Be careful - The lounge access is limited to AMEX issued Amex cards, not bank issued Amex cards! That said, Bradesco manage Amex cards in Brasil, so a Bradesco issued Amex card MAY work for the Bradesco lounge. I can certainly confirm that a Bradesco issued Amex Platinum card will NOT give you access to the American Express Centurion lounge at Guarulhos.

I THINK that the simplest way to tell is that if you can access your Amex card account through www.americanexpress.com then your card gives you access. If you access your Amex card account through your bank website, then it doesn't.