Well, further info:
lathyrogens (sorry, I’m not sure, whether this is correct english name) are causing lathyrismus, their typical source are peas (Lathyrus; http://www.biolib.cz/cz/taxon/id39975/ 😉 ). These are amines, which are able to inhibit enzymes like amino oxidase or also lysyl oxidase. The second catalyse oxidation of lysines to allysine, which forms bridges in collagen afterwards.
It is believed, that also Niccolò Paganini did have lathyrismus, and thus had long and flexible fingers 😉
Thank you for your help, I was sure that nature had already produced a molecule with this kind of effect. Although it seems dangerous if ingested in the whole body. Not something you’d take to just be more flexible…