Photodynamic control of human pathogenic parasites in aquatic ecosystems using chlorophyllin and pheophorbid as photodynamic substances

Abstract

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.

Potential applications of porphyrins in photodynamic inactivation beyond the medical scope

“…However, the use of porphyrins for this purpose was only mentioned from the late 1980s of the last century [118][119][120][121]. Since then, the use of natural or synthetic porphyrin derivatives has been increasingly exploited to control and eradicate various types of insects, including pest flies capable of inducing significant damage to agricultural crops, and mosquitoes vectors of pathogens responsible for malaria (Anopheles), yellow fever (Culex, Aedes) dengue fever (Aedes) and encephalitis (Aedes, Culex, Anopheles) [46][47][48]50,[66][67][68]. Nowadays, there is a global distribution of these organisms.…”

“…As well as in other studies, some dark toxicity has also been observed. Other small animals, like Daphnia and fish (Chaoborus) larvae are also affected by chlorophyllin [66]. On the other hand, unlike fish larvae, more mature fish are unharmed and survive chlorophyllin treatment at concentrations, at which, for example, Culex larvae are severely affected.…”

Photodynamic Toxicity of Chlorophyllin against Fasciola gigantica Carrier Snail Indoplanorbis exustus in Visible Spectral Band

“…30,31 Photodynamic chlorophyllin was capable to kill mosquito larvae and other small animals within a few hours in sunlight. 11 Recent research on chlorophyllin has been advocated by researchers. As Erzinger et al 32 demonstrated that photodynamic chlorophyllin was able to kill four different species, a small crustacean (Daphnia similis), a unicellular alga (Euglena gracilis) and two species of fish (Astyanax bimaculatus and Cyprynus carpio) which are the vector of parasitic diseases.…”

“…14 In the presence of light chlorophyllin becomes more effective and toxic. 11,15 In recent times, it has been reported that chlorophyllin is a potent cercaricide against F. gigantica cercaria larva in sunlight. 16 Previously, it has been observed that different spectral bands of the visible light stimulate the orientation and locomotion of snails towards the light source.…”

Bait Formulations of Chlorophyllin against Infected/Uninfected Lymnaea acuminata in Red and Sunlight

“…Earlier, Tripathi and Singh (2013) noted, that L. acuminata is more attracted in red light. Photodynamic chlorophyllin a derivative of chlorophyll is a potent larvicides and cercaricides (Singh and Singh, 2015;Wohllebe et al, 2009Wohllebe et al, , 2011Mahmoud et al, 2013). The aim of the present study is to explore the efficacy of photodynamic Chlorophyllin in bait formulations against both infected and uninfected L. acuminata in monochromatic visible red-light and sunlight.…”