[galligator]

I can't tell from the picture - are these suede? If so, a suede protector spray should work on this - as well as a suede water protectant.

For plain leather, almost any leather conditioner like Apple Guard should to the trick.

You may also be able to use a scotch-guard protectant as well. Most shoe stores, cobblers & even some grocery stores will have a selection of protective products that can be sprayed onto shoes.