"Photo" chemistry without light?

Abstract

In 1974, independently, Giuseppe Cilento (São Paulo University) and Emil White (Johns Hopkins University) provoked the scientific community with the hypothesis that typically photochemical reactions may take place in dark tissues of animals and plants. They were anchored on the then ongoing photochemistry and chemiluminescence research about enzymatically generated 1,2-dioxetanes and other peroxides that decompose thermally to carbonyl compounds in the triplet state. These species emit ultraweak chemiluminescence, however, being long-lived and reactive, can instead transfer electronic energy to or react like alkoxyl radicals with biological targets (proteins, lipids, DNA), triggering physiological or pathogenic responses. These ideas were pursued by them and various researchers, who ambitiously tried to validate the hypothesis coined as "photochemistry in the dark", which would broaden the field of photobiology.