For over 2 billion years, melatonin was synthesized by archaea and bacteria, the two major domains of life on earth. But it’s function could not be an antioxidant because there was simply not enough oxygen to produce reactive oxygen species that can cause cellular damage. [⅔] pic.twitter.com/wAybsgnp0L

— Doris Loh (@DorissLoh) July 25, 2024

"The Mitochondria Chronicles of Melatonin and ATP: Guardians of Phase Separation," Dorish Loh and Russel J. Reiter, 2016.