2-(3-Hydroxy-2-oxoindolin-3-yl)-acetic acid (compound 29) is a natural polyphenol compound found in hop bract.

Heptanoic acid is an organic compound composed of a seven-carbon chain terminating in a carboxylic acid. It is an oily liquid with an unpleasant rancid odor. It contributes to the odor of some rancid oils. It is slightly soluble in water but well soluble in ethanol and ether.

INT is used in various dehydrogenase colorimetric analysis of the electron acceptor.