The Synthesis Of Deuterated Puerarin And Its Application

Pueraria lobata(Gegen)and Pueraria thomsonii(Fenge)are two common herbs in traditional Chinese medicine.They have a long history and are widely distributed.Gegen is a dry root of the leguminous plant Pueraria lobata(Willd.)Ohwi,commonly known as Kudzu.The 2015 Pharmacopoeia requires that the product be based on dried products and contain no more than 2.4%puerarin(C21H20O9).Fenge is the dry root of the leguminous plant Pueraria thomsonii Benth.According to the Pharmacopoeia,the content of puerarin(C21H20O9)should not be less than 0.30%on a dry product basis.Both are sold as Gegen in the pharmacy,but Puerarin content is quite different,and its were producted from Guangdong,Guangxi,Hunan,Anhui ect.,quality is not the same,so the requirements of its quality testing have been raised accordingly.Paper spray ionization is a new type of ambient mass spectrometry ionization technology,which not only has fast analysis speed(within 30 s),high throughput,and it does not require complicated sample preparation,and has low solvent consumption,but its ability of quantification is weak.In this paper,the preparated isotope-labeled puerarin was used as the internal standard,and it was applied in paper spray mass spectrometry(PS-MS)to establish a rapid and accurate method for quantitative analysis of puerarin in Gegen and Fenge.The main content of this paper was as follows:1.Synthesis deuterium-labelled puerarin by using homogeneous catalyst optimize the catalyst type,the ratio of the catalyst to the substrate,the concentration of acid and alkali,temperature,reaction time and other conditions,the optimized condition was 20%The K2PtCl4,NaOD concentration was 0.04 mol/L,the optimal temperature was 110 ?,the reaction time was 6 h,the mass peak of the original puerarin disappeared,the number of deuterated hydrogen was three,the deuteration ratio was 95%,and the selectivity was high.2.Heterogeneous catalysts catalyzed Puerarin H/D exchange reaction,to optimize the catalyst type,the ratio of the catalyst to the substrate,the concentration of acid and alkali,temperature,reaction time,etc.,and select 10%Pt/C as the catalyst,the NaOD concentration was 0.03 mol/L,the best temperature was 120 ?,the reaction time was 5 h,the mass peak of the original puerarin disappears,the number of deuterated hydrogen was three.3.Paper spray mass spectrometry was used to quantify puerarin in Gegen and Fenge,and the synthesized puerarin-d3 was used as an mass internal standard.By modifying the paper base by Na2C03,the problem of dimerization of puerarin in mass spectrometry was solved,and the instrument conditions such as spray solvent,spray voltage,and capillary temperature were optimized.Puerarin was accurately quantified in paper spray mass spectrometry,and the LOD was 0.3 ?g/mL,the linear range of internal standard curve from 1.02 to 51.0?g/mL,R2=0.9991,the intra-and inter-day precision were 1.2%and 2.2%,respectively.the quantitative results compared with the HPLC results was consistent,indicating that he established PS-MS quantitative method is accurate.