Study On The Trace Saponins In Anti-lung Cancer A549 Cells Of The Zhuang Drug "Guo Xia Bo" (Gynostemma Pentaphyllum)

ObjectiveThe heat-processed Zhuang-medicine "Gocaekmbaw"(Gynostemma pentaphyllum)shows stronger antitumor activity than raw materials,and its main medicinal material basis of antitumor activity is the saponins evidenced by our previous research.The present research aims to the further study of the trace saponins in the heat-processed G.pentaphyllum,using the HPLC-UV-BIO method to find the trace saponinwith activityagainst the againstA549 cell growth.Method1.HPLC-UV-BIO method was carried out to find the trace saponin fraction with activity againstA549 cell growth.2.Heat-processed G.pentaphyllum total extract was obtained through heating refluxof the heat-processed G.pentaphyllum.The pure trace saponins saponin monomerswere isloated by silica gel column chormatography and semi-preparative HPLC,and identified through MS and NMR data.3.The trace saponins were synthesized by chemical method.The pure trace saponins saponin monomers were isloated by semi-preparative HPLC,and their structures were identified with MS and NMR data.4.The anti-tumoractivity was investigated using CCK-8 assay against HepG2 cells,SGC7901 cells,PC-3 cells and A549 cells.The activity was measured by halfinhibition concentration(IC50).The structure activity relationship(SAR)was discussed.Result1.Ginsenoside 20(R)-Rg3,20(S)-Rg3,Gypenoside L,Gypenoside L,Damulin A and DamulibB were ilostrated from the heat-processed G.pentaphyllum total extract.An acetyl gypenoside whose quasi-molecular ion peak wasm/z 841.4874[M-H]-and related ion peak was m/z 887.4927[M+HCOOH-H]-was found in the rich trace saponin part.It might be monoacetylated compound of Gypenoside L or Gypenoside LI.2.Four monoacetylated compounds were synthesized by chemical synthesis method using Gypenoside L、Gypenoside LI as the precursor conpounds,glacial acetic acid as acetylation reagent.They wereisloated by semi-preparative HPLC,and identified respectivrly 6’-acetyl-gypenoside L,6’-acetyl-gypenoside LI,4’-acetyl-gypenoside L,among which the 4’-acetyl-gypenoside LI was the original trace saponin in heat-processed G.pentaphyllum through conparing their LC/MS data.3.By comparing activity of 20(R)-Rg3,20(S)-Rg3,Gypenoside L,Gypenoside LI,6’-acetyl-gypenosideL,6’-acetyl-gypenoside LI,4’-acetyl-gypenoside L,4’-acetyl-gypenoside LI against A549 cells,HepG2 cells,SGC7901 cells and PC-3 cells,it was found that thses four acetylation products showed same antitumor activity,which could be comparable with Gypenoside L and Gypenoside LI.Gypenosides with monoacetylated in 6’position showed stronger antitumor activity than monoacetylated in 4’position,and gypenosides with 20(R)structure showed stronger antitumor activity than gypenosideswith 20(R)structure.Conclusion1.Trace saponins in heat-processed G.pentaphyllum also played role in anti-cancer activity and this has enriched itsmaterial basis of antitumor activity.2.Extreme trace components could be obtained through suchstrategies:precursor compounds with similar structures to target compound were firstly isolated from the plant,and then throughmodification and synthesis to be target compound,and a series of valuableby-products could be acquired simultaneously.This has provided asignificant idea for getting trace natural effective products.