Biosynthesis of ergothioneine: current state, achievements, and perspectives Applied Microbiology and Biotechnology Springer Nature Link Dried porcini mushrooms are sources of the antioxidants glutathione (GSH) and ergothionine (ERGO) 40g. Mushrooms (especially porcini) contain the highest levels of 2 powerful antioxidants, ergothioneine and glutathione, the latter of which is sometimes called the mother of all antioxidants and is a very important bodily Ergothioneine: an antioxidant with high potential Ergothioneine rich mushrooms may fight depression, finds US study