The invention relates to the use of quaternary pyridinium salts of formula I, wherein wherein R is NH 2 , CH 3 , or N(H)CH 2 OH, and X- is a pharmaceutically acceptable counterion, for the preparation of vasoprotective agent or a dietary supplement for the treatment or prevention of conditions or diseases associated with dysfunction of vascular endothelium, oxidative stress, and/or insufficient production of endothelial prostacyclin PGI 2 , in particular but not exclusively if the above coincides with hypercholesterolemia, hypertriglyceridemia or low HDL level.