Enocyanin is an anthocyanin extracted from grapes. Enocyanin shows inhibitory effect on the leucine aminopeptidase, acid phosphatase, γ-glutamyl transpeptidase and esterase activity[1].
Enocyanin (0.1%) affects the leucine aminopeptidase, acid phosphatase, γ-glutamyl transpeptidase and esterase activity by 63%, 100%, 134% and 99%, respectively[1].
[1]. Sako F, et al. A study on the toxicity of natural food dyes--toxicity and enzyme inhibition in Paramecium caudatum. J Toxicol Sci. 1978 May;3(2):127-36.