What is "oxindole"

n. 1 (context uncountable organic compound English) A bicyclic aromatic heterocycle containing a benzene ring fused with five-membered cyclic amide 2 (context countable organic compound English) Any derivative of this compound

Oxindole (2-indolone) is an aromatic heterocyclic organic compound. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing ring. Oxindole is a modified indoline with a substituted carbonyl at the second position of the 5-member indoline ring.

Oxindole is a tryptophan derivative and in human biology is formed by gut bacteria ("normal flora"). It is normally metabolized and detoxified from the body by the liver. In excess, it can cause sedation, muscle weakness, hypotension, and coma. Patients with hepatic encephalopathy have been recorded to have elevated serum oxindole levels.