Antony directly insults Brutus and Cassius in only one place in the play. That is when Antony and Octavius have a parley with Brutus and Cassius in Act V, Scene 1, before the battle at Philippi. There are only six lines of significance for your question:
Villains, you did not so when your vile daggers
Hacked one another in the sides of Caesar.
You showed your teeth like apes, and fawned like hounds,
And bowed like bondmen, kissing Caesar's feet,
Whilst damned Casca, like a cur, behind,
Struck Caesar on the neck. O you flatterers!
Antony's funeral speech for Caesar is one of the most recognized speeches in Shakespearean works. Antony does not directly insult Brutus or Cassius for their involvement in Caesar's assassination, but continues to repeat the phrases 'honorable' and 'nobel' and allowing the audience (Roman civilians) to make a judgement of their actions as nobel or honorable themselves.