Study On The Refinement Of Polyprenols In Ginkgo Biloba Leaves And Anti-tumor Activity In Vivo

The process of extraction, purification and detection of polyprenols in Ginkgo biloba leaves were optimized. Individual monomers of polyprenols were generated by the methods of HPLC and their chemical structures were identified. Anti-tumor activity of polyprenols in vivo were analyzed primarily.By the index of the content of polyprenols, the optimum extraction condition was established as follows: polyprenols were extracted from Ginkgo biloba leaves with the extracted solvent of petroleum ether, the ratio of liquid-matter was 7 : 1 according to Soxhlet-extraction method and extracting 10 h at 50℃, the total content of polyprenols, the number of monomers and its relative content in Ginkgo biloba leaves were changed at different times. The loss rate of polyprenols was 58.6% after going moldy.Polyprenyl acetates were hydrolyzed with 4% sodium hydroxide-methanol solution for 2.5 hours at 50°C, and the speed of rotation was 500 r/min. The highest hydrolyzation ratio was 98.70%. Polyprenyl acetates were purified with silica gel column when the flow phase was petroleum ether→petroleum ether-aether (25:1), and high purity (>90%) was obtained. Polyprenols were also purified with silica gel column when the flowing phase was petroleum ether-acetyl acetate (9:1), and the purity of polyprenol was also over 90%.The analyzed and preparation condition of HPLC of polyprenols in Ginkgo biloba leaves Sample of 10.0 μl can be analysized by Kromasil ODS (5 urn, 250 mm×4.6 mm) with isopropanol-methanol-hexane-water (10:6 :3 :1) at 27℃, the wavelength was 210 nm and the flow rate was 0.9 ml/min. Polyprenols were prepared by YWG-C₁₈ with isopropanol-methanol-hexane-water (50:27:10:3) at 27℃. The wavelength was 215 nm and the flow rate was 10.0 ml/min. The volumn of sample was 200μl. The structures were identified by the methods of UV/VIS, IR, MS, ¹H NMR and ¹³C NMR, its results showed that polyprenols were composed of 12-21 isoprene units and the structures was(ω)-(trans)₂-(cis)_8-17-(α)Crown gall test primary confirmed that polyprenols in Ginkgo biloba leaves have certain anti-turor activity. Polyprenols can also restrain Hela and MCF-7 cell, and the rate of restrain after 72 hours was 70.1% and 64.9% when the drug concentration was 100 μg/ml.