Nope. I caught Zekrom with a Great Ball, full health, 3 tries. It has 120 Def. I caught Skarmory in 5 tries with a Pokéball, it has 140 Def.
The higher it is will not affect the catch rate. However, I used an Electabuzz with Screech to reduce the defense, then I reduced the HP, and paralyzed Reshiram. Took one Pokéball to catch.
If you lower it, you may catch Pokémons easier. On the other hand, raising it has strictly nothing to do with it.