What is "methylpyridinium"

Methylpyridinium is a chemical compound which is the quaternary ammonium compound derived from the N- methylation of pyridine. It is found in some coffee products. It is not present in unroasted coffee beans, but is formed during roasting from its precursor chemical, trigonelline. It is under investigation by scientists regarding its potential anti-carcinogenic properties, particularly an effect on colon cancer.