Isolation Of Lipids, Synthesis Of Polyprenols Derivatives And Biological Activity From Ginkso Biloba L. Leaves

Ginkgo biloba L. leaves lipids contained alkanes, polyprenols, terpenoids, sterols and soon. Ginkgo biloba polyprenols（GBP） are important lipids components from Ginkgo biloba L.leaves. It was reported on antiviral, improving immune function, hepatoprotective andantitumour effects of GBP. The main content of this paper contains chemical constituentsresearch on Ginkgo biloba leaves lipids, the synthesis of polyprenols derivatives,antibacterial/antifungal activity and antioxidant effects of them. It is provided theoretical basisfor efficient utilization of Ginkgo biloba leaves effective bioactive components, expanding thescope of application in pharmacological effect and the research and development of health careproducts and new drug.Lipids from Ginkgo biloba leaves were isolated by extraction with solvent andsaponification. The frozen sediment, the light and heavy distillates were isolated byrefrigerated and molecular distillation. The light Distillates of lipids were analyzed by thePyrolysis-Gas Chromatography-Mass Spectrometry technique and the result showed that therelative content of monoterpene and sesquiterpene compounds is approximately23%, therelative content of chainlike alcohol （ketone, ester） and diterpanes compounds is approximately47%and the relative content of alkylphenol and steroids compounds is approximately30%.Fifteen known compounds were identified by physical and chemical properties andspectroscopic data. The separated and identified compounds: β-sitosterol acetate, palmitamide,glycerol tripalmtate, hendecane, β-caryophyllene, isophytol, nerolidol, linalool and terpineolare reported here for the first time in Ginkgo biloba leaves.Chemical structure modification of-OH in α-terminal unit of GBP was preparated for fivepolyprenols derivatives that were identified by spectroscopic data. Polyprenyl acetate（GPA）was preparated by esterification using acetic anhydride and the yield was91%. N-amylpolypentylene（GAP） was preparated by coupling reaction using n-amyl magnesium bromide as the grignard reaction intermediate and the yield was90%. Polyprenyl-3-isoamyl benzylether（GPB） was preparated by coupling reaction using （R）-4-benzyloxy-2-methyl-1-butyl-magnesium bromide as the grignard reaction intermediate and the yield was86%. Polyprenyldichlorophosphite（GPD） was preparated by phosphorus acylation reaction using phosphorusoxychloride in alkaline condition and the yield was90%. Polyprenyl phosphate disodiumsalt（GPP） was preparated by basic hydrolysis using GPD and salifing using inorganic salt, theyield was79%.Antibacterial and antifungal tests of five selected stains （Salmonella enterica,Staphylocococus aureus, Aspergillus niger, Escherichia coli and Bacillus subtilis） were carriedout using a disc-diffusion method by measuring inhibition halos and comparing with MIC,MBC, MFC values and FIC Index of different samples that were polyprenols, other lipids andfive polyprenols derivatives. Nerolidol showed the highest activity against the four tapes ofbacteria（Salmonella enterica, Staphylocococus aureus, Escherichia coli and Bacillus subtilis）among all the tested samples, linalool showed the highest activity against Aspergillus nigeramong all the tested samples and the GBP with β-caryophyllene mixture group had thestrongest synergistic effect against Bacillus subtilis among all mixture groups against the fivetested strains. The proportion of β-caryophyllene and GBP was43.42%:56.58%（wt/wt） thatwas determinated by Mixture Design as the optimal proportion of synergistic effect on GBPwith β-caryophyllene against Bacillus subtilis. The proportion of isophytol and GBP was38.19%:61.81%（wt/wt） that was determinated by Mixture Design as the optimal proportion ofsynergistic effect on GBP with isophytol against Salmonella enterica. GPD showed the highestactivity against all tapes of stains among five polyprenols derivatives. The proportion of GBPand GPP was62.59%:37.41%（wt/wt） that was determinated by Mixture Design as the optimalproportion of synergistic effect on GBP with GPP against Salmonella enterica.Determination of antioxidant effect of different polarity fractions of light, heavy distillatesand polyprenols of ginkgo lipids used4methods （DPPH, ABTS, superoxide anion and hydroxyradical） with Sigmoidal curve fitting method arriving at respective IC50values. The resultsshowed that the light fraction2（95%petroleum ether/5%acetic ether） had the highest antioxidant effect in all tested light fractions. the IC₅₀ values of the polyprenols group werelower than all the fractions groups and the positive control groups（Vc and BHT） in usingsuperoxide anion and hydroxy radical methods. The fraction5（60%petroleum ether/40%acetic ether） had the highest antioxidant effect in all tested fractions except the positive controlgroups and the polyprenols group in using the4methods.