Someone else listed them but again there are plenty of companies that manufacture complete, balanced feedsin equine-only mills. Aside from the grain, the rest of the crap in CA is just that, crap. Not needed by the horse and zero data supporting the claims. If you are concerned about things like inflammation and antioxidants, that even more so supports feeding a complete feed-trace minerals like Se, Zn, Mn and Cu and VE all are components of the bodies anti-oxidant system thus feeding CA, which would result in a deficiency in these nutrients, would actually cause a pro-oxidant status.
At a cup a day, even if those ingredients have magically powers you would not feed enough to make a difference.
As for ānaturalā, any processed grain product is not natural even CA. Horses are grazers and are not designed to consume grain-hence why their A&P evolved the way it did. They also do not graze āvines and plantsā they are selective grazers and what you describe are ābrowsersā.
I would suggest downloading the NRC and educating yourself on equine nutrition. The most recent version is available for free. It will explain exactly what a horse of a X kg BW and X activity level needs on a daily basis. It will also explain why all of those nutrients that are not in CA are so important and why they are not found in other sources, hence why CA is not a complete feed and their marketing campaign is deceptive as you DO need to feed a TM&V supplement if you feed it.
That being said, from your posts it sounds like you have made up your mind and no amount of sense being posted here would change it.