SSAO inhibitors

[Allylbenzene]

Semicarbazide-Sensitive Amine Oxidase (SSAO/AOC3/VAP-1) is an enzyme in humans that catalyzes the oxidative conversion of primary amines to their corresponding aldehydes. Like monoamine oxidase (MAO), SSAO can deaminate short-chain primary amines, but is insensitive to MAO inhibitors. Semicarbazide was one of the first compounds found to inhibit this enzyme.

- https://doi.org/10.1351/pac200173091393

Some SSAO inhibitors...

Geraniin:

IC50 = 0.00658 mM​

Potent competitive inhibitor of SSAO with an IC50 of 6.58 μM.
Geraniin is a hydrolysable tannin found in Geranium maculatum (Cranesbill root).

Caffeine:

IC50 = 0.8 ± 0.3 mM (fairly weak)​

SSAO exists in mammals both as a plasma-soluble and as a membrane-bound form, and its active site is able to come into contact with numerous xenobiotic, amine-containing compounds. The kinetic studies performed in this work showed that caffeine inhibition of bovine serum amine oxidase was noncompetitive when benzylamine was used as substrate and mixed when the substrate used was methylamine. Since caffeine contains an imidazole ring, it cannot be excluded that it might bind to an inhibitory imidazoline-binding site on SSAO.
- https://doi.org/10.1002/jbt.20356

Glucosamine:

We have shown that amino sugars (galactosamine, glucosamine and mannosamine), which are not SSAO substrates, can bind to the enzyme as reversible inhibitors.
- https://doi.org/10.1007/s00702-007-0683-y

L-lysine:

Earlier work had suggested that lysine might function as a recognition molecule for SSAO/VAP-1. The present work reports the kinetics of the interaction of L-lysine and some of its derivatives with SSAO.
Binding was shown to be saturable, time-dependent but reversible and to cause uncompetitive inhibition with respect to the amine substrate. ... It was also specific [to l-lysine], since d-lysine, l-lysine ethyl ester and ε-acetyl-l-lysine, for example, did not bind to the enzyme.
- https://doi.org/10.1016/j.bbapap.2010.01.003

They are useful for phenethylamine and possibly tryptamine, but mescaline is a special case.