2-pyridone-5-carboxylic acid (also known as 6-hydroxynicotinic acid) is formed from the nicotinic acid under the action of Pseudomonas aeruginosa and Serratia marcescens. The quantity of 6-hydroxynicotinic acid produced correlates well with the viable bacterial count. All others bacteria causing urinary infection, such as Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes, Enterococcus faecalis, Streptococcus gp B and Staphylococcus aureus do not metabolize nicotinic acid under similar conditions.

3-Phenylpropionic acid (hydrocinnamic acid, HA) is an end-product of the bacterial degradation of unabsorbed phenylalanine in the intestinal lumen. HA is used in ice cream, drinks, and candy manufacture field as a flavoring agent. In recent years, HA is widely used in the pharmaceutical industry. Hydrocinnamic Acid inhibits the currents of WT and SQT3 syndrome-related mutants of Kir2.1 channel.