Natural preservatives of ink

Would pure compounds like thymol, carvacrol, and cinnamaldehyde work as preservatives of fountain pen ink? I'm specifically interested in three properties -


1. Prevention of growth (mostly fungal) in the bottle of water-based ink.
2. Not be caustic to fountain pen materials - metals, plastics, and rubber.
3. Does not cause an allergy when handling or if some ink ends up on the user's skin.


Would the compounds I mentioned be suitable for this purpose? Thank you very much in advance.


