Investigations on 2,3′-Biquinolyl. 16. The Regioselectivity of Reduction of 1-Alkyl-3-(2-quinolyl)quinolinium and 1,1′-Dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-biquinolyl Iodides Using Metallic Zinc,Lithium and Potassium

The reaction of 1-alkyl-3-(2-quinolyl)quinolinium iodides with excess zinc in THF gives a diastereomeric mixture of 1,1′-dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-tetrahydro-4,4′-biquinolyls. An excess of lithium in THF gives a mixture of 1′,2′-dihydro-2,3′-biquinolyl and 1′-alkyl-1′, 4′-dihydro-2,3′-biquinolyl with the former predominating. The reduction by lithium in THF of 1,1′-dialkyl-3,3′-di(2-quinolyl)-1,1′,4,4′-tetrahydro-4,4′-biquinolyls leads to analogous products. Reduction of 1-alkyl-3-(2-quinolyl)quinolinium iodides by metallic potassium gives 1-alkyl-1′,4′-dihydro-2,3′-biquinolyls. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1208–1212, August, 2005.     

The stir-frying can reduce hepatorenal toxicity of Fructus Tribuli by inactivating β-glucosidase and inhibiting the conversion of furostanol saponins to spirostanol saponins

The purpose of this study was to illustrate the mechanism of “enzyme inactivation and toxicity reduction” of Fructus Tribuli (FT) after being heating processed. Ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) was used to quantitatively analyze the contents of four steroidal saponins in crude Fructus Tribuli (CFT) and stir-fried Fructus Tribuli (SFT) under different storage times at room temperature. The enzyme activity of β-D-glucosidase in CFT and SFT were determined and calculated by ultraviolet–visible spectrometry (UV-VIS spectrometry). In addition, the enzyme hydrolysates of FOT and tribuluside A were qualitatively analyzed by ultra-high-performance liquid chromatography coupled with quadruple-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS). The hepatorenal toxicity of spirostanol saponins in FT were further confirmed by in vivo and in vitro experiment. This study confirmed that “enzyme inactivation and toxicity reduction” was one of the reasons why the stir-frying can reduce hepatorenal toxicity of FT, and further enriched the exploration on the mechanism of processing toxicity reduction.