The influence of fulvic and ulmic acids from peat, on the spontaneous contractile activity of smooth muscles.

The aim of the presented studies was to evaluate which classes of compounds of peat ingredients could be responsible for the partial agonistic effect of aqueous peat extract on the alpha2 adreno and D2 dopamine receptors of smooth muscles, which we have reported from former investigations. Based on the different solubility of peat ingredients, water-soluble components of fulvic and ulmic acids were separated according to the pH-value and chemical structure of the solvent. The biological activity of these acids was examined in peat baths using smooth muscle fibers of guinea pig stomach. The results demonstrate that the water-soluble components of fulvic and ulmic acids have a partially agonistic effect on the alpha2 adreno and D2 dopamine receptors, but at the same time quite different effects in terms of their influence on the spontaneous contractile activity (SCA) of smooth muscles have to be noted. From these investigations, we can conclude that aqueous peat extract and the water-soluble components of fulvic acid exhibit similar partial agonistic effects on the alpha2 adreno and D2 dopamine receptors. Therefore it is likely that the mentioned effects of the peat extract derive from the fulvic- and ulmic acids only. The water-soluble component of ulmic acid also showed partial agonistic effects on alpha2 adreno and D2 dopamine receptors. In this case, another substance group is involved, which has a faster blocking effect on these receptors, but was barely soluble in water at a normal pH-value (pH 7).