I'm not much of a plant guy either... and I see no place where the OP mentioned plants so I don't think it's an issue for him...
UV lights do bond small particles together which makes it possible for them to get caught in fine filtration. This is part of how they "clarify" the water. But I do not think the minerals that are usable to plants would fall victim to this...
UV lights do not do anything to ammonia, nitrite, nitrate or phosphorus, which are all beneficial to plants... I'm quite certain UV lights would not affect any organic based elements other than killing living organisms.
If you have questions regarding plants and UV lights I would suggest seeking out the information from a site that specializes in plants. In my opinion it is simply to refined of a topic to trust general MFKers on... (no offense MFKers)