Hi Christian,

it's not in the NW database, since the workflow definitions are stored in SharePoint.  So potentially, you could query the SP Content Databases, but I'm afraid I don't know where the specific data you need is stored.

What I've done in the past, is run a PowerShell script on the server you installed NW on.  It'd go through all the workflows in your farm, and look for ones with a specific action.  You'd need to tweak this to look for your email address that you're after.

Nintex Workflow - PowerShell Find Workflows that contain a Specific Action Part 4 - Vadim Tabakman

cheers,

Vadim