Green synthesis of Chlorin e6 and tests of its photosensitive bactericidal activities

Phototoxic treatments of pathogenic bacteria and fungi of trees induce oxidative damage that is preferable to toxic chemical treatment. Here, we used green methods to synthesize Chlorin e6 from chlorophyll a, which was extracted from crude silkworm excrement using concentrated (strong) alkali hydrolysis and acidification. The photosensitive bactericidal activities of the new chlorin were tested in vitro, and possible mechanisms of action are discussed. The results showed that Chlorin e6 can be light-activated to have bactericidal activity against Escherichia coli, Bacillus subtilis and Fusarium oxysporum, but it had little bactericidal effect in the dark. This kind of chlorin compounds has great potential as a natural phototoxic antimicrobial compound to control harmful bacteria on the leaves in forestry systems.