There are no items that reduce corruption that I remember, but completing missions reduces corruption, and that includes the repeatable side missions of beating up a few enemies if I remember correctly. I'm not 100% sure, it's been a while since I did my full run. It might just be main missions that reduce corruption.
Because the corruption isn't just about you, it's also about how corrupt everyone else is. So defeating enemies helps stem the tide of corruption, and on the other hand, losing missions results in more corruption because they spread it more unopposed.
Because the corruption isn't just about you, it's also about how corrupt everyone else is. So defeating enemies helps stem the tide of corruption, and on the other hand, losing missions results in more corruption because they spread it more unopposed.