Studies On The Chemical Constituents Of Ilex Kudingcha C.J.Tseng And Its Interaction With Proteins

Ilex kudingcha C.J.Tseng is a tree plant of Hollyceae,which is mainly produced in Guangxi,Hubei,Hunan,Guangdong,Hainan and other places.Ilex kudingcha C.J.Tseng contains triterpenoid saponins,flavonoids,polysaccharides,polyphenols,volatile oils and other chemical composition.Modern pharmacological experiments show that Ilex kudingcha C.J.Tseng has many biological activity include anti-tumor,antibacterial,hypoglycemic,hypolipidemic,etc.In this experiment,70% ethanol was used to extract the dry leaves of dried leaf of Ilex kudingcha C.J.Tseng,and then all parts were extracted with petroleum ether,ethyl acetate and n-butanol.The column chromatography and the physical and chemical properties,MS,NMR and other methods was used to identify its structure: Kudinoside G(1)?Kudinoside D(2)?Kudinoside C(3)?Kudinoside E(4)?Kudinoside A(5)?Latifoloside G(6)?Latifoloside H(7)?Kudinoside F(8)?Kudinoside N(9)?Kudinoside L(10)?Kudinoside M(11)?Latifoloside C(12)?ileKudinoside H(13)?Oleanolic acid(14)?Ursolic acid(15)?Kaempferol-3-O-?-D-glucoside(16)? Kaempferol-3-O-?-D-rhamnoside(17)?isorhamnetin-3-O-?-D-rhamnoside(18).Among them,compounds 16,17,18 for the first time from the Ilex kudingcha C.J.Tseng isolated.HPLC-DAD-ELSD technique was used to establish the chromatography fingerprint of Ilex kudingcha C.J.Tseng,and seven common control components were identified by HPLC-MS?In recent years,the interaction of small molecules and proteins has become one of the important research topics in the field of chemical biology and pharmacy.In this paper,the interaction between bovine serum albumin and pancreatic lipase was studied by fluorescence spectroscopy and circular dichroism.The experimental results were as follows:Fluorescence spectrometry and circular dichroism spectroscopy were used to study the interaction between Kaempferol-3-O-?-D-rhamnoside(Flavonoids A)?isorhamnetin-3-O-?-Drhamnoside(Flavonoids B)and bovine serum albumin(BSA)under different temperatures.The results showed that both Flavonoids A and Flavonoids B could effectively quench the intrinsic fluorescence of BSA mainly by combination of static and dynamic quenching.According to the thermodynamic parameters,it was inferred that Van der Waals interactions and hydrogen bonding acted as the main intermolecular forces between Flavonoids A and BSA,and hydrophobic interaction was the main intermolecular force between Flavonoids B and BSA.Then the binding constants and number of binding sites between these 2 compounds and BSA were calculated.The results of circular dichroism spectroscopy showed that the internal structure of BSA was changed after the binding of the above two flavones and BSA.Fluorescence spectrometry and circular dichroism spectroscopy were used to study the interaction between L(kudinoside L)/N(kudinoside N)and bovine serum albumin(BSA)under different temperatures.The results showed that both kudinoside L and kudinoside N could effectively quench the intrinsic fluorescence of BSA mainly by static quenching.According to the thermodynamic parameters,it was inferred that hydrophobic interaction acted as their main intermolecular forces,and then the binding constants and number of binding sites between these two compounds and BSA were calculated.The results of circular dichroism spectroscopy showed that the internal structure of BSA was changed after the binding of the above two saponins and BSA.The results showed that the interaction between the flavonoids and the BSA was stronger than that of the saponins.In addition,fluorescence spectrometry and circular dichroism spectroscopy were used to study the interaction between Kaempferol-3-O-glucosid(Flavonoids A)?Kaempferol-3-O-rhamnoside(Flavonoids C)? Kaemarin(Flavonoids D)? Quercetin(Flavonoids E)? Rutin(Flavonoids F)and bovine serum albumin(BSA)under different temperatures.The results showed that five Flavonoids could effectively quench the intrinsic fluorescence of BSA mainly by combination of static and dynamic quenching.According to the thermodynamic parameters,it was inferred that Van der Waals interactions and hydrogen bonding acted as the main intermolecular forces between these Flavonoids and BSA,and hydrophobic interaction was the main intermolecular force between these flavonoids and BSA.And quercetin and its glycosides were more potent than that of kaempferol and glycosides,and the levels of flavonoid aglycone were higher than that of flavonoid glycosides.According to the thermodynamic parameters,the main forces of Flavonoids D,Flavonoids E,Flavonoids E and Pancreatic lipase were the main hydrophobic forces.Flavonoids A,Flavonoids C,Flavonoids F and pancreatic lipase were mainly hydrophobic,Part of the electrostatic effect.