Structure and biological properties of 2H-1-benzopyran-2-one (coumarin) derivatives

The physicochemical and pharmacological properties of some natural derivatives of 2H-1-benzopyran-2-one (coumarin) have been studied, including decursinol and obtusifol, which are the most promising compounds for practical applications. Using high-resolution 1H and 13C NMR spectra in comparison to the published data, the structure of obtusifol is finally established. Decursinol exhibited the most pronounced antiarrhythmic activity on the model of calcium-chloride-induced arrhythmia in rats: in a doze of 0.5 mg-kg, this compound prevented the loss of experimental animals and restored the sinusoidal rhythm in 100% of cases. The therapeutic antiarrhythmic index (AI = LD50/ED50) of decursinol (AI = 470) significantly exceeds the values for well-known drugs such as quinidine, novocainamide, and lidocaine (AI = 16.5, 17.0 and 22.2, respectively). The antiarrhythmic activity of campestrinol and obtusifol was close to that of decursinol. It was found that obtusifol, decursinol, diumancal, and their analogs (representing calcium ion antagonists of the new generation) significantly influence the potential-dependent conductivity of calcium channels not only of the L-type (encountered in muscles, heart and vessels), but also of the N-and T-types, most widely distributed in the central nervous system and ganglion. © 2006 Springer Science+Business Media, Inc.