The Structure Modification Of Apigenin And Quercetin & 5-PBDMA Block The Potassium Channel, HERG

Section 1: The synthesis of 4', 7 - dimethylapigeninAim: To investigate more efficient methods about the synthesis and depuration of 4', 7 - dimethylapigenin (DMA), to confirm the structure of it, and to develop a specific and sensitive HPLC detect methods. Methods: Dimethylapigenin was synthesized by reacting apigenin with Me₂SO₄ in acetone under basic condition. To use orthogonal test optimizes the synthesis process about reagent ratio, temperature, reaction time. Using HPLC detects the purity of the synthesis product, and using MS, ¹H NMR, ¹³C NMR to confirm the product structure. Results: Using UV, MS, 1H NMR, ¹³C NMR, the products was qualified as DMA. This experiment also conducted the detection of DMA, and the results showed that this method is sensitive and specific. The optimized condition follows: the react tempareture, the react time, and the reactant ratio, correspondinly are 25℃,6h, and 1 : 4 : 6(API∶Me₂SO₄∶K2CO3). The product was recrystallization in alcohol, and product yield is 58.66%, product purity> 99%. Conclusion: This synthesis method can complete easily, and DMA can have high yield and purity.Section 2: The synthesis of 4', 5,7 - trimethylapigeninAim: To investigate more efficient methods about the synthesis and depuration of 4 ', 5, 7 - trimethylapigenin (TMA), to confirm the structure of it, and to develop a specific and sensitive HPLC detect methods. Methods: Trimethylapigenin was synthesized by reacting apigenin with Me₂SO₄ in acetone under basic condition. To use vasorelaxation action optimizes the synthesis process about reagent ratio, temperature, reaction time. Using HPLC detects the purity of the synthesis product, and using MS, 1H NMR, ¹³C NMR to confirm the product structure. Results: Using UV, MS, 1H NMR, ¹³C NMR, the products was qualified as TMA. This experiment also conducted the detection of TMA, and the results showed that this method is sensitive and specific. The optimized condition follows: At the first, the react tempareture, the react time, and the reactant ratio, correspondinly are 50℃,6h, and 1 : 6 : 9(API∶Me₂SO₄∶K2CO3); then Me₂SO₄(2 Eq) were added and last 2 hours. The product was recrystallization in alcohol, and product yield is 64.13%, product purity>99%. Conclusion: This synthesis method can complete easily, and DMA can have high yield and purity.Section 3: The synthesis of 5-phenoxybutyldimethylapigeninAim: To investigate more efficient methods about the synthesis and depuration of 5-phenoxybutyldimethylapigenin (5-PBDMA), to confirm the structure of it, and to develop a specific and sensitive HPLC detect methods. Methods: 4', 7-dimethylapigenin was synthesized by reacting DMA with 4-PBB in DMF under basic condition. Using HPLC detects the purity of the synthesis product, and using MS, 1H NMR, ¹³C NMR to confirm the product structure. Results: Using UV, MS, 1H NMR, ¹³C NMR, the products was qualified as 5-PBDMA. This experiment also conducted the detection of 5-PBDMA, and the results showed that this method is sensitive and specific. The optimized condition follows: the react tempareture, the react time, and the reactant ratio, correspondinly are 150℃,2h, and 1 : 4 : 6(DMA∶4-PBB∶K2CO3). The product was recrystallization in alcohol, and product yield is 67.26%, product purity>99%. Conclusion: This synthesis method can complete easily, and 5-PBDMA can have high yield and purity.Section 4: The synthesis of 5-phenoxybutyltetramethylquercetinAim: To investigate more efficient methods about the synthesis and depuration of 5-phenoxybutyltetramethylquercetin (5-PBTMQ), to confirm the structure of it, and to develop a specific and sensitive HPLC detect methods. Methods: 5-phenoxybutyltetramethylquercetin was synthesized by reacting 3, 3', 4, 7-TMQ with 4-PBB in DMF under basic condition. Using HPLC detects the purity of the synthesis product, and using MS, 1H NMR, ¹³C NMR to confirm the product structure. Results: Using UV, MS, 1H NMR, ¹³C NMR, the products was qualified as 5-PBTMQ. This experiment also conducted the detection of 5-PBTMQ, and the results showed that this method is sensitive and specific. The optimized condition follows: the react tempareture, the react time, and the reactant ratio, correspondinly are 150℃,2h, and 1 : 4 : 6(TMQ∶4-PBB∶K2CO3). The product was recrystallization in alcohol, and product yield is 71.94%, product purity>99%. Conclusion: This synthesis method can complete easily, and 5-PBTMQ can have high yield and purity.Aim: This study is to investigate whether 5-PBDMA can inhibit hERG channel, and to investigate the future of it in cardiac arrhythmia. Methods: The cell line HEK293 stably expressing hERG channels was maintained in DMEM 10% fetal bovine serum in incubator, and using trypsin to get single cells. The hERG channel current was recorded by a whole-cell patch-clamp technique. Results: The hERG potassium current could be inhibited by 5-PBDMA and the IC50 is 2.84μM. 5-PBDMA decreased the hERG current in a concentration-dependent manner and v oltage-dependent manner, and the inhibition was more significant at depolarization potentials between -10 and +60 mV. Conclusion: The results indicate that the 5-PBDMA can directly block the hERG current in HEK293 cells. It should be cautions when using 5-PBDMA prevents or treats cardiovascular diseases.