eternal youth+ wicked ward

if I use eternal youth with wicked ward will wicked ward protect the recharge of life and will it decrease life regen and leech?

I haven't tried this, but I imagine yes to all. Have you tried plugging in to PoB to see what it tells you?

Eternal Youth
50% less Life Regeneration Rate
50% less maximum Total Recovery per Second from Life Leech
Energy Shield Recharge instead applies to Life

Wicked Ward
Energy Shield Recharge is not interrupted by Damage if Recharge began Recently
50% less Energy Shield Regeneration Rate
50% less Maximum total Recovery per Second from Energy Shield Leech

Seconding GreyLensman: Both Regen and Leech are dampenend at 50%, but Eternal Youth would change anything that regards ES Recharge to Life Recharge. Thus, Wicked Ward would make your recharge last at least 4 seconds.