Study On Separation,Purification And Property Of Tea Saponin

In this paper,purification of crude tea saponin with macroporous resins was studied.The structure of tea saponin monomers which were separated by silica gel column chromatography was analyzed.The antioxidant properties,bacteriostatic properties and inhibitory effects on tyrosinase activity of tea saponin and tea saponin monomers were investigated in vitro.The main contents and results are as follows:The main impurities in crude tea saponin were determined by elemental analysis and color reaction.The results showed that the main impurities in crude tea saponin were sugar and polyphenol,free of protein.The content of tea saponin in crude tea saponin was 65% by weight analysis and spectrophotometry.The AB-8 macroporous resin was identified as the best resin for the purification of crude tea saponin,and the process of purification of crude tea saponin with AB-8 macroporous resin was studied.The optimum conditions of purification were obtained as follows: pH=4,sample concentration 1.538 mg/mL,sample volume 30 mL/g wet resin,eluent 80% ethanol solution,sample volume ratio 3:5,sampele flow rate 4 mL/min,eluent flow rate 3 mL/min.TS was obtained in optimum conditions and the yield of TS was 75.91% and the purity was 96.12wt%.TS was separated by silica gel column chromatography.The optimum mobile pha se was ethyl acetate-(n-propanol)-water,volume ratio was 7:3:1.5.The process of colu mn chromatography was investigated.The optimum conditions of column chromatograp hy were obtained as follows: wet loading,sample mass 0.5 g,column height 15 cm,mobile phase flow rate 0.03 L/h,mobile phase volume 160 mL.Tea saponin monomers which were named TS1 and TS2 were obtained in optimum conditions.The yield of TS1 and TS2 were 11.52% and 11.22% respectively.The structure of two tea saponi n monomers was analyzed by NMR and LC-MS.TS1 was theasapogenol A 3-O-?-D-ga lactopyranosyl(1?2)[?-D-glucopyranosyl(1?2)-?-L-arabinopyranosyl(1?3)]-?-D-glucuron opyranoside,and TS2 was 23-O-acetyl theasapogenol A 3-O-?-D-galactopyranosyl(1?2)[?-D-xylopyranosyl(1?2)-?-L-arabinopyranosyl(1?3)]-?-D-glucuronopyranosideThe antioxidant properties of tea saponin and tea saponin monomers were investigated by DPPH radical scavenging,hydroxyl radical scavenging and total reducing power.The results showed that tea saponin and tea saponin monomers had certain anti-oxidation,oxidation resistance of crude tea saponin was worst,TS and TS2 had better antioxidant properties,antioxidant performance of TS1 was best.The bacteriostatic properties of tea saponin and tea saponin monomers on Escherichia coli,Staphylococcus aureus,Aspergillus niger and Candida albicans were studied by paper strip method and dilution method.It was found that tea saponin and tea saponin monomers had poor antibacterial properties against Escherichia coli and Staphylococcus aureus,and had better antifungal activity against Aspergillus niger and Candida albicans.Compared with crude tea saponin,TS and TS2 had better antibacterial properties,and the best antibacterial properties of TS1 were found.The effects of tea saponin and tea saponin monomers on the inhibition of potato tyrosinase catalyzed conversion of L-DOPA to dopaquinone were investigated.The results showed that tea saponin and tea saponin monomers had inhibitory effect on tyrosinase activity,the maximum inhibitory rate of TS and TS1 on tyrosinase activity was greater than 90%.The inhibition type of TS and TS1 were competitive inhibition,which was due to its ability to complex with copper ions at tyrosinase activity sites.