phenprocoumon and 4-hydroxycoumarin

4-Hydroxycoumarins such as warfarin 1 have been the mainstay of oral anticoagulation therapy for over 20 years. Yet little detail is known about the molecular interactions between 4-hydroxycoumarins with vitamin K epoxide reductase (VKER), inhibition of which produces a deficiency of vitamin K and consequently a deficiency of vitamin K-dependent proteins involved in thrombus formation. Using molecular probes, such as 4-sulfhydrylwarfarin 7 and 4-chlorowarfarin 10 it is shown in vitro that inhibition of VKER by warfarin is dependent on deprotonation of the 4-hydroxycoumarin moiety. In addition, the nature of the substituent on carbon 3 of the 4-hydroxycoumarin modulated inhibition. More specifically, a linear isoprenyl side chain increased inhibition of VKER when compared to cyclical substituents as present in warfarin. An example of a 4-hydroxycoumarin with an isoprenyl side chain is the natural product ferulenol 19 derived from Ferula communis. Ferulenol 19 confers approximately 22 times more potent inhibition than warfarin and is approximately 1.5 more potent than the rodenticide brodifacoum in this in vitro assay. Based on these data it is hypothesized that 4-hydroxycoumarins bind to the active site of VKER thereby mimicking the transition state of the elimination of water from substrate 2-hydroxyvitamin K.

Topics: 4-Hydroxycoumarins; Animals; Anticoagulants; Binding Sites; Enzyme Inhibitors; Microsomes; Mixed Function Oxygenases; Rats; Structure-Activity Relationship; Vitamin K; Vitamin K Epoxide Reductases; Warfarin

The low oral bioavailability and rapid biliary excretion of peptide-derived HIV protease inhibitors have limited their utility as potential therapeutic agents. Our broad screening program to discover non-peptidic HIV protease inhibitors previously identified compound I (phenprocoumon, Ki = 1 microM) as a lead template. Structure-based design of potent non-peptidic inhibitors, utilizing crystal structures of HIV protease/inhibitor complexes, provided a rational basis for the previously reported carboxamide-containing 4-hydroxycoumarins and 4-hydroxy-2-pyrones. The amino acid containing compound V (Ki = 4 nM) provided an example of a promising new series of HIV protease inhibitors with significantly improved enzymatic binding affinity. In this report, further structure-activity relationship studies, in which the carboxamide is replaced by a sulfonamide functionality, led to the identification of another series of nonamino acid containing promising inhibitors with significantly enhanced enzyme binding affinity and in vitro antiviral activity. The most active diastereomer of the sulfonamide-containing pyrone XVIII (Ki = 0.5 nM) shows improved antiviral activity (IC50 = 0.6 nM) and represents an example of a new design direction for the discovery of more potent non-peptidic HIV protease inhibitors as potential therapeutic agents for the treatment of HIV infection.

Topics: 4-Hydroxycoumarins; Chromatography, High Pressure Liquid; Crystallography, X-Ray; Drug Design; HIV Protease Inhibitors; HIV-1; HIV-2; Models, Molecular; Molecular Structure; Phenprocoumon; Pyrones; Stereoisomerism; Structure-Activity Relationship; Sulfonamides

Topics: 4-Hydroxycoumarins; Coronary Artery Bypass; Coumarins; Estrogens; Female; Humans; Middle Aged; Necrosis; Phenprocoumon; Terminology as Topic

The interaction of coumarin anticoagulants with polyvinylpyrrolidone (PVP) was investigated using a fluorescence technique. The fluorescence intensities of warfarin and phenprocoumon were greatly enhanced following binding to PVP, while the fluorescence of 4-hydroxycoumarin was little enhanced in the presence of PVP. The enhanced fluorescence of warfarin and phenprocoumon bound to PVP can be explained by their incorporation into the hydrophobic environment in the PVP and by a decrease in the internal rotation of the alpha-substituted benzyl group in the drugs. The binding parameters of warfarin and phenprocoumon were estimated by the Klotz method; the binding constants for phenprocoumon and warfarin were found to be 2.6 X 10(4) and 2.2 X 10(4) M-1, respectively. The 13C-NMR measurements suggest the lactone moiety in the 4-hydroxycoumarin and the substituted benzene ring play an important role in the binding to PVP.

Topics: 4-Hydroxycoumarins; Coumarins; Molecular Structure; Phenprocoumon; Povidone; Spectrometry, Fluorescence; Warfarin

Topics: 4-Hydroxycoumarins; Anticoagulants; Chemistry, Pharmaceutical; Chromatography; Chromatography, Paper; Coumarins; Esters; Ethyl Biscoumacetate; Pharmacy; Phenprocoumon; Research

Topics: 4-Hydroxycoumarins; Anticoagulants; Coumarins; Phenprocoumon

Topics: 4-Hydroxycoumarins; Coumarins; Phenprocoumon

Topics: 4-Hydroxycoumarins; Blood Platelets; Cell Count; Coumarins; Humans; Megakaryocytes; Phenprocoumon

Topics: 4-Hydroxycoumarins; Anticoagulants; Antidotes; Coumarins; Female; Hemostatics; Humans; Phenprocoumon; Prothrombin Time; Thrombophlebitis; Vitamin K; Vitamin K 1

Topics: 4-Hydroxycoumarins; Anticoagulants; Coumarins; Phenprocoumon