Acai berry is a total scam. Sure, it's healthy stuff, but on better than any other berry. Promotors of the stuff have spread all kinds of hype.
No single food is going to solve your blood pressure problem. It's diet that's important, not foods. It's an important distinction.
A balance of minerals is essential to regulating blood pressure and you get this by eating a varied diet of natural, whole and unprocessed foods. If you have this type of diet and you still have hbp it's being caused, and needs to be treated, in some other way.