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

Background: Fasciolosis is one of the most debilitating diseases caused by liver flukes Fasciola hepatica and F. gigantica. Snail Lymnaeidae and Planorbidae is the intermediate host of these flukes. Snail population management is a good tool to control fasciolosis because gastropods represent the weakest link in the life-cycle of trematode. Aim of the present study is to explore the molluscicidal activity of chlorophyllin in visible spectral band against Fasciola gigantica carrier snail Indoplanorbis exustus. Methods: Chlorophyll was transformed into water-soluble chlorophyllin in 100% ethanol by using different types of chemicals. Ten snails Indoplanorbis exustus were placed in a glass aquarium containing 3 L of dechlorinated tap water. These snails were treated with different concentrations of chlorophyllin in sunlight as well as exposed to different visible spectral band of light. Results: Pure chlorophyllin (96 h LC₅₀ 6.54 mg/l) in sunlight was more toxic than extracted chlorophyllin (96 h LC₅₀ 939.65 mg/l). There was a significant variation in the toxicity of chlorophyllin with snails, exposed to visible spectral band of light. The highest and lowest toxicity of chlorophyllin against I. exustus was noted in yellow light (96 h LC₅₀ 2016.79 mg/l) and green light (96 h LC₅₀ 2433.16 mg/l). High performance liquid chromatography (HPLC) study reveals that the active molluscicidal component extracted in spinach leaves is chlorophyllin. Conclusion: Due to the photodynamic nature of chlorophyllin, it has the potential to control the population of vector snails and ultimately fasciolosis in developing countries.