Photodynamic control of human pathogenic parasites in aquatic ecosystems using chlorophyllin and pheophorbid as photodynamic substances.
When used at low concentrations and added to the water body, water-soluble chlorophyllin (resulting from chlorophyll after removal of the phytol) and pheophorbid (produced from chlorophyllin by acidification) are able to kill mosquito larvae and other small animals within a few hours under exposure of solar radiation. Under laboratory conditions, the use of chlorophyllin/pheophorbid as photodynamic substances for pest control in water bodies promises to be not only effective and ecologically beneficial but also cheap. The LD50 (50% of mortality in the tested organisms) value in Culex sp. larvae was about 6.88 mg/l, in Chaoborus sp. larvae about 24.18 mg/l, and in Daphnia 0.55 mg/l. The LD50 values determined for pheophorbid were 8.44 mg/l in Culex, 1.05 mg/l in Chaoborus, and 0.45 mg/l in Daphnia, respectively. In some cases, chlorophyllin and pheophorbid were also found to be (less) active in darkness. The results presented in this paper show that chlorophyllin is about a factor of 100 more effective than methylene blue or hematoporphyrine, which were tested earlier for the same purpose. It is also much cheaper and, as a substance found in every green plant, it is 100% biodegradable.
Wohllebe
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Department of Biology, Chair of Ecophysiology of Plants, Friedrich-Alexander-University, Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany.
Richter
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Richter
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Häder
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DP
D000818:Animals; D002734:Chlorophyll / Q000031:analogs & derivatives* / Q000494:pharmacology; D002735:Chlorophyllides / Q000494:pharmacology*; D003465:Culex / Q000187:drug effects*; D003621:Daphnia / Q000187:drug effects*; D004175:Diptera / Q000187:drug effects*; D017753:Ecosystem; D007306:Insecticides / Q000494:pharmacology*; D007928:Lethal Dose 50; D009032:Mosquito Control / Q000379:methods; D017319:Photosensitizing Agents / Q000494:pharmacology*; D014867:Water
D002735:Chlorophyllides; D007306:Insecticides; D017319:Photosensitizing Agents; D014867:Water; D002734:Chlorophyll; C007020:chlorophyllin; C032623:pheophorbide a