Studies On Biotransformation And Pharmacological Activities Of Saponins In Ilex Kudingcha

Ilex kudincha C.J.Tseng,one of the species in Ilex genus,is an evergreen plant which is one of the maintream products of kudingcha.I.kudingcha is rich in chemical constituents,among them,treterpenoid saponins are the main active components,and how to improve the content of saponin in I.kudingcha is a hot spot in recent years.In this paper,biotransformation methods are used,screening efficient strains,the initial pH value,fermentation temperature,fermentation time,shaking speed and other conditions were studied,the optimal fermentation conditions were obtained,the antioxidant and antitumor effects of the transformed products were also investigated,it provides experimental data for further development and application of saponins from I.kudingcha.Four kinds of microbial strains were selected;they are Escherichia coli,Bacillus coagulans,Rhizopus nigricans,Aspergillus niger,which are used in fermentation and then test the total saponins in I.kudingcha with HPLC to systematically analyze and compare the content of the compounds before and after transformaion.The results show that,after the fermentation of E.coli and B.coagulans,the content of saponin in each monomer did not change obviously,and each monomer saponin content decreased significantly after fermentation of R.nigricans,A.niger fermentation.The content of Kudinoside C and Kudinoside E decreased significantly,the content of Kudinoside A and Kudinoside D increased significantly.The content of Kudinoside A and Kudinoside D were used as the indexes in the basis experiment of single factor,after that the orthogonal experiments were used to optimize the conditions for the transformation of total saponins to Kudinoside A and Kudinoside D.The optimal process conditions thus are identified as: the initial pH value is 6.0,the fermentation temperature is 25?,the fermentation time is 7d,and the shaking speed is 120r/min.The transformed products were separated and purified by silica gel column chromatography and ODS column chromatography,HPLC and NMR were used to identify the samples,determine the structure of the transformed products,the external standard method showed that the purity greater than 95%.The antioxidant effects of transformed products were also systematically studied,including reduction ability,DPPH radical scavenging ability,hydroxyl radical scavenging capacity,superoxide anion radical scavenging ability,and inhibition of lipid peroxidation ability.The results show that,the inhibition of lipid peroxidation by Kudinoside A was higher than control,the DPPH radical scavenging by Kudinoside D was higher,the hydroxyl radical and superoxide anion radical scavenging by Kudinoside C were higher,the antioxidant activity of Kudinoside E was consistent with the antioxidant activity of Kudinoside C.The antitumor effects of transformed products were also studied systematically,including human lung cancer cell line NCI-H460,human hepatoma cell line Bel-7402,human gastric adenocarcinoma cell line SGC-7901,human colorectal adenocarcinoma cell line HCT116,and human glioma cell line U251.The results show that,the inhibitory effect of Kudinoside A on human lung cancer cell line NCI-H460 was higher than control,the inhibitory effect of Kudinoside D on human lung cancer cell line SGC-7901 and Bel-7402 were higher,the inhibitory effect of Kudinoside C on human lung cancer cell line HCT116 and U251 were higher,the inhibitory effect of Kudinoside E was low.