Can you sue for interest on an unpaid accounts receivable on oral contract in Arizona?

Generally no, unless you can prove that the oral contract included interest to be paid. It's going to be difficult enough to prove an oral contract existed if the person you are suing denies that such contract was ever made. If you have witnesses to the fact, this helps, otherwise it is going to end up being your Word against theirs and depending on the judge, the outcome may not be favorable.