgolic acid.Comparing the ginkgolic acid in different parts of the ginkgo seeds in different varieties and regions,it was found that the ginkgolic acid content in the seed embryos of different varieties was the highest,and the ginkgolic acid content of the ginkgo seeds picked in Guizhou at high altitudes was about 5.4 times lower than that of ginkgo seeds picked from low altitude areas.Therefore,the content of ginkgolic acid in ginkgo seeds is greatly affected by the region,climate,and cultivation conditions,and can be used as an important basis for later picking of ginkgo seeds.(6)The effects of heat treatment and adding different compatibility agents on the content of ginkgolic acids in ginkgo seeds were also studied.The results showed that cooking,microwave and ultrasound could all reduce ginkgolic acids.And the cooking treatment had the best effect on the degradation of ginkgolic acids in ginkgo seeds,but too long cooking time would affect the quality and taste of ginkgo.Different compatibility agents were added to the homogenate of ginkgo seeds,and the mixture of NaCl and NaHCO3 had the best effect on the removal of ginkgolic acid.