I did some googling and found a wiki on phenols. Most of it over my head. But it says that one naturally occuring phenol is calll thymol, found in thyme. Also in some hops. One article mentioned a correlation between thymol and beta acid, and that it can be isomerized in low levels of ethanol (like when dry hopping?). There was a beekeeper forum that was talking about a pesticide for mites that contains thymol.
By the way, the article on thymol says that it is used as an antiseptic in some mouthwashes (chloroseptic I wonder?)
Once I used 4 oz of Mosaic dryhopped in an IPA and that beer was phenolic. Makes me wonder if they might be high in thymol, since there is no chlorine in my system.