Solanaceae glycoalkaloids: α-solanine and α-chaconine modify the cardioinhibitory activity of verapamil

Many plants from various genera produce secondary metabolites which have high biological activity as α-solanine and α-chaconine — glycoalkaloids from the Solanaceae family. In plants, they act as a natural weapon against herbivorous and as antipathogenic agents during fungal or bacterial infection. Thus, they are of interest to many researchers searching for new pharmacologically active compounds with the potential for use as drugs in therapies of different diseases. Moreover, they are commonly found in popular agricultural products like tomatoes, potatoes, or eggplants, and therefore, they may be consumed in quite high amounts. Because of their biological activity, glycoalkaloids may interact with many drugs used in therapies of various disorders. In our studies, we wanted to check, if Solanaceae glycoalkaloids, α-solanine, and α-chaconine, interact with popular drug verapamil, a calcium channel blocker used in the treatment of hypertension and as an antiarrhythmic drug, and in this way change its effectiveness. Our studies conducted on insect myocardium showed, that glycoalkaloids act antagonistically to this drug. They decreased the maximal effects evoked by pure verapamil and changed the pharmacokinetic parameters of verapamil action; hence, it seems that the consumption of glycoalkaloid-reach products during verapamil administration should be considering. Moreover, the analysis of L-type calcium channel transcript distribution in insect tissues indicated the presence of two splicing variants, one more present in the myocardium, and the second one in the nervous system.